U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2012–1059

Prepared in cooperation with the Platte River Recovery Implementation Program

Foraging Ecology of Least Terns and Piping Plovers 

Nesting on Central Platte River Sandpits and Sandbars
Cover photograph. Least tern and piping plover nesting habitat on Central Platte River sandpit, May 11, 2009. 

Photograph by Mark H. Sherfy, U.S. Geological Survey.
Foraging Ecology of Least Terns and Piping 

Plovers Nesting on Central Platte River 

Sandpits and Sandbars

By Mark H. Sherfy, Michael J. Anteau, Terry L. Shaffer, Marsha A. Sovada, and 

Jennifer H. Stucker

Prepared in cooperation with the Platte River Recovery Implementation Program

Open-File Report 2012–1059

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

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Suggested citation:

Sherfy, M.H., Anteau, M.J., Shaffer, T.L., Sovada, M.A., and Stucker, J.H., 2012, Foraging ecology of least terns 

and piping plovers nesting on Central Platte River sandpits and sandbars: U.S. Geological Survey Open-File Report 

2012–1059, 50 p.
iii

Acknowledgments

We thank the Platte River Recovery Implementation Program for funding and logistical support 

of this study. Chad Smith, Jim Jenniges, Mark Czaplewski, Mark Peyton, Mike Fritz, Martha 

Tacha, and Justin Brei provided valuable insights, advice, and guidance on conducting research 

on the Platte River system. We appreciate the cooperation of Mary Bomberger Brown and Joel 

Jorgenson from the Tern and Plover Conservation Partnership with ensuring the use of unique 

color band combinations. 

Our crew, including crew leaders John Campbell, Nate Emery, and Megan Ring and technicians 

Nick Altadonna, Kasey Clark, Justin Edwards, Anna Fasoli, Elizabeth Hanson, Megan Ring, 

Jhanine Rivera, Gabrielle Robinson, Jessi Tapp, Jason Tappa, and Jennifer Williams, worked 

many long hours and provided valuable insights into tern and plover ecology on the Platte River. 

We appreciate their dedication and hard work on collecting many diverse types of ecological 

data. Finally, we appreciate the leadership, oversight, and quality control provided by Colin 

Dovichin, Megan Ring, and Mark Wiltermuth

Contents

Acknowledgments........................................................................................................................................iii

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Objectives........................................................................................................................................................2

Study Areas.....................................................................................................................................................2

Methods...........................................................................................................................................................2

Movements ............................................................................................................................................2

Behavior.................................................................................................................................................3

Foraging Habitat....................................................................................................................................4

Productivity............................................................................................................................................4

Results .............................................................................................................................................................4

Movements ............................................................................................................................................4

Behavior.................................................................................................................................................6

Foraging Habitat..................................................................................................................................12

Productivity..........................................................................................................................................12

Discussion.....................................................................................................................................................15

Regulatory Compliance...............................................................................................................................16

Injury .....................................................................................................................................................17

Death.....................................................................................................................................................17

Human Disturbance............................................................................................................................17

References Cited..........................................................................................................................................17

Figures 7–15..................................................................................................................................................19

Tables 14–22..................................................................................................................................................29
iv

Appendixes 1–4............................................................................................................................................43

Appenidx 1. Behavior Sampling Protocol.............................................................................................44

Access and Timing of Behavioral Observations............................................................................44

State Behavior Categories ................................................................................................................44

Least Tern (LETE) Protocols ..............................................................................................................44

Piping Plover (PIPL) Protocols..........................................................................................................45

Habitat Classes (dominant classes within the foraging area) ....................................................46

Landform......................................................................................................................................46

Moisture ......................................................................................................................................46

Vegetation ...................................................................................................................................46

Active Nests/Surviving Broods ........................................................................................................46

Spot Mapping ......................................................................................................................................46

Appendix 2. Terrestrial Habitat Sampling Protocol.............................................................................47

Appendix 3. Fish Sampling Protocol......................................................................................................48

River Sampling.....................................................................................................................................48

Sandpit Pond Sampling......................................................................................................................48

Sampling Equipment...........................................................................................................................48

Appendix 4. Invertebrate Sampling Protocol.......................................................................................49

Figures

1. Map showing locations of dataloggers used to monitor presence of radio-marked

least terns and piping plovers on the Central Platte River during 2010...............................5

2. Graph showing distribution of movement events across hours of the day for

radio-marked piping plovers on the Central Platte River, 2009–10.......................................9

4. Graph showing distribution of movement events across hours of the day for

radio-marked least terns during four stages of the reproductive cycle on the

Central Platte River, 2009–10.......................................................................................................9

3. Graph showing distribution of movement events across hours of the day for

radio-marked least terns on the Central Platte River, 2009–10 .............................................9

5. Graph showing mean maximum distance (plus or minus 95-percent confidence

interval) moved by radio-marked least terns across hours of the day on the

Central Platte River, 2009–10.......................................................................................................9

6. Graph showing mean maximum distance moved by radio-marked least terns

across hours of the day during four stages of the reproductive cycle on the

Central Platte River, 2009–10.....................................................................................................10

7. Map showing spot-mapped locations of foraging least terns and piping plovers

from 2009–10 at Dippel Tract, near Gibbon, Nebraska .........................................................20

8. Map showing spot-mapped locations of foraging least terns and piping plovers

from 2009–10 at Dinan Tract, near Gibbon, Nebraska ..........................................................21

9. Map showing spot-mapped locations of foraging least terns and piping plovers

from 2010 at Broadfoot-South Pit, near Kearney, Nebraska ...............................................22

10. Map showing spot-mapped locations of foraging least terns from 2009–10 at the

Diversion Gates, near Elm Creek, Nebraska ..........................................................................23
v

11. Map showing spot-mapped locations of foraging least terns and piping plovers

from 2009–10 at Bluehole Pit, near Elm Creek, Nebraska....................................................24

12. Map showing spot-mapped locations of foraging least terns and piping plovers

from 2009–10 at Johnson Pit, near Elm Creek, Nebraska ....................................................25

13. Map showing spot-mapped locations of foraging piping plovers from 2010 at

Dyer Pit, near Overton, Nebraska ............................................................................................26

14. Map showing spot-mapped locations of foraging least terns and piping plovers

from 2009–10 at Lexington Pit, near Lexington, Nebraska...................................................27

15. Map showing spot-mapped locations of foraging least terns from 2009 at

Lexington Island, near Lexington, Nebraska..........................................................................28

Tables

1. Number of adult piping plovers and least terns to which radio transmitters 

were applied on the Central Platte River, 2009–10..................................................................4

2. Locations of telemetry dataloggers used to detect radio-marked least terns 

and piping plovers on the Central Platte River, 2009–10 ........................................................6

3. Number of noise filtered data records for frequencies of radio transmitters

deployed on least terns and piping plovers on the Central Platter River, 

2009–10 ...........................................................................................................................................7

4. Distribution of noise filtered data records at noncolony locations for frequencies 

of radiotransmitters applied to adult piping plovers on the Central Platte River, 

2009–10 ...........................................................................................................................................8

5. Distribution of noise filtered data records at noncolony locations for frequencies 

of radiotransmitters applied to adult least terns on the Central Platte River, 

2009–10 ...........................................................................................................................................8

6. Summary of movement and colony events for radio-marked piping plovers and

least terns on the Central Platte River, 2009–10 ......................................................................9

7. Number of data collection sessions, length of data collection, and number of

recorded all-occurrence behaviors for adult least terns on the Central Platte 

River in 2009 and 2010 ................................................................................................................10

8. Summary of behavioral observation effort by research technicians (sessions,

minutes), foraging effort by least terns (plunges, plunge rate, successful 

plunges, percent success), and success rate by foraging least terns (minutes/

successful plunge) for sandpit and riverine foraging habitats on the Central Platte 

River, 2009–10 ..............................................................................................................................11

9. Number of behavior data collection sessions and summary of recorded state

behaviors for adult piping plovers on the Central Platte River, 2009–10 ...........................13

10. Length of observation time and number of substrate pecks counted for 

foraging piping plovers on the Central Platte River, 2009–10 ..............................................14

11. Frequency of aquatic habitat types at locations where foraging least terns 

were spot-mapped on the Central Platte River, 2009–10 .....................................................14

12. Frequency of terrestrial habitat types at locations where foraging piping plovers

were spot-mapped on the Central Platte River, 2009–10 .....................................................14

13. Number of samples, fish caught, and fish species collected on the Central Platte

River, 2009–10 ..............................................................................................................................15
vi

14. Number of fish species caught in 189 trawl samples, by location on the Central

Platte River, 2009–10...................................................................................................................30

15. Mean, lower 95-percent confidence limit and upper 95-percent confidence 

limit for habitat variables measured at least tern foraging locations and random 

points in sandpits on the Central Platte River, 2009–10........................................................32

16. Mean, lower 95-percent confidence limit and upper 95-percent confidence 

limit for habitat variables measured at least tern foraging locations and 

random points at river sites on the Central Platte River, 2009–10 ......................................32

17. Number of large (greater than 3 millimeters) and small (less than 3 millimeters)

invertebrates caught on sticky traps during 33 sampling sessions on the Central

Platte River, 2009–10...................................................................................................................32

18. Mean, lower 95-percent confidence limit, and upper 95-percent confidence 

limit for habitat variables measured at piping plover foraging locations and 

random points on the Central Platte River, 2009–10..............................................................33

19. Number and fate of least tern nests monitored on the Central Platte River, 

2009–10 .........................................................................................................................................33

20. Number and fate of piping plover nests monitored on the Central Platte River,

2009–10 .........................................................................................................................................33

21. Banding and marking records for least tern and piping plover adults on the 

Central Platte River, 2009–10.....................................................................................................34

22. Banding and marking records for least tern and piping plover chicks on the 

Central Platte River, 2009–10.....................................................................................................36

Appendix Table

2–1. Daubenmire classification of cover.........................................................................................47
vii

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) .03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) .6214 mile (mi)

kilometer (km) .5400 mile, nautical (nmi) 

meter (m) 1.094 yard (yd) 

Area

square meter (m2) 0.0002471 acre 

hectare (ha) 2.471 acre

square meter (m2) 10.76 square foot (ft2) 

square centimeter (cm2) .1550 square inch (ft2) 

hectare (ha) .003861 square mile (mi2) 

Conversion Factors

SI to Inch/Pound 

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

 °F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

 °C=(°F-32)/1.8

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Abstract

Federally listed least terns (Sternula antillarum) and piping plovers (Charadrius melodus) nest on riverine sandbars 

on many major midcontinent river systems. On the Central 

Platte River, availability of sandbar habitat is limited, and 

both species nest on excavated sandpits in the river’s floodplain. However, the extent to which sandpit-nesting birds 

use riverine habitats for foraging is unknown. We evaluated 

use of foraging habitats by least terns and piping plovers by 

collecting data on movements, behavior, foraging habitat, and 

productivity. We radiomarked 16 piping plovers and 23 least 

terns in 2009–2010 and monitored their movements using a 

network of fixed telemetry dataloggers. Piping plovers were 

detected primarily by the datalogger located in their nesting 

sandpit, whereas least terns were more frequently detected 

on dataloggers outside of the nesting sandpit. Telemetry data 

and behavioral observations showed that least terns tended to 

concentrate at the Kearney Canal Diversion Gates, where forage fish were apparently readily available. Fish sampling data 

suggested that forage fish were more abundant in riverine than 

in sandpit habitats, and behavioral observations showed that 

least terns foraged more frequently in riverine than in sandpit 

habitats. Piping plovers tended to forage in wet substrates 

along sandpit shorelines, but also used dry substrates and 

sandpit interior habitats. The greater mobility of least terns 

makes a wider range of potential foraging habitats available 

during brood rearing, making them able to exploit concentrations of fish outside the nesting colony. Thus, our data suggest 

that different spatial scales should be considered in managing 

nesting and foraging habitat complexes for piping plovers and 

least terns. 

Introduction

The Central Platte River Valley (CPRV) is a resource 

area of continental significance to a variety of migratory birds 

(Krapu and others, 2004). Habitats and foods provided in this 

area are important for migration and successful breeding in 

many species, including waterfowl, shorebirds, and passerines 

(Sherfy and others, 2011). The CPRV also provides breeding 

habitat for a variety of migratory birds, including Federally 

endangered interior least terns (Sternula antillarum) and 

threatened piping plovers (Charadrius melodus; Faanes, 1983; 

Sidle and Kirsch, 1993; Jenniges and Plettner, 2008). Both 

of these species nest throughout the northern Great Plains, 

co-occurring on many large mid-continent river systems where 

they nest in loosely organized mixed colonies (Thompson and 

others, 1997; Haig and Elliott-Smith, 2004; Sherfy and others, 

2012; Catlin and others, 2011). 

Prior to human alteration, the Platte River probably supported nesting least terns and piping plovers on midchannel 

sandbars that were largely devoid of vegetation because of 

high spring flows (Ziewitz and others, 1992). Modification of 

the river’s flow pattern has lowered the frequency and intensity of high water events, resulting in vegetation encroachment and stabilization of sandbars (Sidle and others, 1989). 

This has led to declining quality and abundance of unvegetated sand nesting habitat favored by least terns and piping 

plovers (Faanes, 1983; Sidle and Kirsch, 1993; Ziewitz and 

others, 1992). Foraging habitat for piping plovers, consisting 

of sparsely vegetated moist or dry sand with high invertebrate production, has probably also declined in quality and 

abundance. However, least terns forage on small fish in side 

channels, sloughs, tributaries, shallow-water habitats adjacent 

to sandbars, and in the main channel (Wilson and others, 1993; 

Stucker and others, 2011). Therefore, changing quality and 

abundance of least tern foraging habitat are probably more 

linked to Platte River flow and water quality than to vegetation 

dynamics on midchannel sandbars. 

A substantial sand and gravel excavation industry has 

developed in the Platte River floodplain, resulting in numerous 

sandpits in close proximity to the river channel. These sandpits 

often contain abundant unvegetated sand that can provide suitable nesting habitat for least terns and piping plovers (Faanes, 

1983; Sidle and Kirsch, 1993; Kirsch, 1996; Jenniges and 

Plettner, 2008). Sandpits often contain impounded water and 

moist sand that can provide suitable foraging habitat for least 

terns and piping plovers. This emergence of suitable habitat 

features on sandpits in conjunction with declining quality of 

riverine habitat features has been a major factor in the distribution of nesting least terns and piping plovers. The majority 

of nesting effort in the CPRV in recent years has occurred on 

sandpits, although the incidence of nesting on sandbars was 

Foraging Ecology of Least Terns and Piping Plovers 

Nesting on Central Platte River Sandpits and Sandbars

By Mark H. Sherfy, Michael J. Anteau, Terry L. Shaffer, Marsha A. Sovada, and Jennifer H. Stucker
2 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

higher in 2007 and 2008 than in previous years (Platte River 

Recovery Implementation Program, 2008). 

Adult least terns and piping plovers differ in their means 

of obtaining food and in the degree of parental care offered 

to young. Piping plovers produce precocial young that forage 

for invertebrates alongside adults (Haig and Elliott-Smith, 

2004). Thus, breeding habitats must contain nesting areas and 

foraging habitat to support both adults and flightless young. 

However, adult piping plovers may be more flexible in their 

use of foraging habitat during courtship and nesting, exploiting high-quality foraging areas within flight distance of nesting territories. Least terns produce semi-altricial young that 

are incapable of acquiring food and are provisioned by adults 

carrying fish back to nesting colonies (Thompson and others, 

1997). Consequently, adult least terns are not constrained to 

foraging within their nesting colonies during brood rearing and 

can select the highest quality foraging habitats within profitable traveling distance of their nest sites. These differences in 

development of young and use of foraging habitats may have 

consequences for management of nesting habitats, particularly where single management strategies are intended to have 

multispecies benefits.

Least terns and piping plovers in the CPRV nest primarily 

in sandpit habitats, possibly because of the greater abundance 

of unvegetated sand in this habitat type than on riverine sandbars (Sidle and Kirsch, 1993; Platte River Recovery Implementation Program, 2008). There is substantial management 

interest in restoring a wide variety of habitat conditions that 

were present prior to human alteration. In the case of nesting 

habitats for least terns and piping plovers, the principal means 

of achieving this goal is vegetation removal on midchannel 

sandbars. Although it is known that least terns and piping 

plovers favor sandy substrates with sparse to absent vegetation 

for nesting, the extent to which these habitats must be linked 

to suitable foraging habitat is not known, as is the suite of 

features that define suitable foraging habitat.

Linkages between foraging and nesting habitat also are 

important to understanding the relative role and value of different nesting habitats in supporting productive least tern and 

piping plover populations. For example, if birds nesting in 

both of the principal breeding habitats (sandpits and sandbars) tend to prefer feeding in only one of these habitats, then 

management efforts might focus on improving access to foods 

in the lesser-used foraging habitat, or focus nesting habitat 

conservation on habitats closely linked to foraging habitat.

Objectives

This report summarizes data collected to answer four specific objectives that were developed to collectively contribute 

to understanding of foraging habitat use by adult least terns 

and piping plovers in the CPRV:

1. Movements—Quantify frequency and distance of movements away from nesting colonies for least terns and 

piping plovers nesting in sandpit and riverine sandbar 

habitats. 

2. Time allocation—Quantify time allocation to foraging 

and foraging success rate for adult least terns and piping 

plovers in sandpit and riverine sandbar habitats.

3. Foraging Habitat—Quantify features of foraging habitats 

used by adult least terns and piping plovers during nesting 

and brood rearing in sandpit and riverine habitats.

4. Productivity—Evaluate linkages between indices of productivity and measures of foraging effort for adult least 

terns and piping plovers nesting in sandpit and riverine 

sandbar habitats.

