Delays northbound
31 May 2013
The BirdTrack reporting rates for returning migrants have received even more attention than usual this year, even featuring on the BBC's Springwatch Unsprung! The reason for all the interest has been the topsy-turvy spring, with a very cold March and early April delaying some early-arriving species like Chiffchaff and Sand Martin, before more unseasonably cold weather in early May slowed the progress of some later-arriving species.
Compare and contrast Swallow (top right) with House Martin: although the initial Swallow arrival was a week or two late, the reporting rate quickly caught. The House Martin arrival, on the other hand, suffered a 'stall' in early May, and has yet to catch up. A similar pattern can be seen in another black-and-white summer visitor, Pied Flycatcher (middle left), whilst the situation for Turtle Dove (bottom left) looks considerably worse.
Not all migrants were late back though; as well as Swallow, both Reed and Willow Warbler (middle and bottom right) were being detected at near-normal levels throughout May.
Share this page