Short-eared Owl © Richard Steel
Both of the Asio owls undertake long-distance migration, with long sea crossings no barrier to them. Our wintering population is likely to comprise birds from northern England and Scotland, and immigrants from Fennoscandia (Migration Atlas). Young birds disperse in all directions, but many recoveries suggest a movement away from upland moors and hills to coastal localities. The Atlas map shows that most of the winter records are along the edges of our estuaries, with a scattering of tetrads visited elsewhere in lowland Cheshire. Apart from one bird making an early return to the eastern hills, their breeding season sites are vacated. The winter habitat codes reinforce the impression of a bird of rough open land. Of the 34 records, 13 are semi-natural grassland and marsh (8 of them saltmarsh), 3 bog, 12 farmland (7 of them unimproved grassland) and 5 estuarine.
In winter, Short-eared Owls take more birds than in the breeding season, also preying on wood mice and brown rats as well as the staple fare of Field Voles. In some years, large numbers reach Britain following the periodic crashes in abundance of small rodents, especially voles, but there is no evidence that numbers in Cheshire and Wirral fluctuate greatly. Totals of 24, 23 and 21 birds were recorded for the three winters of this Atlas period, similar figures to most winters for the last decade. Where several birds are present, they roost communally on the ground, possibly sharing a site with Hen Harriers. Two areas held most of the birds. Counts from the Dee saltmarsh included five on Heswall Shore (SJ28K) in 2005/ 06 and nine on Gayton Sands (SJ27U) in 2006/ 07. Frodsham Marsh (SJ47Y/ SJ57E) held groups of 4, 4 and 3 in the three winters.
Although there is little indication of numbers and their true status before the onset of modern recording, wintering Short-eared Owls might have been more numerous and widespread a century ago, when Coward (1900) wrote that ‘this well-known autumn visitor is found in open situations in Cheshire, from the coast sandhills to the moors of the East, and is often flushed by shooting parties from its resting place amongst the turnips or in the heather’. Bell’s summary in 1962 sounds little different from today: ‘the bird is now only an autumn to spring visitor and confined almost entirely to the Mersey marshes around Frodsham, and in West Wirral, where it appears regularly in small numbers’.
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