Today I was driving to the store when high over the road I saw two birds flying together in the air. One was large, brownish, and the size of a bird-of-prey, like a hawk or eagle (doubt it) or maybe a vulture. In other words, big, with wide, stretched-out wings. The second bird was much, much smaller, looked black, with smaller wings that were flapping much more often than the larger bird, which was gliding gently around in short circles (like you see vultures doing). Now the smaller bird seemed to be following it, rather frantically, flying up above the larger bird and sort-of dive-bombing it. Over and over, the smaller bird seemed to be attacking the larger one from above. I watched this for several minutes until the drivers behind me started getting angry.
Note this is in St. Louis, Missouri, in broad daylight, far, far over a highway. No other birds in sight, no trees even remotely close, and, again, very high in the air. Seems like the larger bird could have had the smaller one for breakfast, but it was decidedly the smaller, black bird that was being the agressor…and it was as though the larger bird wasn’t even bothered by it, hardly even flapping its wings.
Any ideas on what the birds were? And what was going on? I could see something like this happening if the smaller bird’s nest had been nearby, but like I said: they were practically in orbit from the way it looked. I’ve seen a shark attacked by a dolphin, and been dive-bombed by what I think was a bluejay, but I’ve never seen this.
I’ve seen mockingbirds attack other birds and, like you, have had the occasional dive-bombing bluejay go after me. Even had a mockingbird chase me into a building once and all I could figure was that I had walked too near a tree/bush where its nest was.
Any more details on the smaller bird? Maybe a crow? By comparison with a vulture (we call 'em buzzards) it would be smaller, and since they’re both carrion eaters maybe the big bird swiped the smaller bird’s lunch.
Right now in California, it’s nesting season for Blackbirds, and they are very aggressive in protecting their nests. A lot of the ones around here have nests in low shrubbery and rain gutters, so trees aren’t necessary for them to be present.
I regularly see them chasing other birds, including hawks, divebombing people, (I usually get pecked in the head a few times a day just doing my daily rounds. It doesn’t hurt, but it is surprising the first few times it happens.), and even chasing cars down the street.
You may have seen something different, but it certainly sounds like the bird behavior around here.
Almost cartainly the smaller bird was harrasing the predator to drive it away.
The absence of trees tells us nothing much. Many birds are ground nesters. Even if it were a tree nester, birds will chase predators for considerable distances. Unless you can say there were no trees, buildings or shrubs for a mile or so around then it’s fairly irrelavant.
Perhaps most importantly, birds will harrass predators when they have no nests. It isn’t just a nest defense mechanism, it serves to stop the adults being eaten as well. Like you said, the raptor could have had the smaller bird for breakfast. This is not conducive to reproductive success.
What it comes down to is that a bird can’t go about its business while there is a raptor in the area. It’s faster and safer to let the hawk know it’s been spotted and chase it out of the area than to simply sit down under cover and wait until it decides to move on of its own accord.
Haha! That’s great! I’m going to have to borrow that line from you, Blake. Yes, I’m sure there were some trees within a mile, just none closeby (I guess “closeby” becomes a relative term when you can fly). But I had no idea most birds were ground-nesters. I guess it makes sense…why wait to make a stand when you know you’re being hunted? That was one tough little bird, though.
I’ve seen this fairly often, in southern California and Texas. My bird-watching sister always referred to it as harrying. A glance at google for ‘raven harried hawk’ (as every time I’ve personally seen it, it’s been one to four ravens harrying a small hawk) turned up quite a few bird-watching logs using the same term.
It’s quite common behaviour - the term I’ve always heard used for it is “mobbing”. It’s very common behaviour for crows, & I see it quite frequently over the highways around here (East Kansas - there’s a lot of big hawks around, and a lot of crows - which look quite large till you see them take on the hawks).
A google on mobbing hawks also turns up a lot of hits & bird species - it looks like a common behaviour for blue jays too.
Usually the birds do it in a group, hence mob & mobbing, but they will attack in ones & twos too if they have to & the hawk is near its nest/fledgelings.