Study Areas

This study addressed the population of interior least terns 

and piping plovers that nests within the CPRV, defined as a 

3.5-mile buffer of the Platte River between Lexington and 

Chapman, Nebraska. Within this area, the Platte River Recovery Implementation Program (PRRIP) monitored least tern and 

piping plover productivity on 28 sites during 2007, including 

12 sandbar and 16 sandpit sites. However, efforts in 2009–10 

were focused on sites where the highest numbers of least tern 

and piping plover nests previously had occurred. Based on 

PRRIP (2008) data, four sandpits (Bluehole, Johnson, Lexington, and Dyer Pits) and two sandbars (Dinan Tract and Dipple 

Tract) were selected as focal areas. Other potential sites for 

inclusion were sought each year by (1) accompanying PRRIP 

staff during airboat surveys of the river in June, (2) conducting 

canoe surveys of the river in May and June, and (3) observing movements and distribution of birds during behavioral 

observations on the river. Because none of these approaches 

revealed additional concentrations of nesting birds, work in 

nesting colonies was limited to the six preselected focal areas. 

Access limitations precluded data collection at the Dinan Tract 

in 2010.

Methods

Movements

The goal for collecting movement data was to estimate 

timing, frequency, and distance moved by birds beyond their 

nesting colony (hereafter “colony”). Movement data were 

collected using radiotelemetry with adult birds. Birds on nests 

were trapped with the goal of deploying radios on eight birds 

per species on sandpits and eight birds per species on sandbars. The primary method of trapping birds was remote-triggered bow nets (Hill and Talent, 1990), which were deployed 
Methods 3

early or late in the day or when air temperature was between 

15°C (60°F) and 32°C (90°F), wind was minimal or not disrupting nests, and there was no precipitation. All trapping took 

place after at least 1 week of incubation but prior to pipping of 

eggs. Trapping attempts were aborted if they exceeded 20 minutes (departure of the bird from the nest to completion of the 

trap attempt). Prior to trap deployment, eggs were exchanged 

from targeted nests with artificial eggs to reduce potential risk 

of injury to eggs; real eggs were stored in a small plastic container cushioned with synthetic batting. Once captured, birds 

were moved to a nearby area away from the colony and other 

nesting birds. Birds were weighed with a Pesola-type spring 

scale, bill and culmen depth were measured with calipers, and 

natural wing chord was measured using a wing rule. 

Each adult least tern was banded with a numbered stainless steel band (size 1A) on the lower leg and up to three celluloid bands (XCL) on the upper leg (two bands per leg). However, birds receiving transmitters had the transmitter attached 

to a numbered aluminum band that was placed on the upper 

rather than the lower leg. Each adult piping plover was banded 

with a numbered U.S. Geological Survey (USGS) aluminum 

band (size 1A) on the upper leg, a light blue Darvic short flag 

on the opposite upper leg, and up to two Darvic color bands 

on each of the lower legs. Band and color combinations were 

coordinated with other agencies and research entities (for 

example, Platte River Tern and Plover Conservation Partnership) to ensure consistency and to prevent duplicating color 

combinations. Birds were released adjacent to the colony 

within 10 minutes of capture and then observed to document 

resumption of normal behaviors (for example, incubation or 

foraging).

Holohil BD-2 transmitters (approximately 1.1grams) 

were used for both least terns and piping plovers. For terns, 

the transmitter was secured to the numbered aluminum leg 

band using dental floss, which deteriorates over time and 

allows the transmitter to fall off. The leg band/transmitter 

package was attached to one of the upper legs. One to three 

smears of indelible marker were applied under the wings, on 

the side of the breast, or near the vent of radio-marked terns 

to facilitate identification of radioed birds during behavioral 

observations. For piping plovers, the transmitter was glued to 

feathers in the intrascapular region. 

Radio-marked birds were monitored using automated 

dataloggers (ATS R4500S with one or more Yagi antennas), 

which were programmed to scan all deployed frequencies at a 

preset interval (every 5–10 minutes). All equipment (dataloggers, receivers, antenna) was housed in blinds or hidden so as 

not to provide a perch for raptors or other birds. Dataloggers 

were positioned strategically to provide meaningful records 

of bird use of target habitats (for example, in colonies where 

birds are radio marked, adjacent to potential foraging areas). 

Blinds were positioned so that visits to download data or 

replace batteries did not disturb nesting or foraging birds; 

maintenance visits were conducted in conjunction with other 

field work.

Procedures to filter telemetry data were similar to those 

used in telemetry studies of least tern movements on the Missouri River. A “beacon” transmitter was positioned in each 

colony at a location representative of tern and plover nesting 

habitat. These transmitters were identical to the transmitters 

deployed on birds but were placed in fixed locations and monitored by the dataloggers. 

Detection records of transmitter frequencies represent 

potential detections of radio-marked birds, but each record at 

a noncolony location does not necessarily represent a unique 

movement event. Duration of a movement event could exceed 

the dataloggers’ search interval, resulting in multiple detection 

records for a single event. Therefore, 1-hour (h) intervals were 

treated as independent units, with each hour being labeled 

by its start time (that is “8 a.m.” indicates 8:00–8:59 a.m.). 

Each hour that contained one or more detections of a radioed 

bird away from its nesting colony was classified as a movement event, and each hour that contained only detections of 

a radioed bird at its nesting colony was classified as a colony 

event. Productivity data (see below) were used to classify each 

movement event into one of four reproductive stages: incubation (transmitter deployment to nest hatch), brood rearing (nest 

hatch to fledging or brood mortality), post-fledging (fledging 

to departure from the study area), and nonbreeding (failed 

nests, brood mortality).

Behavior

Behaviors of adult least terns and piping plovers were 

observed with the principal goal of quantifying time allocation 

to foraging. Data included measures of timing, frequency, and 

location of foraging, capture success, and frequency of prey 

delivery to colonies for least terns. Data were collected from 

portable blinds or other inconspicuous locations, including 

blinds established to protect telemetry dataloggers. Observation points included “colony sites,” which were within the 

focal sandpits and sandbars, as well as “noncolony sites,” 

which were near the fixed telemetry stations.

Behavior was observed using binoculars or spotting scopes during 4-h periods between sunrise and sunset 

(0600–1000, 1200–1600, and 1700–2100 h). The field season 

was divided into six 2-week blocks, with the goal of obtaining 3 h of observation at each colony and foraging site for 

each of the 4-h periods during each 2-week block. Duration of 

behavior was reported in units of total hours and total minutes 

(HH:MM). 

The data collection approach differed between terns and 

plovers because of differences between the species in foraging 

ecology and location. For plovers, an attempt was made to follow focal adults and broods, whereas for terns the focus was 

on foraging habitats rather than following individual birds. A 

detailed protocol for collection of behavior data is provided in 

appendix 1.
4 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Foraging Habitat

Habitat features were quantified at locations where successful foraging by least terns or piping plovers was observed 

during behavioral observations. At least tern foraging locations, aquatic habitat variables were recorded including water 

depth, temperature, turbidity, and flow rate. At piping plover 

foraging locations, a suite of terrestrial habitat variables were 

collected at 1-square meter (m2) quadrats centered on the 

foraging location. For both least tern and piping plover foraging locations, data were collected at two paired random points 

within 75 meters (m) of the foraging location. Random points 

were constrained to be within the same land-cover classification (wet sand) as the foraging location. A detailed terrestrial 

habitat data collection protocol is provided in appendix 2. 

During 2010, random locations were sampled in sandpit ponds 

and riverine sites to characterize baseline fish abundance in 

these habitats.

Trawls were deployed that drew the net horizontally 

through the surface of the water column for a distance of 50 

m. The sampled area of the trawl was 2.16 m2 (width, 2.4 m, 

depth, 0.9 m; Stucker and others, 2011). All caught fish were 

identified to species, measured, and counted. The goal was to 

measure forage abundance biweekly at each location where 

behavioral data were collected and at chosen river sites. A 

detailed fish sampling protocol is provided as appendix 3.

Sticky sticks were used to measure surficial invertebrate 

abundance at locations where piping plover adults or broods 

were observed successfully foraging. Identical methods were 

used in sandpit and sandbar sites. The sampling unit consisted 

of four paint stir-sticks (two placed vertically and two placed 

horizontally) covered with Tanglefoot insect trap coating. The 

traps were deployed for 30-minute intervals, after which all 

invertebrates greater than 3 millimeters (mm) in size were 

counted. An attempt was made to measure forage abundance 

two to three times per week for each pair of plovers. A detailed 

invertebrate sampling protocol is provided as appendix 4.

Paper maps or Global Positioning System (GPS) units 

with mapping capability (Trimble GeoXT) were used to map 

locations at which foraging least terns or piping plovers were 

observed. Each foraging location was recorded in a shapefile 

and the Universal Transverse Mercator (UTM) coordinates 

were entered into a master database. These data include foraging events observed during behavior data collection sessions 

as well as opportunistic observations of foraging birds.

Productivity

The goal was to quantify nest and chick survival for 

both target habitats (sandpits and sandbars). Suitable nesting 

habitat was searched in each study site at approximately 2- to 

3-day intervals, and nests were monitored to determine fate. 

Based on evidence at the nest site, each nest was classified 

as Known Successful, Probable Successful, Known Failure, 

Probable Failure, or Unknown. For successful nests, hatched 

young were captured by hand and a unique combination of 

color bands was applied. Tern chicks were marked with three 

celluloid color bands, and chicks surviving to 15 days were 

recaptured for application of numbered metal leg bands. Plover chicks were marked with a numbered aluminum 1A band 

on the upper leg, a light blue Darvic short flag on the opposite 

upper leg, and four Darvic color bands on the lower legs.

Resighting data for banded chicks were obtained by 

visually scanning plover brood-rearing areas and searching 

suitable habitat for tern and plover chicks. These searches 

were conducted during visits to each site for other purposes 

(behavior data collection, nest searching). When necessary 

to observe band combinations, chicks were briefly (less than 

1 minute) picked up and immediately returned to the location 

where encountered.

Results

Movements

In 2009 and 2010, 19 adult plovers and 23 adult terns 

were radio marked in the CPRV (table 1). Dataloggers were 

deployed at each of the 6 focal colonies and at 13 off-colony 

sites that were strategically chosen to detect movements 

(fig. 1; table 2). 

Beacon transmitters were used to filter noise from the 

data; only records with a signal strength equal to or greater 

than 70, 37–40 pulses per minute, 3–20 detected pulses, 

and 5–6 verified pulses were retained. After telemetry data 

were filtered based on the beacon transmitters, there were 

198,591 data records for 2009–10, each record representing 

a likely detection of a radio-marked bird (table 3). Of these 

records, 41,587 records of transmitter frequencies were at 

locations other than the nesting colony in which the transmitter was deployed (noncolony records; table 3). Noncolony 

records included 1,612 records for piping plovers (table 4) and 

39,975 records for least terns (table 5).

Table 1. Number of adult piping plovers and least terns to 

which radio transmitters were applied on the Central Platte River, 

2009–10.

Site location

(fig. 1) Piping plover Least tern

Bluehole Pit 6 8

Johnson Pit 2 2

Lexington Pit 5 13

Broadfoot-South Pit 2 0

Dyer Pit 1 0

Dinan Tract 2 0

Dippel Tract 1 0
Results 

5

98°40' 98°50' 99° 99°10' 99°20' 99°30' 99°40'

40°50'40°40'

40°30'40°20'

0 20 KILOMETERS 100 20 MILES 10

Platte River

Wood River

Lexington

Kearney

Arp Tract

(RM 252)

Lexington Island 

(RM 250)

Lexington Pit

(RM 250.5) West Jefferies

Island

(RM 246)

East Jefferies

Island

(RM 241)

Dyer Pit

(RM 240)

Cottonwood

Ranch

(RM 235)

Johnson Pit

(RM 230)

Bluehole

Pit

(RM 230.5)

DiversionGates(RM 229)

Broadfoot

South Pit

(RM 214)

WyomingTract(RM 212)

Younkin

Tract 

(RM 207)

Dinan

Tract

(RM 205)

TripletTrail(RM 203)

DippelTract (RM 199)

Uridil

Tract

(RM 190)

Kearney Lexington Wood River

NEBRASKA

Platte River

Base from U.S. Geological Survey digital data, 2009Universal Transverse Mercator projectionZone 14

Figure 1. Locations of dataloggers used to monitor presence of radio-marked least terns and piping plovers on the Central Platte River during 2010.
6 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Nearly 75 percent of the noncolony detections of piping plovers (1,207) occurred at Bluehole Pit. Birds that 

were radio-marked at colonies on Johnson Pit, Dyer Pit, and 

Lexington Pit were also detected at Bluehole Pit (table 4), 

representing distances of up to 20 river miles from the nesting colony. Sandpits dominated the noncolony detections 

of piping plovers, with 1,443 detections (90 percent) in this 

habitat type. Noncolony detections for least terns were more 

numerous (39,975) than for piping plovers and occurred at 

many additional sites but rarely occurred at sandpits with only 

1,501 detections (4 percent; table 5). Terns from the colony at 

Johnson Pit primarily were detected at the nearest noncolony 

dataloggers (Diversion Gates and Bluehole Pit/River), whereas 

terns from Bluehole Pit and Lexington Pit were detected 

throughout the Central Platte River (table 5).

Movement events for piping plovers were few (200) 

and were essentially absent during the postfledging period 

(1). Colony events (6,969) were much more numerous than 

movement events for plovers, and four reproductive periods 

were well represented. However, relatively few colony events 

were associated with the nonbreeding period (947; 14 percent; 

table 6).

In contrast, movement events for least terns (5,495) were 

substantially more abundant than colony events (2,963), and 

were distributed across all four reproductive periods. Total 

number of events (movement + colony) during the nonbreeding period for terns was 3,577, with 50 percent of these 

(1,782) being colony events. In contrast, 24 percent of events 

for terns during the other three periods combined (4,881) were 

colony events.

Despite occurring infrequently in the dataset, there was a 

distinct pattern of piping plover movement events in relation to time of day. Plover movement events occurred almost 

exclusively between 8 p.m. and 5 a.m. (113; 86 percent), and 

infrequently during the daytime hours of 6 a.m. to 7 p.m. (18; 

14 percent) (fig. 2). The more frequent movement events of 

least terns showed a pronounced diurnal pattern, with the 

majority of movement events (4,678; 82 percent) occurring 

between dawn and dusk (4 a.m. to 9 p.m.). Among daytime 

movement events, there was a pronounced bimodal pattern of 

frequency, with movements being most frequent in midmorning and late afternoon but dropping off during the midday 

hours (12 p.m. to 2 p.m.). Tern movement events also occurred 

throughout the nighttime hours but were substantially less frequent (968; 18 percent) than during daytime (fig. 3). This pattern held through all stages of the reproductive cycle, although 

the bimodal distribution was most pronounced and the overall 

frequency of movement events was greatest for nonbreeding 

and brood-rearing stages, and least for the incubation and postfledging stages (fig. 4). There were too few movement events 

for piping plovers to make similar assessments of variation 

across reproductive stages.

Each movement event represented an hour of the day during which multiple detections on dataloggers could occur. A 

maximum distance was assigned to each event as the farthest 

distance between the bird’s nesting colony and the dataloggers on which it was detected. The mean of these maximum 

movement distances for least terns was greatest when movement frequency was lowest (during nighttime hours) and 

was lowest when movement frequency was greatest (during 

daytime hours; fig. 5). This pattern remained evident through 

all reproductive stages, with the longest movement distances 

occurring during nonbreeding and postfledging periods, and 

the shortest movement distances occurring during incubation 

and brood rearing (fig. 6).

Behavior

Behavioral observations were conducted on least terns 

during 378 sessions occurring between June and August 

2009–10 and on piping plovers during 237 sessions occurring 

between May and August 2009–10. A total of 21 noncolony 

observation sessions were conducted on piping plovers in 

2010 during airboat river surveys by the PRRIP and during 

canoe river behavior observations by the USGS. 

Table 2. Locations of telemetry dataloggers used to detect 

radio-marked least terns and piping plovers on the Central Platte 

River, 2009–10. 

[Superscripts indicate datalogger was only present for the labeled year; RM, 

river mile]

Datalogger type Location

Colony RM 250.5-Lexington Pit

Colony RM 240-Dyer2010

Colony/movement RM 230.5-Bluehole Pit

Colony RM 214 -Broadfoot-South Pit2010

Colony/movement RM 199-Dippel Tract1

Movement RM 252-Arp2010

Movement RM 250-Lexington Island

Movement RM 246-West Jefferies

Movement RM 241-East Jefferies

Movement RM 235-Cottonwood Ranch

Movement RM 229-Diversion Gates

Movement RM 212-Wyoming Tract

Movement RM 207-Younkin Tract2009

Movement RM 203-Triplet Trail2009

Movement RM 205-Dinan Tract

Movement RM 190-Uridil Tract1

1During high flows (June 23 to July 7, 2010) the Dippel datalogger 

was moved to the Uridil Tract until flows decreased sufficiently to allow 

the telemetry station to be returned to its original location without risk 

of flooding.
Results 7

Table 3. Number of noise filtered data records for frequencies of radio transmitters deployed on least terns and piping plovers on the 

Central Platter River, 2009–10. 

