Field Validation of GIS-based Models for Regional and Refuge Bird
Conservation Planning: 2005 Field Season Report

Les D. Murray and Christine A. Ribic, USGS BRD WCWRU, Department of
Wildlife Ecology, University of Wisconsin, 204 Russell Labs, 1630 Linden
Dr, Madison, WI 53706.

# INTRODUCTION

The North American Bird Conservation Initiative (NABCI) is a new bird
conservation effort that seeks to integrate various bird conservation
plans and "deliver the full spectrum of bird conservation through
regionally-based, biologically-driven, landscape-oriented partnerships".
The USGS Upper Midwest Environmental Sciences Center, La Crosse, WI
(hereafter the La Crosse Lab) and USGS Patuxent Wildlife Research
Center, Laurel, MD, are developing GIS data layers and GIS management
tools for managing and conserving high quality habitat for multiple bird
species.

The relationship between bird abundances and local vegetation
characteristics has been well defined by numerous studies. Researchers
also have begun to examine the relationship between landscape variables
and bird abundances. Understanding relationships between abundances of
bird species and landscape factors will help managers to identify areas
of importance for some species of birds. The La Crosse Lab has begun
using Breeding Bird Survey data to create such predictive models of bird
abundances in Bird Conservation Region (BCR) 23 based on relationships
to landscape variables.

This study is being conducted to gather data to be used to validate the
results of the predictive models. The project also will collect data to
compare abundances of grassland birds in landscapes composed of
different amounts of grassland and forest in southwestern Wisconsin. The
information collected by this project will be used to test the accuracy
of predictive models and further understand the relationship between
grassland birds and the surrounding landscape.

# METHODS

[Study Areas]{.smallcaps}

The validation portion of our study was conducted in the Iowa,
Minnesota, and Wisconsin portions of BCR 23. Grids of 3 different scales
(approximately 800 ha, 8,000 ha, 100,000 ha) were then overlayed on a
GIS coverage of the BCR. These scales were defined by the La Crosse Lab
for their landscape models. To sample the BCR geographically, the BCR
was divided into 5 subregions of equal area and equal sampling occurred
in each of the subregions. Fifteen 8,000 ha landscapes were randomly
selected in each subregion in 2003. Within each 8,000-ha landscape, we
randomly chose three 800-ha landscapes that were at least 50% contained
in the 8,000-ha landscape. Thus a total of 225 800-ha landscapes were
surveyed in 2003. For the 2004 field season, we randomly selected 1/3 of
the 15 8,000-ha landscapes in each subregion selected in 2003 to be
surveyed in 2004 and 2005. The same 800-ha landscapes surveyed in 2003
within each 8,000-ha landscape were surveyed in 2004 and 2005. An
additional 10 8,000-ha landscapes were then selected for each subregion
to be surveyed only in 2004. In 2005, we randomly chose 10 8,000-ha
landscapes and three 800-ha landscapes in each 8,000-ha landscape to be
surveyed only in 2005. Thus a total of 225 800-ha landscapes were
surveyed in 2005, 1/3 of which were the same as those surveyed in 2003
and 2004.

The portion of our study that focused on the relation of grassland
associated birds to landscape composition took place in southwestern
Wisconsin, specifically Dane, Iowa, Green, Lafayette, and Grant
counties. This area was divided into 800-ha landscapes and the
landscapes were classified into 6 landscape types using the National
Landcover Data (Table 1). Five landscapes of each type were then
selected for our study in 2003, except an error was made in classifying
one selected landscape. Thus, four low grass-low forest landscapes and
six low grass-high forest landscapes were surveyed in 2003. We selected
enough landscapes of each type (2 low grassland:low forest landscapes, 1
of the other landscape types) so that a total of six landscapes of each
type were surveyed in 2004 and 2005. The landscape cell that was
classified incorrectly in 2003 was surveyed in 2004 and 2005, but
because of its adjacency to another low grass-high forest landscape will
not be considered as part of the study design.

