Mistle Thrush (Turdus viscivorus)



Mistle Thrush © Richard Steel

Mistle Thrush © Richard Steel

Mistle Thrushes are somewhat more widespread in winter than in the breeding season, being found in 606 tetrads, an increase of 23. Adult birds are highly sedentary but first-year birds may disperse short distances (Migration Atlas), and it is presumably the young birds who move to fill in many of the gaps in rural Cheshire. None was found on Hilbre during this Atlas. Although it is widely distributed, the density of Mistle Thrushes is low. After the early-autumn gatherings break up, this species is seldom found in large flocks. The vast majority of submitted counts were of one or two birds, according with the tendency of adults to maintain territories in winter. There were only fifteen counts in double figures, with a maximum of 40 at Toft (SJ77N) counted by Pete Hall.

The habitat records for this Atlas show that, compared to the breeding season, fewer Mistle Thrushes were in woodland (which is primarily used for nesting rather than for feeding) and human sites, and more were located in open farmland. Fieldworkers noted that they often shared their feeding areas with livestock, including sheep on the hillsides, where the thrushes benefit from close-cropped grassland and are able to probe for worms and other soil invertebrates amongst the animals. Studies elsewhere have shown that birds in farmland show a strong preference for feeding on grazed grass fields during winter, especially permanent pastures or long-term leys where soil invertebrate populations have not been affected by cultivation for several years (Wilson et al 1996), and they avoid ungrazed grass and arable crops. In this Atlas, the proportion of Mistle Thrushes using improved grassland was more than double that of Blackbirds or Song Thrushes, but in winter Mistle Thrushes have to compete with the flocks of Fieldfares and Redwings, which are even more likely to favour the grazed pastures. Perhaps it is this rivalry that has led to Mistle Thrushes defending some winter food supplies.

Most adult birds, either as individuals or, more often, as pairs, choose a bush covered with berries, usually holly, mistletoe or haw, occasionally yew or ivy, and keep away all other birds, of every species. They start in October and preserve this supply for their own future needs, seldom eating from their defended bush until late in the winter, and perhaps not even then; some bushes keep their fruit into the breeding season, when the Mistle Thrushes feed them to their chicks. A holly bush that still has its fruit at Christmas, certainly in a hard winter, is almost certainly being defended by Mistle Thrushes (Snow & Snow 1988), and their liking for mistletoe must have been known for centuries, as it led to the species’ English name and the scientific name, from viscum album. The defence of their chosen bush may break down in the face of concerted attacks by a flock of birds, perhaps in hard weather by Fieldfares. The ornamental rowan trees in Runcorn town centre (SJ58B) visited by Waxwings in January 2005 had been the property of a pair of Mistle Thrushes, but they were no match for the hordes of invading Waxwings, which largely ignored the thrushes’ attempts to keep them off. Even Europe’s largest thrush had to admit defeat.

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