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Annual Variation in Seabird Attendance and Productivity on East Amatuli (lsland,

Barren Islands, Alaska: Natural and Human-Induced Effects

Final Report 1992-1994

P. Dee Boersma

Professor

Julia~. Parrish . f

Research AssIstant Professor

Department of Zoology

University ofWashington

Seattle, WA 98195

March 1996

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OCS Study

MMS 96-0005

Annual Variation in Seabird Attendance and Productivity on East Amatuli Island,

Barren Islands, Alaska: Natural and Human-Induced Effects

Final Report 1992-1994

P. Dee Boersma

Professor

Julia K. Parrish

Research Assistant Professor

Department of Zoology

University of Washington

Seattle, WA 98195

submitted to:

Minerals Management Service

Environmnetal Studies Section

949 E. 36th Ave. .

Anchorage AK 99508

March 1996

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PROJECT ORGANIZATION

Principle Investigator:

Dr. P. Dee Boersma

Professor, Zoology Department

University ofWashington

Seattle,WA 98195

Project Manager:

Dr. Julia K. Parrish

Research Asst. Professor, Zoology Department

University of Washington

Seattle, WA 98195

Technician:

Karen Jensen

Student Hourly Employees:

Matt Wasson

Jen Cesca

Trista Patterson

Johanna Salatas

Nick Stathis

Anna Stathis

Jim Walseth

Time-Lapse Camera Consultants:

Polar Alpine Inc.

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The opinions, fmdings, conclu~ions.. 9r recommendations expressed in this report or

product are those of the authorS and do not necessarily reflect the views of the Minerals

Management Service, nor does mention oftrade names or commercial products constitute

endorsement or recommendation for use by the Federal Government.

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TABLE OF CONTENTS

Project Organization iii

Table of Contents iv

List of Figures v

List of Tables vi

Executive Summary 1

Introduction 3

Methods 6

General 6

Common Murre 7

Attendance 7

Reproductive Activity 8

Fork-tailed Stonn-petrel 9

Monitoring Areas 9

Results and Discussion 11

Common Murre 11

Attendance Patterns 11

Reproductive Success 12

Fork-tailed Stonn-petrel 14

Reproductive Success 14

Chick Growth 15

General Discussion 16

Acknowledgments 20

References 21

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LIST OF FIGURES

Figure 1. Map ofstudy island.

Figure 2. Monthly sea surface temperature anomalies, 1975·1991.

Figure 3. Common Murre attendance on four multiple-count plots, 1990-1993.

Figure 4. Common Murre breeding phenology.

Figure 5. Fork-tailed Storm·petrel nest occupancy, 1990·1994.

Figure 6. Fork-tailed Storm-petrel hatching success, 1990-1994.

Figure 7. Fork-tailed Storm-petrel fledging success, 1990-1994.

Figure 8. Fork-tailed Storm-petrel hatching success versus human disturbance.

Figure 9A-E. Fork-tailed Storm-petrel growth curves, 1990-1994.

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LIST OF TABLES

Table 1. Common Murre reproductive success, 1991, 1993, and 1994.

Table 2. Fork-tailed Storm-petrel reproductive success, 1990-1994.

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EXECUTIVE SUMMARY

The Barren Islands, (580 55' N, 1520 W), have the largest seabird breeding

colonies in the North Gulf of Alaska (Bailey 1976). Because they are often abundant,

conspicuous, and relatively high on the food chain, changes in seabird population

dynamics can mirror changes in the bio-physical environment, including food supplies,

oceanographic events such as El Nino-Southern Oscillation (ENSO), and marine

pollution such as oil spills. Not all species will react similarly to a given environmental

change; however, when several species within a single system are considered, patterns of

environmental change may emerge. Aerial and ship-based surveys have shown thatthe

waters surrounding the Barren Islands support a dense assemblage offoraging seabirds.

However, the islands are particularly susceptible to marine perturbations, as evidenced by

the Exxon Valdez oil spill of 1989. Some estimates ofBarren Islands seabird losses

resulting from this spill (e.g. murres) range as high as 50%. From 1990 through 1994, we

monitored the population activity, diet, and reproductive success of two of the most

abundant species ofseabirds in the Barren Islands: Fork-tailed Storm-petrels

(Oceanodromafurcata) and Common Murres (Uria aalge), in order to determine the

degree to which each species responded to known changes in the environment, both

natural and human-induced. For each species, methods were developed to monitor

population activity, phenology, reproductive success, and, in the case of Fork-tailed

Storm-petrels, chick growth. For the most part, methods and censusing sites were based

on OSCEAP studies conducted by Boersma and Manuwal during the late 1970's and

early 1980's. Seabird population monitoring usually commenced by the beginning of

July and ended during the fIrst week in September.

For Common Murres, patterns of population activity were estimated by counting

murres present on four separate nesting areas (approximately 2-3% oftotal island

attendance), after the murres had laid eggs but before chicks had fledged. Phenology was

assessed from the timing of egg production on a 5x5m study plot on the top ofLight

Rock, established in 1977, as well as 35mm time-lapse movie ~ameras set up in 1991,

1993, and 1994. In addition, reproductive success was calculated for all pairs within the

camera plots which could be visually followed. From 1975 through 1979, murre

attendance estimates on East Amatuli Island ranged from a low of 19,000 to a high of

61,000. From 1990 to 1992, we counted between 31,000 and 35,000 murres in

attendance on East Amatuli Island. Attendance in three of the four census areas

increased steadily from 1990 to 1993; in total, attendance rose an estimated 18%

annually. In all years, murres nesting on Light Rock produced eggs and chicks, although

there were differences in both phenology and reproductive success. Egg laying on the 5

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by 5 m plot in 1977 and 1978 was early relative to 1979; the former years are

phenologically comparable to 1993 and 1994, while 1979 is closer to the timing of 1990.

Reproductive success of murres in the time-lapse camera plots ranged from 0.65 to 0.93

fledglings per pair over the 243 pairs followed. Although there has been some concern

that the Exxon Valdez oil spill caused a persistent decline in the reproductive output of

the remaining East Amatuli population, we found no evidence to support or refute this

contention. However, the pre-spill data available for accurate comparison was lacking,

greatly weakening any fInn conclusion about the effects of the spill.

For Fork~tailedStonn-petrels, patterns of population activity were estimated by

assessing occupancy, reproductive success, and chick growth at approximately 650

marked burrows located in six study sites (A~E, Z). Throughout the 1990's, occupancy in

marked nests has hovered between 40 and 50 percent. Hatching success and fledging

success appeared to rise throughout the 1990's to a high of nearly 70% (hatching) and

90% (fledging) in 1994. Both tissue growth rate and weight gain fluctuated throughout

the 1990's. In 1993 and 1994, it took approximately 57 days for the average chick to

grow their wings from 10% (birth) to 90% of adult wingchord length. By contrast, the

average length of time required in 1990 was 68 days, an approximately 20% difference.

Weight gain followed a similar pattern. These dramatic differences in annual growth

may reflect fledging success to some degree, but also reflect the fact that Fork-tailed

Storm-petrel growth is regulated by food supply. Changes in weight gain probably

reflect food quantity, while changes in wingchord growth rate reflect changes in food

quality. Food availability may change on an intraseasonal basis and in an unpredictable

fashion, while food quality may be changing over longer periods of time (e.g. decades).

Because seabirds can modify their behavior and foraging patterns, many species

are able to ameliorate the effects of environmental change, regardless ofsource (Le.

natural or human-induced). For this reason, an understanding of natural biological ,

variation and what causes variation to differ in direction or degree is also needed.

Ainley, Sydeman and Norton (in press) argue thatthe intensity and geographical extent of

the Aleutian Low Pressure System may alter wind patterns, upwelling patterns, and

consequently affect the food supply, thereby affecting seabird reproductive and

population biology in the Farallon Islands. It is interesting to note that in years when

murre reproductive success is high in California, it is low on the Barren Islands. This

"trade-off' effect may represent evidence of alternating strengths and weaknesses in the

Alaska and California current systems, as both originate from the North Pacific Current.

However, this alternating pattern is disrupted in years when the entire Pacific basin is

affected, suggesting that major oceanographic perturbations can dwarf local

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oceanographic trends. Thus, 1992 was a very poor reproductive year for murres in both

the Farallon Islands and the Barren Islands, presumably because of El Nino.

In contrast to most natural perturbations, which can have either negative or

positive impacts, most human perturbations have negative impacts on seabirds. Oil spills

are among the most dramatic human perturbations in the marine environment. Without

long-term monitoring of specific populations, it will be impossible to make blanket

statements about the effects of oil spills on seabird populations, relative to other mortality

agents, whether natural (e.g. ENSO, food availability, winterkill) or anthropogenic (e.g.

gillnet bycatch, direct competition with fisheries, introduced predators). The Barren

Islands data do not appear to shed light on this dilemma, in that although the Exxon

Valdez oil spill killed many thousands of seabirds, it was impossible to detect long-term

differences in response to the spill by Common Murres and Fork-tailed Storm-petrels. In

part, our inability to detect change may be a result of the paucity of information on the

non-breeding, or "at-sea" component of the Barren Islands population. Seabird

populations may be buffered from adverse effects, both natural and human-induced, by

their non-breeding pool. The level ofresilience provided by non-breeders would thus be

affected by the frequency and magnitude of disturbance. Additional human-induced

disturbance in a system already susceptible to broad fluctuations in natural perturbation,

may deplete the built-in reserve offered by non-breeders. Whether this is true, and how

important the non-breeding pool of birds is, remains to be tested.

INTRODUCTION

Many authors argue for the use of seabirds as indicators ofthe marine

environment (Boersma 1986, Furness 1987, Furness & Barrett 1991). Because they are

often abundant, conspicuous, and relatively high on the food chain, changes in seabird

population dynamics can mirror changes in: 1.) the food supply (Piatt 1990, Springer et,

al. 1986); 2.) oceanographic events such as EI Nino-Southern Oscillation (ENSO)

(Boersma 1978, Graybill & Hodder 1985, Wilson 1991, Massey et al. 1992); and 3.)

levels of marine pollution, at the lethal (Piatt et al. 1990) as well as sublethal (Boersma

1986, Gilbertson et al. 1987) levels. It is generally accepted that not all species of

seabirds will react similarly to a single environmental change (Furness & Barrett 1991).

This is because each species has different foraging and nesting behavior, such that

varying aspects of the physicaI/biological environment will impinge directly on each

species' fi~ess. For instance, species with greater flight range may be less susceptible to

changes in the food supply than species with limited range, because the former can adjust

for nearshore food depletion by searching over greater distances from the colony.

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Population-level measurements, such as attendance, diet, hatching success, chick growth

rate, etc. may give us an' integrated, albeit selective, window on the environment.

However, when several species within a single system are considered, patterns of

environmental change may emerge. The Barren Islands, with its abundant resident

seabird colonies, provide such a system within which to quantify environmental change.

Located at the mouth of Cook Inlet, the Barren Islands, (580 55' N, 1520 W), have

the largest seabird breeding colonies in the north Gulf of Alaska (Bailey 1976). East

Amatuli Island, located on the east side ofthe island group (Figure 1), supports a

particularly diverse assemblage of avian fauna that includes surface feeders and pursuit

divers (Bailey 1976). These islands are ideally suited for seabirds due to three

complimentary factors: First, the local topography and physical oceanography result in

upwelling with a concomitant surge' in productivity. Aerial and ship-based surveys have

shown that the waters surrounding the Barren Islands support a dense assemblage of

foraging seabirds (Piatt pers. comm.). Second, the system is not only uninhabited by

man, but is protected as part of the Alaska Maritime National Wildlife Refuge

(AMNWR). Lastly, although the island system supports a small number ofraptors and

river otters, predators are by-and-Iarge absent. The latter two factors minimize

disturbance to breeding habitats. All three factors contribute to the continuing

reproductive success of the Barrens' ~eabirds and also highlight the importance of the

islands as a population center for seabirds in the north Gulf of Alaska. However, the

islands are particularly susceptible to marine perturbations because of their location at the

mouth of Cook Inlet. As evidenced by the Exxon Valdez oil spill, pollutants that are

introduced into Prince William Sound and the north Gulf of Alaska are likely to flow

through the Barren Islands and may linger there for several weeks because of the large

tidal exchange.

From 1990 through 1994, we monitored the population activity, diet, and

reproductive success of two of the most abundant species of seabirds in the Barren

Islands: Fork-tailed Storm-petrels (Oceanodromafurcata) and Common Murres (Uria

aalge). Prior to 1990, extensive data was collected on Fork-tailed Storm-petrels

(Boersma et al. 1980, Boersma unpub. data) and occasional data was collected on murres

(ManuwaI1980). These datasets have allowed determinations of the degree to which

each species responds to known changes in the environment, both natural and humaninduced. For example, Fork-tailed Storm-petrel burrow occupancy (# occupied!#

checked) and egg volumes were significantly lower in 1983 and 1984, years in which an

EI Nino-Southern Oscillation (ENSO) event was known to have affected physical

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oceanography conditions in the Pacific (see chapters in Diaz & Markgraf 1992). During

this period, sea-surface temperature (SST) anomalies in a four-degree sided square

surrounding the Barren Islands were often in excess of 1.0oC (Figure 2). Anomalously

high SST conditions have been associated with downturns in oceanic productivity (Sharp

1992), and thus potentially the food supply of lowerfood chain feeders such as Forktailed Storm-petrels (see references in Wooster & Fluharty 1985, Ainley & Boekelheide

1990). Thus, while not strictly causative, there is a definite, and biologically

interpretable, correlation between a change in the larger physical environment and the

reproductive biology of the seabird species.

Natural variation is not the only source of environmental change. Human-induced

perturbations affect the environment on several scales. At a global level, changes such as

rising cO2 emissions can affect temperature, which in turn may affect both terrestrial and

aquatic productivity (Halpert & Bell 1993). Regionally, human interaction with the

oceanic environment may have produced changes in aquatic community structure due to

fishing pressure (Springer et a1. 1986). Such changes can often have far reaching effects

on the food supply, and thus abundance, ofregional seabird and marine mammal species

(Springer et al. 1986).

Locally, point-source pollution can have a drastic effect on the marine

environment. A case in point is the Exxon Valdez oil spill of 1989 (Piatt et al. 1990).

Approximately 30,000 bird carcasses of 90 species were recovered following this spill

(Piatt et a1. 1990), and current estimates of total bird mortality have run as high as

500,000 (Parrish & Boersma, in press). Because over 70% of the recovered carcasses

were murres, and the Barren Islands murre colonies (located on East Amatuli and Nord

Island, respectively) comprise the largest murre colony in the path of the spill, both

assessment ofthe damage to, and monitoring recovery of, the Barren Islands murre

popula.tion is ofserious scientific and management interest.

While it is possible to ascribe a potential cause, such as the Exxon Valdez oil

spill, to a measured effect, such as a decline in the murre population, in general the

pattern of population activity and reproductive effort of each species is going to be

influenced by a complex combination offorces, both natural and anthropogenic (Hunt

1987). It thus becomes imperative to not only monitor seabird populations, but to also

collect accurate measurements on the physicallbiological environment (Hunt 1987,

Parrish & Boersma 1995). These two pieces must then be superimposed such that

measured environmental change is applicable on a biological scale appropriate to the

species in question. In this context, scale is relevant to both time (as in the average life of

a seabird) and space (as in the foraging range of the bird). For instance, nearshore

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changes in food supply may affect the alcids, (murres and puffins), more than Fork-tailed

Storm-petrels, because the former have a restricted foraging range around the nesting

colony. Thus, localized shortages may affect the diet, and eventually the reproductive

success, ofthese species; Fork-tailed ~torm-petrels may be able to compensate for local

shortages by increasing search distance and time. While this may increase egg neglect

and slow chick growth, reproductive success, measured as fledglings per pair, may be

unaffected. Furthermore, species with limited foraging ranges may be more susceptible,

to marine pollutants such as oil, should the oil cover a broad proportion of the species

foraging range. During the breeding season, murres and Tufted Puffins should

experience the brunt of any oiling in the Barren IsI~ds' area, because their at-sea

distribution is limited to close to the island. Thus, there is potential forpaturally-induced

downturns, such as those caused by changes in food supply, to be synergistically

exacerbated by oiling events.

Because ofthe islands' high vulnerability to oil spill impacts due to its geographic

location at the mouth of the Cook Inlet ( an area of shipping traffic and potential oil and

gas development), a three-year study to monitor the major marine avifauna was funded,

by the Outer Continental ShelfEnvironmental Assessment Program (OCSEAP) from

1977 through 1979 (ManuwaI1980). That study concentrated primarily on three species:

Fork-tailed Storm-petrels, Tufted Puffins and Common Murres. For each species,

methods were developed to monitor population activity, phenology, reproductive success,

and in some cases chick growth. From 1980 through 1984, these studies were continued

under Boersma and concentrated on the Fork-tailed Storm-petrel. Monitoring of the

Fork-tailed Storm-petrel population and, to a lesser extent, Tufted Puffins and Glaucouswinged Gulls (Larus glaucescens) was conducted intermittently 'from 1985-1989 by the

U.S. Fish & Wildlife Service AMNWR staff (Nishimoto et al. 1986, Nishimoto et al.

