A European city is rolling out a plan to feed its pigeon population contraceptives as a way of curbing a population spike. Local government officials in Barcelona, Spain, say the addition of the drug nicarbazin to the pigeon’s corn feed has staggered population numbers.
Conservationists and academics believe curbing the population with birth control in the feed is a better control method than culling the animals. Just 10g of corn is enough to make both male and female birds infertile for a five-day period. The rollout of birth control in pigeon food supplies had been considered by Norwich council as a way to control the population but was scrapped over worries that vigilanties armed with rifles would take matters into their own hands.
Pest control drug licensing also affected the policy, which was scrapped early in development despite its success in parts of Europe.
Baroness Hayman of Ullock, a minister in the Department for Environment, Food and Rural Affairs (Defra), says the contraceptive rollout is a vital part of controlling pigeon populations.
Lady Hayman told The Telegraph: “I believe wildlife contraceptives can have a vital role in maintaining ecological balance and also preserving biodiversity.
“I believe this progress in wildlife contraception is innovative, ethical and effective, and by embracing such solutions we can protect native species and ensure future generations inherit a richer, more balanced natural world.”
Giovanna Massei, a professor at the University of York who is also Europe director of BIWFC, went on to flag how a lack of natural predators to pigeons and other species had led to an overpopulation.
Professor Massei said: “Conflicts between humans and wildlife throughout the world are increasing – populations of certain species – and one of the reasons is that there aren’t enough natural killers in the world and people themselves don’t like killing.”
Barcelona has tackled its pigeon population with more than 40 dispensers made to look like bins, planted and moved to places where populations are deemed to be too high. Around 500g of corn can be fitted into the device, which is enough to feed around 50 pigeons. A timer releases kernels filled with nicarbazin, sealed in place with silicone, at 8am every day.
Dr. Marco Pellizzari believes that, despite criticism of the ineffectiveness of nicarbazin as a population solver, the results speak for themselves.
“Other research has found reductions of between 45 and 70% in colonies over three or four years,” he said. “Besides, the approach is wrong. It is not a battle between humans and pigeons – there are probably about 90,000 pigeons in Barcelona. We are reducing the density in certain areas.
“There is a threshold that is normally around 400 pigeons per square kilometre. Anything above this threshold and there is an issue with human conflict.”
