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Quite a productive bit of birding from Brunel Dock to Aberavon Beach and back produced a couple of Sand Martins heading up-river over Brunel Dock. A Short-eared Owl and male Merlin in Baglan Dunes. The Merlin put up a Sky Lark and gave chase for about 30 seconds while the Sky Lark appeared to be in complete control of the situation; celebrating the positive outcome by bursting into song as the Merlin carried on its way. Close by in the flooded part of the dunes 2 Water Rail and 1+ Jack Snipe.
2 comments:
Hi Mark, great observation of the merlin attack on the singing skylark -here is a remarkable explanation by Will Cresswell in one of my all-time favourite natural history papers:
Song as a pursuit-deterrent signal, and its occurrence relative to other anti-predation behaviours of skylark (Alauda arvensis) on attack by merlins (Falco columbarius)
Will Cresswell 1994,
Behavioral Ecology and Sociobiology
Volume 34, Issue 3, pp 217-223
Skylarks show a range of anti-predation behaviours including flocking, refuge-seeking and song. Responses by skylarks to merlin attack were recorded over three winters on a Scottish estuary to determine the effectiveness of song as a pursuit-deterrent signal, and its use with respect to other anti-predation options such as flocking. Mortality due to merlin predation was high. Skylarks used song as a pursuit-deterrent signal. Merlins chased non- or poorly singing skylarks for longer periods compared to skylarks that sang well. A merlin was more likely to catch a non-singing than a poorly singing than a full-singing skylark. Temperature did not affect chase lengths, song types or success rates of attacks. Larger flocks of skylarks were preferentially attacked so that the individual probability of being attacked within some larger flock sizes was greater than in a smaller flock. Success rate did not vary with flock size. Merlins chose skylarks before any song was heard, so there was no cost for non-singing skylarks in joining flocks. The frequency of capture on merlin attack depended on the escape response used by the skylark. Non-singing skylarks were probably more likely to escape by seeking a refuge or staying on the ground on attack, while singing skylarks were more likely to escape if they flew. The optimal escape option available to a skylark on merlin attack was probably dependent on its condition, as indicated by its ability to sing on attack.
Wouldn't it be funny if the details show it was ringed in Canada!
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