Date of this Version
PROCEEDINGS OF THE NORTH AMERICAN CRANE WORKSHOP 14:46-55
Agricultural fields may provide an important supplementary foraging habitat for whooping cranes (Grus americana) in the reintroduced Eastern Migratory Population (EMP). We developed methods and gathered preliminary data regarding whooping crane foraging efficiency and habitat use to better understand the use of agricultural fields by breeding cranes. We generated a simple null hypothesis that cranes would spend more time in the habitat type (wetlands vs. agricultural fields) in which they were able to obtain a higher foraging efficiency to maximize food intake, along with several alternative hypotheses pertaining to reasons cranes may prefer wetlands or agricultural fields during periods of the breeding season regardless of foraging efficiency. We collected habitat use and measures of foraging efficiency (stepping rate, striking efficiency, and capture rate) from videos of 2 pairs of cranes recorded for a concurrent study. Cranes spent more time in the habitat with higher foraging efficiency during the pre-nesting period (wetlands) but more time in the habitat with lower foraging efficiency during the incubation period (also wetlands). There was no significant difference in foraging efficiency post nest-abandonment. Our data imply that cranes are willing to undergo lower foraging efficiencies in order to remain on territory during incubation. However, our data should be considered preliminary due to the small sample size of individuals studied.