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New York City, NY, United States

Washburn B.E.,U.S. Department of Agriculture | Elbin S.B.,New York City Audubon | Davis C.,201 County Route 631
Waterbirds | Year: 2016

During the 20th century, gull populations in North America experienced considerable changes in abundance and geographic ranges. The objective of this study was to describe population trends of Herring Gulls (Larus argentatus) and Great Black-backed Gulls (L. marinus) in the New York Bight, USA, over a 40-year period (1974-2013). A variety of data sources using different survey methods provided estimates of the number of breeding pairs for both species. In the Long Island portion of the New York Bight, overall Herring and Great Black-backed gull nesting populations appear to have fluctuated considerably in size during this time period, and the largest numbers of breeding individuals of these two species occurred in the 1980s. In coastal New Jersey, the Herring Gull nesting population has remained relatively constant, whereas the Great Black-backed Gull nesting population has increased. Individual nesting colonies are dynamic and can vary in size considerably during even short time periods. Several factors, including sea-level changes and the availability of anthropogenic food sources (i.e., at landfills and fisheries by-catch), likely have strongly influenced individual colonies and the overall Herring and Great Blackbacked gull breeding populations in the New York Bight.

Parkins K.L.,New York City Audubon | Parkins K.L.,Fordham University | Elbin S.B.,New York City Audubon | Barnes E.,New York City Audubon | Barnes E.,New York University
Northeastern Naturalist | Year: 2015

Building collisions are a significant threat to birds in North America, and urban areas can be particularly hazardous to birds using city parks as stopover habitat. We examined the effects of light and glass on bird-building collisions in an urban park using New York City Audubon's collision-monitoring data from fall migration 2013 and photographic analysis of building facades. We found a significant positive relationship between the number of collisions and interior building light (rho = 1); however, the amount of light was strongly correlated with the amount of glass in building facades (r2 = 0.82). Carcass persistence at the site was examined using tagged, dead birds. Only 37 percent of carcasses were found by our monitors, suggesting that our estimate of bird mortality due to collisions has been too conservative. The amount of glass on a building facade may have an equal or greater effect on bird- building collisions than the amount of light emitted from the facade. Mitigation of both light and glass are needed to reduce bird-building collisions in urban areas. © Author(s) 2015.

Craig E.C.,Columbia University | Elbin S.B.,New York City Audubon | Danoff-Burg J.A.,Columbia University | Palmer M.I.,Columbia University
Waterbirds | Year: 2012

Colonially nesting waterbirds transfer large quantities of aquatically derived nutrients into terrestrial systems, potentially altering community and ecosystem structure. Over the past three decades, the Double-crested Cormorant (Phalacrocorax auritus) has undergone rapid population expansion throughout much of its historic range in North America, recolonizing habitats that had not supported colonial waterbirds for decades. Mounting evidence suggests that these populations are degrading the habitats they colonize primarily through the destruction of vegetation and the alteration of soil conditions. The study examined the effects of cormorants and cooccurring long-legged wading bird species including Black-crowned Night-Herons (Nycticorax nycticorax). Great Egrets (Ardea alba) and Snowy Egrets (Egretta thula) on their nesting habitats by observing plant and arthropod community structure as well as soil and leaf litter characteristics at colonized and non-colonized sites on two islands in New York Harbor. Understory plant species richness and total plant cover were reduced, and the arthropod community shifted from primarily plant feeders to primarily carrion and dung feeders beneath cormorant nests in comparison to adjacent non-colonized habitats. On the island where cormorants have been established longer, the colony tended to be denser and larger and was associated with larger ecological impacts on plants, arthropods and soils. Long-legged wading bird colonies and more recently established cormorant colonies were smaller, less dense, and were generally associated with fewer ecological impacts.

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