Frequency Year Species Total records Noncolony records Noncolony (percent)

169.18 2009 Least tern 1,146 858 74.9

169.207 2009 Least tern 8 8 100

169.295 2009 Least tern 5,480 1,073 19.6

169.309 2009 Least tern 2,211 2,073 93.8

169.321 2009 Least tern 16,588 3,881 23.4

169.333 2009 Least tern 5,643 3,260 57.7

169.357 2009 Least tern 1,246 190 15.2

169.37 2009 Least tern 4,543 1,760 38.7

169.382 2009 Least tern 2,189 498 22.8

169.408 2009 Least tern 7,036 4,033 57.3

169.522 2009 Least tern 2,250 1,632 72.5

169.558 2009 Least tern 1,830 1,236 67.5

169.621 2009 Least tern 142 34 23.9

170.358 2009 Least tern 5,691 2,348 41.3

170.443 2009 Least tern 7,245 945 13

170.472 2009 Least tern 9,254 2,189 23.7

169.347 2010 Least tern 9,878 2,956 29.9

169.383 2010 Least tern 1,253 1,253 100

169.395 2010 Least tern 4,607 4,607 100

169.507 2010 Least tern 802 802 100

169.535 2010 Least tern 5,689 1,675 29.4

169.571 2010 Least tern 209 209 100

169.658 2010 Least tern 4,055 2,455 60.5

169.008 2009 Piping plover 912 2 .22

169.068 2009 Piping plover 247 0 0

169.106 2009 Piping plover 36 0 0

169.132 2009 Piping plover 57 0 0

169.155 2009 Piping plover 20,800 0 0

169.22 2009 Piping plover 1448 0 0

169.119 2010 Piping plover 10,811 1 .009

169.131 2010 Piping plover 7,200 144 2

169.309 2010 Piping plover 10,391 0 0

169.321 2010 Piping plover 14,687 0 0

169.37 2010 Piping plover 15,486 0 0

169.708 2010 Piping plover 66 0 0

169.73 2010 Piping plover 997 117 11.7

169.745 2010 Piping plover 3,158 1,210 38.3

169.757 2010 Piping plover 3,143 1 .032

169.845 2010 Piping plover 0 0 0

169.857 2010 Piping plover 2,022 0 0

170.405 2010 Piping plover 6,212 22 .35

170.444 2010 Piping plover 1,923 115 6
8 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Table 4. Distribution of noise filtered data records at noncolony locations for frequencies of radiotransmitters applied to adult piping 

plovers on the Central Platte River, 2009–10.

[RM, river mile; n, number; double asterisks (**) represent the corresponding colony datalogger]

Datalogger location

(fig. 1)

RM 199-

Dippel Tract 

(n=1)

RM 214- 

Broadfoot-South Pit 

(n=2)

RM 230- 

Johnson Pit 

(n=2)

RM 230.5- 

Bluehole Pit 

(n=6)

RM 240- 

Dyer Pit 

(n=1)

RM 250.5-

Lexington Pit

(n=5)

Total

RM 205-Dinan Tract 0 117 0 0 0 0 117

RM 214-Broadfoot-South Pit1 0 ** 0 1 0 0 1

RM 229-Diversion Gates 0 0 0 2 0 0 2

RM 230-Johnson Pit 0 0 ** 0 1 5 6

RM 230.5-Bluehole Pit/River 0 0 144 ** 962 101 1,207

RM 235-Cottonwood Ranch 1 0 0 0 1 0 2

RM 241-East Jefferies 0 0 0 0 24 0 24

RM 250-Lexington Island 0 0 0 0 3 31 34

RM 250.5-Lexington Pit 0 0 0 0 219 ** 219

1 2010 only.

Table 5. Distribution of noise filtered data records at noncolony locations for frequencies of 

radiotransmitters applied to adult least terns on the Central Platte River, 2009–10.

[RM, river mile; n, number; double asterisks (**) represent the corresponding colony datalogger; --, no data]

Datalogger location

(fig. 1)

RM 230- 

Johnson Pit 

(n=2)

RM 230.5- 

Bluehole Pit 

(n=8)

RM 250.5-

Lexington Pit 

(n=13)

Total

RM 190-Uridil Tract 0 64 121 185

RM 199-Dippel Tract 0 452 169 621

RM 203-Triplet Trail1 0 116 906 1,022

RM 205-Dinan Tract 0 161 669 830

RM 207-Younkin Tract1 0 400 935 1,335

RM 212-Wyoming Tract 0 10 110 120

RM 214-Broadfoot-South Pit2 0 213 115 328

RM 229-Diversion Gates 1,378 10,814 364 12,556

RM 230-Johnson Pit ** 4,371 238 4,609

RM 230.5-Bluehole Pit/River 1,738 ** 283 2021

RM 235-Cottonwood Ranch 18 1,058 162 1,238

RM 240-Dyer Pit2 0 45 337 382

RM 241-East Jefferies 0 73 1,582 1,655

RM 246-West Jefferies 0 234 2,990 3,224

RM 250-Lexington Island -- 83 6,517 6,600

RM 250.5-Lexington Pit 0 165 ** 165

RM 252-Arp Tract2 0 15 3,069 3,084

1

2009 only.

2

2010 only.
Results 9

Table 6. Summary of movement and colony events for radio-marked piping plovers and least terns on the Central Platte 

River, 2009–10.

[Percentages (number in parentheses) reflect distribution of events within species and event types]

Movement events Colony events

Reproductive stage Piping plovers

(percent)

Least terns

(percent)

Piping plovers

(percent)

Least terns

(percent)

Incubation 81 (40) 859 (16) 1,956 (28) 296 (10)

Brood rearing 78 (39) 1,445 (26) 2,007 (29) 546 (18)

Postfledging 1 (1) 1,396 (25) 2,059 (30) 339 (11)

Nonbreeding 40 (20) 1,795 (33) 947 (14) 1,782 (60)

Total 200 5,495 6,969 2,963

Hours after midnight

Number of movements

0

0

(midnight)

4

4

8

8

12

12

(noon)

16

16

20

20 24

Number of movements

100

150

200

250

300

350

0 4 8 16 20 24

(midnight)

12

(noon)

Hours after midnight

Figure 2. Distribution of movement events across hours of the 

day for radio-marked piping plovers on the Central Platte River, 

2009–10.

Figure 3. Distribution of movement events across hours of 

the day for radio-marked least terns on the Central Platte River, 

2009–10.

Number of movements

0

20

40

60

80

100

120

140

Incubation

Postfledge

Brood rearing

Nonbreeding

EXPLANATION

Hours after midnight

0

(midnight)

4 8 12

(noon)

16 20 24

Maximum distance moved, in kilometers

0

4

8

12

16

20

24

0 4 8 16 20 24

(midnight)

12

(noon)

Hours after midnight

95-percent confidence interval

EXPLANATION

Figure 5. Mean maximum distance (plus or minus 95-percent 

confidence interval) moved by radio-marked least terns across 

hours of the day on the Central Platte River, 2009–10.

Figure 4. Distribution of movement events across hours of 

the day for radio-marked least terns during four stages of the 

reproductive cycle on the Central Platte River, 2009–10.
10 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Number and total time of behavior observation sessions 

for least terns were heavily skewed toward sandpits (tables 

7 and 8). Despite this allocation of technician effort toward 

sandpit observations, foraging effort by terns was substantially 

higher on river sites. Total number of plunges observed on 

the river (8,139) was over 10 times higher than on sandpits 

(770), and foraging plunges were over 20 times more frequent 

on river sites (1.09 per observation minute) than on sandpit 

sites (0.05 per observation minute). Total number of successful plunges also was substantially higher on the river (552; 

7 percent success rate) than on sandpit ponds (7; 0.9 percent 

success rate). Scaled to technician observation time, successful 

plunges by terns occurred once every 2,002 minutes on sandpit 

ponds and once every 13.5 minutes on river sites (table 8).

Early in the study recognition was made that terns 

frequently were observed at the Kearney Canal Diversion 

Gates, and that this site might represent a profitable tern foraging location. A substantial amount of the river observation 

effort was spent at this site (76:33), with the remaining time 

(47:18) distributed among 27 other river sites. When data were 

Mean distance moved, in kilometers

0

2

4

6

8

10

Incubation

Postfledge

Brood rearing

Nonbreeding

EXPLANATION

4 8 16 20 24

Hours after midnight

0

(midnight)

12

(noon)

Figure 6. Mean maximum distance moved by radio-marked 

least terns across hours of the day during four stages of the 

reproductive cycle on the Central Platte River, 2009–10.

Table 7. Number of data collection sessions, length of data collection, and number of recorded all-occurrence behaviors for adult 

least terns on the Central Platte River in 2009 and 2010.

All-occurrence behaviors

Location

(fig. 1) Sessions

Length 

of time

hour:

minute

Carry Eat

Forage 

deliver 

adult

Forage 

deliver 

chick

Forage 

deliver 

unknown

Hover Leave Out of 

view

Plunge 

not 

sucessful

Plunge 

success

Plunge 

unknown Total

RM 192.5 1 0:05 0 0 0 0 0 0 0 0 0 0 0 0

RM 199-

Dippel 

Tract

20 15:34 5 1 5 0 0 232 1 12 70 12 58 396

RM 203-

Triplet Trail 1 1:01 0 0 0 0 0 0 0 0 0 0 0 0

RM 204 1 0:08 1 1 2 0 0 7 0 1 2 3 0 17

RM 205-

Dinan Tract 15 14:54 16 4 4 3 2 99 1 14 39 6 25 213

RM 205.5 1 0:11 1 1 0 0 0 5 0 1 0 0 1 9

RM 206 1 0:14 0 0 0 0 0 3 0 1 0 0 2 6

RM 207.1 1 0:22 0 0 0 0 0 4 0 0 1 0 0 5

RM 212-

Wyoming 

Tract

3 2:19 2 1 1 0 0 23 1 4 7 3 4 46

RM 213.5 2 0:26 3 0 0 1 1 40 0 1 14 2 6 68

RM 213.9 1 0:07 1 0 0 0 0 13 0 0 7 1 0 22

RM 214-

BroadfootSouth Pit10 9:49 1 2 4 0 0 1 0 0 2 0 0 10

RM 214.1 1 0:03 0 0 0 0 0 3 0 1 0 0 0 4

RM 228 1 0:12 0 0 0 0 0 0 0 0 0 0 0 0

RM 229-

Diversion 

Gates

76 76:33 285 197 5 3 2 3,112 233 221 2,128 503 283 6,972

RM 230-

Johnson Pit 35 37:36 7 2 1 5 0 27 1 12 7 3 11 76
Results 11

All-occurrence behaviors

Location

(fig. 1) Sessions

Length 

of time

hour:

minute

Carry Eat

Forage 

deliver 

adult

Forage 

deliver 

chick

Forage 

deliver 

unknown

Hover Leave Out of 

view

Plunge 

not 

sucessful

Plunge 

success

Plunge 

unknown Total

RM 230.3 1 0:04 1 0 0 0 0 7 0 0 3 1 0 12

RM 230.5-

Bluehole 

Pit

80 79:45 52 0 8 5 4 29 4 32 32 1 16 183

RM 234.9 1 0:05 0 0 0 0 0 0 0 0 0 0 1 1

RM 235-

Cottonwood 

Ranch

4 3:15 4 6 1 1 0 60 0 7 40 3 4 126

RM 235.9 1 0:05 0 0 0 0 0 6 0 0 2 0 3 11

RM 236.7 1 0:07 0 2 0 0 0 13 0 0 6 2 1 24

RM 240.7 1 0:04 0 2 0 0 0 2 0 0 0 2 0 6

RM 241-

East 

Jefferies

3 1:52 0 0 0 0 0 4 0 2 1 0 2 9

RM 246-

West 

Jefferies

1 1:00 0 0 0 0 0 0 0 0 0 0 0 0

RM 246.7 1 0:03 0 3 0 0 0 5 1 0 1 3 2 15

RM 247.3 1 0:07 0 4 0 0 0 21 2 0 11 5 2 45

RM249.6 1 0:06 0 0 0 0 0 7 2 0 6 0 1 16

RM 250-

Lexington 

Island

4 1:47 6 2 0 0 0 24 1 7 14 6 4 64

RM 250.5-

Lexington 

Pit

105 106:27 56 8 2 21 6 148 4 47 141 3 65 501

RM 251.4 1 0:05 0 0 0 0 0 11 1 0 5 0 4 21

RM 251.5 2 3:01 0 0 0 0 0 14 0 5 0 0 12 31

Total 378 357:27 441 236 33 39 15 3,920 252 368 2,539 559 507 8,909

Table 7. Number of data collection sessions, length of data collection, and number of recorded all-occurrence behaviors for adult 

least terns on the Central Platte River in 2009 and 2010.—Continued

Table 8. Summary of behavioral observation effort by research technicians (sessions, minutes), foraging 

effort by least terns (plunges, plunge rate, successful plunges, percent success), and success rate by 

foraging least terns (minutes/successful plunge) for sandpit and riverine foraging habitats on the Central 

Platte River, 2009–10.

[--, not calculated because rates and percentages are only meaningful within habitat types]

Sessions Minutes Plunges

Plunge rate 

(plunges per 

minute)

Successful 

plunges

Success

(percent)

Minutes per 

success

Sandpit 230 14,017 770 0.05 7 0.9 2,002

River 148 7,431 8,139 1.09 552 7 13.5

Total 378 21,447 8,909 -- 559 -- --
12 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

examined separately for the Diversion Gates site the foraging 

effort was found to be slightly higher at the Diversion Gates 

(1.5 plunges/minute) than at other river sites (0.4 plunges/

minute), and foraging success was also slightly higher at the 

Diversion Gates (7 percent) than at other river sites (4 percent). Successful plunges by terns occurred more frequently at 

this site (once every 9.1 minutes) than at other river sites (once 

every 57.9 minutes). However, foraging frequency and success 

were still higher at river sites than sandpit ponds when the 

Diversion Gates data were excluded. 

The majority of observation sessions (203/237; 86 percent; table 9) and time (103:49/107:49; 96 percent; table 10) 

for piping plovers occurred on 5 sandpits where plovers 

nested, while the remaining observations occurred across 

17 river sites. During 3,880 minutes of observation for foraging adult plovers on sandpits, 8,645 pecks were counted for 

a total peck rate of 2.2 pecks/minute. Adult plovers foraged 

less intensively on river sites, with an overall peck rate of 

9.2 pecks/minute. Nearly all of the observation time for 

chicks came from sandpit sites (1,978 minutes for sandpits, 

200 minutes for river sites), but chick foraging rates were 

similar between habitat types (12.9 pecks/minute on sandpits, 

11.0 pecks/minute on river sites).

Foraging Habitat

Least tern foraging observations in 2009–10 were spotmapped at 3,138 locations. Main and braided channels were 

the dominant habitats at foraging sites, with the majority of 

observations occurring at the Kearney Canal Diversion Gates 

(table 11). Foraging tern locations spot-mapped in 4 sandpit 

ponds accounted for less than 9 percent of the total number 

of observations (table 9). A total of 1,164 locations of foraging piping plovers were spot-mapped, of which 98 percent 

occurred within nesting colonies (4 sandpits, 1 sandbar; 

table 12). Plovers foraged primarily in wet sand habitat on 

sandpits and river sites, with about 28 percent of locations 

occurring in dry sand. Spatial distributions of spot-mapped 

foraging locations for 2009–10 are shown in figures 7–15 (at 

the back of this report).

A total of 189 fish trawl samples were collected in 

2009–10 (table 13). Fish were sampled every 2 weeks at sites 

where tern nesting colonies occurred and consistently at three 

riverine sites. Of the 189 trawl samples, 17 caught no fish. 

All but two of these occurred in sandpits before mid-June. A 

total of 12,353 fish were caught, with the greatest number of 

individuals and fish species occurring at the river sites (tables 

13 and 14, at the back of this report). Mean number of fish 

caught per sample was 34.5 for sandpits and 81.9 for river 

sites. The relatively high fish abundance on river sites was not 

an artifact of high fish abundance at the Diversion Gates, as 

this site had a mean abundance of 69.6 fish/sample. However, 

the Diversion Gates site produced more fish species than 

any other site, including 12 species that were caught only at 

this site (table 14). The only other site producing unique fish 

species was Bluehole Pit (two black crappies). Turbidity and 

water temperature were measured at 22 foraging locations and 

44 random locations in sandpits, and 95-percent confidence 

intervals for both variables overlapped between foraging and 

random locations (table 15, at the back of this report). Turbidity, water temperature, and velocity were measured at 38 

foraging locations and 86 random locations at river sites, and 

95-percent confidence intervals for all three variables overlapped between foraging and random locations (table 16, at 

the back of this report).

Terrestrial surficial forage samples were collected during 

33 sampling sessions in 2009–10. Each session consisted of 

sampling one plover forage location and two paired random 

points. Samples were collected at the Dinan Tract (2 sessions), 

Johnson Pit (3 sessions), Bluehole Pit (13 sessions), Dyer Pit 

(2 sessions), and Lexington Pit (13 sessions). For each sample 

collected, the number of large (greater than 3 mm) and small 

(less than 3 mm) invertebrates was quantified (table 17, at the 

back of this report). Mean number of large invertebrates per 

sample appeared comparable between foraging sites (12.7) and 

random points (13.4). However, sample sizes were low due to 

low abundance of foraging plovers, particularly at river sites. 

The Daubenmire cover classes of terrestrial habitat 

variables were converted to the midpoint value for the range 

of percentages represented by the class and then these values 

were treated as continuous variables (Sherfy and others, 2009). 

Five variables were excluded from summary because they 

were essentially absent (boulder, cobble, and large debris) or 

were meaningless given the sparse vegetation cover on plover 

foraging sites (maximum vegetation height, mean vegetation 

height). The remaining variables were measured at 30 foraging 

locations and 60 random points. Among these points, habitat 

variables were similar between foraging and random locations, 

except that wrack tended to be more abundant and terrestrial 

vegetation less abundant at foraging locations than at random 

points (table 18, at the back of this report).

Productivity

A total of 98 least tern nests was monitored in 2009–10; 

95 of these were on sandpits, primarily on Bluehole and Lexington Pits (table 19, at the back of this report). We monitored 

39 piping plover nests in 2009–10; 31 occurred on sandpits, 

and 8 occurred on sandbar sites (table 20). 

Nest fate determinations were based exclusively on 

evidence observed at the nest site on the day that monitoring 

was terminated. Accordingly, nests classified as unknown fate 

(tables 19–20, at the back of this report) may have hatched. 

