Western striped squirrel Tamiops mcclellandii: A non-avian sentinel species of bird waves

Abstract

© National University of Singapore. The presence of “avian sentinels” in bird waves (mixed-species foraging flocks), which mob or alarm-call in response to predators, is widely recognised. Yet in the highly threatened lowland deciduous forests of South-east Asia, a mammal, the western striped squirrel Tamiops mcclellandii, which usually accompanied bird-waves, was a more obtrusive sentinel than any bird. It called most often in response to predators (40 out of 70 observations) and was the first species to emit alarm calls on 24 occasions (60%) where studied in Huai Kha Khaeng Wildlife Sanctuary, western Thailand. The squirrels fed in close proximity to drongos (Dicrurus spp.), suggesting they may benefit from the drongos’ tendency to mob predators. Additionally, the drongos actively followed the bark-foraging squirrels in order to capture flushed arthropods. The presence of the western striped squirrel both helped reduce the need for vigilance among avian flock members and contributed to flock cohesion.