Loser - 2. Tree Sparrow
In some ways the Tree Sparrow has shown the greatest decline of all the birds in my 50+ years of birding across the uberpatch. From expected flocks of over 200 birds to none at all is some fall from grace, one that is all the harder to take as the Tree Sparrow was considered a flagship species - an icon even - for Beddington SF. When I first trod the fields and sludge lagoons of this fabled sewage farm they were ubiquitous. Flocks were easy to come by, feeding on the seeds of fat-hen or grazing on the screening deposits that included filtered food particles, their chocolate brown crowns, black splurged cheeks and conversational chatter a welcome - and expected - part of any visit. They bred in the outbuildings and the holes in the concrete dykes. My peak counts of 200 all occurred in 1978 (25 February, 22 March and 26 November) but three-figure returns were made in many of the subsequent years up until the early 1990s. The thought that one day they would all be gone and their chatter be reduced to silence was not comprehendible. But it happened. My final Tree Sparrow at Beddington was seen around the edge of the North lake sometime in 2017, and the last by anybody in March 2020.
It was never a bird to be found easily elsewhere. The only other sites that I recorded it from across the uberpatch were at Leatherhead (1975), Searrs Park, Cheam (1983) and Holmethorpe (1991) and the latter site was the only one where I had multiple sightings although these did not last long and were at much reduced numbers compared to Beddington. When did the rot set in?
Nationally the Tree Sparrow has been in decline since the 1960s, particularly in the south and west of England, with another noticeable dip in the 1980s after a stabilisation of sorts - that 30-year decline was never a firm base from which to hope that some sort of redemption were possible. Agricultural intensification and a poor winter survival rate are two reasons given for the sparrows fall in numbers and subsequent loss across large parts of the UK.
It is worth looking at the reasons why this species was lost to Beddington SF. I have drawn this information from two major sources - 'The Birds of Beddington Farmlands' (Alfrey, Milne, Coleman) and a paper by Derek Coleman that appeared in the London Bird Report of 2020. Both are well researched and worth seeking out.
At Beddington the loss of mature elm trees in the 1960s and the flooding or silting up of holes found in the concrete dykes took away traditional breeding sites from the species and led to a fall in the breeding population by the 1970s, with a 10-20 pair retention from the 1962 estimate of 70 pairs. What with the gradual change of the land use at Beddington from sewage farm to landfill during the late 1980s a concerted effort by the Beddington Farm Bird Group (BFBG) saw the erection of 100 nest boxes in 1992 to help the dwindling Tree Sparrow population, this followed by the addition of 100 more in 1997. There was an initial bump in wintering numbers, with 350 recorded in January 1993 helped somewhat by disturbance on site that resulted in an increase in seed-bearing ruderal vegetation. The nest boxes were, after a short while, taken up by the Tree Sparrows with 75 pairs in 1994 and although dips in the population did follow by the turn of the millennium the number of broods raised were into three figures and an estimated 135 pairs bred in 2007. Supplementary feeding started in December 1998 (with members of the bird group filling a number of large feeders on site) to help mitigate the loss of natural seed on the farm caused by the intensification of the landfill operations. Even after good breeding seasons the number of wintering birds on site remained low, illustrating perfectly the species wish to disperse. Unfortunately, dispersal consigned the sparrows to a land of increased agricultural intensification and lessened their chances of survival. Thus fewer and fewer birds returned to Beddington to breed. It was a spiral of doom.
Could they return? With birds still hanging on in other parts of England (mostly to the north of southern England) and with this species regarded as having a breeding population cyclical in nature, it is tempting to have some hope. However, agricultural intensification and the continuing degradation of habitat across farmland continues. One area where Tree Sparrows cling onto in south-east England (Walland Marsh in Kent) has been subject to recent mass hedgerow removal which does little to build up any slender hope that there may be.
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