Apparent nest success for least terns was 33 percent (1 successful nest, 3 total nests) on river sites and 51 percent (49 

successful and probable successful nests, 95 total nests) 

on sandpits. Apparent nest success for piping plovers was 

25 percent (2 successful or probable successful nests, 8 total 

nests) on river sites and 48 pecent (15 successful or probable 

successful nests, 31 total nests) on sandpits.

A total of 23 adult least terns, 24 adult piping plovers 

(table 21, at the back of this report), 109 least tern chicks, and 
Results 13

Table 9. Number of behavior data collection sessions and summary of recorded state behaviors for adult piping plovers on the 

Central Platte River, 2009–10.

State behaviors

Location

(fig. 1) Sessions Active Foraging Inactive Locomotion Missing Out of view

Stationary 

parental 

care

Active 

territory/

parental 

care

Total

RM 184 1 3 0 1 2 2 3 0 0 11

RM 199-

Dippel Tract 4 1 10 6 10 7 3 28 5 70

RM 203-Triplet Trail 0 0 0 0 0 0 0 0 0 0

RM 204 1 0 2 0 0 0 1 0 0 3

RM 205-Dinan Tract 10 18 89 60 69 109 15 23 5 388

RM 207-Younkin Tract 1 1 2 0 0 0 0 0 0 3

RM 212-

Wyoming Tract 0 0 0 0 0 0 0 0 0 0

RM 214-BroadfootSouth Pit 7 3 8 3 27 11 9 68 0 129

RM 229-

Diversion Gates 1 1 11 0 3 2 2 0 0 19

RM 229.8 2 0 35 5 2 8 0 0 0 50

RM 230-Johnson Pit 27 33 139 49 86 76 67 184 3 637

RM 230.3 3 3 12 4 8 3 0 0 0 30

RM 230.4 1 0 2 0 0 0 0 0 0 2

RM 230.5-Bluehole Pit 85 138 677 241 365 617 127 374 13 2,552

RM 230.6 3 9 18 1 0 3 1 0 0 32

RM 234.9 1 0 4 0 0 0 0 0 0 4

RM 235-

Cottonwood Ranch 0 0 0 0 0 0 0 0 0 0

RM 235.4 1 0 2 2 0 0 0 0 0 4

RM 236.2 1 0 12 0 0 0 0 0 0 12

RM 240-Dyer Pit 11 4 113 42 20 29 18 63 3 292

RM 240.2 1 0 5 0 0 1 0 0 0 6

RM 240.7 1 0 4 0 0 2 0 0 0 6

RM 246-East Jefferies 0 0 0 0 0 0 0 0 0 0

RM 245.5 1 1 10 0 0 0 0 0 0 11

RM 246-West Jefferies 0 0 0 0 0 0 0 0 0 0

RM 248.8 1 0 1 0 1 1 0 0 0 3

RM 250-

Lexington Island 0 0 0 0 0 0 0 0 0 0

RM 250.5-

Lexington Pit 73 128 420 237 259 490 98 291 46 1,969

RM 251.5 0 0 0 0 0 0 0 0 0 0

Total 237 343 1,576 651 852 1,361 344 1,031 75 6,233
14 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Table 10. Length of observation time and number of substrate 

pecks counted for foraging piping plovers on the Central Platte 

River, 2009–10.

[RM, river mile]

Adults Young

Location

(fig. 1)

Time

hours:

minutes

Pecks

Time

hours:

minutes

Pecks

RM 184 0:07 9 0:00 0

RM 199-Dippel Tract 1:10 18 0:13 94

RM 203-Triplett Trail 0:00 0 0:00 0

RM 204 0:00 7 0:00 0

RM 205-Dinan Tract 3:35 1,405 1:13 561

RM 207-Younkin Tract 0:05 55 0:00 0

RM 212 0:00 0 0:00 0

RM 214-BroadfootSouth Pit 3:43 77 0:00 0

RM 229-Diversion 

Gates 0:22 121 0:11 64

RM 229.8 0:37 263 0:08 30

RM 230-Johnson Pit 11:03 793 2:44 2,711

RM 230.3 0:00 0 0:26 248

RM 230.4 0:05 105 0:00 0

RM 230.5-Bluehole Pit 24:48 3,738 17:01 12,414

RM 230.6 0:04 95 0:26 326

RM 234.9 0:09 259 0:00 0

RM 235 0:00 0 0:00 0

RM 235.4 0:00 0 0:12 183

RM 236.2 0:36 1,429 0:00 0

RM 240-Dyer Pit 2:49 0 2:58 3,323

RM 240.2 0:01 10 0:03 34

RM 240.7 0:00 0 0:10 77

RM 241-East Jefferies 0:00 0 0:00 0

RM 245.5 0:00 0 0:18 590

RM 248.8 0:00 0 0:00 0

RM 250-Lexington 

Island 0:00 0 0:00 0

RM 250.5-Lexington 

Pit 22:17 4,037 10:15 7,062

RM 251.5 0:00 0 0:00 0

Total 71:31 12,421 36:18 27,717

Table 11. Frequency of aquatic habitat types at locations where 

foraging least terns were spot-mapped on the Central Platte River, 

2009–10.

[RM, river mile]

Location

(fig. 1) Sandpit Main channel

Braided 

channel

Secondary 

channel

RM 199-Dipple Tract 0 0 55 0

RM 205-Dinan Tract 0 0 57 0

RM 214-BroadfootSouth Pit 5 0 0 0

RM 229-Diversion 

Gates 0 1,137 1,610 9

RM 230-Johnson Pit 23 0 0 0

RM 230.5-Bluehole 

Pit 27 0 0 0

RM 250-Lexington 

Island 0 0 3 0

RM 250.5-Lexington 

Pit 212 0 0 0

Total 267 1,137 1,725 9

Table 12. Frequency of terrestrial habitat types at locations 

where foraging piping plovers were spot-mapped on the Central 

Platte River, 2009–10.

[RM, river mile]

Location

(fig. 1) Sandpit Sandbar Rivershoreline

RM 199-Dippel Tract 0 10 0

RM 205-Dinan Tract 0 46

RM 214-Broadfoot-South Pit 8 0 0

RM 230-Johnson Pit 115 0 0

RM 230.5-Bluehole Pit 554 113 111

RM 240-Dyer Pit 111 0 0

RM 250.5-Lexington Pit 296 0 0

Total 1,084 69 11

1RM 230.5 sandbar and shoreline observations were made on the Platte 

River just south of Bluehole Pit.
Discussion 15

89 piping plover chicks was banded in 2009–10 (table 22, at 

the back of this report). Tern and plover chicks were considered fledged if they survived to 16 and 21 days, respectively, 

or were observed in flight. Based on these criteria, an estimation was made that 1 banded plover chick fledged from a sandbar, 19 tern chicks fledged from sandpits, and 32 plover chicks 

fledged from sandpits within the study area in 2009–10. 

Discussion

A motivation for this study was a desire to understand 

differences in use of foraging habitats by least terns and piping plovers nesting on sandpits and river sandbars. However, 

nesting effort by both species was very low on sandbars. Only 

3 least tern nests and 8 piping plover nests were found on 2 

sandbar sites. Low use was further complicated by restrictions on research access to sandbars in 2010, which placed 

additional constraints on the study’s ability to compare these 

habitat types. Accordingly, rigorous analyses could not be 

conducted on the role of nest-site habitat type (sandpit compared to sandbar) in use of foraging habitat by Platte River 

least terns and piping plovers. Although low nesting effort on 

sandbars is a statistical hurdle, it should not be overlooked as 

a potential indicator of how terns and plovers perceive habitat 

conditions. The relative roles of nest-site habitat and foraging habitat in driving selection of nest sites by these species 

have not been rigorously evaluated. There are certainly some 

distinct qualitative differences between sandbar and sandpit 

habitats on the Central Platte River, including topography, 

elevation profile, grain size, and vegetation community. These 

factors can be important for tern and plover nest-site selection 

(Anteau and others, 2012; Sherfy and others, 2011) and a more 

complete understanding of relations between preferred nestsite features and those available in the Central Platte River will 

be needed to understand the importance. River sandbars on the 

nearby Lower Platte River, which are used more frequently by 

nesting terns (Kirsch, 1996) than Central Platte River sandbars, may be a useful basis for comparing habitat features and 

understanding lack of use on the Central Platte River.

Proximity and quality of foraging habitat can also potentially influence nest-site selection and productivity (Atwood 

and Kelly, 1984; Massey and others, 1992; Dugger, 1997; 

Catlin and others, 2011; Stucker and others, 2011). Least terns 

are known to forage near their nesting colonies (Faanes, 1983; 

Wilson and others, 1993; Schweitzer and Leslie, 1996), but 

the extent to which nesting colony use is constrained by flight 

distance to foraging areas is poorly known. Telemetry data 

suggest that nesting least terns are capable of using habitat 

complexes that span substantial distances, as movement events 

greater than 10 kilometers (km) regularly occurred in the 

dataset. Although greater movement distance would equate to 

greater energetic cost, it is not known how the costs of these 

larger-scale movements are offset.

The Kearney Canal Diversion Gates (RM 229) was a 

site at which adult least terns previously were known to be 

common. At this site, a diversion structure and canal confluence create flow patterns atypical of the Platte River’s main 

channel. Data showed that terns from all nesting colonies were 

detected at this site, although movements to the Diversion 

Gates were far more frequent for birds nesting at the nearest 

colony (Bluehole Pit). Fish sampling data suggested this site is 

a profitable tern foraging location, containing a relatively high 

abundance of fish and potentially some taxa relatively uncommon elsewhere in the river system. The foraging frequency 

and success rates observed at this site suggest terns could 

more readily obtain forage fish than at other sites. This could 

be a function of higher fish abundance or enhanced availability 

because of diversity of flow patterns and structure. Although 

the Diversion Gates site was heavily used by Bluehole Pit 

terns (76 percent of movement events by these birds), it was 

not the most heavily used site by terns from other colonies. 

For example, terns radio-marked at Lexington Pit were most 

frequently encountered at two sites within 4 miles of the 

colony (West Jefferies; 35 percent of movement events and 

the Arp Tract; 23 percent of movement events). Lexington 

Pit birds were detected at the Diversion Gates at a frequency 

slightly higher than other nearby sites, but overall use was 

substantially lower than by Bluehole Pit birds. These observations suggest that proximity of foraging habitat to a nesting 

colony is an important factor contributing to its use, and the 

presence of nearby foraging habitat may enhance use of a nesting colony.

Table 13. Number of samples, fish caught, and fish species 

collected on the Central Platte River, 2009–10.

[RM, river mile]

Location

(fig. 1) Samples Fishcaught

Fish

species

RM 180 3 106 8

RM 199-Dippel Tract 9 171 4

RM 205-Dinan Tract 17 3,552 12

RM 212-Wyoming Tract 3 47 1

RM 214-Broadfoot-South Pit 6 42 3

RM 229-Diversion Gates 51 3,548 41

RM 230-River 4 561 8

RM 230-Johnson Pit 18 786 5

RM 230.5-Bluehole Pit 18 856 9

RM 235-Cottonwood Ranch 3 162 13

RM 241- East Jefferies 18 620 23

RM 246-West Jefferies 12 1,235 25

RM 250-Lexington Island 3 69 4

RM 250.5-Lexington Pit 24 598 7

Total 189 12,353
16 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

O’Shea and others (1990) sampled fish in Platte River 

sandpits and the river’s open channel and concluded that differences in flow regime and vegetation community were key 

factors distinguishing fish assemblages between sandpits and 

river sites. Wilson and others (1983) found that terns nesting on Platte River sandpits did not forage exclusively on 

the sandpit but traveled to forage elsewhere and frequently 

returned from the Platte River carrying fish. Wilson and others (1983) also reported a greater frequency of successful 

plunges and greater proportion of small fish in the river than 

in sandpits. The data showed similar patterns of greater plunge 

frequency, higher foraging success, and higher fish abundance 

at river sites than in sandpits. Breeding success of California 

least terns was correlated with proportion of northern anchovies (Engraulis mordax), suggesting that abundance and 

composition of the prey base can influence tern productivity 

(Elliott and others, 2007). Although the dataset was sparse, 

tern productivity was similar on the two sites where the greatest number of adult terns were radio marked (Bluehole and 

Lexington Pits), suggesting that variable access to prey did not 

have a differential influence on tern productivity among Platte 

River sites. 

Both river sites and sandpits were used by foraging terns 

and plovers, but river sites appeared to be more important for 

tern foraging and sandpits appeared to be more important for 

plover foraging. Prey sampling data suggested prey abundance may have been partially responsible for these differences in use. Fish tended to be more abundant on river sites, 

and the single river site sampled for invertebrates had lower 

abundance than the sandpits sampled. A targeted study would 

be needed to make reliable conclusions about differences in 

forage abundance between these habitat types. However, it is 

probably more important, especially for plovers, to understand 

the factors that influence nest-site and nest-habitat selection 

on the Central Platte River. The mobility of terns throughout 

the reproductive cycle makes a wide range of foraging habitats 

available, which was evident in the substantial movements 

throughout the river corridor by sandpit-nesting birds that was 

observed. In contrast, brood-rearing plovers are constrained to 

foraging in habitats connected to nesting areas. Consequently, 

the spatial scale at which habitat complexes (nesting, broodrearing, and foraging) should be managed for these two species is substantially different.

When the mean value of a habitat variable at a used 

location differs from the value at a random location, selection 

for that variable can be inferred (Sherfy and others, 2012). 

Although the sample of plover foraging locations was small, 

the data indicate that selection may be occurring in two cases. 

Wrack tended to be more abundant and terrestrial vegetation tended to be less abundant at foraging locations than 

at random points (table 18). This suggests that plovers may 

select sites with more wrack and less vegetation for foraging. 

Presence of wrack could favor abundance of invertebrate prey, 

whereas lack of vegetation could enhance ability to detect 

predators. Both features could also be indicators of wet shoreline habitats where plovers preferentially foraged.

Data also have implications for how forage abundance 

and habitat use of terns and plovers are monitored in the 

future. Pronounced diurnal variation in frequency of movements outside nesting colonies by both species was documented, with terns more frequently moving outside colonies 

during daylight hours and plovers more frequently moving 

outside colonies during nighttime hours. Collectively, movement distance and frequency data for terns suggest that birds 

made frequent, short-distance movements out of colonies 

during daylight hours and less frequent, longer-distance movements out of colonies at night. It cannot be conclusively stated 

that movements by either species were timed to coincide with 

peaks in prey availability, although piping plovers are known 

to forage at night in coastal habitats where prey abundance 

may be higher and human disturbance may be lower at night 

(Staine and Burger, 1994). Behavioral observations and fish 

sampling data for terns show that foraging occurred at noncolony sites, and that foraging effort and frequency were higher 

at river than sandpit sites. Movement frequency and distance 

increased in later stages of the breeding cycle, suggesting that 

adult terns explored a wider range of habitats and potentially 

capitalized on more distant resources when there was a lower 

premium on colony attendance.

Nocturnal predation has been implicated as a factor contributing to low colony attendance by terns at night (Nisbet, 

1975; Nisbet and Welton, 1984; Arnold and others, 2006). 

However, several factors suggest that nocturnal predation was 

not the primary influence on nocturnal tern and plover behavior on the Platte River. First, it would be expected that terns 

and plovers nesting in the same colonies would exhibit similar 

patterns of response to predation pressure, but the opposite 

was observed, with tern movements occurring primarily in the 

daytime and plover movements occurring primarily at night. 

This observation is consistent with Bluso-Demers and others 

(2010), who found that colony attendance by Forster’s terns 

(Sterna forsteri) pairs was relatively high at night. Second, 

Zimmerman (2008) found that temporary predator-mediated 

desertion of colonies by least terns was brief (15.5 plus or 

minus 3 minutes). In contrast, nocturnal movements by 

least terns were farther from the colony than daytime movements, and the distances involved (mean distance greater than 

10 miles near midnight; fig. 5) likely translated into longer 

recesses. Third, apparent nest success was around 50 percent 

for both terns and plovers on sandpits, which is higher than 

would be expected if predation substantially influenced these 

sites. Collectively, this evidence suggests that predation pressure was not a principal cause for the movement events that 

were documented.

Regulatory Compliance

This research was conducted under a Federal Threatened 

and Endangered Species Permit (#TE-121914-5) and a Scientific and Educational Permit from the Nebraska Game and 
References Cited 17

Parks Commission. The following observations and incidents 

of bird death, bird injury, and human disturbance are reported 

in accordance with these permits for 2010 [comparable information for 2009 is available in Sherfy and others, (2009)].

Injury

• On June 5 at the Dinan Tract (RM 205) during the 

release of an adult piping plover, the banding technician felt a pop from the bird’s left leg. The adult piping 

plover was observed not using its left leg but was 

observed flying and bathing after release.

• On June 25 at the Bluehole Pit (RM 230.5), a banded 

least tern chick was found with what appeared to be a 

broken leg and a clamped colored band on the leg. The 

colored band was removed; the chick was observed 

twice in the following week. 

Death

• Along the Central Platte River, 3 dead piping plovers 

(1 adult and 2 chicks) and 8 dead least terns (1 adult 

and 7 chicks) were found in 2010. Some were collected 

for further examination. 

• On May 14, 2010, at the Dippel tract (RM 199), an 

adult piping plover was found dead. The dead plover’s 

feathers had been plucked and presumed killed by an 

avian predator. The bird was not collected.

• On June 21, 2010, at the Bluehole Pit (RM230.5), five 

least tern chicks were found dead in or near nest bowls. 

An intense storm the previous night/morning might 

have been the cause of death, but no direct evidence 

was observed. Two of the chicks were previously 

banded and all chicks were collected.

• On June 23, 2010, at the Bluehole Pit (RM 230.5), a 

dead banded piping plover chick was found. A gash 

in the abdomen was observed; no other evidence was 

found. Intense storms had occurred the previous two 

nights. The bird was collected.

