Belgium: Contraceptive grains to control the pigeon population

In Ixelles this method has already reduced the number of pigeons by 40% within three years and is inspiring other cities across Europe.

On an autumn morning in Ixelles, a dispenser for the contraceptive grains is being filled on the Rotkreuzplatz. The pigeons hiding in the trees remain calm at first. Fifteen minutes later, at 7.45 am, the feed distribution works better and almost 200 pigeons swoop down on the grains.

«We wanted to find a solution that reduces the pigeon population while respecting animal welfare,» says Yves Rouyet, a municipal councillor of Ixelles.

Instead of killing pigeons, which is criticised by animal welfare advocates, the municipality has relied on contraceptive grains since 2021. This has reduced the pigeon population in Ixelles by around 40%.

The municipality received many complaints about the large number of pigeons. «The great number and the droppings of the pigeons damage buildings,» Rouyet explains.

The dispensers are located at six sites in the municipality and are filled twice each morning. This measure costs the municipality 10,000 euros per dispenser annually.

The pigeon is a flock animal, and within a colony there is a clear hierarchy, particularly at feeding time. The dominant animals make up 15% of the flock, receive the most food and reproduce quickly. This group is the target of Vets For City Pigeons This means that by targeting this group, the entire population is indirectly reached. By feeding Ovistop during the breeding season, the dominant group automatically ingests the correct dose of the effective product. The result: fewer offspring.

Pigeons are very site-loyal. This is why the managed dovecote (Augsburg model) does not work everywhere, partly because no suitable location can be found, such as at railway stations. That is why contraception can be another piece of the puzzle there, in pigeon management.

After repeated brooding and through the theft of eggs, pigeons may notice that something is not right here and go looking for new/old nesting sites again around the managed dovecote.

«It is better to involve the feeders»

The municipality has also involved the people who feed pigeons in the programme and no longer imposes fines. «It is better to integrate them into the system,» says Rouyet, speaking to euronews.

Volunteers, mostly women, are allowed to distribute the grain at certain places and times in order to guide the pigeons.

Stéphanie De Jonghe, who has been feeding pigeons for ten years and has now been working within the programme for four years, explains: «I fed them every day because they need food.»

De Jonghe stresses that the pigeons must be fed to prevent them from becoming undernourished. She believes it would be cruelty to animals to give them only the contraceptive, as this would lead to a rapid reduction.

The activist points out that pigeons are heavily dependent on humans, since they were originally bred and then came into the cities without getting what they need.

Other European cities such as Brussels, Strasbourg, Barcelona and many more have also introduced systems using the contraceptive grain (Ovistop) and are supported by animal welfare organisations too, on the basis of specialist literature and case studies.

Alternative facts

There are also critical voices regarding Ovistop, with some rather far-fetched claims.

The fact that it is mostly veterinarians and animal welfare advocates who distribute Ovistop, or the active ingredient nicarbazin, on the front line (in Belgium alone at over 100 locations), and evidently make no negative experiences or observations with regard to the critics' prejudices, speaks for itself.

Ovistop has been in use for decades and there are no empirical studies on any harmfulness to pigeons at low doses. Not from ETH Zurich either. According to studies, pigeons can suffer neither acute nor chronic intoxication from the medication. The results of the studies clearly show that administering nicarbazin can lead to a reduction in the number of colony-forming pigeons without any lethal effects or notable side effects.

Studies:

• Botstiber Institute for Wildlife Fertility Control
• Wikipedia
• Arxius de Miscel·lània Zoològica
• Efficacy of nicarbazin (Ovistop®) in the containment and reduction of the populations of feral pigeons (Columba livia var. domestica) in the city of Genoa, Italy: a retrospective evaluation
• PAZ
• Controlling urban pigeons populations humanely
• Use of Fertility Control (Nicarbazin) in Barcelona: An Effective yet Respectful Method towards Animal Welfare for the Management of Conflictive Feral Pigeon Colonies
• Pigeons in Urban Landscapes
• On the use of pharmacological sterilisation to control feral pigeon populations
• Cities Are Testing Birth Control to Solve Pigeon Problems

Were this not the case, there would hardly be an EU-wide authorisation. Ovistop is used on pigeons not only in several countries in Europe – Italy (since 1996), Spain, Hungary, France, Malta, Belgium, Austria, or in Germany since spring 2023 – but worldwide.

Anyone who promotes Ovistop in the German-speaking world finds themselves exposed to massive pressure from aggressive egg thieves. Interestingly, it is precisely these circles that demand animal experiments to justify their claims for something that has already been tried and tested for decades.

The medication seems to us to be a proven means of counteracting the excessive pigeon population with all its side effects. What we have done so far – feeding the pigeons and swapping out the eggs – was ultimately not so successful. Martin Adamski, Environmental Councillor of Bielefeld

The Austrian city of Linz says that the population has declined by more than half since the start of the Ovistop project in 2001. 

Medications in human and veterinary medicine can always affect others too – the keyword being antibiotic resistance, for example. Every medication, whether plant-based or synthetically produced, can have side effects.

Anyone who generally does not opt for organic food or a meat-heavy diet also spreads disease-causing toxins such as traces of antibiotics, hormones, genetically modified feed, pesticides, sprays, herbicides, and so on, which are demonstrably harmful to health and damage the soil, the environment, drinking water and living creatures.

Under Art. 5 para. 3 of the Federal Act on Hunting and the Protection of Wild Mammals and Birds (Hunting Act, JSG, SR 992.0), city pigeons are considered feral domestic pigeons that may be hunted all year round, which, according to the IG Wild beim Wild, is not part of a recommendable pigeon management.