The city of Leuven has reduced its pigeon problem in some areas by more than 50%, by using a specially-developed avian contraceptive pill.
Leuven started its programme to reduce the number of pigeons some 18 months ago, after the pigeon population had grown to intolerable numbers. Pigeons roost on buildings, and are attracted to the food supply provided for them by humans. Their body waste is ruinous for buildings, paintwork and cars; they tear open rubbish bags on the street, and they are merciless in chasing away other species of bird.
However the solution to the problem in this day and age is not to kill them, whether by poison or by recruiting birds of prey. Instead, Leuven opted to try out bird contraceptive.
The use of avian oral contraceptive is simple: the drug is contained within pellets of food which the pigeon is happy to eat. The drug then goes to work on the reproductive system, preventing the ovum or unfertilised egg from becoming fertilised, and so making reproduction impossible.
The makers, including the manufacturers of a leading brand OvoControl, claim that their product is safe for the birds – its active ingredient (Nicarbazine) has been used for decades to treat coccidiosis, a parasite in chickens. It is also safe for smaller birds who may be attracted to the food source, as well as to birds of prey who may consume the flesh of a pigeon on the drug.
The effect, in addition, is fully reversible, should the pigeon for example change its feeding to a territory where the pill is no longer available.
Leuven went down the contraceptive route when the populations of pigeons in the city centre, in particular the station area, became too much.
“We have four locations where the feeders have been kept for a year and a half, and we find that at those locations there has been a decline of 57%,” said city councillor Thomas Van Oppens, in charge of waste management.
“The outlier is the station, where the population has decreased by 69%.”
The results are enough to satisfy the aims of the campaign, he said. Eradication of the pigeons was never on the agenda.
“The pigeons belong in Leuven. We had to reduce the population, and I think halving is a good result which I am happy with,” Van Oppens said.
“The result is already noticeable in the streets, because the pigeon droppings, which you can regard as a nuisance, are much less present, and it also relieves our city services of the task of cleaning it up.”
The chosen method has also been supported by animal rights organisation Gaia, Van Oppens said. Gaia has supported the use of contraceptives since 2017, in preference to alternative methods including trapping and sterilisation.
But contraception is not enough, Van Oppens said. The people of the city also have an important role to play, by not feeding the birds on table scraps, which are not only bad for the birds, but also encourage them to congregate in places and in numbers which then become a public nuisance.