• On June 29, 2010, at the Bluehole Pit (RM 230.5), a 

dead piping plover chick was found with no signs indicating cause of death; the bird was collected.

• On July 3, 2010, at the Bluehole Pit (RM 230.5), a 

banded least tern chick was found dead with a gash 

in the abdomen. No other evidence was observed; the 

bird was collected.

• On July 3, 2010, at the Bluehole Pit (RM 230.5), a 

dead banded least tern chick was found covered in ants 

near some wrack. No other signs indicated cause of 

death; the bird was collected.

• On July 14, 2010, at the Lexington Pit (RM 250.5), a 

banded adult least tern was found dead. The body had 

advanced decomposition; therefore cause of death was 

unknown. Band combination indicated the bird was 

banded in 2009 as a chick. The bird had primary feathers and likely could fly. It is possible the bird died the 

previous year. The bird was collected.

Human Disturbance

No confirmed human disturbance events were observed 

along the Central Platte River in 2009–10.

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ground-nesting bird (Charadrius melodus) using reservoir 

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18 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

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waste corn, more land in soybeans, and the switch to genetically modified crops—Trends with important implications 

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Figures 7–15
20 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

98°48' 98°48'20"

40°42'

40°41'50"40°41'40"

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 Universal Transverse Mercator projectionZone 14

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

Foraging locations

0 0.1 0.05 KILOMETER0 0.1 0.05 MILE

[Foraging locations may have shifted slightly

because of the use of a snap grid while 

digitizing points in the field]

Figure 7. Spot-mapped locations of foraging least terns and piping plovers from 2009–10 at Dippel Tract, near Gibbon, Nebraska.
Figures 7–15 21

98°54'30" 98°54'45"

40°40'10"

40°40'

0 0.1 0.05 KILOMETER

0 0.1 0.05 MILE

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

[Foraging locations may have shifted slightly

Foraging locations

because of the use of a snap grid while 

digitizing points in the field]

Figure 8. Spot-mapped locations of foraging least terns and piping plovers from 2009–10 at Dinan Tract, near Gibbon, Nebraska.
22 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars 99°05'45" 99°06' 40°40' 40°39'50"

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 Universal Transverse Mercator projectionZone 14 0 0.1 0.05 KILOMETER

0 0.1 0.05 MILE

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

[Foraging locations may have shifted slightly

Foraging locations

because of the use of a snap grid while 

digitizing points in the field]

Figure 9. Spot-mapped locations of foraging least terns and piping plovers from 2010 at Broadfoot-South Pit, near Kearney, Nebraska.
Figures 7–15 23

99°20'15" 99°20'30" 99°20'45" 99°21'

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 Universal Transverse Mercator projectionZone 14

40°41'30"40°41'20"40°41'10"

40°41'

0 0.2 0.1 KILOMETER

0 0.2 0.1 MILE

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

[Foraging locations may have shifted slightly

Foraging locations

because of the use of a snap grid while 

digitizing points in the field]

Figure 10. Spot-mapped locations of foraging least terns from 2009–10 at the Diversion Gates, near Elm Creek, Nebraska.
24 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars 99°22' 99°22'15" 99°22'30" 40°41'10" 40°41'

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 Universal Transverse Mercator projectionZone 14 0 0.1 0.05 KILOMETER

0 0.1 0.05 MILE

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

[Foraging locations may have shifted slightly

Foraging locations

because of the use of a snap grid while 

digitizing points in the field]

Figure 11. Spot-mapped locations of foraging least terns and piping plovers from 2009–10 at Bluehole Pit, near Elm Creek, Nebraska.
Figures 7–15 25

99°22' 99°22'10"

40°40'15"40°40'10"

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 Universal Transverse Mercator projectionZone 14 0 0.05 0.25 KILOMETER

0 0.05 0.25 MILE

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

[Foraging locations may have shifted slightly

Foraging locations

because of the use of a snap grid while 

digitizing points in the field]

Figure 12. Spot-mapped locations of foraging least terns and piping plovers from 2009–10 at Johnson Pit, near Elm Creek, Nebraska.
26 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars 99°33'10" 99°33'20" 40°40'40" 40°40'35"

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 Universal Transverse Mercator projectionZone 14 0 0.05 0.25 KILOMETER

0 0.05 0.25 MILE

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

[Foraging locations may have shifted slightly

Foraging locations

because of the use of a snap grid while 

digitizing points in the field]

Figure 13. Spot-mapped locations of foraging piping plovers from 2010 at Dyer Pit, near Overton, Nebraska.
Figures 7–15 27

99°43'40" 99°43'30" 99°43'20"

40°44'10"

40°44'

40°43'50"

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 

Universal Transverse Mercator projection

Zone 14 0 0.05 0.1 KILOMETER

0 0.05 0.1 MILE

2009 piping plover 

2010 piping plover

2009 least tern

2010 least tern

EXPLANATION

Foraging locations

[Foraging locations may have shifted slightly

because of the use of a snap grid while 

digitizing points in the field]

Figure 14. Spot-mapped locations of foraging least terns and piping plovers from 2009–10 at Lexington Pit, near Lexington, Nebraska.
28 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars 99°43'20" 99°43'25" 40°43'26" 40°43'24" 40°43'22"

Base from Platte River Recovery Implementation Program, 2008, 1:4,800 Universal Transverse Mercator projectionZone 14 0 0.05 0.25 KILOMETER

0 0.05 0.25 MILE

2009 piping plover 2010 piping plover

2009 least tern2010 least tern

EXPLANATION

[Foraging locations may have shifted slightly

Foraging locations

because of the use of a snap grid while 

digitizing points in the field]

Figure 15. Spot-mapped locations of foraging least terns from 2009 at Lexington Island, near Lexington, Nebraska.
Tables 14–22 29

Tables 14–22
30 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars Table 14. Number of fish species caught in 189 trawl samples, by location on the Central Platte River, 2009–10. [RM, river mile; BF-S, Broadfoot-South] Fish species RM180 RM 199- Dippel RM 205- Dinan RM 212 RM 214- BF-S Pit RM 229- Diversion RM 230- River RM 230- Johnson Pit RM 230.5- Bluehole Pit RM235 RM 241- East Jefferies RM 246- West Jefferies RM 250- Lexington Island RM 250.5- Lexington Pit Total Black crappie (Pomoxis nigromaculatus) 0 0 0 0 0 0 0 0 2 0 0 0 0 0 2 Brook stickleback (Culaea inconstans) 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 Brook silverside (Labidesthes sicculus) 0 0 0 0 9 1 0 438 493 0 0 0 0 298 1,239 Bluegill (Lepomis macrochirus) 0 0 0 0 0 13 0 1 0 1 0 1 0 89 105 Bigmouth buffalo (Ictiobus cyprinellus) 0 0 0 0 0 4 0 0 0 0 0 0 0 0 4 Bigmouth shiner (Notropis dorsalis) 0 0 0 0 0 0 0 0 0 0 0 271 0 0 271 Bluntnose minnow (Pimephales notatus) 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 Brassy minnow (Hybognathus hankinsoni) 0 0 0 0 0 3 0 0 0 0 0 0 0 0 3 Common carp (Cyprinus carpio) 0 0 4 0 0 21 10 0 0 15 4 0 0 0 54 Creek chub (Semotilus atromaculatus) 0 0 0 0 0 1 1 0 0 10 5 0 0 0 17 Central stoneroller (Campostoma anomalum) 0 0 0 0 0 4 0 0 0 1 8 10 0 0 23 Common shiner (Luxilus cornutus) 0 0 0 0 0 0 0 0 0 0 1 6 0 0 7 Channel catfish (Ictalurus punctatus) 3 0 5 0 0 30 1 0 0 0 0 0 0 0 39 Emerald shiner (Notropis atherinoides) 0 0 0 0 0 8 0 0 0 0 2 1 0 0 11 Fathead minnow (Pimephales promelas) 0 1 1 0 0 0 2 0 0 2 8 0 0 0 14 Green sunfish (Lepomis cyanellus) 0 0 0 0 0 8 0 0 0 0 0 0 0 0 8 Golden shiner (Notemigonus crysoleucas) 0 0 0 0 0 1 0 0 0 0 2 0 0 0 3 Gizzard shad (Dorosoma cepedianum) 1 0 0 0 0 0 0 7 1 0 51 0 0 0 60 Hybognathus spp. (Hybognathus sp.) 44 0 12 0 0 0 0 0 0 3 0 0 0 0 59 Largemouth bass (Micropterus salmoides) 0 0 0 0 1 69 0 324 14 1 3 1 0 145 558 Longnose gar (Lepisosteus osseus) 0 0 0 0 0 2 0 0 0 0 0 0 0 0 2 Mimic shiner (Notropis volucellus) 0 0 0 0 0 18 0 0 0 0 64 40 0 0 122 Western mosquitofish (Gambusia affinis) 1 0 0 0 0 0 8 0 7 1 0 25 0 2 44 Orangespotted sunfish (Lepomis humilis) 0 0 0 0 0 4 0 0 0 0 0 0 0 0 4 Plains killifish (Fundulus zebrinus) 0 5 678 0 0 6 2 0 0 18 10 4 0 0 723

Quillback (Carpiodes cyprinus) 6 0 0 0 0 0 0 0 0 0 31 2 0 0 39Red shiner (Cyprinella lutrensis) 0 0 0 0 0 165 0 0 0 0 5 6 0 0 176River carpsucker (Carpiodes carpio) 0 0 0 0 0 3 0 0 0 0 1 4 0 0 8River shiner (Notropis blennius) 0 0 0 0 0 27 0 0 0 0 26 6 0 0 59Spotfin shiner (Cyprinella spiloptera) 0 0 0 0 0 1 0 0 0 0 0 1 0 0 2
Tables 14–22 31

Fish species RM180 RM 199- Dippel RM 205- Dinan RM 212 RM 214- BF-S Pit RM 229- Diversion RM 230- River RM 230- Johnson Pit RM 230.5- Bluehole Pit RM235 RM 241- East Jefferies RM 246- West Jefferies RM 250- Lexington Island RM 250.5- Lexington Pit Total

Shorthead redhorse (Moxostoma macrolepidotum) 0 0 0 0 0 4 0 0 0 0 4 1 0 0 9Smallmouth bass (Micropterus dolomieu) 0 0 0 0 0 13 0 0 0 0 0 0 0 0 13Suckermouth minnow (Phenacobius mirabilis) 0 0 2 0 0 18 0 0 0 1 4 15 0 0 40Sand shiner (Notropis stramineus) 0 0 0 0 0 349 0 0 0 0 135 240 0 0 724Spotted bass (Micropterus punctulatus) 0 0 0 0 0 0 0 16 0 0 0 0 0 1 17Spottail shiner (Notropis hudsonius) 0 0 0 0 0 50 0 0 0 0 8 112 0 0 170Unidentified buffalo (Ictiobus sp.) 0 0 4 0 0 25 0 0 0 0 0 0 0 0 29Unidentified Cyprinella (Cyprinella sp.) 4 19 74 0 0 667 0 0 0 12 0 0 7 0 783Unidentified carpsucker (Carpiodes sp.) 0 0 0 0 0 4 1 0 0 0 0 2 0 0 7Unidentified sucker (Unidentified Catostomidae) 0 0 0 0 0 3 0 0 0 0 0 0 0 0 3Unidentified minnow (Unidentified Cyprinidae) 0 0 5 0 0 6 0 0 0 0 0 0 0 0 11Unknown gar (Lepisosteidae sp. ) 0 0 0 0 0 0 0 0 0 0 1 1 0 0 2Unidentified Lepomis (Lepomis sp.) 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1Unknown narrow bodied 0 1 0 0 0 8 0 0 0 0 0 20 1 0 30Unknown insect/invertebrate 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1Unidentified 0 0 0 0 0 5 0 0 0 0 0 0 0 0 5Unknown other 0 0 14 0 0 4 0 0 0 0 0 0 0 0 18Unidentified shiner (Notropis sp.) 46 145 2,742 47 0 1,983 536 0 1 92 80 419 59 0 6,149Unidentified crappie (Pomoxis spp.) 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1Unidentified redhorse (Moxostoma sp.) 1 0 0 0 0 11 0 0 0 0 0 0 0 0 12Unknown spiny dorsal 0 0 0 0 0 0 0 0 0 0 0 0 0 0 4Western silvery minnow (Hybognathus 

argyritis) 0 0 0 0 0 0 0 0 1 0 166 43 0 0 210

White bass (Morone chrysops) 0 0 0 0 32 0 0 0 0 0 0 0 0 0 32White sucker (Catostomus commersoni) 0 0 11 0 0 4 0 0 0 5 1 0 2 0 23Yellow bullhead (Ameiurus natalis) 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1Young of the year 0 0 0 0 0 0 0 0 0 0 0 0 0 22 22Yellow perch (Perca flavescens) 0 0 0 0 0 0 0 0 336 0 0 0 0 41 377Total 106 171 3,552 47 42 3,548 561 786 856 162 620 1,235 69 598 12,353

Table 14. Number of fish species caught in 189 trawl samples, by location on the Central Platte River, 2009–10.—Continued[RM, river mile; BF-S, Broadfoot-South]
32 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Table 15. Mean, lower 95-percent confidence limit and upper 95-percent confidence limit for habitat variables 

measured at least tern foraging locations and random points in sandpits on the Central Platte River, 2009–10.

[n, number; LCL, lower confidence level; UCL, upper confidence level; NTU, nephelometric turbidity units; °C, degrees Celsius]

Foraging locations Random locations

n Mean LCL UCL n Mean LCL UCL

Turbidity (NTU) 22 5.4 3.6 7.2 44 5.5 4.2 6.8

Water temperature (°C) 22 24.4 21.9 26.8 44 24.4 22.7 26.1

Table 16. Mean, lower 95-percent confidence limit and upper 95-percent confidence limit for habitat variables 

measured at least tern foraging locations and random points at river sites on the Central Platte River, 2009–10.

[n, number; LCL, lower confidence level; UCL, upper confidence level; NTU, nephelometric turbidity units; °C, degrees Celsius; 

m/s, meters per second]

Foraging locations Random locations

n Mean LCL UCL n Mean LCL UCL

Turbidity (NTU) 38 37.5 30.4 44.6 86 33.4 29.5 37.3

Water temperature (°C) 38 24.4 22.9 25.9 86 25.3 24.3 26.2

Water velocity (m/s) 38 .5 .4 .6 86 .5 .4 .6

Table 17. Number of large (greater than 3 millimeters) and small (less than 3 millimeters) 

invertebrates caught on sticky traps during 33 sampling sessions on the Central Platte 

River, 2009–10.

[Each session consisted of one sample at a piping plover foraging site and two samples at random points. 

Numbers are raw counts of invertebrates that are uncorrected for differences in sampling area between 

vertical and horizontal sticks and length of sampling time. RM, river mile]

Location

(fig. 1)

Foraging sites Random points

Sessions Large Small Large Small

RM 205-Dinan Tract 2 13 24 10 18

RM 230-Johnson Pit 3 51 326 34 850

RM 230.5-Bluehole Pit 13 209 901 194 2,161

RM 240-Dyer Pit 2 28 26 36 24

RM 250.5-Lexington Pit 13 120 246 168 630

Total 33 421 1,523 442 3,683
Tables 14–22 33

Table 18. Mean, lower 95-percent confidence limit, and upper 95-percent confidence limit for 

habitat variables measured at piping plover foraging locations and random points on the Central 

Platte River, 2009–10.

[LCL, lower confidence limit; UCL, upper confidence limit]

Foraging locations Random points

Mean LCL UCL Mean LCL UCL

Gravel 2.0 0.1 3.9 1.7 0.5 2.9

Leaf litter 0.5 .1 .9 0.8 .0 1.6

Pebble 14.6 4.9 24.3 20.9 12.9 29.0

Sand 59.1 46.4 71.8 59.0 50.3 67.7

Silt 5.2 -1.7 12.1 3.1 -0.4 6.5

Terrestrial vegetation .6 .2 1.0 1.1 .6 1.6

Wetland vegetation .2 -.1 0.4 .3 0 .7

Woody vegetation .2 -.1 .4 0.1 0 .2

Wrack 2.9 -1.0 6.9 1.3 .2 2.3

Table 19. Number and fate of least tern nests monitored on the Central Platte River, 2009–10.

[RM, river mile]

Site

(fig. 1) Successful Probable successful Failed Probable failure Unknown Total

RM 199-Dippel Tract 0 0 2 0 0 2

RM 205-Dinan Tract 1 0 0 0 0 1

RM 214-Broadfoot-South Pit 2 0 1 0 0 3

RM 230-Johnson Pit 2 0 4 0 4 10

RM 230.5-Bluehole Pit 19 4 12 1 7 43

RM 240-Dyer Pit 0 0 0 0 0 0

RM 250.5-Lexington Pit 15 7 8 0 9 39

Total 39 11 27 1 20 98

Table 20. Number and fate of piping plover nests monitored on the Central Platte River, 2009–10.

[RM, river mile]

Site

(fig. 1) Successful Probable successful Failed Probable failure Unknown Total

RM 199-Dippel Tract 1 1 3 0 0 5

RM 205-Dinan Tract 0 0 2 0 1 3

RM 214-Broadfoot-South Pit 0 2 0 0 0 2

RM 230-Johnson Pit 1 1 1 0 2 5

RM 230.5-Bluehole Pit 5 2 3 0 2 12

RM 240-Dyer Pit 1 0 0 0 0 1

RM 250.5-Lexington Pit 2 1 5 0 3 11

Total 10 7 14 0 8 39
34 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Table 21. Banding and marking records for least tern and piping plover adults on the Central Platte River, 2009–10.