1987, Nishimoto & Beringer 1988, Nishimoto & O'Reilly 1989). In 1990, Boersma

resumed monitoring, and has continued surveying the seabird activity on East Amatuli

Island through 1994.

METHODS

General

At the beginning of each field season (late June), a crew offield technicians and

volunteers was transported from Homer to East Amatuli. As in previous years, camp was

set up in a depression in the primary dune on the east side of Amatuli Cove. In 1993 and

again in 1994, the camp was expanded to accommodate U. S. Fish & Wildlife

Servicepersonnel. Seabird population monitoring usually commenced by the beginning

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ofJuly and ended during the fIrst week in September. In all years, camp was dismantled

by mid~September. During years in which time-lapse movie cameras were installed on

Light Rock, a brief dismantling trip was made in October. In 1991 and agairi in 1993,

data on Fork-tailed Storm-petrels was also collected during the October visit. In 1994,

three separate visits were made to East Amatuli, en lieu of a permanent fIeld camp. Visit

timing and adverse weather conditions precluded collection of mune population

information. However, these data were collected by US Fish & Wildlife Service

personnel.

Common Murre

Attendance

From 1990 through 1992, island attendance was estimated by counting munes

present on the island after the murres had laid eggs but before chicks had fledged (see

Wanless et al. 1982, Hateh·& Hatch 1989). Counts were made when the water around

the island was relatively calm (seas less than 1 m) and visibility was good. All counts

were restricted to between 1100 Hand 1900 H. Before censuses began, observers

pr~cticed counting selected areas by making independent counts and then comparing

data. The practice area was then censused more closely by both observers counting

together. Independent counts were then made again. Ifthese counts differed by more

than ten percent, the entire process was repeated until the counters agreed which birds

had been missed or invented. Attendance was defIned as the number of murres directly

counted on the cliffs. This fIgure does not take into account the percentage of the

population that was riot present, (i.e. foraging). Therefore, we did not attempt to use the

attendance count to calculate the number of pairs nesting on the island. Instead,

islandwide attendance censuses were used to provide a broad-brush picture of changes in

East Amatuli colony size. In 1993, US Fish & Wildlife Service personnel assumed the

responsibility of estimating island murre attendance.

In addition to the island census, four areas (Oval, Swatch, and Triangle Rock NW

and S, respectively;,Figure 1) were censused several times throughout the day on

different dates throughout the breeding season to provide a more in-depth dataset for the

determination ofinterannual trends (1990-1993). Counts were made as described above.

In 1990-1992, counts were made from beyond the kelp bed (far), at unspecifIed locations

affording a clear view ofthe area. In 1993, counts were made much closer from within

the kelp (near). It is possible that closer counts could be higher because individual birds

would be easier to spot. To test for methods effects, far and near counts were conducted

in 1993 on the same day and compared. There were no statistical differences, indicating

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';Jnear counts did not bias attendance upwards. In 1993 and 1994, U.S. Fish & Wildlife

Service personnel also made duplicate counts of these multiple-count areas.

Reproductive Activity

During all boat surveys murre phenology was qualitatively assessed. Specifically,

we observed: 1) whether the murres were occupying breeding ledges or continuing to

raft, and 2) whether "flyoffs", defined as large numbers of murres (>1(0) flying from the

cliffs in unison, occurred. Flyoffs were taken as an indirect indication that laying had not

started in an area. We also noted whether recently laid murre eggs or freshly eaten eggs

were seen on Light Rock during occasional visits. As our field season started in early

July, it was impossible to detennine when ledges were initially colonize<I. However, we

operationally defined the beginning ofreproductive activity as the time when the majority

of the murre population was present on the breeding ledges and remained there .1'

throughout the day (Le. no flyoffs).

Phenology was also assessed from the timing of egg production on a study plot on

the top ofLight Rock, established in the densest part ofthe colony in 1977 (Manuwal

1980). Originally 17.6 m2, the plot was expanded to 25 m2 in 1978 a!1d located in the

same general area as in the previous year (Boersma pers. obs.). The plot was reestablished in 1990, and surveyed through 1992. As in the 1970's the plot was visited

after the initiation of egg laying (7 July and 1 August) and again after chicks started to

hatch (1 September) in order to count eggs and chicks. Visits invariably flushed the

resident adults, so an attendance count was never possible. The number of eggs and

chicks appearing on the 5 x 5 m plot was used as an indication ofrelative reproductive

success for the murre population. During the first two visits, all eggs within the plot were

marked such that a loss rate between visits could be calculated. This loss rate is assumed

to be the result of disturbance, primarily created by visiting the plot. Losses occurred

because Glaucous·winged Gulls entered the plots after murres flushed, and preyed upon

some percentage of the eggs. Because of this disturbance, our measures of egg and chick

production from the 5 x 5 m plot are somewhat lower than what would actually have been

produced.

D~ng 1991, two 35mm time-lapse movie cameras were installed on Light Rock,

one on the flat top and one on the North-sloping side. In 1993 and 1994, four such

cameras were installed (1993 - two on flat top, two on North side; 1994 - three on flat

top, one on North side). Cameras were set-up before the onset of the murre laying season

(late June) and removed after murres had left for the season (late September - early

October). Cameras took pictures every 6 (1991) or 10 minutes (1993; 1994), from dawn

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to dusk. Subplots within the frame of each camera were used to assess daily and seasonal

patterns of attendance and phenology. Reproductive success was calculated for all pairs

within the plot which could be visually followed. Pairs whose position on the camera

subplot occluded them from clear view were not followed, as it was difficult to

impossible to clearly distinguish their reproductive output. Pair occlusion was a

particular problem in the sloping plots, which led to the reduction in sloping camera

plots from 1993 to 1994 as they were not useful with respect to accurate assessment of

murre reproductive success. Although this method may be somewhat ambiguous, we had

no a priori reason to believe there was a potential correlation between proximity to the

camera and reproductive success.

For clearly visible pairs, all frames within each day were examined for sightings

of eggs or chicks. As murres are protective oftheir eggs/chicks, and the cameras were

taking "snapshots" in time (albeit tens of frames/day), there were days in which clear

sightings for each pair's reproductive output were not possible. This was particularly true

during stormy weather, when picture quality was reduced, as well as during hatching

when parents remainded extremely close to new chicks. Therefore, we used a series of

conservative operational definitions, based on range of days an egg or chick was sighted,

to categorize the likelihood of hatching and fleding success. For each pair, successful

fledgling production was operationally defined by one of the follo~ing: 1.) chick

sightings over an 18+ day period, or 2.) chick sightings and sightings of adults with

wings down (indirect evidence of chick presence) over a 20 day period, or 3.) chick

sightings and sightings of adults with wings down over an 18 day period combined with

egg sightings over a 30+ day period. Chicks were defined as having probably fledged if

they were sighted directly or indirectly or less than 18 days and/or their eggs were sighted

less than 30 days. Therefore, reproductive success was defmed conservatively as:

fledglings/(eggs - relays)

and liberally as:

(fledglings + probable fledglings/(eggs - relays)

Fork-tailed Storm-petrel

Monitoring Areas

All permanently staked burrows in 6 study areas (A, B, C, D, E, and Z; Figure 1)

were examined for evidence of nesting activity at the beginning, middle, and end of each

field season. During each year, new burrows were identified and added to the

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pennanently staked list. Area checks were used to detennine burrow usage and . reproductive success of a known population as follows:

occupied burrow=presence of adult, egg, or chick

ourrow occupancy=occupied burrows/total burrows checked

active burrow=presence of an egg or chick

burrow activity=active burrows/total burrows checked

hatching success=chicks produced/egg-s

chick mortality=dead chicks/chicks produced

fledging success=chicks fledged/chicks produced

reproductive success=chicks fledged/active burrows

Because the field season ended before all chicks had actually fledged, the chick fledged

category included actual fledgers plus all chicks in healthy condition at the end of the

field season.

After the first complete area check, all active burrows were marked for the season

with surveying flags. Active burrows were then monitored at three-day intervals

throughout the nesting season as'follows: Adults in the burrow were checked for band

identification. Unbanded adults were banded. Once both birds of a pair were banded,

adults were no longer removed from the burrow. Ifthe burrow did not contain an egg or

chick, and no adult was found for three consecutive visits, then the burrow was removed

from the monitoring list. Burrow condition (dry, damp, wet, flooded) was also noted.

Eggs were removed from the burrow and measured to the nearest 0.1 mm with

vernier calipers (length and width). Until hatching, relative egg temperature was

consistently checked as a measure ofincubation (wann, cool, or cold), and hatching state

was recorded (presence and number of stars and pips). Pipped eggs usually hatched

within 1-5 days. If an egg was cold for more than 6 sequential visits, it was considered

dead and the nest was removed from the monitoring list.

Once the chick had hatched it was not removed from the burrow until the adult

'was no longer present, usually 2-5 days from hatching. Chicks were aged by classifying

feather tracts on the back (small dots, large dots, lines), back skin color (red, pink,

white/grey), and tarsus color (white, grey) Chick activity was noted on each visit as

follows: responsiveness (active, lethargic, torporous), wing and feet temperature (wann,

cool, cold), down condition (dry, damp, wet). Chick weight (to the nearest g) and wing

measurements (to the nearest mm) were made on every visit. Wing chord was defined as

the distance, on an unstretched wing, from the carpal joint to end of the bone, down,

shaft, and/or feather as they appeared during chick growth. Chicks that were considered

to be near fledging (identified by the presence offully grown flight feathers and no

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down) were banded. The yearly chick growth rate was calculated by taking mean weight

and wing measurements from Day 1 through fledging and performing a best-fit growthcurve regression on the points (Boersma & Parrish, in prep.).

RESULTS AND DISCUSSION

Common Murre

Attendance Patterns

From 1990 to 1992, we counted between 31,000 and 35,000 murres in attendance

on East Amatuli Island (Boersma et al. 1995). In 1993, US Fish & Wildlife Service

personnel estimated the East Amatuli population at 33,000 (Roseneau pers. comm.).

Attendance figures ~ere unavailable for the 1994 season. In all years the majority of the

murre population nested on the southeast side of the main island, and secondarily on East

Amatuli Light Rock. Because whole island censuses were only made once, these figures

should not be taken as accurate representations of either island attendance or population

size. Instead, these figures represent a broad estimate of annual attendance.

There has been a large amount of controversy surrounding the degree to which the

Exxon Valdez oil spill impacted, and continues to impact, the Barren Islands murre

population (Boersma et al. 1995, Nysewander et al. 1993, Parrish & Boersma 1995).

Although the attendance figures reported here can be used as broad-brush baselines for

future years, they are, unfortunately, not directly comparable to earlier census data as the

Jatter were estimates rather than actual counts. In addition, specific information about

counting methods, including number of observers, platform, optics, time of day and time

ofseason are lacking. From 1975 through 1979, murre attendance estimates on East

Amatuli Island ranged from a low of 19,000 to a high of 61,000 (Boersma et al. 1995).

Four areas: Oval, Swatch, Triangle Rock NW and S, respectively, were counted

between 2 and 10 times per season, allowing a more accurate estimation of annual

changes and variation in attendance. These four areas represent 2~3% of the total East

Amatuli population, and are located in three separate locations along the periphery of the

main island. Attendance in three of the four areas increased steadily from 1990 to 1993

(Figure 3). In total, attendance rose an estimated 118 murres per year, or approximately

18% annually (Figure 3). These high annual increases are the strongest indication that

there was a large negative impact on the pre-1990 population (presumably the Exxon

Valdez oil spill of 1989). Annual increases of +20% indicate that following the Exxon

Valdez oil spill either breeding murres stayed away from the colony for several years (see

Sydeman 1993), or adults were immigrating into the Barren Islands population, or some

1 1

~-

combination of the two. However, not all colony locations experienced such dramatic

increases. On East Amatuli Light Rock, timelapse Camera 1 (located on the upper flat

portion ofthe subcolony, to the immediate Northeast ofthe navigation light) attendance

counts did not vary significantly (Table 1). That we did not see an island-wide pattern of

dramatic increase suggests that all parts of the island are not necessarily affected in a

similar manner by a single event such as an oil spill. Some locations on East Amatuli

may be "optimal" nesting habitat, such that vacant spaces were quickly filled by

migrating (local or regional) adults. There is some indication from long-term banded

populations that movement between colonies ofreproductively active adults does occur

(Halley and Harris 1993). By 1991, the first year time-lapse camera data were collected,

"optimal" locations may have already stabilized.

While the breeding population may appear to be in recovery, the total population

(i.e. including the non-breeding component) may have sustained a serious loss. Ifwhat

we are seeing is an equilibration ofthe breeding population at the expense of the

ttstanding stock" of the non-breeding population, further perturbations could seriously

affect murre population numbers and reproductive success. Thus, we still know little

about the Exxon Valdez oil spill effect on murre population resiliency even though we

can fmd no evidence of massive damage, either mortality or denigrated reproductive

success, to the population.

Reproductive Success

In all years, murres nesting on Light Rock produced eggs and chicks, although

there were differences in both phenology and reproductive success; During 1990-1992,

eggs and chicks were observed directly by field personnel visiting Light Rock. In 1991,

1993, and 1994, time-lapse 35mm movie cameras recorded the reproductive aCtivity of

subplots of murres nesting on the flat top (1 to 3 cameras/year) and sloped sides (1 to 2

cameras/year) of the Rock. Because the latter method is remote and does not disturb the

birds, a more accurate picture ofreproductive success is possible.

For thl? time~lapse cameras, we defined reproductive success as a range of values

bounding the probable true value (see Table 1). The pairs we followed do not represent

100% of the birds in each camera plot, but the number of pairs for which we were able to

view eggs and/or chicks repeatedly. In the plots for which eggs, and especially chicks,

could never be seen, the number of pairs followed is much lower than the probable

number ofreproductive pairs (i.e. Cameras 3 and 4). Reproductive success of followed

pairs ranged from 0.65 to 0.93 fledglings per pair over the 243 pairs followed (Table 1).

In 1993, pairs in the Camera 2 plot experienced lower reproductive success (0.58);

12
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,.

"
however, this low value was not a result of natural processes but instead stemmed from a

Coast Guard helicopter landing on Light Rock on August 12, 1993 which caused many

adults to temporarily desert and therefore led to the loss of eleven eggs. Ifthese birds are

not included in the reproductive success calculation, success increases to 0.79 fledglings

per pair. In general, once eggs had hatched, the chance of chick mortality was quite

small, even during large disturbances such as that caused by the helicopter landing in

1993.

In 1991, 1993, and 1994, phenology could be explicitly assessed on the timelapse

camera plots. In other years (1977-1979; 1992) visits were made to the 5 x 5 m plot

(location of Camera 2 in 1993 and 1994), and the number of eggs were counted. Thus, it '

is possible to assess whether egg presence is consistent with phenology patterns ~n the

camera plots, or whether phenology was earlier in non-timelapse years. It is difficult to

determine whether phenology was ever later, as lower egg values might be due to either

later laying, lower overall production, or both. Because visits to the 5 x 5 m plot

disturbed the murres, there was associated egg loss, primarily due to predation by

Glaucous~winged Gulls. Although there was re-alying, egg predation undoubtedly

decreased production, making absolute comparisons with time-lapse camera data

inappropriate.

There are two evident phenological patterns. Within a year, laying was not

necessarily synchronous across Light Rock, although it appeared to be synchronous

within each camera plot. In 1993, murres nesting on the flat top ofthe rock laid 6 days

earlier than murres nesting along side ledges. Between years phenology also changed

(Figure 4). From 1991 'on, lay date appears to get ,progressively earlier, although this

pattern is somewhat confounded by 1992 (Figure 4). There have been claims that murre

phenology following the Exxon Valdez oil spill has been significantly later than in

previous years. It appears that egg laying on the 5 x 5 m plot in 1977 and 1978 was early

relative to 1979, and that egg production in 1977 was very high. Visual inspection

indicates that 1978 is phenologically comparable to 1993 and 1994, while 1979 is closer

to 1990 (Figure 4). Acknowledging that these data are severely limited, we fmd no

consistent pre-post spill pattern.

Although there has been some concern that the Exxon Valdez oil spill caused a

persistent decline in the reproductive output,of the remaining East Amatuli population,

we found no evidence to support this contention. In reality, pre-spill reproductive data do

not provide an accurate picture ofreproductive success, as the only available data come

from visits to the 5 x 5 m plot.(Boersma et al. 1995). If the post~spill population was

indeed severely hampered in egg and chick production, we would have expected that

13
· ..

