Date of Award

5-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Wildlife and Fisheries Biology

Advisor

Patrick Jodice

Committee Member

Patrick Gerard

Committee Member

Autumn-Lynn Harrison

Committee Member

William Mackin

Abstract

Information regarding movement patterns of seabirds is useful for understanding prey abundance and distribution, predicting overlap between bird activity and anthropogenic stressors, and assessing the effectiveness of reserves at protecting nesting or foraging habitat(Cairns 1992, Weimerskirch 2007, Weimerskirch et al. 2010). I examined movement patterns of 40 brown pelicans (Pelecanus occidentalis) satellite tagged in December 2010 in South Carolina, USA, and tracked until July 2013. Birds exhibited individual variability in movement patterns and 25% of individuals remained near the breeding colony during nonbreeding. Birds captured in South Carolina that did migrate wintered as far south as Guatemala, prospected and used other breeding colonies both south and north of the capture location, and exhibited prebreeding and postbreeding dispersal. Overlap between brown pelican home ranges and protected areas in South Carolina was low compared to availability of protected habitat; brown pelicans frequently used unprotected nearshore pelagic areas. The percentage of offshore locations within 10 km of the coast was high (98%), suggesting that brown pelican movements may overlap with future offshore wind development and should be accounted for during spatial planning.

I also examined foraging behavior and habitat use of 77 masked boobies (Sula dactylatra) tracked with GPS units during May and November 2013 at a regionally important breeding colony in the southern Gulf of Mexico. Birds exhibited individual variability in foraging behavior and searched for prey at nested hierarchical scales ranging from 60 m - 30 km. Characteristics of foraging trips and foraging behavior did not differ between sexes but did differ between stages; behavior in incubating birds was more variable compared to chick-rearing birds. The oceanographic variables that were related to foraging behavior at small scales (at the prey patch level) varied widely between individuals, suggesting that individual masked boobies use different foraging strategies. Sea surface height and velocity of water corresponded to foraging most frequently (44% and 38% of birds respectively), a finding that is consistent with the characterization of the Gulf of Mexico as a highly dynamic system strongly influenced by currents and eddies.

The two data chapters included in this thesis represent a substantial enhancement to our understanding of movement patterns and spatial ecology of Pelecaniformes in the north Atlantic system. Data sets from both chapters can provide valuable information for marine spatial planning efforts and provide a baseline for anthropogenic based threats such as development, pollution, and commercial fisheries.

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