Normally we see red-tailed hawks soaring.
Very seldom do we see dead red-tailed hawks. If we do, it is usually along side a road. Red-tails often hunt from a perch and there are plenty of perches along the sides of our country roads. If a hawk dives on a ground squirrel or other rodent, it may do so into a passing car. A couple years ago I collided with a red-shouldered hawk that way.
My friend Joe checked out a road-killed red-tail recently and found it to be banded by the Golden Gate Raptor Observatory. This is a group that calls the Golden Gate National Recreation Area it’s home and bands birds of prey each fall. I apprenticed for them about fifteen years ago. It was a fun way to put my hands on a few hawks. You can’t get any closer while they’re alive.
As unusual as it is to see a dead red-tail, it’s even less likely that you will observe a red-tail dying, but that is what I did a couple days ago.
While walking along my usual hiking trail, a red-tail appeared face down just off the trail. Curious, I walked over and poked the bird with a stick. It moved. It appeared to be barely alive, but not wanting to interfere, I left it alone and checked on it again on my way back to the truck. At that point the bird was dead.
I couldn’t help but wonder what had happened to this bird. It appeared to be a healthy bird, with all it’s plumage in place and no apparent wounds. Could it have died in a mid-air collision? Not likely. Could it have received a wound from a competing hawk? Small chance of that.
When I spoke with my biologist friend, Joe, I asked him what he thought. That’s when he told me about the dead hawk along the side of Vasco Road. He added that the most likely killer of a mature red-tail hawk is secondary poisoning from rodenticides. Having observed the slow death of this hawk first hand, poisoning is logical.
Who puts out rodenticides that can poison predators? Ranchers use rodenticides to kill California ground squirrels, so that is a possibility. Since this trail is near a golf course, I’d have to imagine that the greenskeepers might use rodenticides to kill gophers and ground squirrels that invade the fairways.
It’s now common for marijuana growers to use rodenticides to kill rodents that attack their valuable crop.
When it comes to the death of this red-tail at Del Valle Reservoir, my judgement is very speculative.
I’m not a fan of rodenticides.
Secondary poisoning is one of the reasons we don’t use them on our ranch.