North American Crane Working Group

 

Date of this Version

2022

Document Type

Article

Citation

PROCEEDINGS OF THE NORTH AMERICAN CRANE WORKSHOP 15:81-89

Comments

Used by permission.

Abstract

Vigilance plays an important role in the detection of possible threats and reducing the risk of predation, including during the incubation period. We examined the visual vigilance of incubating whooping cranes (Grus americana) in Juneau County, Wisconsin, during the 2019 nesting season. We deployed 9 trail cameras and tagged crane presence and behavior in 32,801 photos which were used in our analysis. We assessed individual nest and environmental variables and their effects on vigilant behavior of incubating cranes using linear mixed-models. Vigilant behavior was defined by a posture in which the crane’s head was up, neck was erect, and bill was horizontal to the ground. Nesting whooping cranes were less vigilant during the night (x̄ = 14.3 ± 1.4% [SE]) than during the day (25.0 ± 0.7%), and cranes were less vigilant during precipitation events. Cranes nesting closer to closed forest were 11-12% less vigilant than those nesting at medium or far distances from forest. Lastly, cranes nesting in medium-sized wetlands were 4-5% more vigilant than cranes in small or large wetlands. Further research to determine if levels of vigilance affect nest success could help increase productivity for this population.

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