)
reproductive success in 1991 would have been low relative to other closely monitored

populations in Alaska. In fact, this is not the case. It is possible that the birds nesting on

Light Rock occupy the most optimal habitat and, as such, experienced little of the postspill repercussions ascribed to other sectors of the Barren Islands murre population. In

1993 and 1994, the U.S. Fish & Wildlife Service personnel collected data on reproductive

success of pairs nesting on the East Amatuli headland immediately east of Light Rock.

Fork-tailed Storm~petrel

Reproductive Success

Throughout the 1990's, occupancy in marked nests has hovered between 40 and

, 50 percent (Figure 5, Table 2). Although occupancy in 1991 appears to drop, it is

actually higher than calculated because unfound nests (Le. previously marked nests which

remained un-located through the season presumably because the stake disappeared; NNF) , . and collapsed nests (nest collapse occurred over the winter; COLL.) were not recorded,

erroneously inflating the number of available but unoccupied nests. Hatching success

(chicks/eggs) and fledging success (fledgings + healthy end-of-season chicks/hatchlings)

of both marked and new nests appeared to rise throughout the 1990's (Figures 6 & 7).

This pattern may be aD artifact of a change in methods from 1990-1993 to 1994. During

1994, nests were only checked intermittently (2-3 times per trip), as opposed to a regular

three~d3.y schedule in prior years. The number of nest checks prior to mean hatch date

for the colony within year is negatively correlated with hatching success in a stepwise

fashion (Figure 8). In other words, five or fewer nest checks result in lower

abandonment, and thus higher hatching success. Therefore, the higher hatc~g and

potential fledging success in 1994 could be partially the result of lowered disturbance

levels. For nests checked on a regular basis (i.e. 1990-1994), experienced adults from , I

marked burrows appeared more likely to desert (as measured by relative hatching

success) than unbanded adults from nests which were newly found that year (Le. birds

inexperienced with humans). It is unclear what is determining this behavioral pattern in

the adults. However, once chicks had hatched, nest status (marked or new), as well as

number of times nests were checked prior to fledging, appeared to have little influence on

fledging success.

The negative correlation between nest-check frequency and hatching success,

combined with the counter-intuitive difference in hatching success between old (marked)

and new nests, suggests that long-term monitoring projects need to seriously consider

'researcher effects. Chronic trampling ofthe vegetation results in soil compaction and

14
,-
'.

gulley formation. Eventually, this erosional process may decrease the inherent worth of

ne~by nests, forcing the residents to find new nest sites. Therefore, long-term

, monitoring programs need to first assess what level ofreproductive information is

necessary relative to the expected reproductive impairment of the population as a result

of collecting those data. We suggest a hierarchical approach: L) long-term marked nests

should be used for chick growth studies as the latter does not appear to be affected by

human disturbance and 2.) new nests in similar habitat to the marked nests should be used

to determine annual reproductive success. Ideally, the nests used for reproductive

success should be checked intermittently, 2-3 times early in the season to assess

occupancy and forecast mean hatch, 3-4 times around mean hatch, and 2-4 times late in

the season just prior to fledging.

Chick Growth

Both tissue growth rate and weight gain fluctuated throughout the 1990's (Figures

9A-E). In 1993 and 1994, it took approximately 57 days for the average chick to grow

'their wings from 10% (birth) to 90% of adult wingchord length (full adult wingchord

length was set at 162 mm). ,By contrast, the average length oftime required in 1990 was

68 days, an approximately 20% difference. Weight gain followed a similar pattern: at 70

days the average chick weighed 96 grams in 1994 and only 75 grams in 1990. These

dramatic differences in annual growth may reflect fledging success to some degree, asa

higher percentage of chicks fledged in faster growth, heavier years (Le. 1994).

Boersma and Parrish (in prep.) hypothesize that the demonstrable changes in

mean annual growth rate reflect the fact that Fork-tailed Storm-petrel growth is primarily

externally regulated by food supply. Changes in weight gain probably reflect food

quantity, while changes in wingchord growth rate reflect changes in food quality. Thus it

is possible to have high availability of low quality prey (Le. high lipid, low protein

producing fat chicks with slow wing growth), as may have been the case in the 1990's.

Conversely, it is also possible to have high availability of high quality food (Le. high

protein leading to fast wing growth) as was seen in the 1980's. This challenges the idea

that seabird growth, particularly in'the storm-petrels, is regulated by bottlenecks in

anatomical development (Ricklefs 1979). Changes in both wing growth patterns and

weight gain are likely the synergistic result of changing food availability as well as

changing food quality. Food availability may change on an intraseasonal basis and in an

unpredictable fashion. Food quality may be changing over longer periods of time (e.g.

decades) as a result ofseveral potentially interacting events: decadal shifts in oceanic

warming (Royer 1989), chaotic disturbance such as EI Nino-Southern Oscillation, shifts

15
I

'i

I
3

in trophic structure as a result of long-tenn fishing pressure (Springer et al. 1986), and

short~tenn shifts in trophic structure caused by oil pollution.

General Discussion

Detennining how perturbations affect seabird biology is particularly difficult

because both natural and human induced changes are occurring continuously.

Furthennore, the strength and direction of natural perturbations are both variable and

chaotic. However, if we can use these "natural experiments" as indicators of how the

changing environmental conditions will impact seabirds, we will perhaps be able to

forecast how additional human~induced changes will alter seabird population biology.

Because seabirds can modify their behavior and foraging patterns, many species

are able to ameliorate the effects of environmental change. For this reason, it is difficult

to use seabirds as indicators of environmental change without extensive infonnation on

their biology. An understanding of natural biological variation and what causes variation

to differ in direction or degree is also needed (Wiens 1995).

Physical oceano~aphy is largely driven by climatic changes. Intensity of

upwelling and sea-surface temperature are known to be linked to some seabird

demographic parameters (Boersma 1978). There is increasing evidence that seabirds are

sensitive to changes in these physical variables. Population changes ofseabirds in the

Farallons appear to track temporal variation in some large-scale oceanic conditions

(Ainley and Lewis 1974). Ainley, Sydeman and Norton (in press) argue that the intensity

and geographical extent of the Aleutian Low Pressure System may alter wind patterns,

upwelling patterns, and consequently affect the food supply, thereby affecting seabird

, reproductive and population biology in the Farallon Islands. For example, breeding of

Common Murres in the Farallon Islands has become earlier and is correlated with an

increase in sea-surface temperature along the coast ofCalifornia from the 1970's through

the 1990's (Sydeman and Ainley 1994). Both the Common Murre and Cassin's Auklet

(Ptychoramphus aleuticus) delayed reproduction in the Farallon Islands in 1982-1983 and

1992-1993, apparently in response to El Nino. Apparently, higher productivity is

associated with earlier egg laying dates in murres (Sydeman and Ainley 1994).

Interestingly, only two species ofseabirds on the Farallon Islands, both stonn-petrels,

appeared to show little response to annual variability in marine productivity.

Our data from the Barren Islands characterizes a very different system, but a

striKingly similar pattern. Royer (1989) reports that the Gulf of Alaska has been warming

since the mid~1970's. In general, warmer waters are associated with lower productivity.

The negative trend in the'onset of egg laying (i.e. delayed) in the Barren Islands murre

16
. ,

I..

{

I

,

i

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I

:'
population is correlated with a general increase in sea surface temperature in the north

Gulf of Alaska.

One of the most striking aspects of this comparison is the apparent dovetail effect

of north versus south. For instance, egg laying of murres on East Amatuli Island

appeared to be earlier in 1977 and 1978 and later in 1979. The opposite pattern is shown

by murres on the Farallon Islands which laid later in 1977 and 1978 thari they did in

1979. Egg laying in 1979 and 1991 appeared to be earlier than normal in the Farallon

Islands but later than normal in the Barren Islands. This opposition may represent

evidence of alternating strengths and weaknesses in the Alaska and California current

systems, as both originate from the North Pacific Current. However, this alternating

pattern is disrupted in years when the entire Pacific basin is affected, such as an ENSO

year, suggesting that major oceanographic perturbations can dwarf local oceanographic

trends. Thus, 1992 was a very poor reproductive yearfor murres in both the Farallon

Islands and the Barren Islands, presumably because of EI Nino.

Fork-tailed Storm-petrel data from the Barren Islands are consistent with the

interpretation that major oceanographic changes are occurring in the north Gulf of

Alaska. Generally, growth rates ofstorm-petrel chicks have been slower in the 1990's

than in the mid-1970's and early 1980's, suggesting that food availability and/or quality

has changed. This is perhaps a surprising result given that of the 12 species of breeding

birds on the Farallon Islands, only 2 species showed little response to annual variability:

Fork-tailed and Leach's storm-petrels.

In contrast to most natural penurbations, which can have either negative or

positive impacts, most human perturbations have negative impacts on seabirds. Oil spills

are among the most dramatic human perturbations in the marine environment. However,

the relative importance of massive versus chronic oil spills in structuring seabird breeding

populations is unclear. Oil spills often result in a spike in adult seabird monality;

however, the long-term effects on seabird populations are not known. Some researchers

have pointed out that although oil spills undoubtedly kill thousands of seabirds, average

winterkill can reduce a population by 5-20% each year (Dunnet 1982, Clark 1984),

leading one to the conclusion that oil spills are a minor component ofseabird monality.

However, other authors have pointed out that winterkill disproportionately removes

young-of-the-year and juvenile birds, while oil spills can principally affect breeders,

particularly ifthe spill occurs close to breeding colonies during the breeding season (Piatt

et al. 1991). In sum, without long-term monitoring of specific populations, it will be

impossible to make blanket statements about the effects of oil spills on seabird

populations, relative to other monality agents, whether natural (e.g. ENSO, food

17
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'.
availability, winterkill) or anthfopogenic (e.g. gillnet bycatch, direct competition with

fisheries, introduced predators).

The Barren Islands data do not appear to shed light on this dilemma, in that

although the Exxon Valdez oil spill killed many thousands of seabirds, it was impossible

to detect long-term differences in response to the spill by Common Murres and Fork-,

tailed Storm-petrels. The impact on these two species was expected to differ, as large

numbers of murres were killed by the oil and apparently few Fork-tailed Storm-petrels

were killed by the oil (Piatt et al. 1990).

Since we first began working in the Barren Islands in 1~76, use of the water~

around the islands and ofthe islands themselves has increased dramatically due to

increased boat traffic, fishing, scientific visits, and J0uri~m (Boersma pers. obs.).

Distinguishing the negative effects on area seabirds of these increasing human uses of the

area from impacts associated with oil development and transport in the Cook Inlet area

would be difficult. When coupled with natural perturbations and long-term

oceanographic trends, teasing out cause-and-effect becomes impossible without a solid,

long-term database designed to detect subtle changes in population parameters on a broad

scale.

With the effects ofseveral scales of perturbations occurring why haven't there

been more obvious changes in seabird populations in the Barren I~lands? The answer to

this question lies in seabird breeding biology. Seabirds are long-lived and hence changes

in reproductive success may not be apparent for a decade or more. Many species have

the ability to switch food sources should conditions change, a further buffer against

environmental variability. Changes in the level of adult mortality are expected to

produce long-term effects in population structure and reproductive function. Why then

did we see few changes, other than direct mortality, from the Exxon Valdez oil spill? The

answer may be in the non-breeding component ofseabird populations. We know almost

nothing about this component of the population: how big it is, its age structure, and its

geographic range. Seabird populations may be buffered from adverse effects, both

natural and human-induced, by their non-breeding pool. The level ofresilience provided

by non-breeders would thus be affected by the frequency and magnitude of disturbance.

Additional human-induced disturbance in a system already susceptible to broad

fluctuations in natural perturbation may deplete the built-in reserve offered by nonbreeders. Whether this is true, and how important the non-breeding pool of birds is,

remains to be tested.

The Exxon Valdez oil spill demonstrated that the Barren Islands are likely to be

an important reference site. The location, ofthe Barren Islands and extreme tidal

18
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~.
exchange that characterizes the area make them ideal for examining the effects of both

natural and anthropogenic disturbance on seabird populations. Some baseline

information is available and patterns of change can be detected. Reference areas will

become increasingly important in determining both short and long-term environmental

change. However, routine monitoring without scientific innovation will not.be adequate

for the challenge, because refinements in data collection must be made over time in order

to test relevant, time-sensitive hypotheses. For instance, it is clear from our study and

others (e.g. Hatch and Hatch 1989) that single, yearly censuses can only provide a broad

estimate of population size, rather than a specific statistically robust number. However,

the effort required to collect statistically adequate data at the level of elltire colonies may

be economically unfeasible in the long-term. Therefore, we recommend the adoption of

methods, such as our timelapse camera system (allowing extremely accurate data

collection on a small part of the colony), which speak to both long-term monitoring and

statistical robustness; both are needed should future injury and damage assessment be

necessary.

19
!rf,!
ACKNOWLEDGMENTS

We would like to thank the Alaska National Maritime Refuge for allowing access to East

Amatuli and East Amatuli Light Rock. Maritime Helicopters and Homer Ocean Charters

provided much needed logistics and comfort. Bill St. Lawrence of Polar Alpine was an

essential component of the time-lapse camera crew. This study would not have been

possible without the dedicated efforts of many students, volunteers, and technicians,

particularly Sonia deBary and Arthur Kettle who worked on the project during 1990-

1991. Partial funding for the time-lapse camera work was provided by Exxon USA. This

study was funded in part by the U. S. Department of the Interior (USDO!), Minerals

Management Service (MMS),through Intra-agency Agreement No. 14-35-0001-30670

with the USDOI as part ofthe MMS Environmental Studies Program.

20
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I·····'······,

.. . .:,Ii"~

..

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Ainley, D. G., Sydeman, W. J., and Norton, J. In press. Apex predators indicate

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Bailey, E. P. 1976. Breeding bird distribution and abundance in the Barren Islands,

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Boersma, P. D. 1978. Galapagos penguins as indicators of oceanographic conditions.

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Boersma, P. D. 1986. Seabirds reflect petroleum pollution. Science 231:373-376.

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Diaz, H. F. & Markgraf, V. 1992. El Nino: Historical and Paleoclimatic Aspects of the

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Subarctic Pacific Ocean. Washington Seagrant Program, Seattle. 312pp.

23
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,.
Table 1 - Reproductive success for all pairs of Common Murres that could be followed

within each time-lapse camera plot, East Amatuli Light Rock, Barren Islands, Alaska.

Camera-Year

C1 - 1991

C1- 1993

C2 - 1993

C3 - 1993

C4 - 1993

C1 - 1994

C2 -1994

Attendance

(X + SD)

57 ±5.1

57 ±9.6

58±3.0

35±5.0

62 + 7.9

52 + 3.7

59 + 5.1

Number of

e s

46

41

44

19

24

39

41

Number of

rela s

4

1

4

1

o

1

Number of

chicks

34

34

24

17

19

36

38

Reproductive

Success

0.7 -0.76

0.76-0.89

0.58-0.79

0.79-0.89

0.65-0.83

0.90-0.92

0.93

Table 2. Reproductive success for all marked burrows of Fork-tailed Stonn-petrels within 6 study sites (A-E, Z). Status refers

to whether the burrow was marked in a previous year (OLD) or newly marked that year (NEW). Within a year, old burrows'

(TOTAL), could be either not found (NNF), found but collapsed (COLL.), or occupied by at least one adult on one occasion

(OCC.). Within the category occupied, the majority of the burrows had actively reproducing pairs (ACTIVE), indicated by the

presence of an egg. Fledging was defined as chicks which fledged during our field season, or chicks in healthy condition at the

end of the season.

1990

STATUS I AREA' totAL NNF - ,

COLL.' OCC. ACTIVE CHiCKS FLEDGED

OLD A 143 1 1 67 66 17 5

B 53 0 1 30 30 3 2

C 29 0 0 13 13 2 0

D 174 1 0 91 89 14 5

E 122 2 0 56 56 15 7

Z 30 0 0 17 17 6 4

NEW I A 14 14 14 6 1

B 7 7 7 0 0

C 0 0 0 0 0

D 37 36 36 9 3

E 62 60 60 26 7

Z 1 1 1 0 0

1991

STATUS I AREA TOTAL NNF COLL. OCC. ACTNE CHICKS FLEDGED

OLD A 152 - - 51 31 8 4

B 53 - - 18 15 1 1

C 29 - - 11 11 2 1

D 184 - - 42 36 12 11

E 130 - - 26 21 3 2

Z 35 - - 11 9 2 1

NEW I A 12 12 12 3 1

B 0 0 0 0 0

C 0 0 0 0 0

D 28 28 28 5 3

E 47 47 47 27 19

Z 1 1 1 0 0
.-J
199~.

