Ruddy Duck (Oxyura jamaicensis)



Ruddy Ducks © Andrew Mart

Ruddy Ducks © Andrew Mart

The winter distribution of Ruddy Ducks in Cheshire and Wirral is similar to that in the breeding season, but they spread out somewhat to occupy a few more sites, and most birds leave their main breeding sites in the county. At three of the winter tetrads the observer found birds in February and commented on an early return to a breeding haunt. In north America, Ruddy Ducks are migratory, undertaking long journeys to the warmer waters of the west coast and Mexico in winter, but comparatively little is known about the introduced British population. Observations show that birds tend to congregate in large flocks on reservoirs, especially in the midlands and south-east England.

The habitat codes show clearly this move to larger waterbodies: in the breeding season 13 (out of 58) were on G1 or G2 whereas in winter there were only 4 on G2 (out of 55). They feed mostly by diving and swimming along bottom, and favour eutrophic waters with plenty of nutrients to supply their varied diet of pondweeds, algae, seeds and some aquatic insects and crustaceans.

In the compilations of national WeBS counts, Houghton Green Pool (SJ69G) and Woolston Eyes (SJ68P) are the only Cheshire sites listed with five-year (2000/ 01 to 2004/ 05) peak mean counts of more than 30 birds (38 and 31 respectively) (Banks et al 2006). More than half of the Atlas records were of single-figure flocks and, apart from Houghton Green Pool, only two other sites registered counts over 20 birds: Frodsham Marsh (SJ57E) with 50 birds in 2004/ 05 and Appleton Reservoir (SJ68C) with 23 birds on 19 November 2006.

Owing to the secretive nature of female Ruddy Ducks when breeding, the best population estimates are made in winter. These show the rapid rise, by 81% in ten years from 1993/ 94 to 2003/ 04 and by as much as 569% from 1978/ 79 to 2003/ 04 (Eaton et al 2007). The present cull is just as rapidly reversing their numbers.

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