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Monday, December 29, 2008

Predator as Prey

On Sunday Steve, Shane and I joined several teams of birders spread out around Westchester and the Bronx for their Christmas Bird Count (for reasons of practicality, the annual Christmas Count occurs over a three week period). Steve is our team leader and I've been helping in his area for the last 5 years. Early in the morning we observed something I've never seen before and has had me thinking about since.

If you take the time to look closely, it's not unusual to periodically find small piles of feathers scattered around our city parks. They are, for the most part, the remains of an avian predator's kill. Between all the owls, hawks and falcons hunting around NYC's five boroughs these little, blood stained puffs are just a fact of life, especially during the harsher winter months. On Sunday, while scanning the trees within a stand of pines, we came across what looked like the outcome of a pillow fight. It wasn't a just a small cluster of tiny feathers. Large, medium and small feathers were nearly everywhere. At the edge of the scattered plumes was something both familiar and shocking; the tail of a Red-tailed Hawk. A short distance away was the hawk's carcass. Its body had been eaten leaving only the wings, legs and head attached to a stripped backbone. Steve, Shane and I began discussing what predator would be powerful enough to kill and eat a Red-tailed Hawk. Maybe a Great Horned Owl, although I'd never found any information that said these large owls would prey on red-tails. The hawk was relatively small, probably a male. We had seen a Cooper's Hawk in the area, but I don't think that even the largest female coops would be strong enough to take on a Red-tailed Hawk. A Northern Goshawk? I've become very fond of our city's red-tails, but I was more interested in solving the mystery than mourning the loss of one.

I began watching the Red-tailed Hawks around Brooklyn in the 1990s. It wasn't until 2002 that I started to observe them on a regular basis. Over that period of time I never experienced or read any accounts of the top of our food chain becoming prey. We pondered the idea of hawk cannibalism, but if it were a common phenomenon, I probably would have come across it before Sunday. During the course of the day Great Horned Owl became the top suspect, although we had absolutely no evidence other than they are great, big powerful predators. It is possible that the hawk was sick and died before it was scavenged by other animals.

Steve and I had to leave a bit early, so Shane decided to stick around and bird for a couple more hours. He called me later with some disarming news. After we had left he looped back around to the area of the hawk carcass. There was a juvenile Red-tailed Hawk standing over the remains of the dead adult raptor. His initial thought was that it could be an offspring of the deceased bird examining his parent's remains. Then the young bird yanked off one of the wings and flew off with it, no doubt to dine on the small amount of meat that could be found.

On Tuesday I was back in the Bronx and decided to see what was left. The plucked hawk feathers that had embellished the cushy carpet of pine needles had been whisked away by the wind. Some were nearby, trapped within the branches of small trees and shrubs. Perhaps by Spring some will be discovered by small songbirds and used as nest material. The hawk's carcass had been reduced to just the denuded head, vertebrae, ribs and feet. In another week all signs of the Red-tailed Hawk's existence will be gone.


John said...

Fascinating! I think GHO would be the most likely killer.

knithound brooklyn said...

a chilling story! I really hope it wasn't another Red Tail.

Yojimbot said...

Nature brutal outcomes often leave me feeling uncomfortable. The GHO's in the Bx are nesting now, so its not a stretch to think they would be responsible. One likely scenario is that the GHO surprised a roosting RTH and caught it unawares. Rest in Peace noble hawk!

Starz723 said...

My guess would be a GHO..OR the bird died of natural causes and it became a meal for mammals & other carnivores.

There is always something new to be learned about nature, especially in our urban areas. That is why it is so important to report what we observe in the field.

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