Orkin PCO, the pest control firm hired to place bait stations for rats at the city’s temporary dump sites, says there’s no evidence yet of more rats in the city. (It’s not known how many there are.) But pest control experts and biologists say with plenty of food in public places conditions are ideal for the numbers to rise.

Rats will breed more successfully, the babies will be healthier, the females will store reserves of fat and there will be shorter periods between births. Their survival rates will go up, though the strike would have to continue for some months to see this delayed effect.

Exterminators are putting out “rodenticides” in tamper proof stations that are fastened to a wall or fence. The rodenticides are anti-coagulants, which will kill the rats four to six days after feeding.