Date of Degree

2007

Document Type

Dissertation

Degree Name

Ph.D.

Program

Biology

Advisor

Richard R. Veit

Committee Members

P. A. Buckley

Frank Burbrink

Katharine C. Parsons

William G. Wallace

Subject Categories

Biology

Abstract

Over 1,700 pairs of colonial wading birds (i.e., herons, egrets, and ibis) breed and forage in the industrialized ecosystem of metropolitan New York City (NYC). Wading bird colonies are located on 7 islands that lie between western Staten Island and Long Island Sound. The Black-crowned Night-Heron (BCNH), a mainly nocturnal forager, is the numerically dominant breeding heron in these colonies, and has been undergoing population declines both locally and region-wide since the mid-1990s. My objective was to determine how BCNHs forage in NYC's urban estuarine, freshwater, and terrestrial environments. From March-September 2002-2004, I conducted weekly night surveys on Staten Island, NY to describe BCNH foraging flight patterns from an active breeding colony, abundance and foraging success in 4 habitat types (salt marsh, shoreline, freshwater, terrestrial); and prey availability. I found that: (1) individuals flying from a major breeding colony followed similar flight paths regardless of date or tide; (2) there was a tradeoff between prey size and capture rate, where freshwater foragers captured few large prey while salt marsh and shoreline foragers captured more smaller prey; (3) foraging techniques differed among habitats; (4) activity level was constant through the entire night; and (5) prey composition of nestling diet reflected what was available at foraging sites.

Comments

Digital reproduction from the UMI microform.

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