The Late Great Flaco Is Poster Boy for Rat Birth Control

New York City is about to try a new approach to tackle its persistent rat problem: using birth control on the prolific rodents instead of poison. Last week the City Council passed a bill to dole out birth-control pills to rats in a pilot program covering 10 city blocks in two neighborhoods.

“The standard mitigation strategies seem to not be working overall,”  the bill’s sponsor, Council Member Shaun Abreu, said at a hearing earlier this year. 

The new mitigation strategy is centered around ContraPest, a contraceptive bait developed by the biotechnology company SenesTech that stifles reproductive capabilities of both sexes. ContraPest affects ovarian function in female rats and stunts sperm cell production in males; the delivery system is a salty, fat-filled pellet.

Key to this novel approach is the unwieldy verb “containerize,” as in securing garbage in rat-proof containers. Rats will choose street garbage over ContraPest if given a choice, so we can’t give them a choice. The city is determined to remove the ubiquitous piles of black plastic garbage bags that rats have been using as an all-you-can-eat buffet. 

To that end it has decreed that residential buildings with fewer than ten units will be required to containerize as of November 12, a rule that should cover about 70% of all trash in New York City. Last year the city imposed containerization rules on food-related businesses — restaurants, bars, bodegas, grocers. Now come the birth-control pills.

The new birth-control bill has been dubbed “Flaco’s Law,” so named for the beloved owl who escaped from the Central Park Zoo in 2023, spent a year endearing himself to New Yorkers, but was eventually found dead after consuming rat poison. (A similar fate befell Barry the barred owl, another Central Park raptor celebrity who also died in a poison-related incident.)

Stifling rats’ reproductive prowess is no small feat (a single pair of rats can potentially produce 15,000 offspring in a year), but taking rodenticide out of the equation could have a knock-off effect. If we don’t poison our urban raptors – owls, hawks, the occasional eagle – they will live long enough to take another bite out of the rat population, currently estimated to be about 3 million strong.

Photo credit: David Shankbone / Wikimedia Commons