ABSTRACTS, Kearney 2011 page 1 of 92 Aubrey Alamshah and Edward H. Burtt, Jr., Dept. Zoology, Ohio Wesleyan Univ., Delaware, OH 43015. SSeasonal variation in the maintenance behavior of House Sparrows, Passer domesticus. The percentage of House Sparrows (Passer domesticus) with feather-degrading bacilli is significantly greater in the winter than in the spring and summer (Burtt and Ichida, 1999). One possible explanation is that the sparrows engage in less maintenance behavior in winter than in summer. There are several reasons why this might be: higher energy demands, which would necessitate more time foraging; shorter days; colder temperatures and lower humidity so that feather-degrading microorganisms are a lower risk to the plumage than in warm, humid weather (Burtt and Ichida 2004). However, seasonal changes in the maintenance behavior of passerines are a largely unstudied subject. House Sparrows bathe, dust bathe, head scratch, bill wipe, sun, and preen (Summers-Smith 1963, Anderson 2006). We observed changes in the form and frequency of the behavior in wild-caught House Sparrows held in an outdoor aviary. We observed the birds for 2-3 hours/week, noting the occurrence of maintenance behavior in each individual, its type, sequential organization, and bout length. We also took samples of microorganisms from the feathers of the birds on a monthly basis. We compared changes in maintenance behavior and time allotted to such behavior throughout the year. We determined that the birds do in fact exhibit more maintenance behavior in the spring and summer than they do in the fall and winter. Further study is needed, but our results suggest increased maintenance behavior may help to reduce the amount of feather-degrading bacteria on the bird. CO18: Fri, 11 Mar 15:00 Amber Albores and Jeffery P. Hoover, Dept. Natural Resources and Environmental Science, Univ. Illinois, Champaign, IL, and Institute of Natural Resource Sustainability, Illinois Natural History Survey, Champaign, IL. SCowbird parasitism increases after high fledging success of cowbird, but not host, nestlings. Brown-headed Cowbirds (Molothrus ater) are obligate brood parasites that rely solely on hosts to raise their young. Although cowbirds parasitize 200+ species, recent evidence suggests that females avoid unsuitable hosts that either reject parasitic eggs or provide incompatible parental care. Female cowbirds may be able to improve their own reproductive success by collecting information pertaining to the fledging of cowbird or host offspring. This, in turn, could influence the laying decisions and host choices of cowbirds in subsequent years. To determine whether host reproductive success and/or cowbird reproductive success in one year affects the likelihood of cowbird parasitism the following year, we examined nesting data for a highly suitable host, the Prothonotary Warbler (Protonotaria citrea). We recorded parasitism status (yes or no), number of cowbird eggs, and the number of host and cowbird fledglings for each of over 3,500 warbler nests from 1994-2010 in southern Illinois. Data were analyzed using a generalized linear mixed model (GLMM) with binomial distribution. We accounted for variation in site and year in our analysis as random effects and included warbler density as a covariate. The probability of parasitism increased with cowbird reproductive success in the previous breeding season but decreased with warbler reproductive success. This is the first study to suggest that cowbird fledging success may influence future host selection by cowbird females. Future work will focus on laying decisions of individual female cowbirds to determine if they adjust their host selection between years. CO22: Fri, 11 Mar 15:45 Cameron L. Aldridge and D. Joanne Saher, NREL, Colorado State Univ., Fort Collins, CO, Theresa M. Childers and Kenneth E. Stahlnecker, National Park Service, Black Canyon of the Gunnison National Park and Curecanti National Recreation Area, Gunnison, CO, and Zachary H. Bowen, USGS, Fort Collins, CO. Crucial nesting habitat for Gunnison sage-grouse: a spatially explicit hierarchical approach. Gunnison Sage-Grouse (Centrocercus minimus) is a species of special concern and is currently a candidate for listing under the Endangered Species Act. Careful management is therefore required to ensure that suitable habitat is maintained, particularly because much of the species’ current distribution is faced with exurban development pressures. We assessed hierarchical nest site selection patterns of Gunnison Sage-Grouse inhabiting the western portion of the Gunnison Basin, Colorado, USA, at multiple spatial scales, using logistic regression-based resource selection functions. Models were selected using Akaike Information Criterion and predictive