Breeding birds use alligators to protect nests from raccoons, opossums

Published: Wednesday, March 2, 2016 - 22:02 in Biology & Nature

Florida Fish and Wildlife Conservation Commission

Breeding birds that nest above alligators for protection from mammalian predators may also provide a source of food for the alligators living in the Everglades, Florida, according to a study published March 2, 2016 in the open-access journal PLOS ONE by Lucas Nell from the University of Florida and colleagues. For many bird species, nest predation is the greatest threat to raising chicks. Long-legged wading birds, like herons, egrets, ibises, storks, and spoonbills may choose nesting sites above resident American alligators, likely to take advantage of protection from nest predators such as raccoons and opossums. While the benefits to the bird species of having alligators nearby are well-documented, few studies have explored the effect on the protector, the alligator. Specifically, some previous research has shown that wading bird nesting colonies could provide substantial food for alligators in the form of dropped chicks, which are chicks ejected from the nest when a bird lays more eggs than they can raise. In this study, the authors compared the body condition of ~40 female alligators living with and without long-legged wading bird nesting colonies in similar habitat in the Everglades, Florida. To measure body condition, they took blood samples and measured the mass and length of the alligators.

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