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World Sparrow Day

…interesting new results…

The British Trust for Ornithology’s (BTO’s) Garden BirdWatch survey has provided exciting new results for World Sparrow Day. House Sparrows are increasingly being lost from gardens between summer and autumn. However, House Sparrows have only really struggled in English, not Welsh or Scottish, gardens.

House Sparrow populations are no longer considered to be secure across Europe and, on the 20th March 2011, World Sparrow Day will highlight the plight of this charismatic and confiding bird.

To coincide with the big day, BTO’s year-round Garden BirdWatch has provided illuminating new results, charting the House Sparrow’s decline.

The results, which have been welcomed by wildlife expert Chris Packham, show big seasonal and geographical differences in the downward trend of this species. Overall, however, almost one in four British and Irish gardens that hosted a House Sparrow in 1995 no longer have any visiting. 

Summer and autumn: critical times
The number of householders who have lost their House Sparrows between summer and autumn has doubled since 1995, supporting the theory that this is the crunch period. The BTO’s Nest Record Scheme shows that brood sizes of House Sparrows have declined steadily since the 1960s, with a shortage of invertebrate food with which to feed young in urban areas thought to be an important factor. Food scarcity can also cause chicks to fledge in poorer condition, thereby reducing their survival prospects. With increased demand for off-street parking and so called ‘garden grabbing’ (development of gardens for housing), feeding areas for urban sparrows have been reduced. Moreover, use of pesticides and planting of non-native evergreen vegetation are likely to have diminished invertebrate availability for these birds further.

Regional differences
The House Sparrow’s demise has been most marked in England, with an average of 86% of gardens visited between 1995 and 1998, down to 66% over the past four years. Over the same period, however, only around one in 20 Scottish and Welsh householders have lost their House Sparrows, with 74% and 78% of gardens still occupied in each country, respectively. Preliminary results from gardens in Northern Ireland and the Republic of Ireland suggest that House Sparrows may be faring quite well here too. Chris Packham, Vice-President of the BTO, commented: “World Sparrow Day brings into focus the evidence surrounding the decline of this iconic garden bird. By monitoring garden birds all through the year, BTO Garden BirdWatch participants have identified summer and autumn as the critical seasons during which House Sparrow are being lost. We need more people to join this Citizen Science project in order to keep a close eye on this much-loved species in future.” 

Tim Harrison, BTO Garden BirdWatch, added: “The precipitous decline of House Sparrows in England is illustrated starkly in London. Once famed for its large House Sparrow community, fewer than half of Greater London gardens were, on average, visited by this familiar bird in 2010 – a smaller percentage than in any other English region. Clearly, the factors that trouble this species vary in their strength regionally, and these new results highlight the importance of examining these differences more closely.” 

House Sparrows demonstrate how rapidly the fortunes of any bird can change and the importance of recording their numbers.

To try your hand at BTO Garden BirdWatch, please contact the BTO for a free ‘taster’ pack: gbw@bto.org or 01842-750050.

4th July 2014