An intensely controversial trial in which hawks were trapped and taken away from pigeon lofts has proved nothing because the number of birds involved was so small and the data was so unreliable.
The final report of the trial, seen by the Sunday Herald and due to be published tomorrow, is bound provoke a storm of claims and counterclaims. But it has failed to resolve any of the major disagreements, and it is not going to be repeated.
Disputes about the conflict between sparrowhawks and homing pigeons have raged for many years. Wildlife groups say that predation is natural, and only leads to the loss of a tiny proportion of pigeons.
The owners of urban doocots, however, insist it’s cruel and damaging. They become deeply angered when they see their birds being torn apart by the avian predators.
In November 2007, the then environment minister, Michael Russell, decided to conduct an experiment to see if trapping and relocating sparrowhawks would protect the pigeons. The idea was opposed as ineffective by the government’s wildlife advisers, and was delayed in 2008.
Nevertheless the £25,000 trial eventually went ahead, and ran from January to April 2009. Attempting to bring together the Scottish Homing Union, which represents 3,500 pigeon-fanciers, and the government’s conservation agency, Scottish Natural Heritage, it was dogged by strife over its scientific methods.
Its final report, which was originally due out last year, was delayed for months while they argued behind the scenes over how to interpret the results. The main problem was that so little data had been gathered.
Tomorrow’s report will reveal that only seven sparrowhawks were relocated from five pigeon lofts. One of them returned twice to the vicinity of the loft, and two others were replaced by new sparrowhawks.
The sample of lofts was “insufficient” and there were “issues” over the design of the experiment, the report says. “The quantity and quality of the observational data collected meant that it was impossible to draw any firm conclusions.”
There was a “high variability” in the number of observed attacks by sparrowhawks, and none of the comparisons between control methods were statistically significant. It was even impossible to be sure of the long-term heath of the relocated sparrowhawks because the batteries in their tracking devices only lasted nine days.
The Scottish government accepted that the trial had not proved anything. “No conclusive data was found on whether relocation of sparrowhawks is an effective way of reducing predation in racing pigeons,” said a government spokeswoman.
“The Scottish government will continue to work with the Scottish Homing Union to find solutions to the predation problem. The government has no plans for further research involving the trapping or translocation of raptors.”
The homing union, however, completely rejected the report’s findings. It insisted that the trial had demonstrated that trapping and relocating sparrowhawks “was both a humane and effective way of reducing attacks at pigeon lofts”.
It claimed that the data showed that when sparrowhawks were removed the number of attacks on pigeons dropped from one every ten days to one every 34 days. “Pigeon fanciers are very optimistic that licensed trapping and translocation of sparrowhawks could at last provide some protection for their pigeons,” said the union’s secretary, Linda Brooks.
“This would be the preferred option of the Scottish Homing Union rather than illegal killing, which at the moment would be the only way to prevent attacks.”
But the figures used by the union are based on observations at only one or two pigeon lofts. And, according to the Royal Society for the Protection of Birds (RSPB), there is also a critical mistake in the key table in the government’s report which undermines the figures.
“We do not believe that removing sparrowhawks is either a practical solution or a suitable response to dealing with claims of sparrowhawk predation of racing pigeons,” said Duncan Orr-Ewing, head of species at RSPB Scotland.
“Following this inconclusive trial, it is time to move on and look for solutions involving non-lethal scaring methods and other deterrents around lofts to try and help alleviate some of the concerns of pigeon fanciers.”
The sparrowhawk report will be published at 06.00 on Monday January 25 here.