[Band combinations are reported by leg position (left leg top, left leg bottom: right leg top, right leg bottom), with each leg position including up to two 

bands. Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; t, radio transmitter; Y, yellow; /, split band; V, violet; 

R, red; O, orange; G, green (kelly); L, pastel blue or light blue; C, cobalt blue or bright blue; K, black; W, white; PIPL, piping plover; X, metal; NT, no 

transmitter; P, pink; D, dark green (not used)]

Band number Date banded Species River mile Nest number Color band combination Transmitter frequency

2211-29913 6/18/2009 LETE 250.5 106 - T, - Y/V : - -, R R 169.180

2211-29915 6/18/2009 LETE 250.5 108 - T, - Y/V : - -, Y R 169.207

2211-29921 6/18/2009 LETE 250.5 117 - T, - Y/V : - -, O R 169.295

2211-29922 6/19/2009 LETE 250.5 109 - T, - Y/V : - -, G R 169.309

2211-29923 6/19/2009 LETE 230.5 212 - T, - Y/V : - -, L R 169.321

2211-29924 6/19/2009 LETE 230.5 210 -T, - Y/V : - -, C R 169.333

2211-29926 6/23/2009 LETE 250.5 114 - V, - R : - T, - V/K 169.357

2211-29927 6/23/2009 LETE 250.5 110 - V, - O : - T, - V/K 169.370

2211-29928 6/25/2009 LETE 250.5 116 - T, - Y/V : - -, L O 169.382

2211-29946 6/25/2009 LETE 250.5 119 - T, - Y/V : - -, G O 169.621

2211-29992 6/25/2009 LETE 230.5 216 - T, - Y/V : - -, Y O 170.358

2211-29997 6/25/2009 LETE 230 305 - T, - Y/V : - -, O O 170.443

2211-29999 6/25/2009 LETE 230 306 - T, - Y/V : - -, R O 170.472

2211-29930 6/30/2009 LETE 230.5 220 - T, - Y/V : - -, W R 169.408

2211-29939 6/30/2009 LETE 230.5 222 - T, - Y/V : - -, V R 169.522

2211-29941 6/30/2009 LETE 230.5 218 - T, - Y/V : - -, K R 169.558

0861-43443 6/15/2010 LETE 250.5 109 - -, C W : - T, V V 169.347

0861-53446 6/16/2010 LETE 250.5 105 - -, O W : - T, V V 169.507

0861-53445 6/16/2010 LETE 250.5 115 - -, G W : - T, V V 169.395

0861-53444 6/16/2010 LETE 250.5 113 - -, R W : - T, V V 169.383

0861-53447 6/17/2010 LETE 230.5 212 - -, V W : - T, V V 169.535

0861-53448 7/7/2010 LETE 230.5 224 - -, K W : - T, V V 169.571

0861-53450 7/19/2010 LETE 250.5 125 - -, Y W : - T, V V 169.658

2301-46480 5/21/2009 PIPL 230.5 200 - LF, Y Y : - X, R R NT

2301-46491 5/21/2009 PIPL 250.5 100 - LF, Y Y : - X, R Y NT

2301-46484 5/22/2009 PIPL 230 300 - LF, Y Y : - X, R K NT

2301-46496 5/22/2009 PIPL 230 301 - LF, Y Y : - X, R G NT

2301-46473 6/1/2009 PIPL 205 400 - LF, G V/P : - X, R C 169.132

2301-46474 6/1/2009 PIPL 230.5 202 - LF, G V/P : - X, R G 169.008

2301-46475 6/1/2009 PIPL 230.5 203 - LF, G V/P : - X, R R NT 

2301-46487 6/1/2009 PIPL 250.5 105 - LF, G V/P : - X, R K 169.106

2301-46489 6/1/2009 PIPL 250.5 102 - LF, G V/P : - X, R O 169.068

2301-46472 6/8/2009 PIPL 230.5 203 - LF, G V/P : - X, C O 169.155

2301-46470 6/12/2009 PIPL 250.5 111 - LF, G V/P : - X, G G 169.220

1991-92196 5/13/2010 PIPL 250.5 101 - X, K/W C : - LF, C C 170.444

2301-46475 5/15/2010 PIPL 230.5 204 - LF, K/W G : - X, R R 169.857

1991-92198 5/15/2010 PIPL 250.5 102 - X, K/W R : - LF, C C 170.405

No band 5/15/2010 PIPL 205 602 - -, K/W G : - LF, C C 169.845

1991-92199 5/17/2010 PIPL 230.5 202 - X, K/W Y : - LF, C C 169.757
Tables 14–22 35

Band number Date banded Species River mile Nest number Color band combination Transmitter frequency

2301-46459 5/26/2010 PIPL 214 502 - X, K/W L : - LF, R K 169.708

2301-46460 5/26/2010 PIPL 214 501 - X, K/W Y : - LF, R K 169.730

2211-29694 6/1/2010 PIPL 230.5 205 - X, K/W K : - LF, R K 169.370

2211-29683 6/5/2010 PIPL 230 302 - X, K/W R : - LF, R K 169.131

2211-29682 6/5/2010 PIPL 230.5 207 - X, K/W G : - LF, R K 169.309

2211-29684 6/9/2010 PIPL 199 603 - X, K/W Y : - LF, R O 169.119

2211-29685 6/11/2010 PIPL 230 303 - X, K/W O : - LF, R O 169.321

2211-29688 7/7/2010 PIPL 240 401 - X, K/W K : - LF, R G 169.745

Table 21. Banding and marking records for least tern and piping plover adults on the Central Platte River, 2009–10.—Continued

[Band combinations are reported by leg position (left leg top, left leg bottom: right leg top, right leg bottom), with each leg position including up to two 

bands. Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; t, radio transmitter; Y, yellow; /, split band; V, violet; 

R, red; O, orange; G, green (kelly); L, pastel blue or light blue; C, cobalt blue or bright blue; K, black; W, white; PIPL, piping plover; X, metal; NT, no 

transmitter; P, pink; D, dark green (not used)]
36 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Table 22. Banding and marking records for least tern and piping plover chicks on the Central Platte River, 2009–10. 

[Band combinations are reported by leg position (left leg top, left leg bottom : right leg top, right leg bottom), with each leg position including up to two bands. 

Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; X, metal; UNK, unknown; L= pastel blue or light blue; V, violet; 

/, split band; K, black; O, orange; W, white; C, cobalt blue or bright blue; G, green (kelly); R, red; Y, yellow; PIPL, piping plover; F, flag; P, pink; D, dark green 

(not used)]

Band number Date banded Species River mile Nest number Color band combination

1981-27636 06/16/09 LETE 230.5 204 - -, - - : - -, - X

1981-27634 06/16/09 LETE 230.5 204 - -, - - : - -, - X

1981-27635 06/16/09 LETE 230.5 204 - -, - - : - -, - X

1981-27661 06/26/09 LETE 230 UNK - L, - V : - V/K, - X

1981-27654 06/26/09 LETE 230 UNK - L, - K : - V/K, - X

1981-27619 06/26/09 LETE 230.5 UNK - L, - O : - V/K, - X

1981-27623 06/26/09 LETE 230.5 UNK - V, - W : - V/K, - X

1981-27656 06/26/09 LETE 230.5 213 - L, - L : - V/K, - X

1981-27662 06/26/09 LETE 230.5 213 - L, - C : - V/K, - X

1981-27684 06/26/09 LETE 250.5 UNK -V, - G : - V/K, - X

1981-27620 06/26/09 LETE 250.5 UNK -V, - L : - V/K, - X

1981-27622 06/26/09 LETE 250.5 UNK -V, -V : - V/K, - X

1981-27624 06/26/09 LETE 250.5 113 -V, - C : - V/K, - X

1981-27618 06/26/09 LETE 250.5 113 -V, - K : - K/V, - X

1981-27675 06/26/09 LETE 250.5 UNK - L, - R : - V/K, - X

1981-27684 06/25/09 LETE 250.5 UNK - V, - G : - V/K, - X

1981-22000 06/28/09 LETE 250.5 117 - -, - - : - -, - X

1981-21992 06/28/09 LETE 250.5 117 - -, - - : - -, - X

1981-21990 07/01/09 LETE 250.5 119 - L, - W : - V/K, - X

1981-27625 07/08/09 LETE 230.5 216 - C, - W : - V/K, - X

1981-21987 07/14/09 LETE 250.5 UNK - -, C K : - -, V/K X

1981-27533 07/14/09 LETE 250.5 UNK - -, C V : - -, V/K X

1981-21994 07/14/09 LETE 250.5 UNK - -, C C : - -, V/K X

1981-21992 07/14/09 LETE 250.5 117 - -, C L : - -, V/K X

1981-21988 07/14/09 LETE 250.5 UNK - -, C G : - -, V/K X

1981-21985 07/14/09 LETE 250.5 UNK - -, C R : - -, V/K X

1981-22000 07/14/09 LETE 250.5 117 - -, C O : - -, V/K X

1981-21993 07/14/09 LETE 250.5 UNK - -, W W : - -, V/K X

1981-21997 07/15/09 LETE 230.5 UNK -W, - K : - V/K, - X

1981-21989 07/17/09 LETE 230.5 UNK -W, -V : - V/K, - X

1981-21984 07/17/09 LETE 230.5 UNK - W, - C : - V/K, - X

1981-27535 07/17/09 LETE 230.5 UNK - W, - L : - V/K, - X

1981-27655 07/21/09 LETE 205 403 - W, - G : - V/K, - X

1981-27659 07/21/09 LETE 205 403 - W, - O : - V/K, - X

1981-21995 07/23/09 LETE 230.5 UNK - -, W R : - V/K, - X

1981-21991 07/23/09 LETE 230.5 226 - K/V, - W : - W, - X

1981-36333 07/23/09 LETE 230.5 UNK - K/V, - K : - W, - X

1981-36332 07/23/09 LETE 230.5 UNK - K/V, - V : - W, - X

1981-27625 07/22/09 LETE 230.5 216 - -, C W : - V/K, - X
Tables 14–22 37

Band number Date banded Species River mile Nest number Color band combination

1981-36319 06/18/10 LETE 230.5 213 - K/V, - C : - C, - X

1981-36320 06/19/10 LETE 230.5 216 - K/V, - C : - G, - X

1981-36321 06/19/10 LETE 230.5 216 - K/V, - C : - K, - X

1981-36323 06/19/10 LETE 230.5 210 - K/V, - C : - L, - X

1981-36327 06/19/10 LETE 230.5 210 - K/V, - C : - O, - X

1981-36324 06/21/10 LETE 250.5 105 - K/V, - C : - R, - X

1981-36325 06/21/10 LETE 250.5 105 - K/V, - C : - V, - X

1981-36331 06/21/10 LETE 230.5 212 - K/V, - C : - W, - X

1981-36326 06/21/10 LETE 230.5 212 - Y, - X : - K/V, - C

1981-36330 06/21/10 LETE 230.5 211 - K/V, - G : - C, - X

1981-36329 06/21/10 LETE 230.5 211 - K/V, - G : - G, - X

1981-36328 06/21/10 LETE 230.5 UNK - K/V, - G : - K, - X

1981-36455 06/21/10 LETE 230.5 208 - K/V, - G : - L, - X

1981-36456 06/21/10 LETE 230.5 UNK - K/V, - G : - O, - X

1981-36439 06/22/10 LETE 230.5 212 - K/V, - G : - R, - X

1981-36440 06/22/10 LETE 230.5 UNK - K/V, - G : - V, - X

1981-36442 06/23/10 LETE 250.5 115 - K/V, - G : - W, - X

1981-36451 06/23/10 LETE 250.5 109 - K/V, - G : - Y, - X

1981-36450 06/23/10 LETE 250.5 109 - K/V, - K : - C, - X

1981-36445 06/23/10 LETE 250.5 106 - K/V, - K : - G, - X

1981-36446 06/23/10 LETE 250.5 106 - K/V, - K : - K, - X

1981-36447 06/23/10 LETE 250.5 106 - K/V, - K : - L, - X

1981-36448 06/23/10 LETE 250.5 104 - K/V, - K : - O, - X

1981-36449 06/23/10 LETE 250.5 105 - K/V, - K : - R, - X

1981-36454 06/25/10 LETE 250.5 110 - K/V, - K : - V, - X

1981-36453 06/25/10 LETE 250.5 110 - K/V, - K : - Y, - X

1981-36452 06/25/10 LETE 250.5 UNK - K/V, - L : - C, - X

1981-36357 06/25/10 LETE 250.5 UNK - K/V, - L : - G, - X

1981-36366 06/25/10 LETE 250.5 UNK - K/V, - L : - K, - X

1981-36367 06/25/10 LETE 230.5 218 - K/V, - L : - L, - X

1981-36368 06/25/10 LETE 230.5 218 - K/V, - L : - O, - X

1981-36369 06/25/10 LETE 230.5 214 - K/V, - L : - R, - X

1981-36383 06/27/10 LETE 250.5 120 - K/V, - L : - V, - X

1981-36378 06/28/10 LETE 250.5 113 - K/V, - L : - W, - X

1981-36379 06/28/10 LETE 250.5 UNK - K/V, - L : - Y, - X

1981-36380 06/28/10 LETE 250.5 UNK - K/V, - O : - C, - X

1981-36381 06/28/10 LETE 250.5 UNK - K/V, - O : - G, - X

1981-36382 06/28/10 LETE 250.5 UNK - K/V, - O : - K, - X

1981-36384 06/30/10 LETE 230.5 UNK - K/V, - O : - L, - X

Table 22. Banding and marking records for least tern and piping plover chicks on the Central Platte River, 2009–10.—Continued

[Band combinations are reported by leg position (left leg top, left leg bottom : right leg top, right leg bottom), with each leg position including up to two bands. 

Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; X, metal; UNK, unknown; L= pastel blue or light blue; V, violet; 

/, split band; K, black; O, orange; W, white; C, cobalt blue or bright blue; G, green (kelly); R, red; Y, yellow; PIPL, piping plover; F, flag; P, pink; D, dark green 

(not used)]
38 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Band number Date banded Species River mile Nest number Color band combination

1981-36385 06/30/10 LETE 250.5 UNK - K/V, - O : - O, - X

1981-36387 06/30/10 LETE 250.5 UNK - K/V, - O : - X, - R

1981-36388 06/30/10 LETE 250.5 UNK - K/V, - O : - X, -V

1981-36390 07/03/10 LETE 230.5 UNK - K/V, - O : - Y, - X

1981-36389 07/03/10 LETE 230.5 UNK - K/V, - O : - W, - X

1981-36395 07/03/10 LETE 250.5 118 - K/V, - R : - G, - X

1981-36397 07/03/10 LETE 250.5 118 - K/V, - R : - K, - X

1981-36394 07/03/10 LETE 250.5 120 - K/V, - R : - C, - X

1981-36398 07/06/10 LETE 250.5 121 - K/V, - R : - L, - X

1981-36399 07/06/10 LETE 250.5 UNK - K/V, - R : - Y, - X

1981-36404 07/06/10 LETE 214 503 - K/V, - V : - C, - X

1981-36405 07/06/10 LETE 214 503 - K/V, - V : - G, - X

1981-36400 07/08/10 LETE 230.5 221 - K/V, - R : - O, - X

1981-36401 07/08/10 LETE 230.5 221 - K/V, - R : - R, - X

1981-36471 07/12/10 LETE 250.5 UNK - K/V, - V : - R, - X

1981-36470 07/14/10 LETE 250.5 123 - K/V, - R : - W, - X

1981-36469 07/14/10 LETE 250.5 123 - K/V, - R : - V, - X

1981-36468 07/16/10 LETE 181 UNK - K/V, - V : - K, - X

1981-36467 07/16/10 LETE 181 UNK - -, K/V V : - -, L X

1981-36318 07/16/10 LETE 181 UNK - -, K/V W : - R, - X

1981-36317 07/16/10 LETE 181 UNK - K/V, - W : - V, - X

1981-36417 07/16/10 LETE 181 UNK - K/V, - Y : - -, R X

1981-36466 07/20/10 LETE 250.5 UNK - -, K/V V : - O, - X

1981-36465 07/23/10 LETE 250.5 126 - K/V, - V : - V, - X

1981-36460 07/24/10 LETE 250.5 126 - K/V, - W : - K, - X

1981-36462 07/24/10 LETE 250.5 125 - K/V, - W : - G, - X

1981-36461 07/25/10 LETE 250.5 125 - K/V, - V : - Y, - X

1981-36316 07/27/10 LETE 181 UNK - -, K/V Y : - -, O X

1981-36315 07/27/10 LETE 181 UNK - K/V, - Y : - G, - X

1981-36458 07/28/10 LETE 214 504 - K/V, - W : - C, - X

1981-36459 07/29/10 LETE 214 504 - K/V, - W : - L, - X

1981-36424 07/31/10 LETE 214 504 - K/V, - W : - O, - X

1981-36423 08/01/10 LETE 230 307 - K/V, - W : - Y, - X

1981-36421 08/01/10 LETE 230 307 - K/V, - Y : - V, - X

1981-36431 07/30/10 LETE 181 UNK - -, K/V Y : - -, C X

1981-36456 06/25/10 LETE 230.5 UNK - -, - G : - O, - X

1981-36383 06/28/10 LETE 250.5 120 - K/V, - L : - V, - X

1981-36378 07/06/10 LETE 250.5 113 - -, K/V L : - -, W X

Table 22. Banding and marking records for least tern and piping plover chicks on the Central Platte River, 2009–10.—Continued

[Band combinations are reported by leg position (left leg top, left leg bottom : right leg top, right leg bottom), with each leg position including up to two bands. 

Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; X, metal; UNK, unknown; L= pastel blue or light blue; V, violet; 

/, split band; K, black; O, orange; W, white; C, cobalt blue or bright blue; G, green (kelly); R, red; Y, yellow; PIPL, piping plover; F, flag; P, pink; D, dark green 

(not used)]
Tables 14–22 39

Table 22. Banding and marking records for least tern and piping plover chicks on the Central Platte River, 2009–10.—Continued

[Band combinations are reported by leg position (left leg top, left leg bottom : right leg top, right leg bottom), with each leg position including up to two bands. 

Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; X, metal; UNK, unknown; L= pastel blue or light blue; V, violet; 

/, split band; K, black; O, orange; W, white; C, cobalt blue or bright blue; G, green (kelly); R, red; Y, yellow; PIPL, piping plover; F, flag; P, pink; D, dark green 

(not used)]

Band number Date banded Species River mile Nest number Color band combination

1981-36455 07/06/10 LETE 230.5 208 - -, K/V G : - -, L X

1981-36440 07/09/10 LETE 230.5 UNK - -, K/V G : - -, V X

1981-36383 07/10/10 LETE 250.5 120 - -, K/V L : -V, - X

1981-36388 07/10/10 LETE 250.5 UNK - -, K/V O : - X, -V

1981-36394 07/10/10 LETE 250.5 120 - -, K/V R : - C, - X

1981-36366 07/10/10 LETE 250.5 UNK - -, K/V L : - -, K X

1981-36442 07/10/10 LETE 250.5 115 - -, K/V G : - -, W X

1981-36454 07/10/10 LETE 250.5 110 - -, K/V K : - -, V X

1981-36387 07/10/10 LETE 250.5 UNK - -, K/V O : - X, - R

1981-36383 07/12/10 LETE 250.5 120 - -, K/V L : - -, V X

1981-36385 07/12/10 LETE 250.5 UNK - -, K/V O : - -, O X

1981-36394 07/12/10 LETE 250.5 120 - -, K/V R : - -, C X

1981-36399 07/12/10 LETE 250.5 UNK - -, K/V R : - Y, - X

1981-36399 07/15/10 LETE 250.5 UNK - -, K/V R : - -, Y X

1981-36466 07/21/10 LETE 250.5 UNK - -, K/V V : - -, O X

1981-36470 07/27/10 LETE 250.5 123 - -, K/V R : - -, W X

1981-36327 06/21/10 LETE 230.5 210 - K/V, - C : - O, - X

1981-36455 06/22/10 LETE 230.5 208 - K/V, - G : - L, - X

1981-36455 06/23/10 LETE 230.5 208 - K/V, - G : - L, - X

1981-36450 06/25/10 LETE 250.5 109 - K/V, - K : - C, - X

1981-36451 06/25/10 LETE 250.5 109 - K/V, - G : - Y, - X

1981-36461 07/26/10 LETE 250.5 125 - K/V, -V : - Y, - X

1981-36460 07/27/10 LETE 250.5 126 - K/V, - W : - K, - X

2301-46486 05/30/09 PIPL 230.5 200 - LF, R C : - X, Y Y

2301-46493 05/30/09 PIPL 230.5 200 - LF, K O : - X, Y Y

2301-46482 06/03/09 PIPL 230 300 - LF, K R : - X, Y Y

2301-46476 06/03/09 PIPL 230 300 - LF, K K : - X, Y Y

2301-46494 06/03/09 PIPL 230 300 - LF, K C : - X, Y Y

2301-46471 06/05/09 PIPL 230 301 - LF, G V/P : - X, G C

2301-46478 06/05/09 PIPL 230 301 - LF, G P/V : - X, R C

2301-46490 06/01/09 PIPL 250.5 100 - LF, O R : - X, Y Y

2301-46498 06/01/09 PIPL 250.5 100 - LF, O G : - X, Y Y

2301-46499 06/01/09 PIPL 250.5 100 - LF, O O : - X, Y Y

2301-46497 06/01/09 PIPL 250.5 100 - LF, O K : - X, Y Y

2301-46495 06/08/09 PIPL 250.5 102 - LF, G V/P : - X, C O

2301-46488 06/08/09 PIPL 250.5 102 - LF, G V/P : - X, C C

2301-46477 06/16/09 PIPL 230.5 UNK - LF, G V/P : - X, K K

2301-46483 06/16/09 PIPL 230.5 UNK - LF, G V/P : - X, K C
40 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Band number Date banded Species River mile Nest number Color band combination

2301-46479 06/16/09 PIPL 230.5 UNK - LF, G V/P : - X, G O

2301-46481 06/16/09 PIPL 230.5 UNK - LF, G V/P : - X, G R

2301-46485 06/16/09 PIPL 230.5 200 - LF, G V/P : - X, G K

2301-46462 06/22/09 PIPL 205 400 - LF, G R : - X, Y Y

2301-46463 06/22/09 PIPL 205 400 - LF, G G : - X, Y Y

2301-46464 06/22/09 PIPL 205 400 - LF, G O : - X, Y Y

2301-46468 06/26/09 PIPL 250.5 UNK - LF, G K : - X, Y Y

2301-46451 06/26/09 PIPL 250.5 UNK - LF, G C : - X, Y Y

2301-46455 06/26/09 PIPL 250.5 UNK - LF, R R : - X, Y Y

2301-46469 06/26/09 PIPL 230.5 UNK - LF, R G : - X, Y Y

2301-46401 05/23/10 PIPL 250.5 101 - LF, C C : - X, K/W O

2301-46402 05/23/10 PIPL 250.5 101 - X, K/W K : - LF, C C

2301-46403 05/23/10 PIPL 250.5 101 - X, K/W L : - LF, C C

2301-46466 05/25/10 PIPL 250.5 101 - X, K/W L : - LF, C C

2301-46465 05/25/10 PIPL 230.5 204 - X, K/W C : - LF, C R

2301-46467 05/25/10 PIPL 230.5 204 - X, K/W R : - LF, C R

2301-46404 05/25/10 PIPL 230.5 204 - X, K/W G : - LF, C R

2301-46405 05/25/10 PIPL 230.5 204 - X, K/W O : - LF, C R

2301-46466 05/26/10 PIPL 250.5 101 - X, K/W L : - LF, C G

2301-46458 05/31/10 PIPL 250.5 102 - X, K/W K : - LF, C R

2301-46457 05/31/10 PIPL 250.5 102 - X, K/W Y : - LF, C R

2301-46456 06/01/10 PIPL 250.5 102 - X, K/W L : - LF, C R

2301-46454 06/01/10 PIPL 250.5 102 - X, K/W C : - LF, C G

2301-46406 06/07/10 PIPL 230.5 UNK - X, K/W R : - LF, C G

2301-46407 06/07/10 PIPL 230.5 UNK - X, K/W G : - LF, C G

2301-46408 06/07/10 PIPL 230.5 UNK - X, K/W O : - LF, C G

2301-46409 06/07/10 PIPL 230.5 UNK - X, K/W K : - LF, C G

2301-46410 06/09/10 PIPL 230.5 UNK - X, K/W Y : - LF, C G

2301-46411 06/09/10 PIPL 230.5 UNK - X, K/W C : - LF, C L

2301-46412 06/09/10 PIPL 230.5 UNK - X, K/W R : - LF, C L

2301-46413 06/09/10 PIPL 230.5 UNK - X, K/W G : - LF, C L

2301-46453 06/11/10 PIPL 214 UNK - X, K/W O : - LF, C L

2301-46415 06/10/10 PIPL 214 UNK - X, K/W K : - LF, C L

2301-46452 06/10/10 PIPL 214 UNK - X, K/W L : - LF, C L

2211-29687 06/17/10 PIPL 230.5 206 - X, K/W K : - LF, C O

2211-29692 06/17/10 PIPL 199 603 - X, K/W C : - LF, C K

2211-29691 06/17/10 PIPL 199 603 - X, K/W R : - LF, C K

2211-29690 06/17/10 PIPL 199 603 - X, K/W G : - LF, C K

Table 22. Banding and marking records for least tern and piping plover chicks on the Central Platte River, 2009–10.—Continued

[Band combinations are reported by leg position (left leg top, left leg bottom : right leg top, right leg bottom), with each leg position including up to two bands. 

Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; X, metal; UNK, unknown; L= pastel blue or light blue; V, violet; 

/, split band; K, black; O, orange; W, white; C, cobalt blue or bright blue; G, green (kelly); R, red; Y, yellow; PIPL, piping plover; F, flag; P, pink; D, dark green 

(not used)]
Tables 14–22 41

Table 22. Banding and marking records for least tern and piping plover chicks on the Central Platte River, 2009–10.—Continued

[Band combinations are reported by leg position (left leg top, left leg bottom : right leg top, right leg bottom), with each leg position including up to two bands. 

Examples: YF is yellow flag; V/W is violet over white split band. LETE, least tern; -, no band; X, metal; UNK, unknown; L= pastel blue or light blue; V, violet; 

/, split band; K, black; O, orange; W, white; C, cobalt blue or bright blue; G, green (kelly); R, red; Y, yellow; PIPL, piping plover; F, flag; P, pink; D, dark green 

(not used)]

Band number Date banded Species River mile Nest number Color band combination

2211-29689 06/17/10 PIPL 199 603 - X, K/W O : - LF, C K

2301-46414 06/18/10 PIPL 214 UNK - X, K/W Y : - LF, C L

2301-46450 06/18/10 PIPL 214 UNK - X, K/W C : - LF, C O

2301-46416 06/18/10 PIPL 230.5 206 - X, K/W R : - LF, C O

2301-46417 06/18/10 PIPL 230.5 206 - X, K/W G : - LF, C O

2211-29687 06/18/10 PIPL 230.5 206 - X, K/W K : - LF, C O

2301-46449 06/19/10 PIPL 230.5 205 - X, K/W O : - LF, C O

2301-46448 06/19/10 PIPL 230.5 205 - X, K/W L : - LF, C O

2301-46447 06/19/10 PIPL 230.5 205 - X, K/W Y : - LF, C O

2301-46446 06/19/10 PIPL 230.5 205 - X, K/W K : - LF, C K

2301-46445 06/19/10 PIPL 230.5 206 - X, K/W L : - LF, C K

2301-46444 06/21/10 PIPL 230 302 - X, K/W Y : - LF, C K

2301-46443 06/21/10 PIPL 230 302 - X, K/W C : - LF, R C

2301-46418 06/25/10 PIPL 230 303 - X, K/W G : - LF, R C

2301-46442 06/25/10 PIPL 230 303 - X, K/W R : - LF, R C

2301-46441 06/25/10 PIPL 230 303 - X, K/W O : - LF, R C

2301-46419 06/27/10 PIPL 230.5 207 - X, K/W K : - LF, R C

2301-46440 06/28/10 PIPL 230 303 - X, K/W Y : - LF, R C

2301-46421 06/30/10 PIPL 230.5 UNK - X, K/W C : - LF, R R

2301-46422 07/03/10 PIPL 199 606 - X, K/W R : - LF, R R

2301-46439 07/06/10 PIPL 250.5 112 - X, K/W O : - LF, R R

2301-46423 07/06/10 PIPL 250.5 112 - X, K/W K : - LF, R R

2301-46420 07/06/10 PIPL 230.5 UNK - X, K/W L : - LF, R C

2301-46424 07/07/10 PIPL 250.5 112 - X, K/W L : - LF, R R

2301-46425 07/08/10 PIPL 199 606 - X, K/W Y : - LF, R R

2301-46437 07/08/10 PIPL 199 606 - X, K/W C : - LF, R G

2301-46432 07/09/10 PIPL 230.5 205 - X, K/W R : - LF, R G

2301-46430 07/27/10 PIPL 181 UNK - X, K/W K : - LF, R L

2301-46427 07/27/10 PIPL 181 UNK - X, K/W L : - LF, R L

2301-46436 07/27/10 PIPL 181 UNK - X, K/W G : - LF, R G

2301-46434 07/27/10 PIPL 181 UNK - X, K/W O : - LF, R G

2301-46433 07/20/10 PIPL 240 401 - X, K/W C : - LF, R L

2301-46431 07/21/10 PIPL 240 401 - X, K/W G : - LF, R L

2301-46426 07/21/10 PIPL 240 401 - X, K/W O : - LF, R L

2301-46429 07/21/10 PIPL 240 401 - X, K/W R : - LF, R L

2301-46435 07/30/10 PIPL 181 UNK - X, K/W Y : - LF, R L

2211-29700 07/30/10 PIPL 181 UNK - X, K/W L : - LF, R G

2301-46428 07/30/10 PIPL 181 UNK - X, K/W C : - LF, R O

Appendixes 1–4
44 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Appendix 1. Behavior Sampling 

Protocol

The goal for behavior sampling of least terns and piping 

plovers is to identify the (1) proportion of time spent foraging, (2) estimate the rates of foraging behaviors (plovers), (3) 

habitats used for foraging, and (4) success rates of foraging 

(terns only).

Access and Timing of Behavioral Observations

Behavioral observation sessions should occur within a 

4-hour (h) interval (0600–1000, 1200–1600, and 1700–2000 

h). Sessions should be allocated systematically to ensure that 

each location/pair is at least observed during each interval 

once every 2 weeks. However, if a session is missed, the next 

session should occur at the same time as the missed session to 

maintain balance in sessions among intervals. 

Observers should take a path to the blind/observation 

location that minimizes disturbance to least terns and piping plovers. Sessions should not commence until 5 minutes 

(min) have passed since the observer attained position and the 

observer can determine presence is no longer disturbing the 

birds. If a plover moves out of view during focal bird sampling and the observer is able to quickly reposition to maintain observations on the bird, a 5-min no observation interval 

should be added after the observer has repositioned. 

State Behavior Categories

State behaviors will be observed and recorded into statebehavior categories for least terns (LETE) and piping plovers 

(PIPL) on 5-min intervals. Scan sampling techniques will be 

used for least terns and focal animal sampling for piping plovers. At the beginning of the 5-min interval, observers should 

take 5 seconds to assess the state of each bird visible because 

some states may require up to 5 seconds to identify (foraging). 

If any foraging behaviors are observed during the bird specific 

5-second scan, code the state as foraging (even if the foraging 

behavior is very brief), otherwise, record the dominant behavior for the 5-second interval. 

Below are lists of state behaviors (pecking, hover) 

grouped into the categories for data entry (foraging):

1. Foraging: 

PIPL: pecking, gleaning (pecking food from vegetation), foot trembling (gently shakes/trembles extended foot on 

substrate).

LETE: hovering, plunging or diving over water (including dives that don’t conclude in a plunge), consumption of 

food item. 

2. Transport/Deliver Food (LETE only): Carrying food 

items (movement through the field of view when diving 

is not observed), delivering food items to other adults, 

delivering food items to chicks (delivering may occur on 

the ground or by dropping food items from the air). 

3. Active Territorial/Parental Care: Active attendance of 

site or brood (fight, chase, dive directed at another animal, 

mobile guarding often associated with a call to chicks, 

broken wing display). 

4. Stationary Parental Care: Parental care directed at 

chicks or eggs that is not associated with movement, 

including incubation, and brooding and shading chicks.

5. Locomotion: Any movement from one location to 

another (running, walking, flying), excluding Foraging 

and Territorial/Parental Care behaviors. For least terns, 

locomotion does not include any flight when carrying fish.

6. Active: Active stationary behaviors (preen, bathe, courtship, copulation). Breast-wetting of least terns should be 

included in Locomotion. 

7. Inactive/Rest: Inactive stationary behaviors, excluding 

Parental Care behaviors (sleep, rest, including alert resting).

8. Out of View (PIPL only): Bird is in area, but view is 

obstructed and state behavior cannot be assessed.

9. Missing (PIPL only): Bird leaves observation area.

Least Tern (LETE) Protocols

Behavioral observations will be conducted at two main 

types of locations within a nesting colony (sandbar or sandpit) 

and on noncolony riverine or sandpit sites that are used by 

LETE. Colony nesting sites are static and include those outlined in the study plan as well as additional sites selected by 

the crew leader and principal investigators (PIs). Noncolony 

riverine or sandpit sites will be identified by traveling the river 

and looking for aggregations of LETE and by examining data 

from telemetry dataloggers located outside colonies.

LETE colony observation sessions will be up to 3 h long, 

the duration of sessions will be based on the following: (1) if 

there is only one pair/nest visible from a given location then 

sessions should be 1 h; (2) if other pair(s) in the same colony 

can be observed in the same location add 1 h to the session for 

each additional pair visible (up to 3 h); and (3) if other pair(s), 

in the same colony can be visible from different location(s), 

then observe up to 3 pairs/nests for 1-h sessions each. 

Observers will conduct scan sampling on 5-min intervals; 

recording the number of adult LETE visible that are engaged 

in each state (see behavioral states). The interim time between 

each scan will be used differently depending on whether the 

observation is conducted at a colony site or a noncolony site. 

Noncolony sites–In the interim time between each scan 

(3 min), select any visible-foraging adult (if more than one in 
Appendix 1. Behavior Sampling Protocol 45

view, randomly select with a coin, dice, or random number 

function on an electronic device (such as a mobile phone), if 

none in view continue watching until one forages in view or 

interval is over), and record number of all occurrence (AO) 

behaviors for that selected adult, ignoring AO behaviors by 

any other adults in the area. If the adult leaves the area (with 

or without a prey item) or stops foraging (30 seconds without 

an AO), then reselect another foraging adult to observe; record 

when a new adult is selected. Conduct each subsequent observation interval the same as described above. 

• LETE noncolony AO behaviors:

• Hover (hovering briefly over water)

• Plunge nonsuccess (includes dives that do not end in a 

plunge)

• Plunge Success (prey item visible in bill; record length 

class for captured prey item)

• Plunge unknown

• Eat (consumed captured prey item)

• Out of view (individual is partially hidden and AO 

behaviors cannot be determined)

• Carry out of area (leaves area with captured prey item 

in bill)

• Leave area 

Colony sites–The type of observation, done in the interim 

time between scans, will alternate between two different types: 

(1) observations of forage deliveries and (2) observations of 

forage behavior. For example, the first interval will be devoted 

to observing the colony for forage deliveries by adults, the 

second will be used to observe foraging behavior, and the third 

will be used for forage deliveries by adults, and so on. If on 

colony sites there is no ability to observe potential foraging 

locations, or it is apparent that no visible foraging occurs, then 

only conduct forage delivery observations. 

