Reproductive success and nestling growth at a roof and ground colony of roseate terns (Sterna dougallii) in Florida

Few studies have addressed reproductive success and nestling growth of the Caribbean population of Roseate Terns (Sterna dougallii), and no one has studied the most northerly nesting colonies in Florida. Two colonies in Florida, a ground colony (Pelican Shoal), and a roof colony (Marathon Government Center) were examined in 2000 and 2001. This study found the roof and ground colony to have similar incubation periods, days to fledging, linear growth rates, and asymptotic mass. However, clutch size, hatch success, and annual reproductive success were more variable between the colonies and between the two years. Most of this variability resulted from high nest and chick loss at Pelican Shoal due to avian predators, nesting sea turtles, and strong summer storms. Artificial habitat (nest boxes and tires), placed at the two colonies to improve reproductive success, was not utilized by Roseate Terns for nesting but was used by nesting Bridled Terns (Sterna anaethetus ) at Pelican Shoal. Air temperatures were higher at the roof colony than the ground colony and higher in the artificial habitat than in "natural" nesting substrates.