First Records of Least Terns Nesting on Non-Gravel Roofs

Abstract

Sternula antillarum (Least Tern) and other waterbirds have nested on tar-and-gravel roofs in Florida starting from the early 1950s. Habitat disturbance and loss has been implicated as the primary reason for this shift from the ground to roofs. The Florida Fish and Wildlife Conservation Commission conducted a statewide survey of rooftop-nesting birds between April and July 2010. Two buildings with non-gravel roofs were found to contain Least Tern nests; one was located on Islamorada in the Florida Keys, and the other on Pensacola Beach in the Florida Panhandle. Both of these sites were formerly gravel roofs and were used for nesting by Least Terns for several years; however, they had both been recently reroofed. The Islamorada site has a spray polyurethane foam roof, and the Pensacola Beach site has a mineral built-up roof. Both sites produced chicks, but only the Pensacola site fledged young. These are the first published records of a waterbird species nesting on a non-gravel roof. This discovery may have future implications as gravel roofs, particularly in Florida, are being replaced by newer types of roofs that are safer to humans and surrounding structures during tropical storms and are more energy efficient. Further surveys are needed to determine the extent of Least Tern nesting on non-gravel roofs and the productivity of these rooftop breeding colonies.