Passer domesticus is the most widespread bird in the world, being found in the Americas, Australia, Africa, all of Europe and much of Asia – yet on the small, damp isle of Britain this common bird is under threat. Now on the UK red list of conservation concern after a drop in population of around 70% since 1977, it has become scarce in many large urban areas – though still remains a regular sight in most villages and towns. Most famously the House Sparrow has disappeared from almost all of London, but for people who live in more rural areas the idea that this little bird could be endangered is difficult to believe.
I used to think the same; five or six years ago large groups of Sparrows would visit my feeders, spilling the grain everywhere and making a noisy nuisance of themselves. They nested all up my street under the roof tiles and in spring the noise of tens of chirping males was incessant. But as each year went past there were fewer and fewer singing males and only one or two sparrows would come to my feeders at a time. Today Sparrows very rarely come into my garden and there are perhaps only three or four nesting pairs in the whole street. Bird declines can sometimes be difficult to notice for the individual; Curlews seem to me as common as they ever were, yet they have apparently declined by 45% in 15 years. But I have seen first hand the gradual loss of the spadger from my own home town within the space of half a decade – it is happening and it worries me.
Okay, so maybe the species as a whole isn’t in danger of extinction – even in the UK there are still around 4.5 million pairs, but it would still be distressing to lose such a characterful bird from an entire country or do nothing while it declines. One must also remember that large numbers are no guarantee of survival – just think of the Passenger Pigeon.
So why is the Sparrow – a bird associated with man for centuries and seemingly an adaptive, opportunistic species – in such trouble in Britain? The jury is still out as to the exact and primary causes of this species decline, more research is needed, but the evidence we have points to a reduction in nest sites due to modern building methods, loss of winter food because of changes in farming practices and most significantly a reduction in insect prey (for young) probably thanks to chemical use and air pollution. From what I have witnessed in my own town the buildings are largely the same as they were a decade ago (so no loss of nest sites, though I suspect more would help) and the birds are rather sedentary so do not rely on distant farmland grain. But two things have changed which I believe may be behind the local decline at least.
Firstly, invertebrate populations have fallen, butterflies and bees are the most obvious from their absence but many others such as moths, flies and beetles are also lower than they used to be (these are just my personal observations). Young Sparrows rely on insect food as they cannot grow on seeds or fruits, so any drop in the prey abundance would adversely affect the chick survival rate and brood size. This change in invertebrate numbers may have several causes but the increased use of pesticides and fertilisers on agricultural land and in gardens, as well as toxins from car exhausts are likely the chief reasons.
Secondly, you may also have noticed that Sparrows love to socialise in large groups, often gathering in bushes or hedges chattering away to each other – they also need such shrubs to escape predators and as roost sites (plus the foliage contains much insect food). But on streets throughout my town, and I suspect most UK towns, people are paving over their front gardens as driveways, ripping up hedges, lawns and shrubberies to reduce maintenance and as space for their cars. I find it hard to believe that such a loss of greenery would not affect the sparrows in any way – insects would have no habitat, the birds have no place to hide or congregate or dust-bathe. Whenever I see sparrows nearby they are always flying in small groups to and from the few bushes still standing in the street or chirping within them, they rarely perch on fences or forage on paving stones.
Perhaps the use of industrial pesticides, the cleanness of our fuel and the alteration of the crop cycle are things that as individuals we feel we can have little effect upon. But I think we can still aid the chirpy spadger on a small scale; providing nest boxes, regular feeding, keeping our lawns (with a little dirt patch in the corner for their bath), planting shrubs, having hedges instead of fences and planting flowers to encourage insects are all do-able things – as is supporting the BTO and RSPB in their ongoing research.