Urban birds
The little brown bird that should be celebrated, enjoyed and given our protection…
David Lindo throws the spotlight on the Tree Sparrow, the little bird that we should all enjoy and do our best to protect
The Tree Sparrow has fascinated me ever since I was a kid. After weaning on the numerous House Sparrows that frequented my urban garden in Wembley, North London, a winter visit to my local park was my first introduction to the Tree Sparrow. I noticed a shy flock of sparrows in a riverside shrub that all seemed to look identical, with brown caps with a black cheek spots – Tree Sparrows. I was a fledgling birder, but I knew that these birds were different.
Over time, I realised that they were regular winter visitors to my patch of rough ground. I took my wintering party of 70-plus birds for granted, but with each passing year, there were fewer and fewer of them until, one summer, the land was eventually developed. The flock was extirpated and I never saw them again. Little did I know that the same story was being played out across the capital and, indeed, across the nation.
The UK Tree Sparrow population has suffered an estimated loss of 93% between 1970 and 2008, although recent censuses have indicated that there has been a slight upturn in their fortunes. But their decline has been stark.
Once upon a time, Beddington Sewage Farm, on the cusp of South London, was home to one of Britain’s largest breeding populations of Tree Sparrows, with some 300 youngsters fledged in 2008. Now, through habitat destruction, the species is on the verge of extinction even there.
Like the House Sparrow, there are certain corners of the country in which they are now unheard of and other sites where they are still quite common. The Bempton Cliffs RSPB reserve springs to mind as a definite site for them.
Tree Sparrows are around 10% smaller than their more familiar brethren and possess a slightly different tone of chirp that is often phonetically expressed as ‘chup, chup’. Superficially looking like a male House Sparrow, they have a completely chestnut brown crown and a distinctive black cheek spot.
Of all the sparrow species in the world, they are the only ones in which the sexes are similar. Even the juveniles look like a watered-down version of the adults. This is a phenomenon that has always puzzled me. Why did they evolve with no sexual dimorphism? I can find no clear reason as to why. However, some research papers have discussed the notion that the sexes can be told apart due to the male using his slightly larger black throat patch as a display signal to potential female mates.
Despite its relative rarity in Britain, the Eurasian Tree Sparrow, to give it its full name and to not confuse it with the unrelated American Tree Sparrow, is a widespread denizen of most of temperate Eurasia and south-east Asia
Interestingly, this sparrow is abundant in the towns and cities of eastern Asia, especially where the House Sparrow is absent or a migrant, and is sometimes viewed as a pest. To a lesser degree it is also prevalent in urban centres in eastern and south-eastern Europe but, elsewhere on the continent, it is a shy and retiring bird of lightly wooded open countryside, generally shunning human habitations. In common with the UK, populations in western Europe have also generally declined.
The late JD Summer-Smith, a leading world expert on sparrows, noted that the Tree Sparrows in urban Asia were dominant over their House Sparrow cousins, taking first choice over nesting sites and muscling in on the action on the streets.
Whereas, in Western Europe the roles are completely reversed. Indeed, the House Sparrow usurped the Tree Sparrows wherever they met in the early days of the rise of the former species. However, this was not the only reason for the Tree Sparrow’s extirpation in certain areas in the west, as for some unclear reason, they were already disappearing in the extreme west before the House Sparrow came and finished them off.
I always rejoice at the sight of Tree Sparrows; whether it be a chance rare glimpse of one in London or watching gangs chasing around in the streets of Japan. There is something quite endearing about this little brown bird. But I urge you to look out for and cherish the birds that you find in the UK. Like their larger and more recognised cousins, they need our protection.