Friday, December 15, 2006

Oceanodroma leucorhoa

Few could have failed to notice the recent spate of reports concerning large, seasonally atypical, numbers of Leach’s Petrels seen from our shores. The prevailing weather conditions from the west have forced many of these usually ocean-going wanderers to our shores at a time when they are not normally seen. Generally speaking we only witness small numbers in August and September – offshore at Heysham, Blackpool, Formby and in the Mersey estuary at Seaforth – with the biggest count in 2005 (112) seen off Formby Point in October. So numbers witnessed this month are both atypical and unusual.

Nationally birds have been reported from coastal areas extending from the Firth of Clyde in Scotland, south to Land’s End, including the west and south coasts of Ireland, right around to at least Dorset on the south coast of Britain. The largest movements were reported off the Glamorgan coast and Merseyside. Interestingly, obviously disorientated, birds were also seen moving up the River Severn - generating sightings from many inland areas. In all, the consensus seems to be that about 2000 birds were involved in this ‘wreck’, during a seven day period.

The largest number reported anywhere was of 190 flying out of the Mersey near Crosby Marine Park on December 9th. The next biggest total was of a 155 from Glamorgan. Elsewhere, locally, 74 individuals were reported from the North Wirral Coastal Park and 68 from Hoylake; with smaller numbers from other Wirral coastal areas.

Historically birds have only been reported in Lancashire in nine winters (Dec-Feb) since the mid-1960’s. The highest counts from these winters were seven off the Wyre and Lune estuaries in early February 2002; which serves to demonstrate the significance of these recent counts. (If you have any sighting reports, and/or counts, please submit them to the County Recorder Steve White (email removed to prevent spam - Bob) for inclusion in the 2006 Lancs Bird Report). Email me directly and I will pass it on - my contact email should be known to you.

In the last 60 years there have been only twelve ‘Leach’s autumns’ the most significant of which was 1952 when over 7,000 birds were thought to have died, after being forced inland away from their feeding areas during bad weather. Obviously, with the current bad weather set to continue for a few more days we may witness a few deaths amongst this latest influx. However a bit of perspective, the National Trust at Fair Isle predict that, annually, over 14,000 Leach’s Petrels are lost to marauding Great Skuas on this one island alone.

Image from Liverpool Daily Post


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