STATUS I AREA TOTAL NNF COLL. OCC. ACTIVE CHICKS FLEDGED

OLD A 180 6 6 72 68 28 18

B 54 2 4 33 33 14 9

C 29 0 7 12 11 5 2

D 215 27 1 97 97 54 29

E 177 28 7 74 74 32 14

Z 37 4 3 16 16 11 3

NEW I A 10 8 7 3 2

B 1 1 1 0 0

C 0 0 0 0 0

D 10 7 7 5 3

E 8 4 4 3 1

Z r 1 1 1 0

1993

STATUS I AREA TOTAL NNF COLL. OCC. ACTIVE CHICKS FLEDGED

OLD A 188 18 2 70 67 29 21

B 54 0 5 28 23 8 5

C 29 0 0 10 9 3 2

D 230 24 4 105 99 34 23

E 196 33 6 60 56 . 28 15

Z 37 3 0 17 16 5 4

NEW I A 1 1 1 1 1

B 1 1 1 1 1

C 0 0 0 0 0

D 1 1 0 0 0

E 29 29 28 12 8

Z 0 0 0 0 0



East Amatuli IslaO(\ Barren Islands, Ahska

.-J

a

cA

1

Swatch

¥

I.)

Light Rock

" •

"

Figure 1. Topographic map ofEast Amatuli Island. Barren Islands. Alaska, showing the placement ofsix Fork-tailed Stonn-petrel study

areas with pennanently marked burrows (A. B, C, D. E, Z). the Common Murre census areas (Oval. Swatch. Triangle Rock). and Light

Rock - the site ofCommon Murre reproductive success assessment (5x5m plot; 35rnm time-lapse camera plots). Inset is location of East

Amatuli relative to the Barren Islands system.

....)

/>

I

I

I

I

I

I

I

1975 76 77 78 79 1980 81 82 83 84 85 86 87 88 89 1990 91

3.0

-

e

0'-"" = 2.0

- I-l

~'O

=~. . ..... =1.0 ... . i . wm.

~C"

t~

~I-lQJ .. > 0.0 ~o

CJ

=

cC e-1.

O

en=---

ai -2.0 -I Ii· Ii • i .• . , .• I' I ,",. I .I " I I • I" I • Ii'·I I I J

en

year

Figur~~. Sea surface temper~ture anomaly, by month, integrated over a 2° square centered on the Barren Islands (1975-1991).

Temperatures greater or less than 1° are shown by open circles. All data from COADS.
,I'

l
CIJ

u

"C

m

~.

CIJ ....,

<

::s

CIJ

be

CIJ

-- .._,..

o Oval (+43/year; R2 = 0.92)

Swatch (+29/year; R2 = 0.93)

T. Rock S (+46/year; R2 = 0.84)

6

T. Rock NW (+O/year; R2 = 0.00)

1001 -I'" i i

1990 1991 1992 1993

Year

"'. ",

648

25%

811

1%

818

27%

1036 Total Attendance

3-year average = 17.7%

Figure 3. The average annual attendance of Common Murres at folir multiple-count areas (Oval, Swatch, Triangle Rock South and

Northwest, respectively). Lines are least-squares fit. Slopes are indicated as the average gain in attendance per year. R2 values indicate

slope fit. Total attendance sununed over all four areas, and the corresponding percentage increase is indicated below each year. Percent

increase is calculated as (l-(larger value/smaller value» to correct for polarization.
,.
".,

~~

.·30

"

