Pigeons are being fed feeds with nicarbazin in them, an oral contraceptive for the birds ("Drug trial by AVA to curb pigeon population"; Nov 6).

It has been reported that the drug does not harm the birds if consumed at low doses, and it has proven successful in other countries, such as Italy.

I applaud the Agri-Food and Veterinary Authority of Singapore (AVA) as well as relevant stakeholders such as the town councils and the National Environment Agency (NEA) for implementing measures to mitigate the pigeon problem.

Curbing the pigeon population is a top concern as they cause hygiene and environmental issues. Pigeons are known to spread diseases, such as coccidiosis, which pose a health risk to immuno-compromised patients and the elderly.

However, even though this "birth control" method has been proven to be safe, I hope the AVA considers it only as a short-term measure.

There is a possibility that other bird species - such as endangered migratory species - may also consume such feeds, and this may cause unforeseen detrimental effects on them in the long run.

I also hope this measure will be tightly regulated and that such feeds be administered strictly by authorised personnel only.

While I share in the Government's anxiety to resolve this issue, I urge the AVA, NEA and other relevant authorities to consider all possible factors and side effects if this measure is to be implemented for the long term.

Eu Jian Sheng