Stuart Britton wrote:
Sorry if I have caused confusion. Willow Tits are very sedentary - it is believed that where they are known to be breeding, the provision of nest boxes for Great/Blue Tits may put pressure on the Willow Tits through competition.
The 85 % decline in WT numbers between 1970 and 2003 (Eaton et al. 2005) has been blamed on habitat change (principally dessication) in suitable woodlands and potentially on competitions with other tits along with nest-predation by G S Woodpeckers. Maxwell (2002) showed clearly that competition for nest sites (rather than food resources) can be important on a local scale. In his study area, two-thirds of the WT population lost their nest-holes to Blue and Great Tits over a period of 5 years. It is possible that in some suburban areas, numbers of tits have increased dramatically due to a proliferation of bird feeders and nestboxes. This, in combination with the fact that natural nest-sites can be in short supply (because of the removal of older trees from parks and gardens), may mean that competition for nest-holes can result in local Willow Tit declines....
Alex
_________________
Dr Alexander C. Lees
Lecturer in tropical ecologyManchester Metropolitan University
Lab Associate
Cornell Lab of Ornithology,
Cornell University
http://www.freewebs.com/alexlees/index.htm@Alexander_Lees
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