Sex, rather than food, may be on the minds of Alexandra's wild pigeon population.

Attempts by the NZ Transport Agency to cull the 400-strong flock of pigeons that roost on the Alexandra bridge and the old bridge piers were put on hold yesterday after the pigeons refused to take the bait.

"We don't know if it's because they're too busy trying to breed, or what," agency senior asset manager John Jarvis said.

The birds' roosting and excrement were damaging the bridge's structural steel and also posed a health risk, he said. The plan was to use food to entice the pigeons to a spot several hundred metres downstream and, once a good number had been attracted, they would be fed narcotic-laced bait, caught and killed humanely.


"Unfortunately, the birds aren't interested in feeding at all. This is a tried and proven [culling] method, used around the world, but for some reason these birds in Alexandra are not hungry at all. It's got us beaten," Mr Jarvis said.

"We've tried peas and wheat as bait and actually even thrown some down right in front of them and all they do is eat the grit in between the feed. We don't know if they've got some other food source, or whether it's because they live in an urban environment, but they're just not hungry."

Because of the pigeons' lack of appetite, no attempt had been made to lay the narcotic-laced bait.

"The most pigeons we managed to attract with the bait was 12 and we'd hoped to get 400 of them."

The agency had been forced to review and halt its plans and consider other culling options, he said.

"To be honest though, there's not many other solutions at all. This is the best time of year to do it and we would've expected the birds to be hungry. The narcotic works quickest when the weather's colder too, meaning there would've been no chance of them flying away, half-drowsy."