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WOS 2010 ~ ABSTRACTS p. 18
important habitat for grassland birds. This study explored the effects of rotational grazing (RG) and other habitat
variables on relative abundance of grassland birds on small dairy farms in Wisconsin, Pennsylvania and New York.
Grassland birds were more likely to occur on grazing farms than confinement farms, and Bobolinks (Dolichonyx
oryzivorus) showed significantly higher abundances on RG farms. Grassland bird abundance was positively
associated with grassland area at multiple scales. Preliminary analysis suggests that grassland bird abundance is
influenced by interacting factors including land cover, patch area, and landscape fragmentation. Results from this
analysis will help determine best practices for conserving grassland birds on dairy farms.
15 Fifteen years of research on grassland birds in New York State: habitat relations and management implications.
Christopher Norment, Dept. Environmental Science and Biology, College at Brockport, State Univ. New York,
Brockport, NY 14420
Grassland birds are declining throughout North America due to the loss and deterioration of grassland habitat. In the
Northeast, culturally altered landscapes, such as agricultural grasslands, receive the periodic disturbance needed to
maintain habitat for obligate grassland breeding birds. A large body of data from fifteen years of research in western
and northern New York demonstrates that large anthropogenic grasslands dominated by cool season, primarily
nonnative, grasses support high numbers of obligate grassland breeding birds, particularly when the vegetation is
relatively short and less dense. In addition, grassland bird breeding bird productivity in nonnative cool season
grasslands at several non-fragmented study sites in the region is higher than in many parts of the Midwest. In
contrast, many anthropogenic warm season grasslands in the region support few obligate grassland breeding birds,
and may have relatively low productivity. These patterns, along with work by other researchers, suggest that the
large expanses of anthropogenic grasslands in New York State are an important regional and continental resource
for grassland bird conservation, and that management efforts should incorporate privately owned lands in
agricultural landscapes, maintain large areas of grassland habitat, and promote the use of low-stature cool season
grasses.
16 S The effects of exurbanization on the food and habitat of Pileated Woodpeckers (Dryocopus pileatus). Marie E.
Wilson, Jordan M. Casey, and David G. Haskell, Dept. Biology, Univ. of the South, Sewanee, TN 37383, and
Nicholas Hollingshead, Landscape Analysis Lab, Univ. of the South, Sewanee, TN 37383
Pileated Woodpeckers (Dryocopus pileatus) require large and/or dead trees for nesting, roosting, and feeding. In
exurban areas, or places of low-density rural development, the status of such a mature forest habitat is poorly
known. Using proportion impervious cover as a proxy for exurbanization, we hypothesized that as exurbanization
increased, average tree diameter and number of large trees, volume and rot class of standing/fallen dead trees, ant
and grub abundance in the soil and leaf litter, and Pileated Woodpecker presence would decrease. Volume and rot
class of dead wood, ant and grub abundance, and presence of Pileated Woodpeckers did not change as
exurbanization increased. Average tree diameter (P < 0.001) and number of trees above 60 cm in diameter (P =
0.015) however, increased with increasing exurbanization. Number of trees in general did decrease with increasing
exurbanization (P < 0.001) but Pileated Woodpecker presence showed no relation to number of trees and did show a
relation to tree diameter as points with Pileated Woodpeckers had larger average tree size than points without (P =
0.014). Due to such a lack of difference in select habitat characteristics between exurban and forested areas and a
difference in favor of exurban areas in regards to larger trees, our data suggests that some exurban areas may
provide suitable habitat for Pileated Woodpeckers. In addition, forest assessments have commonly noted any
forested areas with residential uses as non-forest, but our data suggests that some exurban areas show structural
similarities to forests and should thus be a sub-group of forested areas.
17 S Ovenbird spatial behavior at an urban stopover site: Movement patterns, stopover durations, and the influence of
arrival condition. Chad L. Seewagen, Dept. Biology, Univ. Western Ontario, London, ON N6G 5B2 and Dept.
Ornithology, Wildlife Conservation Society, Bronx, NY 10460, and Christopher G. Guglielmo, Dept. Biology,
Univ. Western Ontario, London, ON N6G 5B2
Migration routes of many Nearctic-Neotropical landbirds pass through the most urbanized regions of North
America. Migrants are known to use urban habitats as stopover sites and often occur in cities at exceptional density;
yet knowledge of migrant behavior and ecology in such places is surprisingly limited. We radio-tracked ovenbirds
(Seiurus aurocapillus) during stopovers in a New York City park to obtain some of the first detailed information on
how landbird migrants utilize an urban habitat as a stopover site. We examined fine-scale movement patterns, home
range sizes, stopover durations, and how arrival condition affected each of these metrics. During both seasons, most
birds moved widely throughout the site upon presumed arrival and then either continued migration that night or
settled into a more defined area on subsequent days. Area usage varied markedly between individuals during both
seasons, ranging 1-16 ha. Stopover durations averaged 3.0 days (range= 1-10 days) during spring and 2.9 days
(range= 1-14 days) during autumn. Spatial behaviors and stopover durations were not influenced by arrival
condition during spring, and during autumn, only movement rates and displacement distances were significantly