Vocal similarities between Mediterranean and north European Pine Crossbills Loxia spp
Authors: Ron W. SUMMERS y David C. JARDINE
Published: Volume 52(2), December 2005. Pages 269-278.
Aims: To make a comparative study of the flight and excitement calls of Crossbills Loxia curvirostra in the Mediterranean region. Given that different call types (distinguished by combinations of flight and excitement calls) are recognised within the nominate race in northern Europe, we expected that the subspecies endemic to the Mediterranean region would each have a different call type, whilst Pyrenean birds might share calls with one of the call types already described in northern Europe.
Location: Calls of Crossbills were recorded in Mallorca, Cyprus and Morocco, where three Mediterranean subspecies of the Common Crossbill occur. Recordings were also made in the Pyrenées, inhabited by the nominate subspecies.
Methods: Calls were recorded on a Sony Walkman Professional tape recorder using a Pro-sound directional microphone (model YU-36) or a parabolic reflector. The CANARY system was used to make sonograms.
Results: Although different combinations of flight and excitement calls were detected, all four groups of crossbills shared either flight or excitement calls. In particular, the similarity between the flight and excitement calls of crossbills from Mallorca and the Pyrenées suggests that these populations may not be separate. Further, many of the calls of the Mediterranean crossbills were similar to calls of Scottish and Parrot Crossbills in Scotland, rather than Common Crossbills. One individual recorded in Mallorca had flight and excitement calls that matched a call type of the nominate race from northern Europe, confirming that some migrants reach the Mediterranean islands.
Conclusions: The results followed our expectation that the endemic subspecies of Crossbills in the Mediterranean region each have different combinations of flight and excitement calls. However, the sharing of flight or excitement calls adds to the debate about the relations among Mediterranean crossbills and their relationship with crossbills on the Spanish mainland. Further, the similarity in calls between Mediterranean and north European pine crossbills supports the hypothesis based on fossil evidence that the pine-adapted crossbills may share a common ancestry.