Rodenticides are Killing California Hawks

The sight of a hawk seated casually on a phone pole, sweeping across a field, or diving down for prey is awe-inspiring. Unfortunately, that rodent dinner might be the majestic creature’s death thanks to the widespread use of rodenticides across the US.

Many of these poisons are designed to act slowly, encouraging rats and mice to bring poisoned bait back to their nests so that the whole colony is killed off, not just a single individual. The problem is that as long as those living rodents are strolling around, they’re appealing to raptors — in addition to housecats, bobcats, and a variety of other creatures.

In the 1960s, the publication of Silent Spring and a growing pile of evidence convinced the US to move towards banning DDT, a chemical that was once widely sprayed to cut down on insect populations. The problem with DDT was that it also affected other species, specifically raptors, who experienced egg shell thinning as a result of DDT exposure. Their populations dipped, and only recently have they started to show signs of recovery, illustrating how long the effects of environmental pollution can linger.

But in recent years, researchers have started noticing a problem: raptors are dying for no particular reason, in regions with no obvious signs of chemical pollution–until the scientists dug a little deeper and started exploring the use of rodenticides in the area. One of the most commonly used classes of rodenticide in the US are anticoagulants, which work slowly over time. They can also end up poisoning animals that eat the targets for the poison, like rats and mice. The scientists noticed a connection between raptor populations dipping in states like California and use of rodenticides in agricultural facilities, food storage facilities, and marijuana operations.

The problem isn’t limited to California, though. Urban raptor populations are particularly badly affected because of their location in the heart of cities, which attract rats, and which in turn encourages people to put down poison. Numerous urban raptor families have died as a result of poison exposure, a heartbreaking experiences for their fans and the researchers who study them.

In fact, necropsies have shown that rat poison is the most common cause of death for hawks, above power line collisions and car accidents. Urban raptors, as well as their rural brethren, could be helping to deal with the explosion of rats and mice drawn to compost piles, home gardens, and more, but instead, they’re being killed off.

In multiple states, activists are working to change this. Lobbying in California forced the California Department of Pesticide Regulation to ban a number of rodenticides in the state, making it impossible for consumers to walk into stores and buy them. Unfortunately, they’re still available to commercial customers like exterminators, who often turn to these poisons because they’ve proved effective in the past and they’re inexpensive. Lobbying on the issue is only making slow progress in some communities as exterminators and chemical manufacturers oppose changes to dealing with pest infestations, but advocates argue it’s critical to protect hawks.

That’s not just because they’re intrinsically beautiful, although of course that’s a very good reason. Protecting hawks also allows them to do what they do best: killing prey, and ensuring that a predator vacuum doesn’t develop. Hawks provide a great means of steady control for rat and mouse populations, and they do it entirely for free, which is an excellent deal.

Can advocates revive the regulatory climate of the 1960s (DDT was banned in 1972) and encourage the government to do the right thing? Many animal lives may depend on it.

Photo credit: Audrey.


Christine Jones
Christine J.about a year ago

Distressing that these birds are suffering but those of us in the city unfortunately have to rely on poisons. I get regular outbreaks of rats (yes I am clean and tidy) and much as I hate the thought of killing an animal, they have to go. They chew electrical wires and insulation and spread disease. A guillotine type trap would kill them quickly but they are much too smart to go anywhere near them. Even though I have predator animals in the house (cat and dog) the rats are usually smart enough to stay in the wall cavities, the ceilings, or under the floorboards. I would love to be able to invite a hawk or an owl in to get rid of them but it just doesn't work that way.

Waltraud U.
Waltraud U.1 years ago

We and the rest of the world are in need of lawmakers having a brain instead of banknotes and are further able to look over the edge of only one plate.

Karen K.
Karen K.2 years ago

Good article. I don't like mouse traps and dealing with the dead mouse, but the ones in my pantry wouldn't go into the live traps for release, and as the article cited, the poisons are bad for raptors. Takes me hours to bleach down the pantry after a mouse has been there and unfortunately the mice in our area have been known to carry hantavirus, so I can't let them just be. However, after my last bleach down and mouse catch, I found a sachet that repels mice by the smell with balsa fir oil. So far so good. We'll see if that ends my hours of cleaning up all my jars and pantry after them! It's not a bad smell. I did read first and it said to wait a week when there's no sign of any more mouse and in a week the virus will be dead, then to spray the very dilute bleach solution on the area etc to wash down. Not big on using bleach either for the environment, but it is very dilute and the virus is a bad one!

Mark Donners
Mark Donner2 years ago

The target should be the gangs of corporate psychopaths and their government enablers. They would literally poison their own children for a dollar.

Jennifer H.
Jennifer H.2 years ago

It never seems to be understood that for every action there is a reaction. Kill off a rat with poison and the hawk, cat, eagle who eats the rat dies too and possibly the whole family. Dcon is changing in 2015 but that is still way too late.

Elizabeth F.
Elizabeth F.2 years ago


Karen S.
Karen S.2 years ago


Karen S.
Karen S.2 years ago


Ruhee B.
Ruhee B.2 years ago

Get rid of all these God awful poisons!

Melania Padilla
Melania Padilla2 years ago

Oh, another effect of our ignorance... Until when? Stop messing up with Earth!!