Predation and Scavenging by American Alligators on Whooping Cranes and Sandhill Cranes in Florida

Abstract

We documented 15 cases of Grus americana (Whooping Crane) mortality in 6 Florida counties during 1997–2010 that may have been associated with Alligator mississippiensis (American Alligator; hereafter Alligator) predation or scavenging. In four cases, Whooping Crane remains were identified within Alligator mouths or stomachs. The latter is a first in the literature. Other cases were less conclusive but suggestive that Alligators were involved with predation or scavenging of Whooping Cranes. An Alligator was videotaped eating the eggs of G. canadensis pratensis (Florida Sandhill Crane), plus Alligators were implicated in the depredation of eggs from another Sandhill Crane nest and a Whooping Crane nest; the latter was the first record of Alligators depredating Whooping Crane eggs. All 4 populations of Whooping Cranes and 4 populations of Sandhill Cranes in the southeastern United States spend at least part of the year within the range of Alligators. To improve survival of cranes in areas where water management is practiced, water depths should be maintained at optimal levels (10–20 cm) for crane nesting and roosting to discourage intrusion by larger Alligators and to allow the cranes to detect approaching Alligators.