SINGAPORE - Call it birth control for birds.
A corn-based feed containing a drug called nicarbazin, which stops female birds from producing eggs or causes them to lay eggs that do not hatch, has helped to reduce the pigeon population outside Masjid Haji Muhammad Salleh mosque by 60 to 70 per cent.
The population of 400 birds there has dropped to between 120 to 160.
The Agri-Food and Veterinary Authority of Singapore (AVA) revealed the results of the year-long trial of the drug outside the Palmer Road mosque after it had concluded last month (Oct).
Mr Mohamed Idris, secretary of the management board of Masjid Haji Muhammad Salleh, said: "There has definitely been a visible and positive improvement. A stark difference and the best thing is it was achieved without culling".
He said while the birds still find their way into the mosque sometimes, this has become much less frequent. Fewer people are getting soiled by the birds that lurk in the area too.
"In the past, the dropping might hit you as soon as you stepped out," he added.
He said that the mosque management is open to extending the trial and has discussed this with the AVA.
The drug does not harm the birds and is not toxic to animals or humans if taken in small amounts. It would take 40kg of the feed to see toxic effects in dogs and cats, and 60kg for a child.
Commenting on the trial's results, AVA said the drop is unlikely due to the effect of the drug alone, and that other factors may have contributed.
For example, the AVA found 15 dead pigeons at the trial site in April this year (16), which post-mortem examinations found were due to dehydration.
The agency added that it has been keeping watch on the area to prevent people from feeding the birds. Since October last year, it has issued around 60 warning letters and fines to individuals caught feeding the pigeons there.
Feeding pigeons is illegal and those found to have flouted the rules face a fine of up to $500.
As the effectiveness of the nicarbazin feed remains inconclusive, AVA started another year-long trial using the same feed at Waterloo Street outside the Sri Krishnan Temple, in September. There are about 150 pigeons there.
The Waterloo Street trial will also study if the level of human traffic, which is closely linked to the amount of food left for the birds, impacts the effectiveness of the feed. The birds will be fed once a day by a temple staff.
As of last month, the AVA had received feedback 13 times regarding pigeons in the Waterloo Street trial area since the start of the year. This compares to 20 times last year.
Overall, the AVA received 3,500 pigeon-related feedback from January to October this year. Last year it received about 4,000, an increase from about 2,500 in 2014.
It has also received some 6,400 feedback about all kinds of birds, including pigeons, over the same period this year. About 7,300 messages were received last year, and about 5,700 in 2014.