Girton Birdwatch - May 2008
On 11th April my family and I attended a talk at Milton Country Park held under the auspices of the Cambridgeshire Bird Club and delivered by Edward Mayer. Its topic was 'Saving a Place for Swifts' and it turned out to be a very interesting, if not moving, experience. Our Swifts will be arriving in early May, at least I hope they shall, but when they arrive they may be condemned to a fruitless breeding season. Swift numbers are dropping fast: in 1990 the UK population was estimated to be 80,000, but since then they are thought to have decreased by 15-20%. Indeed, between 1994 and 2006 the number of Swifts breeding in South East England halved. So why is this happening? Once again we can't blame the farmers, or at least only very indirectly. Since Roman times Swifts have been nesting in buildings created for human use or habitation. Originally they nested in caves, tree-holes and on cliffs but then gradually switched to sites provided by humans; the higher the better. They are able to creep into the smallest of spaces, under tiles and in the eaves, gaining access to lofts, spires and towers, where they build their delicate-looking nests with minimal materials cemented together with saliva. Victorian buildings proved particularly attractive. Swifts now nest almost entirely in pre-1944 buildings. This is because modern buildings deny Swifts access to breed, as do re-furbished or re-roofed older buildings when their eaves are obstructed or sealed. 10% of homes built before 1919 can house Swifts; the figure drops to 7% for inter-war housing, while the figure for post-1944 housing falls to a mere 1.4%.
Although Swifts and their nests, like many other birds, are protected by law: it is illegal to kill or harm them, to damage their nests or take their eggs, such laws are more often honoured in the breach than the observance; very few people are prosecuted for disturbing or harming birds. The laws exist, however, and organisations dedicated to highlighting the plight of Swifts - such as Mayer's www.londons-swifts.org.uk and, more generally, the RSPB and British Trust for Ornithology, whose campaigning literature/materials I am making use of here - encourage people to ensure their implementation. Despite the existence of such protection, modern building regulations and methods work in the opposite direction, demanding sealed roofs and walls, and ventilation systems designed to conserve heat and exclude insect, bird and animal pests. Our living accommodation is made more comfortable and 'environmentally friendly' but one 'unintended consequence' is that such improvements also permanently exclude Swifts. Of course, repairs and re-roofing are unavoidable but while builders and home-owners, when reminded of the laws against disturbance, may be prevailed upon to cease working on roofs while Swifts are nesting (May to August), if their access holes are covered up, and new ones not provided, resumption of work can usually mean the end of a traditional breeding site. Adult Swifts are intensely loyal to nesting sites, returning year after year and declining to breed elsewhere (youngsters establish new nests if they're able), so if they cannot get to their old nests they can be condemned to a future of infertility and banished virtually over-night. The situation is exacerbated if no new sites are available for returning youngsters.
It is understandable that many householders - there are those that illegally knock down House Martin nests as we know - might be reluctant to encourage 'messy' Swifts to nest in their homes. However, Swifts are very clean and leave few droppings, preferring to 're-cycle' those that they, or their young, do produce (they eat them, probably for their mineral content), so there are no piles of droppings beneath their nests. Moreover, Swifts rarely penetrate further into the roof space than just inside the top of the outer wall. Edward Mayer and London's Swifts points out that it's possible to keep the Swifts separated from the roof space by installing an internal ventilated plywood partition, 30-40cm inside the eaves, while maintaining an open eaves ventilation gap which will provide a safe, clean, cheap, separated space for many Swifts. Alternatively, installing DIY plywood Swift nest boxes under the eaves is a simple way of providing good nest spaces where internal solutions are not feasible. With industrial/commercial buildings special concrete boxes can be integrated into building plans at little extra cost, while special self-contained 'Swift bricks' can be built into exterior walls. The RSPB and BTO suggest that church authorities might consider authorising the erection of specially designed boxes behind louvre windows, giving Swifts nesting accommodation but without allowing access to the tower itself. The Diocese of Ely, apparently, is supporting such an initiative.
It is difficult to establish where Swifts are nesting - perhaps Girton College provides a main site for ours? - but it is clear that if we are to enjoy the sound and sight of these evocative summer visitors in future, we should attempt to find out and do all we can to protect them. Action for Swifts recommends putting pressure on Local Authorities (The Government uses wild bird populations as a Quality of Life Indicator. Local Authorities are tasked to maintain and enhance biodiversity. Some are acting to help Swifts, but so far most are not); housing associations; owners/developers of large new buildings; architects and planners and church authorities.
Appropriately enough, Cocker and Mabey quote an L. Nixon of Pampisford as saying: 'Our greatest joy is on warm summer evenings watching the swifts fly about the house. Alas, all too soon comes the saddest day at the end of summer when the swifts leave on their long journey. To us it is as sad as their arrival is exciting. We can console ourselves, however, that there is always next year to look forward to.'
For how much longer?