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Eastern Bluebirds (<i>Sialis sialis</i>) were found to be utilizing natural nest sites in the vicinity of Blacksburg, Virginia, during 1976 and 1977. Forty-seven natural nest sites, 37 in fencepost cavities and ten in tree cavities were discovered by driving roads in rural areas, scanning fencerows and utility wires with binoculars, and by searching fencerows on foot. Ninety-one percent of nest cavities used by bluebirds were made by woodpeckers. Height of cavity entrance, entrance diameter, and distance from entrance to cavity bottom were best able to distinguish anong bluebird fencepost nest cavities, nest demonstration display sites, and Starling (<i>Sturnus vulgaris</i>) fencepost nest cavities, using discriminant function analysis. Four nest cavities used by bluebirds in 1976 were no longer available in 1977 due to the replacement of fenceposts and tree limb breakage. No new cavities in fenceposts were observed being excavated by woodpeckers. / Master of Science

The demography of ovenbirds (<i>Seiurus aurocapillus</i>) was compared in landscapes highly fragmented by agriculture, moderately fragmented by commercial harvesting, and in contiguous boreal forest of Saskatchewan. Various survey techniques demonstrated that ovenbirds were less common in small, isolated forest patches in fragmented landscapes relative to contiguous forest. Male ovenbirds in fragmented landscapes (84 to 87% paired) had a lower probability of attracting females relative to males in contiguous forest (97%). Competition for territories was intense, as removal experiments demonstrated the presence of non-territorial male floaters. However, floaters were more common in contiguous forest, indicating this habitat was most preferred. Nesting success was lower in small farm fragments (29%) than the other landscapes (43 to 58%), due to high nest predation. Apparent annual survival of males was lower in small farm fragments (30%) relative to the other landscapes (57 to 60%). The difference in adult survival among landscapes was not caused by increased mortality in small farm fragments, but likely occurred because failed breeders (20% annual return rate) dispersed more than successful breeders (50%). Overall, small farm fragments were population sinks, where the number of adult birds lost to mortality and emigration exceeded the number of young produced. However, population size was constant over the length of the study indicating that populations in small farm fragments were rescued from extinction by immigration of birds from contiguous forest, where excess juveniles were produced. Populations in farm fragments were more likely to be rescued from local extinction by first time breeders (95% first time breeders) than the other landscapes (65 to 75%). <p>Increased turnover in small farm fragments, also resulted in a greater proportion of first time breeders (60%) in small farm fragments than the other landscapes (44 to 46%). These results support the idea that forest songbirds select habitat in a ideal preemptive manner. Younger individuals seem to be forced to settle in low-quality farm fragments, due to competition from older birds in the more optimal contiguous forest. Forest fragmentation bad a negative impact on ovenbirds and likely is an important factor influencing the decline of this and other Neotropical migrant species.

Urbanization is a worldwide trend resulting in loss of bird habitat, dominance of invasive species and higher densities of some predatory species. However, cities provide new opportunities for birds because of warmer winter climates and sources of artificial food. Proper management of urban habitat is significant for maintaining diverse bird communities and raising conservation awareness among city dwellers. This study aimed at identifying important urban bird habitats as well as their characteristics in Halifax Regional Municipality, Nova Scotia. Fourteen local birders outlined bird habitats on maps, and the information was compiled and presented using GIS. In total, 28% of the study area was indicated as key habitat for urban birds. By comparing the GIS data with existing conserved areas, coastal areas, marine habitat and urban wetlands were found to be under-represented in conserved areas. Following from the research findings, recommendations for improving habitat identification and management are made.

The USDA Natural Resources Conservation Service (NRCS) implemented the Migratory Bird Habitat Initiative (MBHI) in summer 2010 to provide wetlands for waterbirds inland from the Deepwater Horizon Oil Spill. To evaluate MBHI and associated wetland management practices, I estimated seed and waterbird densities in MBHI and non-managed wetlands in the Mississippi Alluvial Valley (MAV) of Mississippi and Louisiana. Although not statistically different, wetlands enrolled in MBHI contained 1.26 and 1.53 times more seed biomass and seeds consumed by waterfowl than non-managed wetlands, respectively. I also detected 3 times more dabbling ducks and all ducks combined on MBHI wetlands. When I combined density data for all waterbird species, MBHI wetlands contained more than 2 times as many birds than control wetlands. Management via MBHI increased waterbird and potential food abundances, suggesting NRCS consider sustaining MBHI and provide financial incentives to landowners for management of wetlands in the MAV and United States.