1977.5*5 i99Z-SxS

s = g; ~, ;; C5 s g ~, !: - - - - - - - N M M N N

o -I" i 'Wi' i , i i ", • -.- i I Iii i

300

2SO

200

g'" 150

100

199b·SiS

~~~~~2:~~~R~~~

300

2SO

100

200

8'" ISO UJ

~~!!~~~~~~~~~

300

150

200

§'" 150

100

SO

o I i I Iii•. iii iii i

1991·5 x 5 1993 ·TLC

~:~~~:;:~ogS2::l~ ----- .... -NMNNMN

80

100

60

%

40

~:~~~:;:~ogS2::l~ -------MNNMNN

300

250

200

150

100

50

o I i I-' iii I i i-' iii

1978·5 x 5

2~~g:;~~~ogS2~!::

- - - - - - - N N N M N M

300

150

200

'"8150 ILl

100

50

o

1979· Sx 5

o I i j.'.'-'_:'.'.'.'.'.,-,-, -------MMNMNN

2:~~~~~o!Sg~!:

1994· TLC

80

60

20

100

~:~~~:;:~ogS2::l~ -------NNNNNN

o 1-,-,-,-,-, iii , iii i

%

40

1991 ·TLC

80

20

100

60

%

40

o,.,"'''' ... ."oo-~~ ... o ...... <.:J 0000 ClQ 0\0\0\ 0--_

------- MNNM

300

150

200 "'. 8 150 ILl

100

50

O~ I I I" ,I. I I ,I, Iii

JULIAN DAY

Figure 4. Phenology in Julian days, as assessed by the number or percentage of eggs laid, of Common Murres nesting on East Amatuli

Light Rock from 1977 to 1994. 5x5 - the original plot set up by Manuwal and Boersma, which was visited 1-3 times each year (data are

actual number of eggs on the plot); TLC - time-lapse camera #1 plot located above and west of 5x5 plot (data are percentoftotal eggs

laid). A zero (0) indicates a visit was made but no eggs were present. TLC data are cut off when all e~gs are laid (i.e. 100% is reached).
"

i.

A'
I

Q N 'II:!"

Y·ear

-

545 598 - '639

661 -

- 583

-

-

\

30

o

10

20

...

Figure 5. Nest occupancy in permanently marked burrows of Fork-tailed Storm-petrels, 1990-1994.
I

.1
I' "

80

.........

.

- ·60

OJ

.~

::

40

Cl.O

.... -=-

;.c:

- 20 =

=

'. Marked Nests

o NewNests

Q

- N 'o:t' =" =" =" =" =" =" =-. =" =" =" - - Year - - -

Figure 6. Hatching success of Fork-tailed Stonn~petrels, 1990-1994. Pennanently

marked nests are filled bars, new nests, by year, are open bars. Numbers above each bar

are sample sizes.

!
fr-
• Marked Nests

o New Nests ,

<= - N

.~

- _. " Year - - -

100

..- 80

--

{IJ

CI)

60

C.J

rn=

eI)

••=-

eI)

"'0

.~

-r-.

Figure 7. Fledging success of Fork-tailed Storm-petrels, 1990-1994. Permanently marked

nests are filled bars, new nests, by year, are open bars. Numbers above each bar are sample sizes.

20

1991

•

1990

•

1993

.' 8

1992. 1982

• 0

00

o

• Marked Nests

o New Nests

1980

o •

·1981

O.

1994

0.2 0.4 0.6 0.8

Hatching Success

o-l---....----.~--r---_r_-~--r__-.,.....-_,

0.0

Figure 8. Hatching success of Fork-tailed Storm-petrels as a function ofthe average

number of nest checks before mean hatch date, by year. Permanently marked nests are

filled circles, new nests, by year, are open circles. Numbers above each filled circle are

years.
••
165 '1990

1•• I I 132 I

18 I

I e- 99

! 68 !!. '20 66 a48 i .c

u

Il/l

! c

Z8

1. Z. 38 48 58 68

Ace (days)

1991

1993 165

18e 165 I I

I I . 132

Ie 13Z I

I I

I

'8 99

68

'8 99

6e

t

g

66 .- g

48 .a66

4e ... o·

OQ 0

R

..c

..c

i

u

; u

eo

eo

C 33 c Z8 .!:. 33

ZI -

e

11) ze 3lt 48 58 68

28 31 48 58 61 71 Age (days)

Ale (days)

1992 1994 165

165 I 132 I

I 132 ... I ... I i 99

'8 .§. 99

" .§.

;;;

'2 66

48 '2 66 a0

OQ 0

.-

.c

'5 ...

u

;;::

i

DO

DO

C

e c 33

Z8 33

28 0

"

70° 10 20 30 40 50 60

11) Z0 38 40 50 61 Age (days)

Ale (days)

Figure 9 A-E. Wingchord growth (solid line) and weight gain (dashed line), averaged within age (in days) for Fork-tailed Stann-petrel chicks, 1990 _ 1994.
t

!

>,

\
"

"

oes Study MMS 2001-040

Final Report

to

Minerals Management Service

Alaska oes Regi9n

,

Seasonal Movements and Pelagic Habitat Use

ofMurres

Determined by Satellite Telemetry

Paul M. Meyers Scott A. Hatch Daniel M. Mulcahy David C. Douglas

Alaska Science Center

Biological Resources Division, USGS

1011 E. Tudor Road

Anchorage, AK 99503

June 1997
I

I ,

Seasonal Movements and Pelagic Habitat Use of Murres Determiped by Satellite I .

i Telemetry

~MS Final Report

Study History: In 1994, the Natioqal Biological Service (now the Biological Resources

Division ofthe U.S. Geological Surlrey) used in-house funds to conduct a feasibility

study ofsatellite telemetry in comrn~n murres on Middleton Island, north-central Gulf of

Alaska. Results of that effort formed the basis of a proposed 3-year stutly in lower Cook

Inlet and the Chukchi Sea. In 1995,1 in-ho\l~ funds and funds from the jExxon Valdez Oil

Spill Restoration Project were used for the first large-scale deployment ofsatellite 1 . I

transmitters in murres and tufted puffins. Thirty transmitters were imptanted into murres

and 5 into puffins. In 1996, 16 tran~mitter~ were deployed in murres in the Chukchi Sea.

The following account of work conqucted at Cape Lisburne in 1996 is submitted as the

final report for the Minerals Manag~ment Service.

I

I ,

Abstract: We implanted 16 satellitJ tr~smitters into common and thick-billed murres at

Cape Lisburne Alaska to track foraging Patterns and migration and to t¢st the effects of

signal transmission on mortality. D;unng the breeding season, areas around the colony

and east.,northeast of the colony were the most heavily used locations, 'Murres in 1996

covered roughly the same area duriIig the breeding season as in the previous year. All

birds abandoned nesting attempts after implantation. We were able to ~rack several birds

after leaving the breeding area. Th~se bit:ds moved south through Bering Straight to an

area near the Pribiloflslands. This pattem~\\:,as similar to that seen in 1

1

995 by both Cape

Lisburne and Cape Thompson murres, and we suggestthat this area m~y be an important

wintering area for several Alaska mprre colonies. Transmitters were adtive from 0-126

days, and location quality was som~what better than in 1995. Because:8 transmitters

failed afterimplantation, we were unable to determine whether signal transmission

affected mortality. :

I

I ,

After implantation, we compared sJbsequent presence at the colony, n~sting status, and

provisioning to a control group that underwent a simple surgical procedure. In the 10

days following implantation, we re~ighted 10 of 11 control birds at the: colony and 6 of 16

implanted birds. Ofthe birds that did return, 7 of 10 control birds reta~hed breeding

status, while 0 of6 implanted birds:,retained breeding status. We conc\ude that

abdominal implantations alter muri,e nesting behavior.

, ! ,

We also analyzed body temperaturys from 1995 to look at daily and sehsonal variation.

During the breeding season, no predictable circadian pattern occurred. 'In the winter,

however, birds showed a lowered ~ody temperature in the early morning hours and an

increased body temperature during1midafternoon. Seasonally, body teinperature was

higher from the breeding season tilfough migration and lower during t~e winter months.

r '

11
,r..........

Key Words: Alaska, behavior, body temperature, Cape Lisburne, Chukchi Sea,

circadian rhythm, common murre, distribution, foraging, habitat use, implantation,

migration, nesting, PTT, satellite telemetry, satellite transmitter, seabird, seasonal

movements, seasonal variation, thick-billed murre, Uria aalge. Uria lomvia.

Citation: Meyers, P.M., S.A. Hatch, n.M. Mulcahy, and D.C. Douglas. 1997. Seasonal

movements and pelagic habitat use of murres determined by satellite telemetry. Final

Report. Alaska Science Center, U.S.Geological Survey-BRD, Anchorage, AK..

, j

,..

III
, I .

TABLE OF CONTENTS

I

f ' List of Tables : '.. :.. .. ...... .............................. VI

L· fF' I' ,

1st 0 Igures :................................................. VB

List of Appendices '. V111

Seasonal Movements and Pelagic Habitat Use of Murres

Determined by Satellite Telemetry ~............... 1

Abstract ; <,.,:: ,................ 1

i

Introduction , ......... ......... ... ............... ........... . ... 1

Study Area " , t•••••••• ••••• i ..... ..•.•.•.•...•.•........•...•....•••,... 2

Methods . : !................

. 2

I

Results .' : .,. .;................. 3

! "

I

Data Quantity and Qlilality ;................ 3

I

Movements by Speci¢s and year............................................ 4 I

i

Mortality and Transmitter Failure 5

j I '

i._---....:!l

D. . I

ISCUSSlon , : .

Data Quantity and Qhality : .

I

Movements and Distribution ',' "

Mortality and Transrpitter Failure : ..

5

5

5

6

,

Conclusions :' ' ' " ............ 7 , I

Acknowledgments . i . . . . . . . . . . . . . . . 7 j

I

Literature Cited J. .. . .. . .. .. . .. 8

Effect of Implanted Satellite Transmitters on the

Nesting Behavior of Murres : ;................. 26

I

Abstract .L............................................................ 26

iv
:r_

Introduction...... ... .. ... . .. 26

Study Area and Methods '" .. . ... 26

Results .' ~.... . .. ...... . . . .. 27

Discussion 28

Ackno'Yledgments 29

Literature Cited. .. ... ...... ... ........................... .. ... ......... ... ... ... .. .... 29

....... Daily and Seasonal Temperature Variation in Free-ranging Murres 33

Abstract.................................... 33

Introduction :................................................. 33

Study Area and Methods ....... :..,.)................................................ 33

.. Results :.............................................. 34

Discussion............................................................................ 35

Acknowledgments. ................................................................. 35

Literature Cited...................................................................... 35

v
LIST OF TABLES

Table 1.

Table 2.

Table 3.

Table 4.

Table 5.

Table 6.

Table 7.

Deployment of 16 sa~ellite transmitters in common and thick-billed

murres at Cape Lisburne, AK, August, 1996 : ·.. ··.. 11

I

Summary of bird location data obtained through 31 December I

1996 1.................•..... ··.··············· •..... 12

I

i

Comparison of trans~itter performance and data acquisition

between 1995 and 1996 :............... 13

I ,,- ...

Details ofsatellite tnlnsmitter deployment by species, duty

cycle, and performance in 1996 ························· 14

Frequency distributi6n of d~ta by Argos location classeS...... .... ..... 15

Hypothesized causeS of ~urre'mortality associated

with satellite transmitter iI}1piants ;............... 16

,

1 ,.

Nesting stage at tim~ of c~pture, treatment, and post operative

behavior of common and thick-billed murres captured at Cape

Lisburne, August, 1996 ~............... 32

Vl
LIST OF FIGURES

Figure 1.

F· ? Igure ,~.

Figure 3.

Figure 4. '.

Figure 5.

Figure 6.

Figure 7.

Figure 8.

Figure 9.

Figure 10.

Figure 11.

Study site location...... . . 17

Location quality classes assigned by Argos............................... 18

Distribution ofCape' Lisburne murres during the breeding

season, 1996.................................................................... 19

Distribution ofCape Lisburne murres during the breeding

season by year <•",:. •• •. • •••••• •••••••. . •••• . •. . ••. ••. •••. ••••••.. 2a

Minimum convex polygons for Cape LiSburne murres

during the breeding season ............... .. ............. ...... 21

Distribution ofCape Lisbu~e murres during the breeding

season by sex ;...................... ............... ...... 22

! j

Distribution ofCape Lisb\ul1e murres during the breeding

season by species ~................................................ 23

Migration of 3 murres from Cape Lisburne, AK, 1996........... ...... 24

Migration ofCape Lisburne murres by year ........ .. ... ... ... ... .... .. .. 25

Body Temperature ofa female common murre from Cape

Lisburne, AK, 1995 38

Daily temperature cycle in winter of a female common

murre from Cape Lisburne, AK, 1995...................................... 39

vu
LIST OF APPENDICES

Appendix 1. Track lines of individu;al murres from Cape Lisburne, AK\ 1996 40.

..

i

Vlll
SEASONAL MOVEMENTS AND PELAGIC HABITAT USE OF MURRES

DETERMINED BY SATELLITE TELEMETRY

ABSTRACT

, e implanted 16 satellite transmitters into common and thick-billed murres at Cape Lisburne

I

tlaska to track foraging patterns and migration and to test the effects ofsignal transmission on

mortality. During the breeding season, areas around the colony and east-northeast ofthe colony

tere the most heavily used locations. Murres in 1996 covered roughly the same area during the

?reeding seas'on as in the previous year. All birds abandoned nesting attempts after implantation.

f e were able to track several birds after leavi~:the breeding area. These birds moved south

through Bering Straight to an area near the PribilofIslands. This pattern was similar to that seen

ih 1995. Transmitters were active from 0-126 days, and -location quality was somewhat better

I

than in 1995. Because 6 transmitters completely failed soon after implantation, we were unable

t6deterrnine whether signal transmission affected mortality.

I. .' . Key Words: Alaska, Cape Lisburne, common murre, distribution, migration, satellite telemetry,

sbasonal movements, thick-billed murre, U;iq aalge, Uria lomvia.

,.

INTRODUCTION

Because ofthe potential for oil and gas development in the Chukchi Sea, murre populations in

tAat area have been an important target ofseabird monitoring efforts sponsored by the Minerals

¥anagement Service (MMS), Fish and Wildlife Service (FWS), and the Biological Resources

qivision (BRD) ofthe U.S. Geological Survey since 1976 (Springer et al. 1985, Fadely et al.

1989, Mendenhall et al. 1993a, b). To date, this monitoring has emphasized colony population I

size and breeding productivity. On an annual basis, however, seabirds spend most oftheir time

at sea, and even in the breeding season, they are most vulnerable to potential pollution events

,hile on the water. Similar to restoration management, risk assessment for murres requires a

basic knowledge offoraging and migration patterns year-round.

jccurate assessments ofmurre natural history traits are difficult to obtain because ofthe I

distances the birds travel and the difficulty in tracking individuals on the open ocean. Previous

t6 this study. data on traits such as foraging ranges have been estimated through ocean surveys

~ettleship and Gaston 1978, Bradstreet 1979, Gaston and Nettleship 1981, Schneider and Hunt

1984, and Bradstreet and Brown 1985) and calculation of activity times (Cairns et. al 1987).

d1utside ofHatch et al. (1996), few data are available on wintering populations and nonethat

p~rtain to birds from known breeding areas. For this reason, this project was funded by BRD, in

c~nsultation with MMS, to improve our understanding of pelagic movements of murres and our

afuility to interpret variation in conventional measures of population health.

I

The availability ofsatellite transmitters small enough to be implanted in seabirds has made it

pbssible to sample murre movements directly. These transmitters have generated many recent

-
studies into seabird foraging and migrati~n (Jouventin and Weimerskirch 1990, Ancel et al.

1992, Davis and Miller 1992, Weimerskirchet al. 1993, Weimerskirch and Robertson 1994, Fa1k 'I '

and M011er 1995, Petersen et al. 1995). In 1995, we implanted 30 murres with satellite

transmitters at Cape Lisburne, Cape Thompson, and E. Amatu1i Island, AK1(Hatch et al. 1996). , ,

Results ofthat study revealed foraging patterns and migration routes for all :three colonies.

However, data from a single year can be: misleading, as characteristics may:vary from year to

year. In 1996, we returned to Cape Lisb,urne and implanted 16 more murre~ with satellite

transmitters. Our primary objective wa~ to compare movements and distri~ution in 1996 to those

in 1995 to determine whether variation ~n foraging areas and migration occ~rred between

consecutive years. Our second objective was to test whether the transmitter signal was a factor in

the previous year's mortality. In 1995, 40% ofthe birds in the study died Within the first month

ofimplantation. This figure is much higher th~,the yearly adult ~ortality:rate of 7-21%

(Birkhead and Hudson 1977). Between survivors and nonsurvivors, only one factor stood out as

significantly different. Murres with PTTs that transmitted more frequently had significantly

higher mortality. This suggests that th~ transmission ofthe signal'may have affected

survivorship. In 1996, we altered the pi-ogr~ing ofthe transmitters to determine whether this I !

actually occurred. , ' i . i

STlJDYAREA

Cape Lisburne is on the Chukchi Sea about 60 km north of Point Hope on' Alaska's northwest

coast (Fig. 1). The area is the Pacific's northernmost murre colony and supports approximately

70,000 common murres (Uria aalge) and 130,000 thick-billed murres (Uria lomvia) (U.S. Fish

and Wildlife Service, 1997). Black-legged kittiwakes (Rissa tridactyla) also nest in large

numbers at Cape Lisburne. Other seabirds include pelagic cormorants (Pfzalacrocorax

pelagicus), black guillemots (Cepphus, grylle), glaucous gulls (Larus hyperboreus), and horned

puffins (Fratercula corniculata). Cape Lisburne Long-range Radar Station is located

approximately 3 km from the east end'ofthe colony. The buildings ofthts station served as our

base camp. '

METHODS

From 2 August 1996 to 4 August 1996, we captured nesting murres with! a light cable noose

attached to a 9-m telescoping fibergl~ss pole. We took murres from low~r ledges at the east end

ofthe colony in areas that were acces?ible by foot from Cape Lisburne radar station. The birds

were transported in burlap bags to the station, where we banded them wi,th colored tarsus bands

and Fish and Wildlife Service metal tarsus bands. The birds were anaesthetized, surgically

sexed, and implanted. For a full description ofsurgical methods, see H~tch et al. (1996).

Briefly, the transmitter was inserted into the air sac cavity through a vertical ventral incision.

The antenna was drawn through a hO,Ie on the dorsal side so that it pointbd upward when the bird

was on the water. Birds were released 1-3 hours after surgery. All birds were away from the

colony for 6.5-13.5 hours. We attempted to obtain 8 thick-billed murre~ and 8 common murres

with an even sex ratio of each. "

2
J,"., "

1he PTTs weighed approximately 35 grams and were identical to those used in 1995 (see Hatch

et al. 1996) except that rather than 2 small batteries, a single AA-sized battery was used. This

4ade the base ofthe PTT slightly wider than the top. PTTs were constructed to meet the

specifications of Service Argos, Inc. Argos computes locations by measuring the Doppler shift

of the PTT signal transmitting to a moving satellite. For this reason the frequency ofthe

t~ansmitter must be within 4 kHz of 40 1.65 MHz. At the time ofthe study there were 2 active

Argos receivers. Because batteries would wear out quickly ifleft on continuously, we

programmed them to turn on at specific times during the day. In 1995, duty cycles were 6 hours

on, 12 hours off (short cycle), and 6 hours on, 66 hours off(long cycle). As previously stated, I

significantly inore short-cycle birds died than long-cycle birds in 1995. To test whether signal

Jtansmission affected survival, we increased t~e...differ.ence in duty cycles in 1996. Duty cycles

'lere 8 hours on, 8 hours off(short cycle), and 6 hours on, 120 hours off(long cycle). After 40

