Snake-like hissing calls made by nestlings of the open nesting zitting cisticola Cisticola juncidis.

Mimicry is widespread in the animal kingdom, with sound/or acoustic mimicry remaining less studied than visual mimicry. Some incubating female birds in cavity nests emit a hissing call when encountering nest predators, which sounds like a snake hiss and serves to scare off predators; this is considered a form of acoustic Batesian mimicry. Similarly, for nearly defenseless bird nestlings, using a hissing call to scare off predators can improve their survival; however, few studies have reported nestlings making hissing calls. In this study, we report on the hissing calls of nestlings of the open-nesting zitting cisticola (Cisticola juncidis) and compare their hissing calls with those of other animals, such as birds and snakes. The results showed that the hissing calls of C. juncidis nestlings closely approximate the sounds of snakes. This study is the first report of sounds that mimic snakes made by the nestlings of any open-nesting passerine bird species. [ABSTRACT FROM AUTHOR]