Copulatory Behavior of Non-Migratory Whooping Cranes in Florida

Abstract

Whooping Cranes (Grus americana) are a long-lived, monogamous avian species, yet little documentation of copulatory behavior and timing in relation to egg-laying has occurred in wild populations. We monitored 10 crane pairs in Florida before and during the 2010 breeding season to document copulation timing and pre- and post-copulatory behavior. Monitoring began 111 days before incubation initiation for the first nest of the season. Pairs were observed for 124.62 hrs ( = 76.30 min, range = 14–375 min) during 98 observation periods; 17 observation periods occurred on days with precipitation. Three copulations were observed, two by one established pair and another by unpaired individuals. The copulations by the established pair occurred 9 and 18 days before incubation began. The third was an extra-pair copulation, which occurred between a paired female and a lone male, the first documented for the species. No copulations were observed on days with precipitation. We examined flock monitoring accounts from 1999 through 2009 in this non-migratory population; 21 observations of copulations revealed Whooping Cranes copulated up to 62 days before incubation began and between 0510–1345 hrs EST. Our data suggest copulation occurs between early morning and early afternoon and does not appear to be associated with precipitation.