days of operation (expected time at colony after implantation) the short-cycle PITs switched to

ttle long cycle.

I

Not all ofthe location data obtained were reliable. Information supplied by Argos included a

cbded index to the accuracy of each location. Location accuracy depends on the number of

sifgnalS received and parameters internal to thp Argos system (Fig. 2). This accuracy is expressed

as a probability-·two-thirds ofthe locations' in a given class are expected to fall within the stated

b6unds. Thus, while a point assigned locatio~ "class 3 probably lies within 150 m oftrue location,

itlmay in fact be off by a larger, unknown amount. Conversely, a point receiving one ofthe

poorer quality codes (0, A, B, or Z) may in fact be very accurate. To cull erroneous points, we

rdlied on the redundancy oflocations obtained close to each other in time as well as on reported

si~nal strengths. For a full description ofthe criteria we used, see Hatch et al. (1996).

Ij addition to location, each message contained calibration indices for the bird's internal body

te1mperature and the battery's voltage. We retrieved data every 3-4 days through Tyronet, Argos'

obline data distribution system. We also purchased tapes of cumulative data. Data were .

cJnverted to Arc/Info coverages for analysis.

RESULTS

Data Quantity and Quality

Dle to the small number of common murres at the colony, we captured more thick-billed murres

thlan~common murres (Table I). Sex ratios were even for the common murres, but we captured

m1pre male than female thick-billed murres. Three birds died before implantation-one during

surgery and two in transit. A fourth bird also exhibited severe stress and was released within 10

miinutes of capture, Three of these birds had young (~ 3-day-old) chicks. The fourth also had a

ctlick, but the age was undetermined. All other birds survived surgery and were released in I . . aRparently healthy condition.

3
R ~-------~

'" ,1 ..

...:-..-.- .~.

We received 1005 signals, 758 locations, and 535 usable locations (Table 2). Overall, we culled

29.4% of the locations received-~28.1 % 'during the breeding season, 34.4% post-breeding (table

3). These figures are similar to those d*ing the breeding season iri 1995 b~t higher than those

during post-breeding season in 1995. Tpe number of days in contact ranged from 0 to 126 (Table

4). Two transmitters gave 0 locations arid 5 transmitters remained active be'yond the normal

breeding season. Ofthe 16 transmitters: deployed, 7 birds outlived the PTT, 3 birds died, and the

fates of 6 are unknown. Location qualiiy was somewhat better than that in,1995. About 54% of

the locations were of classes 3, 2, or 1 (iTable 5) and were therefore expected to be accurate

within 1000 m. This compares to 42% in 1995. Nearly 72% ofthe locatiops were based on 4

messages received during an overpass (dass 0 or better). This compares tel 66% in 1995. The

additional 28% oflocations were of qU(ility A, B, or Z. Due to redundancy of points and our

method of culling, however, these locations are. probably more accurate th~n the category

implies. Overall, though we obtained donsiderable information, data wereimore sparse than in

1995 due mainly to poorer battery perf9rmance and a higher number oftransmitter failures. II

Movement by Species and Year

All ofthe implanted murres abandoned breeding attempts after implantati9n, and most spent

little time at the colony after release. rh chaP1eJj 2, we present evidence that abandonments were

caused primarily by implantation and riot by' ~apture and other handling. Afew birds did return

to the colony, but none appeared to commute on a regular basis. Murres tended to forage

northeast to northwest ofthe colony (Fig 3). The areas around the colony, and just northeast of

the colony saw the highest use. A common pattern was for the birds to travel northeast before i •

drifting north and away from the colony. Breeding-season distribution in 1996 was similar to that

in 1995 (Fig 4). Birds in 1996 used the area just west ofthe colony some~hat less than in 1995,

and did not drift as far north, but overall, the boundaries of distribution were remarkably similar. . '

Figure 5 shows the minimum convex polygons for breeding-season locat~ons from both years.

Almost all ofthe outermost locations that form the polygons represent noncommuting murres

that had abandoned nesting attempts. IStill, the areas are very similar betWeen years. The area of

intersection constitutes 29,000 km2 of mostly pelagic and some coastal h~bitat.

The area around Point Hope, which v.;as important for Cape Thompson birds in 1995, was

completely avoided by Lisburne murres in 1996, as in 1995. Although tYe have no knowledge of

Cape Thompson murre movements iq 1996, we suspect that the two colo'nies once again foraged

in different areas during the summer ~onths. As was true in 1995, no apparent differences were

seen in the movements between male.~ and females (Fig. 6). Some studies have suggested thickbilled murres forage farther from land than common murres (Swartz 1966, Drury et al. 1981, \ . I

Gould et a1. 1982). We were not able to verify this for commuting birds; but there appeared to be

I ,

no difference in foraging distance between the species for individuals tM.t abandoned nesting

attempts (Fig.7).: '

I

We were able to track 5 murres past the breeding season. Two were still in the vicinity ofthe

colony on 10 and 19 October, respectively, when their transmitters stopped working (Figs. All

and A14). Two left the area 1 and 5 September, respectively (Figs. A2 and A.8), and moved

south through Bering Straight (Fig. $). The fifth murre had a PTT that failed (only 2 locations

4
received) but gave One location afterb,reeding season (Fig. A.16). Migration was similar to that

sFen in 1995 (Fig. 9). No apparent staging areas were used, and final destination appeared to be

an area near the Pribilof Islands.

kortality and Transmitter Faiiure

te biggest single factor in the relatively low number oflocalions was transmitter failure. Ofthe

1

1

6 transmitters deployed, 8 failed within the first 2 weeks of deployment. Six failed completely,

ahd 2 gave sporadic signals up to 3 months later. In addition to transmitter failure, battery life

Jas shorter. The longest time in contact was 126 days in 1996 compared to 258 days in 1995.

Lin 1995, :e encountered murre mortality. Bscause oftransmitter failure, the extent ofthis

clortality was uncertain, and we were not able '"to clarify its cause. We were unable to track 6 of

tlie birds past the 2-3 week window in which we observed most mortality in 1995. Gfthe 10

I

birds for which the fate is known, 3 died (30%), and 7 outlived their transmitters. Ofthe 3 birds

that died, 1 had a short cycle transmitter and 2 "had long-cycle transmitters (Table 4). .

niS}:USSION

,."

iata Quantity and Quality • .

In general, the new batteries did not perform as well as the batteries used in 1995. Due to the I

high internal heat ofthe bird, the batteries tend to discharge even when the transmitter is

s~itched off. In order to counteract this discharge, a chemical coating covers the nodes during

tHe off period. This chemical can, however, build up to such alevel that the electrical current is

u~able to break it down, and the current is not able to flow. This process is known as

pcbsivation, and it caused the early cessation ofmany transmitters in 1995. To overcome this

pioblem, we deployed a battery with larger surface area at the nodes. However, we also

idcreased the offtime for the long-cycle transmitters. The longer the PIT is switched off, the

rrlore likely passivation is to occur, and we believe the extended off period counteracted the

irltproved battery design. ".

I

The high rate oftransmitter failure probably was due also to the new battery type. In addition to

thb differences already discussed, this year's battery also contained a fuse which was not present

id 1995. When examining a recovered 1995 transmitter, we noticed that the PTT case was

I

slightly compressed. We hypothesize that high pressure due to water depths compresses the .

eke, forcing internal parts in the PTT to touch each other, effectively shorting out the circuitry.

S~ch a short would blow the battery fuse, and the transmitter would quit working even though

thb battery might still contain adequate charge. This compression presumably occurred both

yJars, but because no fuse was present in 1995, the PTTs continued to transmit. Data from 1995,

h6wever, do indicate several sporadic transmitters.

5
Movements and Distribution

Some care must be given to the interpretation ofthe distribution charts for this year's data. First,

this year's movements reflect only nonc6mmuting murres or murres that made very few trips

back to the colony. Second, because the~ sampling period between short anq long cycle

transmitters was so different, on maps that contain both, the majority of points are from a few

birds with short-cycle transmitters. Therefore areas with dense clusters of points may look like

higher-use areas but really only represent the movem~nts of one ortwo bircis that were sampled

intensively. Looking at individual movements from the track lines in appel).dix 2 allows one to

assess more accurately where most bird~ are foraging. Taking this into account, we conclude that

the area just around the colony and just east-northeast ofthe colony were iqlportant locations.

The area east-northeast ofthe colony se~med to)e frequented by the birds just after release.

From there they tended to drift northward or eise returned to the colony and then drifted north.

We speculate that this area is a common feeding area while the bird has ties to the colony. Once

the decision is made to abandon the colony, ot~er areas might prove more productive. , I

Although few transmitters lasted until rnigratio.n, we received enough data to corroborate the

migration patterns of 1995. The outer continentalshelf around the Pribilofs has been studied

intensively and has been shown to be a prod~tlve area (Woodby 1984) containing persistent

fronts (Kinder et a1. 1983, Schneider et a1. 1~.90, CoyIe et a1. 1992) that tend to concentrate prey.

This area may be extremely important for wintering murres from several colonies. We have

learned that murres from both Cape Thompson and Cape Lisburne winter in the vicinity. It is not

unreasonable to assume that murres from other colonies along the west coast of Alaska spend

some ofthe winter months in this area. :In addition, the PribilofIslands themselves support a

large number of breeding murres (the colony at St. George contains over a'miilion murres), and it

is likely that some ofthese birds also Jinter in the area. Ifthis is true, the 'well-being of many

,seabird colonies along the coast of Alaska may depend on the health of a relatively small area of

pelagic habitat. '

Mortality and Transmitter Failure

In 1995, we proposed many possible fcictors involved in murre mortality (Hatch et al. 1996). Of

those, most remain possible, but data ITom 1996 allowed us to rule out seVeral. The possibilities , ' , we now consider unlikely are as follows: 1) Picric acid. Because we observed mortality again

this year, and we did not use picric acili, we can probably rule ou~ the effebts ofthis dye. 2)

Hypothermia. These transmitters hav~ now been implanted successfully in spectacled eiders

(Petersen et a1.1995), common loons d<.. Kino, pers. comm.), and harlequin ducks (S. Brodeur,

pers. comrn.). In addition, smaller conventional transmitters have been implanted with the same

surgical technique in harlequin ducks (Dan Esler, pers. comrn.) The succ~ss ofimplantations in

these species suggest that hypothermi~ is not a likely problem, as murres should be at no greater

risk than other birds living in cold-water environments. 3) Bulk oftransmitter causing false

sense of fullness. This hypothesis appears unlikely as harlequin ducks are smaller birds but show

fewer problems. 4) Added weight impairing ability to fly. Although this remains a possibility,

our data show that birds that die are often in the same areas as birds that live. This suggests that

birds are not restricted in finding suitable feeding areas by potential flight problems. We do not

6
" -"

/

-S- M· i_,.j

- ~Iave enough .data to comp~etely rul:~.,~ut)~is hypoth~sis, .po~ever, and it is still possible that

Tcreased weIght and densIty assocrated WIth transmItter Implants affects diving ability.

<pf all the species so far implanted, only murres and puffins have shown increased mortality.

These birds are also the only deep-diving species that have been released immediately to the

tater after surgery. This suggests a problem related to the depths to which the birds dive. The

possibility exists that high pressure on the unhealed incision compromises that incision, either

~ausing pain during foraging or forcing water into the body cavity, thereby producing infection.

The possible effect ofthe transmission on foraging behavior or physiology has not yet been

90nfirmed and also remains a viable hypothesis. Ofthe 16 hypotheses we prop~sed in 1995, we

trOW consider''Only 5 to be reasonable candidates (Table 6). Those 5 all relate to either diving

depths or PIT transmission.

CONCLUSIONS:

~he results ofthis study, together with those frpm 1995, have shown satellite telemetry to"be a

relatively accurate, efficient, and cost-effective way to obtain data heretofore unavailable. We

Have also learned, however, that abdominal'irp.plantations, while effective in many species, are

nbt the preferred method of attachment for mUrres and puffins. Since this study was conducted,

stnall external satellite transmitters have bec~rhe available, and methods are being developed to

Pfrmanently attach external mounts to diving brrds (S. Newman, pers. comm.). We believe these

nrw methods may be the answer to attachment problems for external mounts. In addition, Argos

has plans to launch a new;more sensitive receiver in 1997-1998. This receiver will increase data

qfantity and quality. The combination ofincreased accuracy, the development ofsmaller

t~ansmitters, and the development of new transmitter capabilities (e.g., time-depth recorders) all

f0recast a bright future for satellite telemetry in seabirds.

*O]Ogica1 findings ofthe 1995 and 1996 studies are also encouraging. Previous to this study,

movements ofindividual murres from a given colony were not well understood. We have

e~tablished foraging ranges, migration routes, nursery areas, and wintering areas of birds from

sJveral colonies, as well as identifying several key habitats. We have shown the area around

pbrenosa Bay to be an important foraging area for birds from the Barren Islands. In the Chukchi

Sba, we have learned that both the summer distribution of noncommuting murres and the nursery

atea for post-fledging chicks are extremely large. Finally, we have shown that areas around the

phbilof Islands are important wintering areas with possible ecological importance to many

,sJabird colonies. Further evaluation ofthis area to determine its extent of use by murres from

other colonies is desirable. A small number of PTTs should be deployed on murres from

c~lonies in Kotzebue Sound, Norton Sound, St. Lawrence Island, St. Matthew Island, and

I

Nunivak Island to determine whether these colonies all rely on the same wintering area.

ACKNOWLEDGMENTS

We thank the MMS for their support, and the Alaska Maritime National Wildlife Refuge,

7
)

j

)

~I

../
~J ..., 1_ (~

especially M.F. Chance and P.F. Chance for their logistical support and advice.

LIT~RATURE ~ITED

Ancel A., G.L Kooyman, P.J. Ponganis, J-P Gendner, J. Lognon, X. Mestre, N. Huin, P.H.

Thorson, P. Robisson, and Y. Le Maho. 1992. Emperor penguins foraging behaviour as a

resource detector in winter and summer. Nature 360:336~339.

Birkhead, T.R. and P. 1. Hudson. 1977. Population parameters for the common guillemot Uria

aalge:' Ornis Scand. 8:145-154.

Bradstreet, M. S. W. 1979. Thick-billed mUIT~~ and black guillemots in the Barrow Strait area,

N.W.T., during spring: distribution and habitat use. Can. J. Zoo1. 57:1789-1802.

Bradstreet, M. S. W., and R. G. B. Brown. 1985. Feeding ecology ofthe Atlantic Alcidae. Pp.

263-318 in The Atlantic Alcidae (D. No, Nettleship and T. R. Birkhead, Eds.) Academic

Press. London. '

I ' Cairns, D. K., K. A. Bredin, and W. A. Mont~vecchi. 1987. Activity budgets and foraging

ranges of breeding common murres. 'Auk 104:218-224.

Goyle, K.O., G.L. Hunt, Jr., M.B. Decker, T.J Weingartner. 1992. Murre foraging, epibenthic

sound scattering and tidal advection over a shoal near St. George Island, Bering Sea.

Mar. Ecol. Prog. Ser. 83:1~14.

Davis, L.S. and G.D. Miller. 1992. Satellite tracking ofAdelie penguins. Polar BioI. 12:503~

506.

Drury, W. H., C. Ramsdell, and J. B. French. 1981. Ecological studies in the Bering Strait

region. U.S. Dep. Commer., NOAA OCSEAP Final Rep. 3:175-486.

Falk, K. and S. M0ller. 1995. Satellite tracking of high-arctic northern fulmars. Polar BioI.

15:495~502.

Fadely, B. S., 1. F. Piatt, S. A. Hatch, and D. G. Roseneau. 1989. Populat'ions, productivity, and

feeding habits ofseabirds at Cape Thompson, Alaska. U.S. Fish and Wildlife Serv., Final

Rep., OCS Study MMS 89-0014;

Gaston, A. J., and D. N. Nett1eship. 1981. The thick-billed murres of Prince Leopold Island.

Can. Wildl. Servo Monogr. No.6.

Gould, P. J., D. J. Forsel, and C. J. Lensink. 1982. Pelagic distribution and abundance of

seabirds in the Gulf of Alaska and eastern Bering Sea. U.S. Dep. Int., Fish and Wildl.

Serv" FWS/OBS-82/48. 294 pp. .

8

•
Hatch S.A., P.M. Meyers, D.M. Mulcahy, and D.C. Douglas. 1996. Seaso~al movements and

pelagic habitat use ofmurres and puffins determined by satellite telemetry. Exxon Valdez

Oil Spill Restoration Project Final:Report (Restoration Project 95021), National Biological

Service, Anchorage, Alaska. '

I

Jouventin, P. and H. Weimerskirch. 19?0. Satellite tracking of wandering albatrosses. Nature

343:746-748. I

Kinder, T.H., G.L. Hunt, Jr., D. Schneider, J.D. Schumacher. 1983. Correlations between

seabirds' and oceanic fronts around the PribilofIslands, Alaska. Est., Coastal and Shelf Sci.

16:309,..319.

i ' , . Mendenhall, V. M., (ed.). 1993a. Monitoring of populations and productivity ofseabirds at St.

Matthew Island, Bluff, and Cape Thompson, Alaska, 1991. U.S. Fish and Wildlife Serv.,

Draft Rep., OCS Study MMS 9,1-00_." i

i

I, :.

Mendenhall, V. M., (ed.). 1993b. Monitoring of populations and:productivity ofseabirds at

Cape Pierce, Bluff,and Cape T~ompspn, Alaska, 1990. U.S. Fish!and Wildlife Serv.,

Final Rep., OCS Study MMS 9~-0047: \

Nettleship, D. N., and A. J. Gaston. 1978. Patterns of pelagic distribution ofseabirds in western

Lancaster Sound and Barrow Strait, N.W.T. Can. Wildl. Servo Occ. Pap. No. 39. I ! I

Petersen, M.R., D.C. Douglas, and D.¥. Mulcahy. 1995. Use of implant~d satellite transmitters

to locate spectacled eiders at-sea. Condor 97:276-278.

Schneider, D. and G. L. Hunt, Jr. 198~. A comparison ofseabird diets arid foraging distribution

around the PribilofIslands, AI~ka. Pp. 86-95 in Marine birds: their feeding ecology and

commercial fisheries relationsl1ips (D. N.Nettleship, G. A. Sanger, and P F. Springer,

Eds.) Canadian Wildl. Serv., Ottawa.

I