The Mississippi Alluvial Valley (MAV) was dominated by extensive lowland forests, but during the 20th century most of the MAV was converted to agricultural, aquaculture, and other human uses. These land-use changes created stopover migration and wintering habitats for waterfowl, shorebirds and other waterbird species. Before landscape modification of the MAV, shorebirds likely migrated past the MAV to wetlands along the northern Gulf of Mexico (NGoM). In 2010, the Deepwater Horizon oil spill impacted coastal marshes of the NGoM. The USDA Natural Resources Conservation Service implemented the Migratory Bird Habitat Initiative (MBHI) to provide waterbirds with wetlands inland of oil-impacted areas. My objectives were to 1) statistically model the waterbird community on wetlands in the MAV and NGoM, 2) estimate relative abundance of shorebird and other waterbirds in idled aquaculture ponds enrolled in MBHI and associated wetlands in the MAV and NGoM, and 3) collect shorebird feathers and blood for stable isotope analysis (13C/12C, 15N/14N) to assess foraging niches and potential migratory connectivity between MAV and NGoM habitats during 2012 – 2013. Consequently, autumns of these years were under a drought, extensively wet from Hurricane Isaac, and exhibited average precipitation in the post-hurricane recovery period which may have had an effect on waterbird assemblages differing by year, month, twice-monthly survey period, latitude, region, state, site, and water depth index. Latitude shifted north and water depth was narrowest when abundant wet habitat existed on the landscape in 2012. Bird abundances were greatest in 2011 and never recovered to these levels in 2012 or 2013, which may have reflected effects of drought concentrating birds on remaining wetlands in 2011 and subsequent to the hurricane. Stable isotope analysis of blood indicated spatial segregation of shorebird species. Neither blood nor feather carbon and nitrogen values revealed definitive linkage of sites between the MAV and NGoM. Shallow water habitat inland may be a limiting resource during migration for waterbirds, especially in drought years when other wetlands may have been limited. Thus, provision of wetlands (mudflat – 15 cm) by MBHI and other conservation strategies across the landscape may allow waterbirds access to needed resources during migration.

ABSTRACT AVIAN COMMUNITY PATTERNS IN THE LESSER CAUCASUS (NORTHEASTERN TURKEY) ATKIN GEN&Ccedil / OgLU, G&uuml / lden M. Sc., Department of Biological Sciences Supervisor: Assoc. Prof. Dr. C. Can Bilgin December 2007, 78 pages Species composition, diversity and species-habitat relations are widely used to describe communities. This study aimed to document diversity, composition and habitat relations of avian communities of the Turkish Lesser Caucasus by using point counts and multivariate analyses. 2845 individuals of 101 bird species were observed at 215 stations located in the study area. Point counts were revealed to be a useful method for terrestrial birds, especially passerines. Species richness and diversity changed significantly within parts of the study area and one particular sub-region was found to be considerably more diverse than the other three. Division of the Lesser Caucasus region into sub-ecoregions may not be justified using bird assemblages since habitat parameters, especially the presence of woody vegetation, seemed to be a better predictor of species composition than geographical proximity. Documented bird and habitat associations provide valuable information on the factors which affect bird occurrence or abundance. Baseline data provided by this study will help detect and understand changes in bird populations in the future. Keywords: avian community, species composition, species diversity, point count method, bird-habitat relationship

Hundreds of wetland bird species use ricelands annually in the Gulf Coast Prairie region of Louisiana and Texas. Much of the original ecosystem was transformed for rice and other crops, cattle ranching, flood control, and other human uses. Flooded production and idled ricelands provide critical foraging habitat for breeding, migrating, and wintering wetland birds. Ricelands in coastal Louisiana and Texas provide approximately 42% of the estimated habitat carrying capacity for wintering waterfowl in this region. In 2010, the Deepwater Horizon oil spill in the Gulf of Mexico prompted enactment of the Migratory Bird Habitat Initiative (MBHI) by USDA Natural Resources Conservation Service. The MBHI provided avian habitat, including flooded ricelands, inland from oil impacted areas. My objectives were to: 1) estimate and model variation in biomass of waste rice and natural seeds as potential waterfowl forage in Gulf Coast Prairie ricelands, 2) estimate and model variation in wetland bird use of ricelands, and 3) conduct sensitivity analyses of bioenergetics models by varying foraging thresholds and true metabolizable energy (TME) values. A growing season of ~270 days allows Gulf Coast rice producers to grow two rice crops (i.e., the second termed ratoon). Waste rice was greatest in production fields with harvested and standing ratoon crops, and natural seed biomass was greatest in idled fields with standing vegetation. Wetland bird species richness and waterbird abundance were greatest in shallowly flooded (1–15 cm) ricelands with sparse vertical vegetation (1–20 cm), and duck abundance was greatest in shallow–intermediately (1–30 cm) flooded ricelands with short vegetation (1–15 cm). Shallowly flooded rice fields containing harvested or standing ratoon crops, and shallowly flooded idled fields with standing vegetation provided abundant potential foods for waterfowl and waterbirds. Bioenergetics models indicated that planners in the Gulf Coast Prairie region may be underestimating riceland habitat requirements for waterfowl by 10,000 ha. Models were most sensitive to changes in seed biomass estimates, and less sensitive to changes in foraging thresholds and TME values. Collectively, these results will facilitate conservation partners to refine models for conserving habitats for waterfowl and other waterbirds in the Gulf Coast Prairie.

Rice not collected by harvesters and natural seeds are important foods for waterfowl. Estimation of abundance of these seeds is necessary for calculating waterfowl habitat conservation needs in the Louisiana Chenier Plain (LCP) and Texas Mid-Coast (TMC). My objectives were to quantify dry mass of rice and other seeds from August-November 2010, and estimate waterbird abundances on farmed and idle ricelands in these regions from December 2010-March 2011. Rice abundance in farmed ricelands ranged from 159.7 kg/ha (CV = 66.6%) to 1,014.0 kg/ha (CV = 8.3%). Natural seed abundance in idle ricelands ranged from 99.7 kg/ha (CV = 32.9%) to 957.4 kg/ha (CV = 17.2%). Greatest waterbird densities occurred in shallowly flooded (i.e., ¡Ü30 cm) disked ricelands (mean = 7.35 waterbirds/ha, 90%; CI = 2.37-19.70). Ratoon, disked, and shallowly flooded ricelands are important habitat for non-breeding waterbirds but variable estimates of seed and waterbird abundances warrant continuation of this study.