Worcestershire Record No. 21 April 2007 p. 17


John Clarke

This year we found 23 pairs and although I failed to locate all of the successive nests I did eventually monitor 51. The late Spring meant their was a lack of early cover and a shortage of food, and in addition some areas had high populations of predators such as Grey Squirrel, Jackdaw, Magpie and Jay. As a result, by the end of June 63% of nests found had failed. However, the birds kept trying and later attempts had only a 22% failure rate - a net average of 46%. So much time was required to find these second and third attempts that I failed with several pairs. Frustratingly, on three occasions I found freshly-fledged young in the areas that I had been searching! Nevertheless, the eventual overall productivity (young per pair), based on what I did find, was 4.00 - the highest yet for this survey. This figure does not reflect the potential high productivity of Spotted Flycatchers - in one of my sites, where no nests were predated, three pairs produced 19 young, an average of 6.33 young per pair.

Regarding predation of songbird nests, SongBird Survival commissioned a report on the effects of mammalian predators and it makes fascinating reading. For example it claims that uncontrolled populations of Grey Squirrel can attack more than 90% of songbird nests in their area. I found the report on the web via 'SongBird Survival' and followed the links.

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