Schneider, D., N.M. Harrison, and G.J;.-. Hunt, Jr. 1990. Seabird diet at a' front near the Pribilof

Islands, Alaska. Stud. Avian BioI. 14:61-66. I

I

I

Springer, A. M., E. C. Murphy, D. G.iRoseneau, and M. 1. Springer. 1985. Population status, I

reproductive ecology, and trophic relationships ofseabirds in northwestern Alaska. U.S.

Dep. Commer., NOAA OCSBAP Final Rep. 30:127-242.

,

Swartz, L. G. 1966. Sea-cliff birds. Pp. 611-678 in Environment oftheiCape Thompson region,

Alaska (N. J. Wilimovsky and J. N. Wolfe, Eds.). U.S. Atomic Energy Commission, Oak I '

Ridge, Tennessee.

9

, ~,- f}
.~-~-------------_.-

UJ.S. Fish-and Wildlife Service. 19';)7. Alaska seabird cOlony catalog-eomputer database and

colony status record archives. U.S. Fish and Wildlife Service, Migratory Bird

Management, Anchorage "AK.

Weimerskirch H., and G. Robertson. 1994. Satellite tracking oflight-mantled sooty albatrosses.

Polar BioI. 14:123-126.

Weimerskirch H., M Salamolard, F. Sarrazin, and P. Jouventin. 1993. Foraging strategy of

wandering albatrosses through the breeding season: a study using satellite telemetry. Auk

110:325-342

Woodby, D.A. 1984. The April distribution ofmurres and prey patches in the southeastern

Bering Sea. Lirnnol. Oceanogr. 29:181-188..

~''''.

,J

,.

10
I

Table 1. Deployment of 16 satellite transmitters ; in common and thick-bille'd, murres at Cape

Lisburne, AK, August 1996. !

Number of Transmitters

, ~. - f,

Short Cyple Long Cycle

Common Murre

Thick-billed Murre

Total

Males Females Males Femalys

1 2 2 1

3 2 ,...... 3 2

4 4 5 3

, j

,..

11

Total

6

10

16
Table 2. Summary of bird location data obtained through 31 December 1996.

Breeding Seasona Postbreeding Seasonb Total

MessagesC 758 247 1005

Locations 595 163 758

Culled Locations 167 56 223

Useable Locations 428 107 535

.-... acapture to first migrational movements (3 Aug-31 Aug)

bFirst migrational movements to last location received (1 Sep-31 Dec)

CSatellite overpasses with at least one signa;l received from a PTT

,'

12

-
Table 3. Comparison oftransmitterf

performance and data acquisition between

1995 and 1996. I

1995i 1996

Murres Implanted 30 16

Average Battery Lifea 116 81

Locationslbirda 102 I 87

I ....

Percent of Locations culled 22.1, 29.4

abirds that outlived PTT and transmittersthat

did not fail early

! '

,.'

13
'"

,<-;t·

TabJe~4~Details-of-satdlite-transmitter-deplo-ym@nt-by-speeies,duty-cycle,and-performance-in~1996.

Species PTr Sex Program Date Last Contact Days in Total Useable Outcome

Released3 Contact Locations Locations

COMU 5851 F Short 3 Aug 7 Dec 126 288 196 outlived PTT

COMU 5852 M Short 3 Aug 8 Aug 5 6 6 PTT failed

TBMU 5853 F Short 5 Aug 8 Aug 5 8 7 PTT failed

TBMU 5856 M Long 4 Aug No Signals 0 0 0 PTT failed

TBMU 7875 M Long 4 Aug 4 Aug 1 17 4 died

TBMU 7876 M Short 4 Aug 12 Aug 8 10 4 PTTfailed -,

COMU 7879 F Long 4 Aug 5 Nov 93 . 28 22 outlived PTT .... ..... TBMU 7880 M Short 4 Aug No Signals 0 '" ·0 0", PTT failed I

COMU 7882 F Short 5 Aug 5 Sep 31 29 24 outlived PTT

COMU 7884 M Long 3 Aug 29 Oct 87 32 25 outlived PTT

TBMU 7887 F Long 4Aug 4 Aug <1 6 4 died

COMU 7888 M Long 3 Aug 10 Oct 68 58 49 outlived PIT

TBMU 7901 F Long 5 Aug 21 Dec 138 2 2 PIT failed but indicated bird's

survival through day 138

TBMU 7903 M Long 5 Aug 23 Oct 79 8 6 PIT failed but indicated bird's

survival through day 79

TBMU 7915 M Sp.ort 5 Aug 24 Aug 19 229 165 died

TBMU 7917 F Short 5 Aug 16 Aug 11 37 21 PTT failure

3Date is for Greenwich Mean Time
Table 5. Frequency distribution of data by Argos location classes.

Before Culling After Culling

Argos Signal

Quality Code

No. Locations % oftotal No. Locations! % oftotal

3

2

1

a

a

.b

z

Not classified

Total

35 4.6 34 6.4

95 12.5 89 16.6

.. -"

182 24.0· 167 31.2

143 18.9 94 17.6

122 ·~6.1 82 15.3

138 ! 1J8.2 59 11.0

,. 39 5.1 9 1.7

4 0.5 1 0.2

758 99.9 535 100

;

15
Table 6. Hypothesized causes of murre mortality associated with satellite transmitter

implants.

A. Depth-related

(1) Increased pressure due to diving causes discomfort or rupture of new incision~

leading to chronic pain or infection

(2) Bulk-PIT introduces mechanical pressures on internal organs, especially at

depth.

B. Transmission-related ,j -_.

(1) Transmission causes discomfort or disorientation (neurotransmitter release,

heart arrhythmia, effects on magnetite in brain, radio frequency 'bums',

other?) .

(2) Transmission causes impairme~t ofimmune system (effects on bursa, T-cell

.production, effects on unhealep tnembranes)'

(3) Prey detecting radio signals ~d avoiding predation

16
Figure 1. Study site location.

\

\.

Cape,--.'

Lisburne

17
---r------:-.1

_

At least

2 messages

per satellite pass

Location

Algorithm

At least

.4 messages

;/'

Class 3: better than 150 m

Class 2: better than 350 m

Class 1: better than 1000 m

;. Class 0: above 1000 m

2or3

messages

Class A:

""

3-message

location

Class B: 2-message

location

Unvalidated

Location

Class Z

, igure 2. Location quality Classes assigned by Argos. (Source: Argos, Inc. Newsletter, October,

1995.)

18
Figure 3. Distribution of Cape Lisburne rnurres during the breeding season, 996.

I

ii

o

Chukchi

Sea

I H H

25 0

Kilometers

I '

50

,0

I

100

o OIl

o

o

o

o

,

I

lWl'

19
----r------·~I-------- _

Fi ure 4. Distribution of Cape Lisburne murres during the breeding season by year. Squares

represent 1996 distribution, and circles represent 1995 distribution.

I

o

o

Kilometers

50 100

I H H I

o

25 0

20
Figure 5. Minimum convex polygons for Cape Lisburne murres during the Breeding season. These

foraging areas mainly represent murres that had abandoned nesting and were no longer commuting

to the colony. I I

J

i

.1\

,/" \

'" \ "," '\

// '\ 1995

/ \ /' / \

/ \

",I' \

/ \ / \

// \

/ \

// \

/ \ ' 'I' \

/ \

// \

\

\

\

\

\

\

\

\

\

\

\

\

\

\

\

\

100

\

\

\

\

\

\.,

,

'I'

"j,

, "

"....

"

" "" "'"

50

/

/ !/

/ /1

/ '

/

/

/

/

/

/

/

/

\

\

\

\

\

\

\

\

\

\

\

\

\

\

\

Kilometers

1996

I H H

25 a

21
1_

Figure 6. Distribution ofCape Lisburne murres during the breeding season by sex. Squares represent

fem!les and circles represent males.

I

Kilometers

o

Chukchi

Sea

18 H I

125 a

I

50

< ..

100

22
\~ 4·

,

Figure 7. Distribution ofCape Lisburne murres during the breeding season by species. Squares

represent common murres and circles represent thick-billed murres. i

p

5b I 0

o g~~@IDI 0 I 0 I

i 0

o

0c@

""

o

o

OlllJ

o

100

I

50

Kilometers

I.

Chukchi

Sea

I H H

25 a

23
Figure 8. Migration of 3 murres from'Cape Lisburne, AK, 1996.

-

24
Figure 9. Migration of CapeLisbume muJes by year. Solid lines re~resent 1996 murres and

dashed lines represent 1995 murres. i I

o

25

300 600
EFFECT OF IMPLANTED SATELLITE TRANSMITTERS ON THE NESTING

BEHAVIOR OF MURRES

ABSTRACT

We implanted 6 Common Murres (Uria aalge) and 10 Thick-billed Murres (Uria lomvia) with

~atel1ite transmitters and compared subsequent presence at the colony, nesting status, and chick

Jrovisioning to a control group that underwent a minor surgical procedure. In the 10 days

~ollowing implantation, we resighted 10 of 11 control birds at the colony and 6 of 16 implanted

birds. Ofthe 'birds that returned, 7 of 10 control birds retained breeding status, while 0 of 6

ibplanted birds retained breeding status. We cpnclude that abdominal implantations alter murre I.. ; '" nestmg behavIOr.

lev Word~: behavior, Common Murre, implantation, nesting, PIT, satellite telemetry, satellite

t~ansmitter, seabird, Thick-billed Murre, Una aalge, Una lomvia. . I .

INTRODUCTION ! /

I he advent ofsatellite transmitters small eno'rtgh for use on seabirds has generated many recent

s~dies ofseabird foraging and migration (Jouventin and Weimerskirch 1990, Ancel et al. 1992,

IDavis and Miller 1992, Weimerskirch et aI. 1993, Weimerskirch and Robertson 1994, Falk and

N1011er 1995, Petersen et aI. 1995, Hatch et aI. 1996). Satellite telemetry offers a way to track

ihdividual animals anywhere in the world without the logistics involved in conventional VHF

d~lemetry. Secure attachment of any device without causing behavioral changes, however, has

~een a persistent problem for biologists working with diving birds (Woakes and Butler 1975,

~erry 1981, Wilson et aI. 1986, Wanless et al. 1988 and 1989, Calvo and Furness 1992).

Abdominal implantation (Korschgen et al. 1984) is an alternative to various externally mounted

~ackages and has been used successfully in diving birds (Petersen et al. 1995, D. Esler Biological

Resources Division-USGS, pers. comm.). Implantation results in no appreciable increase in the

~ird' s surface area, does not compromise feathers, and leaves no chance ofthe bird losing the.

transmitter. However, no information is available on the behavioral effects ofimplantation.

Ihterpretation of any telemetry study assumes that normal behavioral patterns are retained or that

I

aherations in behavior can be adequately addressed. To assess possible changes in behavior, we

ifuplanted 16 murres with satellite transmitters and compared returns to the colony, nesting I ,

status, and returns with fish between implanted birds and control birds that underwent minor

I

surgery.

STUDY AREA AND METHODS

Gape Lisburne is on the Chukchi Sea about 60 km north of Point Hope on Alaska's northwest

cbast. This area supports approximately 70,000 common murres (Uria aalge) and 130,000 thickbbled murres (Uria lomvia) (U.S. Fish and Wildlife Service, 1997) and is the northernmost

26
Pacific murre colony of its size. Black-l'egged kittiwakes (Rissa tridactyla)'also nest there in

large numbers. Other seabirds include p'elagic connorants (Phalacrocorax pelagicus), black

guillemots (Cepphus grylle), glaucous gulls (Larus hyperboreus), and horned puffins (Fratercula

corniculata). :

Beginning 2 August 1996, we captured resting murres with a light cable noose attached to a 9-m

telescoping fiberglass pole. We took murres from lower ledges at the east end ofthe colony in

areas that were accessible by foot from Cape Lisburne radar station. Capture areas consisted of 3

ledge complexes ~0.5 km apart. The birds were transported in burlap bags,to the station where

we banded them with colored tarsus bands. To assign birds to the ,implant Or control group, we

chose a bird at random, anaesthetized it; and surgically sexed it using a rigi,d endoscope inserted

through the last two ribs on the left side or through the implantation incision. Our primary goal

was to obtain an even sex ratio for both species"rn the transmittered group.' Upon sexing a bird, it

was assigned to a group depending on the number ofthat sex and species already in the

transmittered group. Because the first few birds were automatically assigned to the treatment , ,

group, control birds averaged longer times in the holding bins than i.mplanted birds. I,

: I

Experimental birds were sexed and implanted (Korschgen et al. 1984, Hatch et al. 1996), and

control birds were sexed and allowed to recbvet; from anesthesia. All surgery was performed by i I·

a veterinarian experienced in implantat~on techniques. Birds were released 1-3 hours after

surgery. Processing time from capture!to release was from 6.5-13.5 hours. The transmitters we

used were 35-gram platform transmitting terminals (PTTs) described by Hatch et al. (1996).

Beginning the day following surgery, ~e performed spot checks for preseAce of banded and

transmittered birds. Each day from 5 August-14 August 1996, we conducted one 6-hour focal

observation ofa capture area, alternatiI,lg areas each day. During the cour~e ofthe study, we

covered all hours of adequate daylight {0600 to 2400 ADT) at each capture area. We recorded "

an'ival and departure times, nesting sta,tus, and returns with fish. Observations were done with

binoculars and a spotting scope from al

point that was out ofthe normal flight path ofthe birds.

After each observation period, we performed spot checks ofthe other caphIre areas. Proportions

were analyzed with 2-tailed Fisher's ebct tests, and differences between fueans were analyzed

with 2-tailed Student's t-tests. ' ,

I

A bird was considered definitely nesting if we observed it taking over or ~eaving a nest, or

bringing fish to a nestling. A bird waS considered probably nesting ifit ~as attending a nesting

bird (e.g., standing very close, placing its bill where the chick would be) but was not actually

seen taking over brooding.: ' , '

RESULTS

We captured 31 murres, 16 of which we implanted (Table 7). Thirteen birds were incubating, 9

were attending chicks, and 9 were nesting but we could not determine nesting stage. Four ofthe

birds exhibited severe stress-3 died and 1 was released 10 minutes after' capture-and were " I

27
excluded from the study. Three ofthese stressed birds, and possibly the fourth, had newly

fuatched (:::; 3 day-old) chicks.

either weight (I 0.70, P 0.49, df 25) nor wing length (I 1.24, P 0.22, df 25) were

1ignificantly different between the treatment and control group. Handling time was longer for

the control birds (mean ± SD = 11.0 ± 2.3 hours) than for the implanted birds (8.9 ± 1.9 hours) (t

+-2.52, P =: 0.02, df= 25). We resighted significantly more (P = 0.015) control birds (10 of 11)

than transmittered birds (6 of 16). Ofthe resighted birds, we tended to see individuals from the

dontrol group more often (3.1 ± 1.8 sightings/bird) than individuals from the implanted group

(12.0 ± 1.5 sightings/bird), but the difference was not significant (t = -1.25, P = 0.23, df = 14).

Ifthe 10 control hirds resighted, 4 definite!y remained nestin~ and 3 addit!onal hirds probably

rfmained nesting. Two control birds either lost"or abandoned their nests, 1 control bird was not

rFsighted either because it brooded continuously or it did not return to the colony, and nesting

s~a~s co~Id ~ot be determined for another. O~ the .6 transmittered birds resighte~, none ren:aim;d

nestmg; sIgmficantly fewer (P =0.011) than bIrds m the control group when we mcluded buds

~robably nesting. The proportion was not sig~ficantly different (P =0.23) when we included

0h1nlY birds definitely nesting. We observed only 4 instance's of birds returning with fish. All of

t ese were in the control group. . I j " ,

~UbSeqUent telemetry signals (unpubl. data) Irtdicated that 3 ofthe 16 implanted birds died, 7

l~ved, and ,6 had transmitters that failed prematurely. The fates ofthese latter 0 are unknown. Of

the 7 that remained in contact, 4 were resighted during observations. Ofthe 9 that died or

I

.qisappeared, 2 were resighted during observations. These proportions were not significantly'

different (P =0.30) from each other.

. DISCUSSION

I e largest difference between groups was the likelihood that birds would return to their former'

ledges--91% of control birds were resighted, compared to 38% ofthe transmittered birds. We

~ay have underestimated the proportion of control birds returning, however, because tarsus

b1ands were difficult to observe when the bird was brooding. Two ofthe control birds may have

r~mained on the nest during entire observation periods and therefore were not recorded as

p1resent. We are reasonably certain that we did not miss any transmittered birds in this way, as

ahtennae were clearly visible. Elimination ofthis potential bias could only increase the

d[fferences we observed; and therefore, not affect our conclusions.

I

Golony abandonment by so many ofthe implanted birds was unexpected. Although the

p~oportion ofresighted birds within groups was not significantly different between those that

shbsequently died or disappeared, power of our test was low ((3 = 0.29). Given that at least 3

i?dividUals died within the observation period, the general health ofthe bird after surgery must

bF considered the most likely explanation for both colony abandonment and disruption of

breeding by those birds that did return.

28
,

I I I I

Ofthe murres that did return to the colorly, fewer implanted birds than control birds remained

nesting. Considering that control birds J.ere removed from th~ nest for anek'en longer period of

time than implanted birds; we cannot atttibute nesting failure to time offthe1nest. Changes were

likely due to the implantation procedure :or to the transmitter itself. Hatch et a1. (1996) stated that

25% of murres from Cape Lisburne and rape Thompson probably remained nesting after

implantation in 1995. Productivity in 1995 was higher than in 1996(D.G. Roseneau, U.S. Fish

and Wildlife Service, pers. comm.), ho~ever, and 1996 may have been a mbre stressful year.

ii,

r i

Murres are probably the deepest diving ~lcid (Piatt and Nettleship 1985), a9d alcids in general

have higher wing loads than other flying seabirds (Pennycuick 1987). Either ofthese factors

(i.e" pressure on a new incision due to diving, ~)I; increased wing load) may! have affected bird

behavior. Smaller transmitters would h~lp in Doth regards. :

i I .

Other seabirds may be better adapted thlm murres, both physically,and beh~viorally, for

implantation. Spectacled Eiders, Somaieria fischeri, (Petersen et a1. 1995)/ are larger (~ 1000 g I I

verses 896 ± 69 g) and remain inland s~veral weeks after implantation, thu~ giving birds time to

recuperate before the stresses of diving 'in a marine environment. ,Harlequip Ducks (Histrionicus

histrionicus) have been successfully implarit~d with VHF transmitters (D. r:sler, Biological

Resources Division-USGS, pers. comm:.), bu~ the devices are smaller and the depths these birds I, ( j

reach are probably much shallower. The effeCts of abdominal implantation may vary among,

species and may also depend on transrrtitter design. Therefore we suggesttlus method be

assessed species-by-species. In the cas~ of murres, we conclude that nestihg behavior of

implanted muri:es differs significantly from nesting behavior of n~n-implahtedmurres. Data

received after abdominal implantation inust be interpreted with this in m~d. I j

I

I

ACkNOWLEDGMENTS

i

!

We thank the Minerals Management Service fo~ their support; M.F. Chance and P.F. Chance

from the Alaska Maritime Refuge for their valuable advise and logistical help; and IW. Hupp,

T.S. Smith, and'W.D. Ostrand for theif manuscript reviews. ' I

I

I

i

I

LfTERATURE CITED I

I , ,i

Ancel A., G.L. Kooyman, PJ. Pongarlis, J.-P. Gendner, J. Lognon, X. Mestre, N. Huin, P.H. I, ' j

Thorson, P. Robisson, and Y L~,"Maho. 1992. Emperor Penguins foraging behaviour as a I

resource detector in winter and summer. Nature 360:336-339. t

• I

Calvo, B., and R.W. Furness. 1992. kreview ofthe use and the' effects bfmarks and devices on

birds. Ringing Migr. 13:129-1511. . j

29

,

i

i,

j

I

,

I

I
! ;

-~-~--.....--~--~~---------

Davis, L.S. and G.D. Miller. 1992. Satellite tracking of Adelie Penguins. Polar BioI. 12:503-

506.

lfalk, K. and S. M011er. 1995. Satellite tracking of high-arctic Northern Fulmars. Polar BioI.

15:495-502.

match S.A., P.M. Meyers, D.M. Mulcahy, and D.C. Douglas. 1996. Seasonal movements and

pelagic habitat use ofmurres and puffins determined by satellite telemetry. Exxon Valdez

Oil Spill Restoration Project Final Report (Restoration Project 95021), National Biological

Service, Anchorage, Alaska.

Jouventin, P. and H. Weimerskirch. 1990. Sat~llite tracking of Wandering Albatrosses. Nature

343:746-748. < ...