[Bird Surveys]{.smallcaps}

### Validation surveys

Roadside surveys consisting of 3 400-m radius point counts were
conducted by volunteers to estimate bird abundances in each selected 800
ha landscape. Surveys were conducted from 1 June to 4 July between ½
hour before sunrise and 4½ hours after sunrise. Most survey routes were
ran twice during the time period, but some routes were only run once
because of weather and lack of volunteers to cover that area. Abundance
information was only collected for species being modeled and species
that we may model in the future (Table 2). Volunteers only counted those
birds seen or heard within 400 m of each point during a 3-minute period.
Observers were careful to try to count each bird only once. A total of
33 observers conducted surveys in 2005.

*Landscape level*

Roadside surveys consisting of 3 400-m, 5-minute point counts were
conducted in each of the 30 selected 800 ha landscapes (Figure 1) and 3
800 ha landscapes surrounding each of the selected landscapes. Roadside
surveys were conducted once from 19 May to 1 June and once between 3
June and 27 June with at least one week between surveys of the same
route. Surveys were conducted between ½ hour before sunrise and 4½ hours
after sunrise. Observers recorded the number of birds seen or heard
during each point count for selected species that often occur or breed
in grasslands (Sample and Mossman 1997) and species recorded during
validation surveys (Table 4). Observers recorded whether each bird was
observed during the first 3 minutes of the survey so that survey results
could be compared with validation surveys. Surveys were conducted by 5
trained observers.

[Ground truthing of selected landscapes in southwest
wisconsin]{.smallcaps}

Observers returned to all roadside survey points and recorded
landuse/landcover within a 400-m radius of each point on an aerial
photograph in 2003, 2004, and 2005. This information will then be
digitized into a GIS to provide finer resolution habitat data for each
landscape.

[Red-headed Woodpecker Sightings]{.smallcaps}

In addition to the roadside surveys, we recorded the approximate
location of all red-headed woodpeckers observed by 8 researchers from
May to July. The landscape characteristics of the locations of these
observations will be compared to random points in the study area using a
GIS. In addition, an observer visited the locations of all sightings of
red-headed woodpeckers from 2003, 2004, and 2005 and an equal number of
random points and counted the number of dead trees and utility poles,
estimated percent coverage of different grassland types (idle, hay,
pasture), relative grass height in pastures, and percentage of forest
that was grazed within 200 m and 400 m of the observation.

# RESULTS

[Bird Surveys]{.smallcaps}

##  Validation surveys

Savannah sparrow and common yellowthroat were the species of interest
observed most often followed by bobolink, sedge wren, and eastern
meadowlark (Table 3). The maximum number of birds of one species
observed on a single route was 25 Savannah sparrows followed by 22
bobolinks and 17 sedge wrens. Henslow's sparrows were the species least
observed with only two observations.

##  Landscape level

Savannah sparrow, brown-headed cowbird, eastern meadowlark, common
yellowthroat, and ring-necked pheasant were the five most often observed
species during surveys (Table 4). Eastern meadowlark were most abundant
in the supergrass landscapes and Savannah sparrows were most abundant in
the high grass-medium forest landscapes (Figure 2). Common yellowthroat
was most abundant in the low grass-high forest, high grass-high forest,
and high grass-medium forest landscapes. Brown-headed cowbirds showed no
pattern of abundance across landscape types. Bobolinks had their three
highest abundances in the high grass-high forest, high grass-medium
forest, and supergrass landscapes, but lower abundances in the high
grass-low forest landscape. Ring-necked pheasants had lower abundances
in the low grass-high forest and low grass-low forest landscapes, but
horned larks had their highest abundance in low grass-low forest
landscapes.

[Red-headed Woodpecker Sightings]{.smallcaps}

Fifty-seven observations of red-headed woodpeckers were made in 2005,
including those that occurred during landscape-level road side surveys
(Figure 3). Some of these observations are probably the same bird or
breeding pair seen on different days and will be considered a single
territory for future analyses. Preliminary analysis suggest that within
a 400-m buffer the amount of pasture, number of dead trees, percent of
tree cover in pasture, and percent of deciduous forest that is grazed
were greater for sites of observations than at random points (Table 5).

# FUTURE WORK

Field work for this study has been completed. Future work for this
project will consist of data analysis and report and manuscript writing.

