Reasons that have been suggested for the decline in house sparrow populations include mobile phone masts, unleaded petrol and change in building methods. House sparrow numbers have fallen by 50% since the 1970s, but no one, as yet, has accurately determined the specific factors behind this worrying decline.
Conservationists believe that fewer nest sites and a reduction in food availability are the key reasons for the dramatic decline. Modern housing provides fewer nooks and crannies for house sparrows to nest in, and high density building is likely to lead to fewer invertebrates, especially insects, the staple food for house sparrow nestlings.
Such is the concern for this most familiar of urban birds, the British Trust for Ornithology (BTO) is asking for volunteers to help with a detailed survey in built areas (from cities to villages) to find out exactly what has caused house sparrow numbers to halve in 30 years.
Results from the BTO’s ‘Garden Birdwatch’ not only show that house sparrow numbers are falling in many urban areas, but also indicate a definite regional variation. However, there are many factors that have yet to be looked at, including housing density, garden vegetation and adjacent land use, any of which might affect house sparrow numbers.
Here is your chance to contribute to both national and Suffolk records*. Recording the data required is quite straightforward. If you are interested in taking part in the survey, ask for an information pack from ‘Garden Birdwatch’, Room R4, FREEPOST, Norfolk IP24 2BR.
*Your records will also be of interest to the Suffolk Ornithology Group.
We stopped supplying zip files of the magazine for download, with issue 53.
This is because the service was very infrequently used and it saves space on the server.
If you miss downloading however please e-mail me, Adrian Chalkley
I will decide whether there is sufficient demand for an alternative method.