Thursday, 20 November 2008

The Sparrow Arrow?



Claims that been made (http://www.guardian.co.uk/environment/2008/nov/20/wildlife-environment-sparrows-birds-rspb) in a RSPB report that the rise of the ubiquitous alien Leylandii hedge is an important factor in the decline (down by 68% in the UK since 1977) of the once common House sparrow (Passer domesticus). The sparrows continue to produce chicks but many die within a few days of hatching. This is said to be a consequence of the parent birds finding insufficient numbers of insects (notably aphids or greenfly) in gardens to feed to their young. The Leylandii are not attractive to UK insects and shade many other plants that might encourage them. The RSPB advocate people with private gardens planting "native deciduous trees and shrubs" (e.g. Hawthorn, Wild rose and Honeysuckle) along with wild flowers and long grass (although this might make pet cats a greater danger to the birds) to encourage insects and hence this avian species. They point out that a loss of green spaces in cities, conversion of front gardens to parking spaces, road traffic and air pollution could also be factors influencing House sparrow populations in the UK. Changes in agricultural practises also appear implicated in countryside locations. There are certainly some potentially complex issues evident in this account. One thing is certain, everything that humans do (even in their 'backyards') results in winners and losers in the 'natural' world.

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