# Acknowledgements

We would like to thank Wayne Thogmartin for constructing the predictive
bird abundance models, supplying comments on our study design, and all
his help with GIS and calculating landscape metrics. We also would like
to thank Melinda Knutson, Stan Temple, Dave Mladenoff, Jun Zhu, Dave
Sample, Doug Johnson, John Sauer, and Mike Guzy for feedback on the
study design. Special thanks to Sonya Knetter for her help with GIS
problems. Chris Walz, Martin Murphy, Daniel Schneider, Joe Veverka , and
a slew of volunteers provided the field assistance that made the project
possible.

# LITERATURE CITED

Baichich, P. J., and C. J. O. Harrison. 1997. A guide to nests, eggs,
and nestlings of North American birds. Second edition. Academic Press,
San Diego.

Sample, D. W., and M. J. Mossman. 1997. Managing habitat for grassland
birds: a guide for Wisconsin. Wisconsin Department of Natural Resources,
Madison. 154 pp.

Table 1. Definitions of landscapes surveyed in southwestern Wisconsin.

  ------------------------------ --------------------- ------------------
  Landscape                      %grass in landscape   %forest in
                                                       landscape

  low grass-low forest           30-45%                \<10%

  low grass-high forest          30-45%                \>20%

  high grass-high forest         60-80%                \>20%

  high grass-medium forest       60-80%                10-20%

  high grass-low forest          60-80%                \<10%

  supergrass                     \>80%                 \<20%
  ------------------------------ --------------------- ------------------

Table 2. Bird species of interest for the validation surveys.

  ------------------------- ---------------------- -----------------------
  Forest                    Grassland              Generalist

  Black-billed cuckoo^a^    Bobolink^a^            Common yellowthroat^b^

  Blue-winged Warblers^b^   Eastern meadowlark^b^  

  Cerulean warbler^a^       Grasshopper sparrow^a^ 

  Golden-winged warbler^a^  Henslow\'s sparrow^a^  

  Red-headed woodpecker^a^  Savannah sparrow^b^    

  Wood Thrush^a^            Sedge wren^a^          

                            Upland Sandpiper^a^    

                            Western Meadowlark^b^  
  ------------------------- ---------------------- -----------------------

^a^ Priority species in BCR23 that have been modeled.

^b^ Species that we may model in the future.

Table 3. Mean number of birds seen per route per survey and associated
standard error, maximum number of birds seen on a route, and total
number of observations for roadside survey routes conducted by
volunteers for use to validate predictive models of bird abundance in
BCR 23 in 2005.

  ---------------------------------- ------- -- ------ -- ------ -- ---------
  Species                            Mean       SE        Max       Total

  Black-billed cuckoo                0.05       0.02      4         20

  Bobolink                           0.70       0.09      22        277

  Blue-winged warbler                0.08       0.02      2         31

  Cerulean warbler                   0.01       0.01      2         3

  Common yellowthroat                1.71       0.08      8         677

  Eastern meadowlark                 0.35       0.04      4         139

  Grasshopper sparrow                0.09       0.02      6         35

  Golden-winged warbler              0.01       0.01      1         4

  Henslow\'s Sparrow                 0.01       0.00      1         2

  Meadowlark spp.                    0.03       0.01      2         10

  Red-headed woodpecker              0.06       0.01      2         23

  Savannah sparrow                   1.87       0.15      25        739

  Sedge wren                         0.48       0.07      17        190

  Upland sandpiper                   0.01       0.01      2         3

  Western meadowlark                 0.05       0.01      3         20

  Wood thrush                        0.08       0.02      3         33
  ---------------------------------- ------- -- ------ -- ------ -- ---------

Table 4. Mean number of birds seen per survey on roadside routes from 19
May to 27 June 2005 in 800-ha landscapes in southwestern Wisconsin
classified into six landscape types (see Table 1 for definitions).