Korschgen, C. E., S. 1. Maxson, and V. B. Kuechle. 1984. Evaluation ofimplanted radio

transmitters in ducks. l Wildi. Manage. '48:982-987.

,

Berry, M.C. 1981. Abnormal behavior ofCan~asbacks equipped with radio transmitters. l .

.Wildl. Manage. 45:786-789.

Bennycuick, C.l. 1987. Flight ofseabirds, p'. '43-62. In J.P. Croxall (ed.), Seabirds: feeding

ecology and role in marine ecosystems. Cambridge Univ. Press.

Retersen, M.R., D.C. Douglas, and D.M. Mulcahy. 1995. Use ofimplanted satellite transmitters

to locate Spectacled Eiders at-sea. Condor 97:276-278.

ii.tt, J.F. and D.N. Nettleship. 1985. Diving depths offour .1cids. Auk 102:293-297.

U.S. Fish and Wildlife Service. 1997. Alaska seabird colony catalog--eomputer database and

colony status record archives. U.S. Fish and Wildlife Service, Migratory Bird

Management, Anchorage AK.

Wanless, S., M.P. Harris, and l.A. Morris. 1988. The effect ofradio transmitters on the 1behavior ofCommon Murres and razorbills during chick rearing. Condor 90:816-823.

anless, S., M.P. Harris, and lA. Morris. 1989. Behavior of alcids with tail-mounted radio

transmitters. Colonial Waterbirds 12:158-163.

Weimer~kirch H., andG. Robertson. 1994. Satellite tracking oflight-mantled Sooty

Albatrosses. Polar BioI. 14:123-126.

Weimerskirch H., M. Salamolard, F. Sarrazin, and P. louventin. 1993. Foraging strategy of

Wandering Albatrosses through the breeding season: a study using satellite telemetry. Auk

110:325-342

30
I.

Wilson, R.P., W.S. Grant, and D.C. Duffy. 1986. Recording devices on free-ranging marine

animals: does measurement affect' foraging performance? Ecology 67:1091-1093.

Woakes, AJ., and PJ. Butler. 1975. An implantable transmitter for monitoring heart rate and

respiratoryfrequency in diving d*ks. Biotelem.2:153-160. .:

".....

, j

i

31

<!' :-

~r. t
'. ,1',

I able 7. Nesting stage at time of capture, treatment, and post-'operative behavior ofCommon and

thick-billed Murres captured at Cape Lisburne, August 1996.

I

Bird Treatment Species3 Sex Nesting Processing Total Remained

I Stage time (hrs) Resightings Nesting?

1 Implant COMU F ?b 8 0 No

I

2 Implant COMU M ?b 7 2 No

oJ Implant TBMU F Egg 7.5 0 No

I

4 Implant TBMU M Egg 8 0 No

I

5 Implant TBMU M Egg 8 0 No

I

6 Implant TBMU M Chick 7.5 0 No I

J Implant COMU F ?b <t' - ...

' 10.5 5 No

Implant TBMU M Egg 10.5 0 No

I

9 Implant COMU F Egg 11 1 No

I

10 Implant COMU M Egg 7 1 No

I

11 Implant TBMU F Egg 10.5 0 No

I

12 Implant COMU M Egg 6.5 1 No

13 Implant TBMU F Chick ' "7 0 No

I . 14 Implant TBMU M ?b

! ' 11.5 0 No

IS Implant TBMU M Egg",., 1l.5 2 No

16 Implant TBMU F Egg 11 0 No

h Control COMU M Egg 8 6 ?b

]8 Control COMU M ?b 8 5 Yes

]9 Control COMU M ?b 7.5 5 Yes

I

20 Control TBMU ?b ?b 10 4 No I

21 Control TBMU M Chick 11 2 No

22 Control TBMU F Egg 13.5 1 Yes I

23 Control TBMU M Egg '11.5 1 Yes

I

24 Control TBMU M Chick 13 0 No

25 Control TBMU F Chick 12.5 2 Yes

26 Control TBMU F ?b 12 3 Yes

I

27 Control TBMU F Chick 13.5 2 Yes

28 TBMU M ?b Died in surgery

29 TBMU Chick Released

310 TBMU' Chick Died in transit

311 TBMU Chick Died in transit I

3~OMU=comrnon Murre; TBMU=Thick-billed Murre

I

b?=Unknown '

32

-
DAILY AND SEASONAL TEMPERATURE VARIATION IN F:REE-RANGING

"r MURRES

ABSTRACT

We implanted 20 common and thick-billed murres with satellite transmitters containing

temperature sensors and looked at daily and seasonal changes in body temperature. During the

breeding season, no predictable circadian pattern occurred. In the winter, however, birds showed

a lowered body temperature in the early morning hours and an increased body temperature in

mid-afternoon. Seasonally, body temperature was higher during the breed~ng season through

migration and lower during the winter fuonths. _..: '

Kev Words: Alaska, body temperaturel Cape Lisburne, circadian rhythm, common murre,

seabird, seasonal variation, thick-billed murre, Uria aalge, Uria lomvia

,

INTRODUCTION

1 !.'

Seasonal and circadian rhythms occur ~n mat1y birds and mammals. Body'temperatures in

particular have been shown to vary as much 3.0-4.5 C dailyin birds (Binkley et al. 1971,

Heldmaeir 1991), and 0.5-1 C in mammals (Aschoff 1982). Body temperatures for many , ,

seabirds have been documented (McNab 1966, Warham 1971, Iversen and Krog 1972, Johnson

and West 1975, Barrett 1984, Platania et al. 1986), and daily cycles have been described (Irving

1955, Howell and Bartholomew 1961,'Bartholomew 1966, Cooper 1979). But data on murre

temperatUre cycles are few, and no studies have tracked seasonal temperature changes of

individuals in the wild. As body temperature can be closely correlated to metabolism (McNab

1966, Gavrilov 1985) knowledge of how temperature changes from seasonto season may be

important in understanding murre energetics and climatic stress. In 1995, we implanted 20

murres with satellite transmitters that 90ntained temperature sensors. We:were able to sample

murre body temperatures over the course of months and record daily cycles and seasonal

changes. I ;

STUDY AREA AND METHODS

Cape Lisburne and Cape Thompson ar~ north and south, respectively of Point Hope on Alaska's

northwest coast. Cape Lisburne SUpP(!)rts approximately 70,000 common1murres (Uria aalge)

and approximately 130,000 thick-billt:rd murres (Uria lomvia) (U.S. Fish ~d Wildlife Service

1997) and is the northernmost Pacific;murre colony. Cape Thompson supports approximately

390,000 murres. Black-legged kittiwakes (Rissa tridactyla) are alsopres~nt in high numbers at

both sites. Other seabirds include pelagic cormorants (Phalacrocorax pelagicus), black

guillemots (Cepphus grylle), glaucous gulls (Larus hyperboreus), and hO,rned puffins (Fratercula

corniculata).

33

.r
:'1\

From 2-6 August 1995, we captured nesting murres with a light cable noose attached to a 9-m

~elescoping fiberglass pole. We took murres from lower ledges accessible from the ground or a

ladder. The birds were transported in burlap bags to a base camp where they were banded,

kaesthetized, surgically sexed, and implanted with transmitters (Korschgen et al. 1984, Hatch et

~l. 1996). Birds were released 2-6 hours after surgery. The transmitters we used were 35-gram

~latform transmitting terminals-PTTs (see Hatch et al. 1996). Each transmitter varied slightly

iln its absolute temperature reading. To calibrate each transmitter, we recorded ambient

t1emperature before implantation and allowed the PTT to transmit this information to a satellite.

I "

<Calibration information was not recorded by the satellite, however, so reported temperature

~alues may not be absolute. However, individual temperature sensors were accurate to within

0.33 C, and we were able to look at relative temperature changes over time in individual birds.

I . "-~ Eight ofthe transmitters were programmed to transmit for 6 hours and rest for 12 hours (short

9ycle). This pattern sampled a different 6-hour segment of~he day for each cycle. Twelve ofthe

transmitters were programmed to transmit for 6 hours and rest for 66 hours (long cycle). This

dattern should sample the same time period everyday. However, there was significant drift in the

i~ternal clock that.resulted in coverage throug~out the 24-hour clock over the course of weeks.

lihe short-cycle transmitters switched to long-cycle after 30 days of operation. I . ! j ""

Flor seasonal analysis, we averaged daily temperatures for each individual and plotted daily

means over time. For daily analysis, we divided the 24-hour clock into 4-hour segments and

a~eraged temperatures for each time segment. Southwick (1980) found that in White Crowned

sbarrows (Zonotrichia leucophrys gambelii), daily body temperatures varied more in winter than

s-ummer. Therefore, we compared data before and after the autumnal equinox (20 September).

Because daily sampling times varied among individuals, we compared means between seasons

b~ averaging mean temperatures ofthe 4-hour time periods and comparing overall seasonal

means with a paired t-test.

RESULTS

In general, average daily body temperature increased after implantation, remained high until late

S~ptember, and declined after that (e.g., Fig. 10). Of 9 birds for which we obtained adequate

d1ta, 8 showed an autumn decline in average body temperature similar to that seen in figure 10.

dfthese 8, 7 appeared to have a plateau of higher temperatures from about mid-August to midS~ptember or early October. This effect occurred regardless of whether the bird remained nesting I

after implantation and regardless ofsex and species (i.e., ofthese 7 birds, 3 were commuting

bilrds and 4 abandoned the colony; 3 were female and 4 were male, 3 were thick-billed murres

arid 4 were common murres). Average temperature after 20 September (38.5 C) was 0.6 Clower

th1an average temperature before that time (P = 0.001, t = 2.3, df= 8).

oh a daily basis, temperature fluctuation (difference between high an~ low averages for 4-hour

tithe periods) averaged 0.41 C before 20 Sep. and 0.65 C after 20 Sep. (P = 0.005, t = -3.8, df=

8)1. Before the autumnal equinox, birds showed no association of high temperature with time of

day. Ofthe 4-hour time periods, neither high temperatures (P < 0.75, X2 = 3.67, df= 5) nor low

34

-
temperatures (P < 0.90, X2 = 2.34, df = 5) were distributed differently than expected at random.

However, after the autumnal equinox, th.e average high temperature was found in the period of

15:00-18:59 AST in 6 of9 birds (P <0.0,05, X2 = 18.33, df= 5). The averag'e low temperature

was found in the period of3:00-6:5'9 AST for 7 of9 birds (P < 0.001, X2 = 25.0, df= 5). A

typical example is illustrated in Figure 1.

DISCUSSION

This study has shown that both seasonal and daily variation exists in the body temperature offree

ranging murres. Although this variation is small, it appears to be fairly consistent and

predictable among individuals. The increase in body temperature after rel~ase may have, in

some cases, been related to increased activity (B.arret 1984, Boyd and Sladen 1971, Howell and

Bartholomew 1962) due to chick provisioning. Hatching occurred just aft~r implantation and

chicks began to fledge around 1 Septeq-ber. This corresponds reasonably kell with the plateau

of higher temperature, given that the males thep escort the chicks out to se~ and provisioning

continues after fledging. The fact that the plateau lasts until mid-Septemb~r or early October

even in birds that abandoned nesting s~ggests·~at this increased temperatUre may be more a

seasonal adaptation, possibly cued by photoperiod (Heldmaier 1991), than' a function of activity. ; 1- j

, J

The change in body temperature throughout '~he day was fairly small when compared to smaller

birds (Welty 1982), but there was a slight drop during the early morning hours in winter. The

most interesting feature of daily temperature profiles was that no definabl~ pattern emerged

during the fall, yet a noticeable pattern occurred during the winter. This may occur for several

reasons. First, as stated, activity can affect body temperature, and activity' patterns may be less

defined during the breeding season. During and leading up to this time, l~ttle darkness occurs at

the latitude ofCape Thompson and Cape Lisburne, and activity is not restricted to certain times

ofthe day. Also, murre activity while:chickprovisioningcan vary accorqing to fish availability

(Burger and Piatt 1990) and may be less influenced by time of day than presence of prey. I ,

Finally, the effects of photoperiod on thermoregulation (Heldrnaier 1991); may playa role in

regulating body tempera,ture apart from activity.

ACKNOWLEDGMENTS

i :

We thank the Minerals Management Service for their support, and M.F. <:hance and P.F. Chance I : ,

from the Alaska Maritime National Wildlife Refuge for their valuable adi"ise and logistical help

UITERATURE CITED

i .' . .

,

Aschoff, J. 1982. The circadian rhythm of body temperature as a functian of body size, p. 173-

188. In C.R. Taylor (ed.), A co~panion to animal physiology. Cambridge University Press.

I

Barrett, R.T. 1984. Adult body temperatures and the development of eridothermy in the Puffin

Fratercula arctica, Razorbill, Alca torda, and Guillemot Uria aalge. Fauna Norveg. Ser. C.

Cinclus7:119-123.: I

35
~---r----------------_._

Bartholomew, G.A. 1966. The role of behavior in the temperature regulation ofthe Masked

Booby. Condor 68:523-535.

Boyd, J.C. and W.J.L. Sladen. 1971. Telemetry studies ofthe internal body temperatures of

AdeIie and Emperor Penguins at Cape Crozier, Ross Island, Antarctica. Auk 88:366-380.

Burger, A.E., and J.F. Piatt. 1990. Flexible time budgets in breeding cornmon murres: buffers

against variable prey abundance. Stud. Avian BioI. 14:71-83.

Oooper,1. 1979. Diel body temperature, posture and activity in a hand-reared juvenile Cape

J

Gannet Sula capensis. Ibis 121 :509-512. - .'

avrilov, V.M. 1985. Seasonal and circadian'c~ariges ofthermoregulation in passerine and nonpasserine birds: which is more important? Proc. Int. OrnithoI. Congr. 18:1254-1277.

Hatch S.A., P.M. Meyers, n.M. Mulcahy, and D.C. Douglas. 1996. Seasonal movements and

pelagic habitat use of murres and puffins determined by satellite telemetry. . -

I j

Heldmaier, G. 1991. Pineal involvement in'avian thermoregulation. In B.D. Bell, R.O. Cossee,

J.E.C. Flux, B.D. Heather, RA. Hitc~ough, C.J.R Robertson, and M.l. Williams (eds.)

Acta Congressus Intemationalis Ornithologici. 4:2042-2051.

Howell, T.R. and G.A. Bartholomew. 1961. Temperature regulation in Laysan and Black-footed

Albatrosses. Condor 63: 185-197.

Howell, T.R and G.A. Bartholomew. 1962. Temperature regulation in the Red-tailed Tropic

1

Bird and the Red-footed Booby. Condor 64:6-18.

ling, L. 1955. Nocturnal decline in the temperature of birds in cold weather. Condor 57:362-

365.

Iv,ersen, J.A. and J. Krog. 1972. Body temperatures in active and resting charadriiforme birds

(murres, puffins and auklets) at different ambient temperatures. Norweg. J. Zool. 20:145-

146.

Johnson, S.R. and G.C. West. Growth and development of heat regulation in nestlings, and

metabolism of adult Common and Thick-billed Murres. Ornis. Scand. 6: 109-115.

Korschgen, C.E., SJ. Maxson, and V.B. Kuechle. 1984. Evaluation ofimplanted radio

transmitters in ducks. J. Wildl. Manage. 48:982-987.

McNab, B.K. 1966. An analysis ofthe body temperatures of birds. Condor 68:47-55.

36
'i", __

~f. f"

Southwick, E.E. 1980. Seasonal therm6regulatory adjustments in White-c~owned Sparrows.

Auk 97:76-85. I

I

Core temperatures of non-r\esting western

I

\

U.S. Fish and Wildlife Service. 1997. A.laska seabird colony catalog-computer database and

colony status record archives. U.S. Fishartd Wildlife Service, Mig~'atory Bird , I

Management, Anchorage AK. i

i

Platania, S.P., a.s. Grant, and D.S. Lee., 1986.

Atlantic seabirds. Brimleyana 12:1:3-18. , i

I·

Warham, J. 1971. Body temperatures 6fpetrels. Condor 73:214-219. , I

I'I -.... 1

Welty, J.C. 1982. The Life ofBirds. Third Edition. CBS College PublisljUng. Philadelphia. I.. I

I

\'.

, i

i

I

, j

i ',",

I

I

1:

, I,

1

I

i

37
Figure 10. Body temperature of a female common murre from Cape Thompson, AK, 1995. .

,! ! , -. ! .

U

'-" i

"

!J~"!I\\~ ll)

"0

c:::

-ll)

f

....

:l

f

ell

. !

l' ....

f

ll)

0-

. . ! E

f ! , ! f ,

• • • •

8/7 8/25 9/14 10/2

Date

38

10/22 11/11
Figure 11. Daily temperature cyCle in winter of a female common murre from Cape

Lisburne, AK, 1995.· :

38.5 -r-------------'-----'---'-------'-----;--------~ , ...

! j

\

0:00-3:59 4:00-7:59: ~:00-11 :59 12:00-15:59 16:00-19:5920:00-23:59

37.5 +- ..------....---l---...------.-----,..-.:...----..------.-J

Time Period

39
APPENDIX 1

Track lines showing breeding-season and postbreeding-season movements of each individual

i!ncluded in the study, 3 Aug - 31 Dec 1996

, j

i

40
Figure A.I. Track lines offemale common murre 5851 from Cape Lisburne, AK, 1996. Short-cycle

transmitter. In contact for 126 days.' .

I HAl

I \

Chukchi

Sea

ll" ...

25

! j

,.

41

a

Kilometers

50

I

I

100
·.

/

Figure A.2. Post-breeding-season movements of female common murre 5851.

o

42

300

Kilometers

600
Figure A.3. Track lines ofmale common murre 5852 from Cape Lisburne, AI<, 1996. Short-cycle

transmitter. In contact 5 days. :

I

IS H I

Kilometers

25

! j

a 50 100

Chukchi

Sea

43
Figure AA. Track lines of female thick~billed murre 5853 from Cape Lisburne, AK, 1996.

Shdrt-cycle transmitter. In contact 5 days.

I

I H H I

25

! i

..

a

Kilometers

50 100

Chukchi

Sea

44
Figure A.5. Track lines of male thick-billed murre 7875 from Cape Lisburne, AK, 1996. Long-cycle

transmitter. In contact 1 day. : . j

.' - ....

I H H I

25 0

, J

,.

Kilometers

50 100

Chukchi

Sea

45
",

Fig re A.6. Track lines ofmale thick-billed murre 7876 from Cape Lisburne, AK, 1996. Short-cycle

trartsmitter. In. contact 8 days.

I

I H H I

25 0

,'

Kilometers

50 100

Chukchi

Sea

46
FigureA.7.

transmitier.

I

i

•

1

I

I

i

I

, I

Track lines offemale commort murre 7879 from Cape Lisburne, AK, 1996. . I

In contact 41 days. . ., •

Long-cycle

'·f; ...

, ...

I H H I

2? . a

! j

,.

Kilometers I

I

q

100

Chukchi

Sea

47
300 600

Kilometers

o

Figure A.8. Post~breeding-seasoIi. movements of female common murre 7879 from Cape Lisburne,

AK] 1996.

"I

48
Figure A:9.

transmitter.

I

i

i

I

,

i

( , I \ I

Track lines offemale common murre 7882 from Cape Lisburne, AK, 1996.

In contact 31 days. I i

f

Short~cycle

,.

j

«......

I H H I

25 0

,'

i

Kilometers

50

i

I

I

, j

100

Chukchi

Sea

49
Figlllre A.1 O. Track lines of male common murre 7884 from Cape Lisburne, AK, 1996. Long-cycle

transmitter. In contact 87 days.

I

Kilometers

I H H I

0( .....

25

! j

a 50 100

Chukchi

Sea

50
Figure A.II. Post-breeding-season movements of male common murre 7884., I

a 50 100

Kilometers

I H H i

Chukchi

Sea

51
Figure A.12. Track lines of female thick-billed murre 7887 from Cape Lisburne, AK, 1996.

Lortg-cycle transmitter. In contact 1 day.

I

Kilometers

I·H H I

( -...

25

! '

o 50 100

Chukchi

Sea

52
FigureA.13. Track lines of male comrnon:murre 7888 from Cape Lisburne, AK, 1996. Long-cycle

transmitter. In contact 68 days. I i

""H H I

25

, j

a

Kilometers

50

,I

100

Chukchi

Sea

53
Post~breeding-season movements of male common murre 7888.

Kilometers

I H H I

Chukchi

Sea

< ..

25

! '

,.

54

a 50 100
I. I

Figure A.15. Location offemale thick-billed murre 7901 from Cape Lisburne, AK, 1996.

Long-cycle transmitter. In contact 14 days. '

, _0

Kilometers

100

I

2~ o 50

, j

Chukchi

Sea

55
300 600

Kilometers

o

Figure A.16. Post-breeding-season movements offemale thick-billed murre 7901 from Cape

LiSb~e, AK, 1996.

56
Figure A.17. Track lines of male thick-billed murre 7903 from Cape Lisbum~, AK, 1996.

Long-cycle transmitter. In contact 74 days.

.,~ ..

'HH I

25

! j

a

Kilometers

50 100

Chukchi

Sea

57
Figure A.18. Track lines ofmale thick-billed murre 7915 from Cape Lisburne, AK, 1996.

Shoh-cYcle transmitter. In contact 18 days. '

I

I H H I

Kilometers

25 o 50 100

Chukchi

Sea

58
f

I

.l

F-i"gure A.19. Track lines of female thick-billed murre 7917 from Cape Lisburne, AK, 1996.

Short-cycle transmitter. In contact 11 days. :

I H H I

25

!

a

Kilometers

50

H

100

Chukchi

Sea

59