Tsip calls of meadow and rock pipits: interspecific comparisons and playback experiments

Abstract

The common Tsip calls of meadow pipits, Anthus pratensis, and rock pipits, A. spinoletta, were recorded and played in the field in sympatric populations in southwest Sweden. The purpose of the playback experiments was to investigate whether meadow pipits are able to discriminate between conspecific and heterospecific calls of similar configurations when the inter-call intervals are equalized. To ascertain that there are interspecific, morphological differences between the Tsip calls, sonagram analyses were made. The Soft calls of migrating pipits were also described and compared though not used in playback experiments. Both calls differe in configuration between the pipit species and Tsip calls transmit species-specific information to territorial males, i.e. they responded to conspecific calls but rarely to heterospecific ones. However, migratory birds frequently responded to both conspecific and heterospecific Tsip calls. This might be due to a change in strategy or to (Particularly young?) birds failing to discriminate between the calls outside the breeding season, or both. Alternatively, territorial males might learn not to respond to vocalizations of congeneric pipits. Future experiments in an allopatric area should shed light on this issue.