  --------------- -------- -- -------- -- -------- -- ---------- -- -------- -- --------
  Species of      Low         Low         High        High          High        Super-
  interest        grass-      grass-      grass-      grass-        grass-      grass
                  high        low         high        medium        low         
                  forest      forest      forest      forest        forest      

  Baltimore       0.79        0.33        1.17        0.17          0.42        0.17
  oriole                                                                        

  Black-billed    0.00        0.00        0.00        0.00          0.00        0.00
  cuckoo                                                                        

  Brown-headed    2.79        2.25        2.17        2.33          3.00        3.08
  cowbird                                                                       

  Bobolink        0.57        0.00        1.00        1.92          0.42        1.50

  Blue-winged     0.36        0.00        0.08        0.00          0.00        0.00
  warbler                                                                       

  Clay-colored    0.07        0.00        0.17        0.00          0.00        0.00
  sparrow                                                                       

  Cerulean        0.00        0.00        0.00        0.00          0.00        0.00
  warbler                                                                       

  Common          2.36        1.08        2.08        2.50          1.83        0.58
  yellowthroat                                                                  

  Dickcissel      0.00        0.33        0.17        0.50          0.83        1.25

  Eastern         0.07        0.17        0.17        0.42          0.08        0.33
  bluebird                                                                      

  Eastern         0.50        1.67        2.33        3.00          3.75        3.92
  meadowlark                                                                    

  Field sparrow   1.43        0.33        0.83        0.92          0.58        0.42

  Grasshopper     0.00        0.00        0.08        0.75          0.58        0.33
  sparrow                                                                       

  Golden-winged   0.00        0.00        0.00        0.00          0.00        0.00
  warbler                                                                       

  Henslow\'s      0.00        0.00        0.17        0.08          0.00        0.00
  sparrow                                                                       

  Horned lark     0.00        3.08        0.50        0.58          1.67        1.00

  Killdeer        1.00        1.58        0.50        1.33          1.75        1.00

  Meadowlark spp. 0.00        0.17        0.08        0.50          0.17        0.42

  Northern        0.00        0.00        0.00        0.00          0.00        0.00
  harrier                                                                       

  Red-headed      0.00        0.08        0.08        0.17          0.25        0.25
  woodpecker                                                                    

  Ring-necked     0.93        0.50        2.25        1.75          2.33        1.75
  pheasant                                                                      

  Savannah        1.71        1.75        1.25        4.17          1.83        2.92
  sparrow                                                                       

  Sedge wren      0.07        0.17        0.50        0.42          0.58        0.42

  Upland          0.07        0.00        0.17        0.00          0.08        0.25
  sandpiper                                                                     

  Vesper sparrow  0.07        0.17        0.17        0.00          0.00        0.08

  Western         0.00        0.17        0.00        0.00          0.17        0.67
  meadowlark                                                                    

  Wood thrush     1.36        0.25        0.08        0.00          0.00        0.00
  --------------- -------- -- -------- -- -------- -- ---------- -- -------- -- --------

Table 5. Average characteristics of landscape within 400 m of
observations of red-headed woodpeckers and random points in southwestern
Wisconsin in 2005.

  ----------------------------------- ----------------------- -- ----------
                                                                 Random

  Landscape characteristics           Observations               Points

  Percent of grassland idle           24.1                       33.3

  Percent of grassland in hay         31.8                       32.9

  Percent of grassland in pasture     42.4                       23.4

  Pasture height^a^                   2.0                        1.9

  Percent tree cover in pasture       8.1                        7.3

  Number of dead trees                6.3                        3.0

  Number of utility poles             6.8                        6.1

  Percent deciduous grazed            9.2                        3.4
  ----------------------------------- ----------------------- -- ----------

^a^ Pasture height was visually estimated and recorded in one of four
categories (1 = \<2" tall, 2 = 2-6" tall, 3 = 6.1-12" tall, 4 = \>12")
and then averaged.

![](media/image1.png){width="8.399305555555555in"
height="5.590277777777778in"}

Figure 1. 800-ha landscapes of six different types selected for
landscape-level study of grassland associated birds in southwestern
Wisconsin.

![](media/image2.wmf){width="9.004166666666666in"
height="5.197222222222222in"}

Figure 2. Number of birds seen per survey on roadside routes in 6
different landscape types (n=6) in southwestern Wisconsin during 2005
breeding season for the four most abundant grassland obligate species.

![](media/image3.png){width="8.399305555555555in"
height="6.1090277777777775in"}

Figure 3. Locations of observations of red-headed woodpeckers in
southwestern Wisconsin in the 2005 breeding season.