Stable isotope and mercury analysis of Black-capped Petrel (Pterodroma hasitata) feathers to investigate trophic position and foraging areas of light, dark and intermediate forms

Abstract

The Black-capped Petrel (Pterodroma hasitata) is a threatened seabird with two color forms, with its only documented nesting sites located in the mountains of Hispaniola in the Caribbean. Its foraging range extends from the Caribbean and Gulf of Mexico to the northwestern Atlantic. Due to the challenges of studying these birds at sea or at their nesting sites, historical foraging ecology has been analyzed using breast feathers from museum specimens collected between 1978 and 1989 at the North Carolina Museum of Natural Sciences. The analysis focused on three stable isotope ratios (δ13C, δ15N, and δ34S) and total mercury (THg) concentrations.