surfaces were generated. Landscape-scale factors influencing nest site selection included the proportion of sagebrush cover > 5%, productivity, and density of two wheel-drive roads. The landscape-scale predictive surface captured 99% of known Gunnison Sage-Grouse nests, implicating 50% of the basin as crucial nesting habitat. Crucial habitat identified by the landscape model was used to define the extent for patch-scale modeling efforts. Patch-scale variables influencing nest site selection were the proportion of big sagebrush cover >10%, distance to residential development, distance to high volume paved roads, and productivity. This model accurately predicted independent nest locations. The unique hierarchical structure of our models more accurately captures the ‘nested’ nature of habitat selection, and allowed for increased discrimination within larger landscapes of suitable habitat. We extrapolated the landscape-scale model to the entire Gunnison basin because of conservation concerns for this ABSTRACTS, Kearney 2011 page 2 of 92 species. We believe this predictive surface is a valuable tool which can be incorporated into land-use and conservation planning as well as the assessment of future land-use scenarios. S2: Thu, 10 Mar 11:00 Catherine Alsford, Brynne Stumpe, and Sara Morris, Dept. Biology, Canisius Coll., Buffalo, NY 14208, and Lindsey Walters, Dept. Biological Sciences, Northern Kentucky Univ., Highland Heights, KY 41099. SBreeding biology of a newly-established population of House Wrens. House Wrens (Troglodytes aedon) are secondary cavity breeders that will commonly use nest boxes. Our goal was to study the breeding biology of a new breeding population of House Wrens in Western New York established in 2009. Of the 60 nest boxes available in 2009, 33 were occupied by wrens. After a predation event on June 4th most females began to re-lay around the same time and further events were relatively synchronized. The average clutch size was 7.2 ± 1.2. During 2010, all 30 nest boxes were occupied. Most pairs were single brooded; however, 9 pairs had a second clutch. The average first clutch size was 6.7 ± 1.0. Neither clutch size nor likelihood of a second clutch was significantly affected by the date of male arrival, the date of female arrival, or the date the first egg was laid. However, second clutches had significantly fewer eggs than first clutches. Neither clutch size, nor the date of first egg laid, varied significantly between years. Additionally, we examined the effect of different levels of human disturbance on their breeding biology in 2010. Interestingly, the first egg in low traffic nests averaged 10 days earlier than either medium or high traffic areas, although this difference was not significant. Likewise, the average first clutch size of low traffic boxes was almost one egg higher than medium and high traffic areas, but this difference was also not significant. CO4: Thu, 10 Mar 11:30 Amy K. Amones and Michael J. Lanzone, Carnegie Museum of Natural History, Powdermill Avian Research Center, Rector, PA 15677, and Andrew J. Farnsworth, Conservation Science Program, Cornell Lab of Ornithology, Ithaca, NY 14850. A novel method to study inter- and intraspecific variation of flight-calls in captivity. Bioacoustics is a powerful method for studying avian migration. Recording flight-calls during nocturnal migration could be a valuable method for censusing populations over a wide geographic area, however incomplete knowledge of flight-call identities and inter- and intraspecific variation in call notes and calling rates limits the utility of using them as a census tool. Because of the difficulty of actively collecting known flight-calls from species during migration, we developed a novel method for recording flight-calls from birds by placing them in a specially designed acoustic studio. To date we have recorded over 40,000 flight-calls from 52 species in the acoustic studio. We tested whether the amount of variation within a species was similar between flight-calls recorded in captivity and wild birds. Results from our principal coordinate ordination analysis indicated that variation was similar between the two methods (92.8 ± 0.05% was explained in the first five PCO axes). We also used mixed models to study inter- and intraspecific variation in flight-calls for 14 warbler species using 28 spectographical measurements. The results indicated that there was interspecific variation in 10 measurements and intraspecific variation in 2 measurements (P < 0.05). There were also some subtle and significant differences between ages and sexes, but the differences were not consistent between species. These studies illustrate some of the complex questions that need answered to fully utilize flight-calls as