ML616282016

觀察細節

The main reason for the visit to the site was to try and confirm the identity of the swifts that looked like African Swift. Some better recordings were made of the flight call (attached). The sonograms of these recordings reveals an even trill at 5khz, with a higher frequency introductory note. In contrast, the flight call of African Swift should be an even trill at 6khz ending with a descending element. Michael Mills has pointed out that these recordings are Mottled Swift, which was a surprise because we've not photographed that species at the site. However, on this occasion I made no attempt to look at the swifts with binoculars, I just tried to get recordings.