Vigilance behaviour of American Wigeon Anas americana foraging in pastures

Abstract

Observations were made of feeding American Wigeon Anas americana to assess their
vigilance levels in relation to foraging location. American Wigeon increased vigilance
levels: 1) while foraging on land compared to on water, 2) while grazing progressively
further away from a water source, and 3) after being on land for long periods of time.
Vigilance patterns were nearly identical to those recorded for Eurasian Wigeon Anas
penelope in earlier studies. Males were more vigilant than females when foraging on
land. This study contributes to understanding the importance of ephemeral pond
habitats to grazing American Wigeon, which are used as anti-predator refuges by
actively feeding flocks.