News: September 2003

Scientists from the British Trust for Ornithology (BTO) have highlighted an apparent correlation between the demise of our house sparrows (Passer domesticus) and burgeoning populations of wood pigeons (Columa palumbus) and collard doves (Streptopelia decaocto).

While populations of house sparrows have collapsed in many parts of the country in recent decades (particularly in London), the wood pigeon has doubled in numbers since 1970 and the collard dove has undergone an eight-fold increase over the same period. Both these species are known to compete with house sparrows for food: grain is a major staple for all three species.

It is thought that changes in farming practices, e.g. the move to autumn-sown crops, have benefited wood pigeons (in contrast to many other species which have struggled to adapt). Collard doves have been undergoing a rapid population increase and range expansion - they only arrived in the UK in the 1950's.

There are likely to be a number of factors which have influenced the house sparrows population decline but this is an entirely new hypothesis to be looked into. Whatever the underlying causes, it is certain that feeding house sparrows in the garden can do much to mitigate against them.

McCarthy, M. 2003. Wood pigeons' grain diet linked to the demise of house sparrows. Viewed on the web at http://news.independent.co.uk/uk/environment/story.jsp?story=439705 on September 4th 2003.