British Birds January 2011
The January issue of British Birds is now out and contains the following:
Two complete migration cycles for an adult Hobby tracked by satellite
A tiny satellite transmitter, a prototype of the smallest unit produced so far and weighing just 5 g, was fitted to an adult Hobby in Germany in August 2008, by Bernd-Ulrich Meyburg and his colleagues. Two whole migration cycles were recorded successfully from the transmitter carried by this particular Hobby. All four migration routes (two in autumn, two in spring) were to the west of a direct line between breeding site and wintering area. The migration route in spring 2010 was up to 2,150 km farther west than that in autumn 2009, so the bird effectively undertook a ‘migration loop’. This was much less pronounced in 2008/09. The direct distance from the breeding site to the southernmost point reached in Zimbabwe in 2008/09 was 10,065 km. The West African equatorial rainforest appears to be a significant ecological barrier, and the significance of this is discussed in the paper. Migration was noticeably rapid there with distances of up to 580 km flown per day – also partly at night. During both wintering periods the falcon spent the majority of its time in the Angolan Miombo woodlands, but in winter it also travelled large distances: from 16th October 2008 to 7th April 2009, the bird covered a total distance of at least 9,025 km between identified night roosts.
The autumn migration of soaring birds at Bourgas Bay, Bulgaria
The results of a survey of the autumn migration of soaring birds via the western Black Sea migration route (‘Via Pontica’), at Bourgas Bay, Bulgaria, are presented here, for five species of waterbird and 33 species of raptor. Tanyo Michev and his colleagues report the results of visual observations carried out on 1,640 days in August, September and October between 1979 and 2003. The mean number of migrating waterbirds logged in autumn during the survey was 169,072 individuals (max. 250,623 in 1999), and the corresponding figure for migrant raptors was 38,534 (max. 65,065 in 1990). These data confirm that Bourgas Bay is one of the most important sites for monitoring the migration of soaring birds in Europe, and the most important for the autumn migration of several species, including White and Dalmatian Pelican, White Stork, harriers, Levant Sparrowhawk, Lesser Spotted Eagle and Red-footed Falcon. The data collected during 20 years of the Bourgas survey provide the opportunity to track long-term changes in the populations of migrant waterbirds and raptors in eastern Europe.
RSPB Conservation Research News
Three interesting subjects are covered in this month’s offering, including the ecology and habitat use of crossbill species in Scotland, the breeding ecology of Twite and the population decline of the Lesser Spotted Woodpecker.
Two notes in this issue describe a marsh tern showing mixed characters of Black and White-winged Black Terns, and the jizz of ‘eastern’ Common Nightingales Luscinia megarhynchos golzii
Robin Chancellor (1921–2010)
As usual, a range of reviews, news & comment and a summary of recent reports complete the issue.
For more details, and to see download a recent issue of the magazine, visit our website at www.britishbirds.co.uk