Tree sparrow
Passer montanus
A scarce relative of the house sparrow, the tree sparrow has a chestnut crown, white head sides with a black cheek patch and a narrow white neck stripe. Unlike the house sparrow the plumage of the two sexes are alike. The tree sparrow is generally found on lowland farmland with arable or mixed farming systems. Tree sparrows have undergone a dramatic decline in population and range in the UK with a 95% decline between 1970 and 1998. It is now patchily distributed across the UK. The main populations are found across the midlands, and southeast England. It is almost completely absent from Wales, northwest and southwest England. The species is a UK Biodiversity Action Plan priority species and it is listed on the Birds of Conservation Concern Red List.
The huge decline in tree sparrow numbers is probably the result of agricultural intensification and specialisation, particularly the increased use of herbicides. A trend towards autumn-sown crops, at the expense of spring-sown crops that produce stubble fields over winter, plus the increased use of insecticides, will have reduced the amount of insect food available for nestlings.
In the Tees Valley, a study of tree sparrows in 1993 estimated a breeding population of about 135 pairs distributed in 10 loose breeding colonies scattered throughout the old county of Cleveland. Less systematic observations have suggested that there has been little change since then, possibly even a slight increase. Flocks of up to 100 birds can be found in the non-breeding season, but these are highly mobile, remaining for only a few days in the same feeding area suggesting that finding food in the winter may be a particular problem.