Forage Deliveries–For the 3-min interval, watch the 

whole colony for all forage deliveries to chicks or adults. Categorize each delivery by recipient (adult, chick, or unknown) 

and location of foraging (in view, out of view, or unknown). 

Foraging Behavior–In the interim time between each 

scan (3 min), select any visible-foraging adult (if more than 

one in view, randomly select with a coin, dice, or PDA function, if none in view continue watching until one forages in 

view or interval is over), and record the colony AO behaviors 

for that selected adult. If the adult leaves the area (with or 

without a prey item) or stops foraging (for at least 30 seconds), 

then select another foraging adult to observe; record when a 

new adult is selected. 

• LETE Colony AO foraging behaviors:

• Hover (hovering briefly over water),

• Plunge nonsuccess (includes dives that do not end in a 

plunge),

• Plunge success,

• Plunge unknown,

• Eat (consumed captured prey item),

• Out of view (individual is partially hidden and AO 

behaviors cannot be determined),

• Carry: out of area (leaves area with captured prey item 

in bill),

• Leaves area, 

• Forage delivery to adult,

• Forage delivery to chick, and

• Forage delivery; recipient unknown.

For all foraging AO recording intervals when a foraging 

AO is recorded (hovers and plunges), also record the habitat 

class associated with the behavior. 

• LETE foraging habitat class (predominate type within 

10-20 meters [m]):

• Sandpit,

• Main channel,

• Secondary channel, and

• Braided/dendritic channel (includes shallow-water 

areas near tails of sandbars).

During AO observations, map all locations where foraging was observed (see below). If it is a forage sampling day 

then sample fish at the most recent successful foraging location observed and at two random locations (see fish sampling 

protocol). 

Piping Plover (PIPL) Protocols

The position of each PIPL adult and accompanying brood 

(if applicable) will be monitored. Behavioral observations on 

PIPL will be focused on individual adults, pairs, or adult(s) 

with broods (hereafter focal unit). Thus, observations will be 

conducted from movable blinds that are relocated specifically 

to watch the targeted focal unit, regardless of location (river or 

sandpit). When possible use hand-held telemetry units to help 

locate targeted adults, so that observers can position themselves for observation in a way that minimizes disturbance. 

Each session will last 1 h per focal unit. Three hours 

are allocated for behavioral sampling so that up to three 

focal units can be sampled per day of field work. Observers will record behavioral states and habitat classes for each 

individual within the focal group on 5-min intervals. Each 

individual (adult and chick) should be observed for 5 seconds 
46 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

to determine the dominant behavioral state (see above classes), 

with behaviors being linked to marked individuals if possible. 

If any foraging behavior (no matter how brief) is observed 

during the 5-second observation period, the period should be 

classified as foraging. Otherwise, the dominant behavior class 

occurring during the 5-second period should be recorded. If 

the focal observation interval is classified as foraging, the 

location of the bird should be spot mapped. 

If marks are not present or cannot be readily observed, 

record each individual as unknown adult or unknown chick. 

This type of sampling may be most easily conducted by two 

people, with one continually observing through a spotting 

scope to track individuals and verbally calling out data to the 

second crew member. 

Habitat Classes (dominant classes within the 

foraging area)

Landform

1. River shoreline

2. Sandbar

3. Sandpit

Moisture

1. Dry substrate

2. Wet substrate

Vegetation

1. Bare (less than 30 percent)

2. Sparse (31–50 percent)

3. Vegetated (greater than 50 percent)

In the interim time between all focal observation intervals, the observer will record all pecks (including gleans) for 

a 3-min. interval on a randomly selected adult or chick (using 

a dice or PDA function). Record when an individual goes out 

of view or when that individual returns into view. Randomly 

select (from all visible individuals within the focal unit) a new 

adult or chick (alternating between adults and chicks for each 

peck-recording interval). If it is a forage sampling day, forage 

will be sampled at the most recent observed foraging location and at two random locations (see Invertebrate Sampling 

Protocol).

Noncolony observations of foraging piping plovers will 

be obtained if the opportunity is available. The data collection approach is identical to colony locations, and the data 

card will reflect that a noncolony site with zero known nests/

broods was sampled. Opportunities to collect these data might 

occur at unexpected times (such as when collecting other types 

of data, when floating the river, when checking telemetry 

stations, during noncolony tern behavior observations). These 

kind of data will be informative regarding the birds’ choices of 

foraging habitat, so it would be worthwhile to spend the extra 

time collecting the data when opportunities arise.

Active Nests/Surviving Broods

During each session, the number of known active nests/

broods in the area will be recorded. For colony sites, this 

will be the number for the species within the colony, not just 

the number visible from a behavior data-collection location. 

For noncolony locations where foraging terns or plovers are 

observed, it is also important to record zero known active 

nests/broods in the area to identify these areas as off-colony 

foraging locations.

Spot Mapping

For piping plovers, each time a foraging state behavior is 

recorded, the location will be spot mapped. It will be impossible and not necessary to spot map each time foraging AOs 

(for example, pecks) are recorded for plovers.

For least terns, each time a plunge or dive is recorded 

as an AO, an attempt will be made to spot map the location, 

including notation of success/fail/unknown status of the dive. 

However, if the number of unsuccessful dives occurring makes 

this cumbersome, the approach may be modified after discussion with the PIs so that spot mapping is only conducted for 

successful dives.
Appendix 2. Terrestrial Habitat Sampling Protocol 47

Appendix 2. Terrestrial Habitat 

Sampling Protocol

Terrestrial habitat data will be collected in conjunction 

with piping plover forage sampling. A terrestrial habitat quadrat will be deployed at each invertebrate sampling location 

(including plover foraging sites and random points). Because 

collecting the invertebrate data can disturb the substrate 

because of placement of sticks and the exclosure, terrestrial 

habitat data will be collected before invertebrate sampling is 

started.

At each invertebrate sampling location, a 1-square meter 

(m2) quadrat will be centered where the exclosure will be 

located. The following data will be recorded at this quadrat:

Land Cover: Record the dominant class within the quadrat 

(* indicates cover types unlikely to occur at plover foraging 

locations):

Dry sand–Sand substrate with no obvious moisture or 

vegetation,

Wet sand–Areas of moist sand with little or no vegetation,

Sparsely vegetated–Mostly sand substrate with 

30–50 percent vegetation,

Mixed vegetation–Areas of greater than 50 percent vegetation with interspersed visible substrate,

Wetland–Water areas with green vegetation present,

*Submerged sand–Submerged sand substrate visible 

through water, and

*Open water–No substrate visible through water. 

Vegetation Visual Coverage Estimates: Record the adjusted 

Daubenmire cover class (table 2–1) for each of the following 

response variables:

Total woody vegetation–Include all woody species,

Terrestrial herbaceous vegetation–Include all terrestrial 

species, and

Wetland herbaceous vegetation–Include all wetland 

species.

Stem Counts: Record the total count of all woody stems in 

the quadrat, counting each stem as an individual if it protrudes 

independently from the substrate (for example, substrate is 

visible between stems).

Vegetation Height: Record mean and maximum vegetation 

height classes as follows, including all vegetation within the 

quadrat:

Mean height – 1 = 0 – 0.5 meter (m), 2 = 0.5 – 1 m, 3 = 

greater than 1 m

Maximum height – 1 = 0 – 0.5 m, 2 = 0.5 – 1 m, 3 = greater 

than 1 m

Substrate Visual Coverage Estimates: Record the Daubenmire cover class (table 2–1) for each substrate class according 

to its grain size:

Silt less than 0.125 millimeter (mm)

Sand 0.125–2 mm

Small pebble 2–0 mm

Gravel 10–64 mm

Cobble 64–256 mm

Boulder greater than 25.6 centimeter (cm) 

Debris Visual Coverage Estimates: Record the Daubenmire 

cover class (table 2–1) for each debris type according to its 

size:

Terrestrial leaf litter All leaf and grass litter

Wrack less than 2 cm stem diameter

Large debris greater than 2 cm stem diameter; 

 include other debris (trash)

Table 2–1. Daubenmire classification of cover (Sherfy and 

others, 2009).

[>, greater than]

Class Cover range

(percent)

Midpoint

(percent)

0 0 0

1 >0–5 2.5

2 6–15 10

3 16–30 23

4 31–45 38

5 46–70 58

6 71–100 85
48 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

the net, then the fish will be placed in a bucket with adequate 

water to reduce chance of mortality. Fish identification guides 

and taxonomic keys used on the Missouri River are available 

to assist in identification. 

Sandpit Pond Sampling

A canoe will be used to navigate to sampling points on 

sandpit ponds. On windy days, it may be necessary to anchor 

the canoe to maintain location; if so, the anchor will be 

deployed as far upwind as possible and the anchor line will 

be scoped out until the point is reached. Once at a sampling 

point, the following habitat data will be collected: UTM, water 

temperature (± 1 ̊C), turbidity (± 1 NTU), depth (± 0.25 m; 

increment minnow traps and anchor lines for minnow traps 

accordingly), benthic substrate (sand, silt/clay/organic, gravel, 

or greater than 0.75 m deep). 

Minnow traps will be deployed by driving the stake ends 

into the substrate and point lead to the center of the pond, if 

depth is less than 0.75 m, or floated at the surface for points 

with depths greater than 0.75 m. Ensure that minnow traps are 

anchored in place after they are floated, and that the line length 

is only slightly longer than the depth to prevent the trap from 

moving if the wind direction changes. The time the trap was 

deployed will be recorded (± 1 minute). The traps will be left 

in place for 24 hours, retrieved, collection time recorded (± 1 

minute), and samples processed as described above. 

Sampling Equipment

1. Fish Kit 

• Fish identification binders,

• Aquatic habitat description key,

• Fish sampling data cards,

• 2–m pole,

• 50-m float cord (throw ropes),

• Turbidity meter,

• Flow meter,

• Fish sampling pans plus grid laminate sheetsrulers,

• Headband- magnifying loup,

• Thermometer,

• Paper cups,

• Preservative and jars,

• Bucket, 

• Camera,

• Index cards, and 

• GPS.

Appendix 3. Fish Sampling Protocol

The goal of fish sampling is to describe the fish abundance, species and size, and aquatic habitats where terns 

forage in relation to available sites. Sampling will occur on 

successful tern foraging locations and two random points 

will be selected relative to foraging location at the end of the 

evening behavior session (1600–2000). Forage sampling will 

be conducted with minnow traps on sandpit-ponds and miniMissouri River trawls on the river. 

Two random points will be selected within 75 meters (m) 

of the forage location. The two-column random number table 

will be used, to modify the northing and easting (-75 to 75m) 

of the Global Positioning System (GPS) point collected at the 

forage site. Random points will be located by navigating with 

the GPS. If a random point is not within the same habitat class 

as the forage location, the next set of numbers will be selected 

from the tables, and then continue until an appropriate point 

is selected; unsuitable points will be recorded. During river 

sampling, the foraging location will be sampled first, and if 

the sampling path (50 m downstream from the point) overlaps 

with a previous sampling path, then another random point 

will be selected. If river sampling points are unsafe to sample 

(excessive flows or depths greater than 1.5 m) then new sites 

will be selected for random points and sampling for forage 

points will be discontinued. 

River Sampling

The following habitat data will be collected from a sampling point: Universal Transverse Mercator (UTM), water temperature (plus or minus [±] 1 degree Celsius [ ̊C]), turbidity (± 

1 nephelometric turbidity units [NTU]), depth (± 0.1 m), flow 

(± 0.1 meter per second [m/s]), benthic substrate (predominantly: sand, clay/silt/organic, or gravel), and habitat class 

(main channel, secondary channel, braided/dendritic channel).

A 50-m floating line will be used to guide the direction and distance of the trawl. Anchor one end of the floating 

line approximately 2 m from the point, perpendicular to the 

current; a stake or weight will be used to anchor the line. The 

trawl will begin at the sampling point and will be towed downstream by two people spaced approximately 3 m apart; thus, 

one person is within 0.5 m of the floating line. The trawl needs 

to be towed slightly faster than the current; if the trawl-net 

inverts during sampling, the sample will not be counted. Net 

inverts or the trawl failures will be recorded and an attempt 

will be made again on the other side of the floating line. Once 

the trawl is complete, the trawl mouth will be held out of the 

water and the sample processed at a nearby sandbar or shoreline that is not being used by piping plovers or least terns.

All captured fish will be (1) identified to species, (2) total 

length measured (± 1 centimeter), and (3) released as soon as 

possible. The net will be inverted to confirm removal of all 

captured fish and detritus. If too many fish are caught and they 

cannot be measured and identified while being pulled out of 
Appendix 3. Fish Sampling Protocol 49

2. Missouri trawl – clean and mended.

3. Three minnow traps, lines, and anchors (incremented with 

1-m and 25-m hash marks). 
50 Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars

Appendix 4. Invertebrate Sampling 

Protocol

The goal of invertebrate sampling is to describe the invertebrate taxa, abundance, and terrestrial habitats where piping 

plovers forage in relation to available sites. Invertebrate sampling will be conducted using four paint stir sticks coated with 

Tanglefoot (The Tanglefoot Company, Grand Rapids, Michigan) insect trap with two placed horizontally and two placed 

vertically within a 1-square meter exclosure (hereafter, sticky 

sticks). Sampling will occur at both brood-specific-foraging 

locations and two random points selected relative to foraging location at the end of each 1-hour (h) behavior session, if 

foraging was observed (see Behavior Protocol). Invertebrate 

sampling will occur only (1) after behavioral observations during the morning interval (0600–1000 h), and (2) when there 

is minimal chance of rain and wind speeds are expected to be 

below 30 kilometers per hour (18 miles per hour) during the 

sampling period.

Two random points will be selected within 75 meters (m) 

of the forage location; the random points must be the same 

habitat class (for example, landform, moisture, and vegetation 

[appendix 2]) as those of the foraging location. The two-column random number table will be used to modify the northing and easting (-75 to 75m) of the GPS point collected at the 

forage site. For example, if the UTM of the foraging site is 

493,962 by 4,500,757, and the random numbers from the table 

are +18 and -17, then the random point is at UTM 493,980 by 

4,500,740. Random points will be located by navigating with 

the GPS. If a random point is not within the same habitat class 

as those of the forage location then the next set of numbers 

will be selected from the tables; continue until two appropriate 

points are selected; and record number of unsuitable points. 

If a foraging location is within a narrow linear habitat class, 

random point selection will be constrained to the same habitat 

class using the change of easting as the distance from the forage sampling location (positive number move norht or east; 

negative number move south or west). If the random point is 

within 100 m of an active least tern or piping plover nest or 

brood, choose another location.

Habitat characteristics will be taken at each sample site 

prior to collection, following the Riverine Habitat Protocol.

Small exclosures must be used around sticky sticks to 

keep piping plovers and other birds from being entangled 

during sampling. The exclosures will be made of 0.25-m tall 

1-square centimeter (cm2) nylon mesh netting held up in the 

corners by four wooden stakes. The traps consist of four sticky 

sticks (paint stir-sticks thinly covered with 20 centimeters 

(cm) of Tanglefoot ® insect trap). Two sticks will be covered 

on one side of the nonhandle end (horizontal stick) and the 

other sticks will be covered on both sides (vertical stick). The 

vertical sticks will be driven handle first into the ground (with 

a wide side facing into the wind) so that the start of the Tanglefoot is even with the surface of the substrate. The horizontal sticks will be placed flat on the substrate (sticky side up), 

10 cm away from the vertical stick (perpendicular to the direction of the wind). The handle of the sticks will be labeled with 

study area, site, brood/nest number, point type (for example, 

forage or random), stick number (H1, V1, H2, V2), date, and 

time set. The study area, site, brood/nest number, point type, 

date, time set, habitat class, and weather will be recorded on 

the forage sampling data sheet. 

Movements in the immediate area should be avoided to 

prevent invertebrates or sand being driven into traps. The traps 

will be retrieved after 2–3 hours; the end time will be recorded 

on the forage sampling data sheet. Invertebrates on retrieved 

sticks will be identified and counted immediately outside the 

study area. Invertebrates less than 3 millimeters (mm) should 

be counted but not identified. Invertebrates 3 mm or greater 

will be counted and identified to order (all) and to family 

in order Diptera. If unknown invertebrates are encountered, 

reference materials will be consulted for identification; if identification is still unresolved (1) preserve a voucher specimen 

in ethanol, (2) name and label it (for example, “unknown A”), 

and (3) make sure all references in data use the same name, 

especially if the unknown taxon occurs in another sample. 

When invertebrates cannot be counted and identified on the 

same day the sample is collected, sticky sticks will be frozen 

for later identification. 

Sampling will include up to 10 minutes of disturbance 

to chicks and adult plovers during setup of the exclosure, 

sticky sticks, and substrate sampling, a 2–3 h passive sampling 

period when investigators are outside the area, and another 

period up to 10 minutes of potential disturbance to remove the 

exclosure and sticky sticks. 

Equipment list:

• Paint stir sticks,

• Tanglefoot,

• Putty knife,

• At least three exclosures,

• Hammer,

• GPS, and

• Datasheets.
Publishing support provided by: 

Rolla and Lafayette Publishing Service Center 

For more information concerning this publication, contact:

Director, USGS Northern Prairie Wildlife Research Center

8711 37th Street Southeast

Jamestown, North Dakota 58401

(701) 253–5553

Or visit the Northern Prairie Wildlife Research Center Web site at:

http://npwrc.usgs.gov/
Sherfy and others—Foraging Ecology of Least Terns and Piping Plovers Nesting on Central Platte River Sandpits and Sandbars—Open-File Report 2012–1059