News for July 2000, Peregrine Problems
Bird On! News
5th July 2000
BIRDWATCHERS love birds of prey, and it's easy to see why. These are birds with a special charisma. Fierce, proud, the supreme athletes of the bird world, they never fail to thrill. Part of their appeal comes from their rarity for, like all predators, they can never be very numerous. However, after years of decline almost all of Britain's diurnal birds of prey are thriving.
Take the peregrine, for example. Our fastest flying bird (estimates of the speed of the peregrine's stoop range from 120 to 250mph) is currently at a high, having recovered from the impact of poisoning by pesticides in the 1960s. Then the number of breeding pairs fell to only 385 and many of these were laying thin-shelled or infertile eggs. The peregrine's future looked bleak but the persistent organochlorine pesticides, such as DDT, were banned and the peregrine population slowly recovered.
Today some 1300 pairs of peregrines breed in Britain. (The number may be higher: next year the British Trust for Ornithology is organising a survey to find the true number - see below.) Almost all the peregrine's traditional eyries have been reoccupied, while pairs are now starting to colonise new inner-city sites where high-rise buildings offer cliff-like nest sites and an abundance of feral pigeons ensures no shortage of prey.
Pigeons are the peregrine's favourite food and in inner cities this hardly creates a problem. Not so elsewhere in the country where racing-pigeon fanciers report that the falcons are decimating their flocks of homing birds. However, despite the claims from the fanciers, the UK Raptor Working Group has found that fewer than 3% of racing-pigeon deaths are attributable to birds of prey. In contrast, 42% of pigeons fail to return to their home loft because of either exhaustion or getting lost, while a further 40% die after collisions with overhead wires and buildings.
Many fanciers refuse to believe this and a constant campaign is being waged to allow peregrines to be killed in areas where they are thought to prey on racing pigeons. In some cases the fanciers are taking the law into their own hands. The RSPB reports that this year there has been an illegal campaign of destruction against peregrines across the UK. At least nine reports have been received by the Society of peregrines being poisoned or where suspected poison bait has been laid next to a peregrine's eyrie. According to Graham Elliott, the head of the RSPB's investigations section:
"At half a dozen locations we suspect pigeon fanciers have left tethered pigeons doused in poison close to peregrine nests in the hope that the adult peregrines are attracted to the distressed pigeons and then prey on them."
A spokesman for the Royal Pigeon Racing Association has countered these claims by saying: "To date, no firm evidence has been tendered to back up these all allegations. The RSPB claims that feral and racing pigeons have been laced with poisons, yet they have yet to produce a pigeon ring that may identify a culprit. This would probably be difficult given that peregrine eyries contain thousands of identity rings from slaughtered racing pigeons."
It's not just racing-pigeon fanciers who dislike peregrines. So, too, do upland gamekeepers who struggle to produce a shootable surplus of grouse on moors where peregrines and other raptors (most notably hen harriers) are abundant. According to a paper in the May issue of the influential academic publicationJournal of Animal Ecology the impact of predation of grouse by raptors is much more severe than originally thought with birds of prey making shooting unviable by halving stocks.
The research on which the paper is based comes from data produced by the Joint Raptor Study at Langholm, one of the Buccleuch Estates in southern Scotland. The paper concludes that if no raptors were present then the grouse density would be four times higher in autumn and twice as high in spring after just two years. According to one of the authors of the paper, Dr Simon Thirgood:
"The aim of the research was to see if raptor predation could limit grouse populations at low density. The raptors were clearly a very important source of grouse mortality and their predation stopped the population from recovering. Summer predation by harriers and peregrines halved autumn grouse densities and nearly 40% of grouse chicks were killed by the end of August. These findings have extremely important implications for wildlife management and biodiversity conservation. If a grouse moor becomes unviable due to predation, then moorland management which is so vital for biodiversity in the uplands will cease."
Peregrines and hen harriers, along with almost all our other raptors, remain protected by special penalties under Schedule 1 of the 1981 Wildlife and Countryside Act. This allows for fines of up to £5,000 for anyone committing offences against these birds. In the current political climate the chance of any bird of prey having its protection removed is unthinkable, regardless of the growing chorus of complaints from keepers, land-owners, shoot managers and racing-pigeon enthusiasts.
I doubt if many conservationists have a great deal of sympathy for the pigeon fanciers; the research has shown conclusively that death in the claws of a peregrine is not a major factor in the failure of pigeons to return to their lofts. It might also be argued that predation by peregrines ensures that the fittest pigeons survive as they invariably select the slowest pigeon in a flock, or the lone lost bird.
In contrast, Dr Thirgood's warning that an abundance of raptors could lead to the loss of moorland management is extremely worrying. Grouse moors managed for shooting are invariably rich in wildlife. These are the best places to look for nesting golden plovers, dunlins, curlews and other typical upland birds as well as endangered species such as black grouse and merlins. Gamekeepers manage the moors by rotational burning, keeping the heath in prime condition, and by controlling ground predators such as foxes and stoats, both of which are just as happy eating golden plovers as grouse. Once the management ceases, the number and variety of birds falls fast.
Thus there is an overwhelming conservation argument for maintaining the balance in the uplands by controlling the numbers of raptors, but the difficulty is deciding how this should be done. Lethal control by shooting or poisoning is out of the question. I believe that licences should be issued allowing surplus raptors to be relocated elsewhere, or that the birds should be prevented from breeding in certain sensitive areas. Some sort of compromise must eventually be reached but it will require everyone with an interest in upland birds - from birdwatchers and conservationists to shoot owners and landowners - to work together. The prospects are not, I'm afraid, good.
(The BTO has launched a major appeal to help fund the 2001 Peregrine Survey. Donations should be sent to Peregrine Appeal, BTO Scotland, 21 Regent Terrace, Edinburgh EH7 5BT. The 2001 Peregrine Survey will be very much a collaborative project as the BTO will be joining forces with raptor study groups, RPSB, Scottish Ornithologists' Club and the statutory conservation agencies, Countryside Council for Wales, English Nature, Environment & Heritage Service of Northern Ireland, Joint Nature Conservation Committee and Scottish Natural Heritage. The aim will be to count peregrines holding territories throughout the UK, and to check on the occupancy of all known traditional nesting sites.)