Posted tagged ‘effect of rodenticides on hawks’

Of Rats, Red-tails and Rodenticides

February 28, 2011

Yesterday’s walk in Riverside Park yielded the now-common but always thrilling sight of a hawk in a tree.

Inelegant rear view of red-tail.

I soon realized the bird was dining, but on what?

Mystery meat.

A downy substance floated on the slow-moving air, leading me to assume the hawk was plucking a bird.  But the shape of the prey just didn’t look quite bird-like. It seemed a little too big and uniformly colored.

What's on the menu?

The hawk seemed to be having difficulty getting the dining table set up just right. It gripped the carcass in one taloned foot and, turning this way and that, repositioned its prey in different spots on the branch.

Does the fork go on the right or the left?

At one point, it lifted high the foot that held the prey, and hopped along the branch for quite a distance on its free foot.  Then it picked up the body in its beak, and, well, leapt to the far side of a bend in the branch.

Leaping

There the hawk laid the body down in such a way that a long, naked tail draped almost gracefully along the side of the branch.

That ain't no songbird. Note the tail to the left of the hawk.

No wonder it didn’t look quite like a bird.  It was a rat. A big, fat street rat. I celebrated in my heart to see a rat being disposed of,  and in my head, I sang along with my great-grandmother:

“Hooray, Hooray, the chicken gelegt an ei!”

Bubba and Zeyde, my great-grandparents with my grandmother (far right) and her siblings. Taken sometime around 1910 in Flatbush, Brooklyn.

(My father recently taught me this catchy litle Yinglish, as in part Yiddish, part English, celebratory chant – “Hooray, hooray, the chicken has laid an egg!” – and I confess I’ve been eagerly seeking occasions to use it.)

Now don’t get me wrong, I don’t hate all rats. My friend, Charlotte of The Rat’s Nest, though currently ratless, has owned several charming and affectionate domestic rats. They would come when she called, and served her family as in-house comediennes, as you can see in Charlotte’s amusing short film, Ratz: The Movie.

And then there are the wonderful life-saving African pouched rats that are trained to sniff out mines and can detect tuberculosis faster than a traditional lab test.  Hey, even here in NYC, I took pleasure in seeing a rat swimming in the Morningside Park pond.

Just another brown rat, but it seemed positively bucolic slipping in and out of the water.

But my neighborhood on the southern edge of Morningside Heights is positively overrun with street rats, and I am only too delighted to see my local rats transformed into hawk fodder.

Had enough?

The hawk eventually flew off, leaving the rat behind on the branch.  I turned to share my discovery with a gentleman who had stopped nearby to admire the hawk.

“It caught a rat,” I said happily.

“Oh no,” he said, lowering his binoculars. “That’s bad.”

“Why?” I asked.

“Rat poison,” he declared. “It can harm the hawks.”  And he is right.

City Notification

Most buildings in the area put out poison bait boxes, as does the city.

The poison in rodenticides causes internal bleeding that kills the rat over a period of days.  During that time, the animals may return several times to feed at the bait station, raising the level of toxins in their bodies until they themselves are poisonous. Secondary poisoning is the term for the poisoning of a predator by eating poisoned prey.  Small predators like hawks are at risk; eyasses (baby hawks) and still-developing juveniles are particularly vulnerable.

Baby hawk in Riverside Park, August 2010. Photo by Nabil Esphahani. Click photo to read Leslie Albrecht's lovely article in DNAinfo.com, and see more photos.

Parent hawks unknowingly feed poisoned rats to their nestlings.  In 2008, tests proved that rat poison was the cause of death for three baby red-tails that had hatched in Riverside Park.  Last year (2010), two Riverside nestlings seem to have successfully fledged. At least one of the hawks that I regularly see in the park is a juvenile.

The eyes of a young hawk start out pale, and darken as the bird matures.

Rat poison is a tricky issue, and not just in NYC. Across the country, the deaths of owls, hawks, and small predatory mammals have been linked to secondary poisoning by rodenticides.

Here in NYC, we desperately need to control our rat population.  But how?  How can we lower the number of rats without also putting at risk the majestic raptors that have taken up residence in our restored urban green spaces?  These wild birds provide an elusive but essential connection to the natural world, offering us glimpses of their alien lives and the strange thrill of recognition that wildness still exists, alongside – and within – us humans, even at our most urbanized.

I hope we can encourage private businesses, restaurants, superintendents, building managers and the Parks department to use only those poisons that are least likely to harm non-target species, like our red-tails, and to use them only when necessary.

But we should all take some responsibility for creating a rat-friendly urban habitat.  After all, it’s the endless supply of food that leads to the city’s swollen rat population.  NYC is a rat gravy train.  So let’s stop feeding the animals.

Photo by Vince Noir at Bedford Avenue (click to visit Subway Art Blog)

“What?” you sputter indignantly. “I would never feed a rat.”

But chances are you do feed them, if indirectly.  Every time you drop food in the park, you’re feeding the animals.

Brunch in Riverside Park: where's the shmear?

Every time you toss a half-eaten pizza or hot dog into the street or the subway tracks, you’re feeding the animals.

Get it while it’s hot: free pizza on 110th Street

Every time you use an open city trash can, you’re feeding the animals.

This sparrow and starling hopped in and out of the trash can, pecking at a sandwich.

Every time you neglect to clean up after your dog, you’re feeding the animals. (Yes, rats eat the undigested food in feces, and no, I will not post an illustration.)

And every time your building places trash bags on the street to await the arrival of garbage trucks, believe me, you’re feeding the animals.

Make yourself comfortable while you wait for the Sanitation Dept.

But what to do?  We have to put our trash somewhere, and trash cans and trash bags are the responsible place to put it.  Yet I know that trash night on my block is rat party night.  The supers pile the big black bags into miniature mountain ranges.

After the blizzard: Himalayan trash bag mountain ranges.

The rats slip beneath the piles and tunnel, like miners, into the bags, gnawing easily through the plastic to reach the rotting riches of refuse.  One evening last week, I heard a strange rustling as I neared Amsterdam Avenue, and saw a trash bag moving as if it were alive. Rats, of course.  We regularly see them running across the sidewalk to or from the trash piles or darting into the shadows behind the wheel of a parked car.  Three times, my dog, Esau, has caught a rat, and once a mouse, while walking, leashed, in New York.

So yes, I’d like to see the rats gone. Disappeared. Vamoose. But I want to protect our hawks.

Anyone know a good piper, pied or otherwise?

The oldest picture of the Pied Piper copied from the glass window of the Market Church in Hameln/Hamelin Germany (c.1300-1633). Painting by Augustin von Moersperg (1592)

(Curious to know if your block has a rat problem? Visit the Rat Map at the city’s Rat Information Portal.)


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