TREE SPARROW

Tree Sparrows are resident in Britain .  They are highly sedentary, and rarely move far from their breeding area.  They usually nest in loose colonies in areas where clumps of mature trees (or nest boxes) provide nest holes.  Trees in hedgerows, and in open woodland, are favoured.

Tree Sparrows are the same size as their much more common relative, the House Sparrow, from which they are distinguished by their all-brown head, smaller neat bib and black cheek spot. The sexes are identical. They are inconspicuous, and easily overlooked.

Their breeding season begins in April.  The first clutch, usually 4-6 eggs, is incubated for 11-14 days.  Young leave the nest 12-14 days later.  Two, or occasionally three, broods are raised each year.

The map from The Atlas (1992) on the previous page shows that the species is widely distributed, but is largely absent from upland areas, and lowland areas with few mature trees.  However, there are apparently suitable areas where they are absent, showing that the national population decline has occurred at the local level. The more recent 2000 – 04 Distribution Map shows the same pattern. The high proportion of confirmed breeding records reflect the Tree Sparrows’ willingness to utilise nest boxes. As the birds are highly sedentary, they are likely to breed in the same areas where they are seen outside the breeding season.  Most records from other times of the year have corresponding breeding season records, but a few do not. Such records are shown on the 2000 – 04 map as small green dots.

Nationally, the species is largely absent from southern and south-west England , and the uplands of Wales , northern England and Scotland .  There has been a considerable contraction of range, and reduction in breeding density.  Between 1970 and 1999 it is estimated that the population declined by 95%, and the species is now on the Red List of the Population Status of Birds in the UK – Birds of Conservation Concern: 2002-2007.  Although the population is now showing a welcome increase (48% between 1994 and 2004), this is within a small remnant population, and numbers are only about 3% of what they were in the 1970s. 

The decline has been caused by poor recent over-winter survival rates, as a result of the disappearance of seeds on farmland, particularly the loss of winter stubbles.

Habitat changes necessary to reverse the population decline of this species therefore include increasing the supply of seeds throughout the year, particularly in winter. Reduced use of herbicides, and increased plant diversity in conservation strips and headlands at the edge of fields, are necessary to help this species.

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