Alarm calls of the Cyprus Wheatear Oenanthe cypriaca—one for nest defence, one for parent–offspring communication?

Abstract

Alarm calling has been interpreted from the viewpoint of parental investment and nest defence. Calling should increase with an increasing value of the brood to the caller or with increasing vulnerability of the brood. Parental alarm calling might also be viewed from assessment–management with callers using vocalisations to elicit affective responses in others, e.g. in silencing offspring. I examined parental alarm calling in the Cyprus Wheatear (Oenanthe cypriaca) at different developmental stages. The Cyprus Wheatear produces two alarm calls, but one is emitted only during a short period of the year (type II alarm call). The commoner alarm call (type I alarm call), however, is used year-round. Predation was simulated using consistent approach by human observers. The brood cycle was divided into (I) incubation, (II) nestling, (III) early fledging, and (IV) late fledging. Type I calls increased from phases I to III, and decreased afterwards. Type II calls were absent during incubating and occurred during nestling and early fledging stages. As a conclusion, I suggest that the type I alarm call might be used to alert the mate, deter the predator and signal strength of nest defence, while the type II alarm call is addressed to offspring.