I've seen this happen fairly often (usually while driving to work) where a crown or red winged black bird will repeatedly torment a perched (or in flight) red-tailed hawk. I've gotten a casual explanation that the birds are just trying to get the hawk out of the area as they are seen as a general threat - but it amazes me how much they tolerate - and that they don't "snap" and just return the favor. I snapped this photo today from my car window while waiting at a stop light (literally as the light turned green) so the techs are awful (it was high noon) but I love the calm demeanor of the hawk as the crow dives. Anyone have a better explanation, or some better photos?
I'm not sure my explanation is much better, but mobbing behaviour by passerines of almost any or all raptors is extremely common - you'll see many songbird species go after owls, hawks and eagles. The most extreme form of mobbing that I've witnessed was a few years back when I watched an Eastern Kingbird riding on the back of a Red-tailed hawk (in flight) and pulling feathers from its back. Every explanation I've read in the ornithological literature comes down to the same thing - removal of the threat of predation by chasing the predator away from breeding and/or nesting territories.
Not sure this is particularly illuminating, but it seems to be the current explanation...
Brad
Posted by Dennis Plank on July 1, 2009 at 12:50 AM
It's interesting how sometimes the mobbing is perfectly on-target, and other times it seems so misdirected. I suppose a red tailed hawk would raid a nest if the opportunity presented itself, but they're not bird chasers. Our major one right now is the swallows and our local Kestrel. However, they have reason in this case, since I've seen the Kestrel go from nest box to nest box trying to find a way to get at those tasty noises coming from inside.
Isn't it crazy? I saw this little guy trying to fight of the blackbirds for about 15 minutes. It was sooo cute but also very confusing as to what is the reason. Is it territorial?
I was shooting this RLH when it was buzzed by a raven. I was so close to the roughie that I didn't get the raven in frame but this was the reaction of the hawk with the raven in it's face. I'm wondering if they sometimes do it simply because they can get away with it and it's "fun".
Mobbing has been intensively studied, but there are still lots of unanswered questions. There are a lot of theories. I am an adaptationist, myself.
Adaptationists would say an organism engages in risky behavior like mobbing for reasons that include advertising their physical fitness and hence uncatchability (much like stotting behavior in gazelles), distracting predators from finding their offspring, warning their offspring, luring the predator away, allowing offspring to learn to recognize the predator species, directly injuring the predator or attracting a predator of the predator itself.
The much lower frequency of attacks between nesting seasons suggests such behavior may have evolved due to its benefit for the mobber's young. Behavioralist Niko Tinbergen argued that the mobbing induces confusion in gull chick predators, distracting them from searching for prey. A marauding Bald Eagle can only avoid incoming attacks by Mew Gulls by facing its attackers, which prevents it from locating its target.
I've watched multiple Ruby-crowned Kinglets, tiny, tiny little birds, mobbing a Bald Eagle, a species highly unlikely to raid a Kinglet nest. So I think it is a generalized reaction. Another puzzle is why mobbing birds from other nearby nests respond cooperatively to the "mobbing" call.
All of which is just another reason why birds are so interesting...
Bravo, Jim. In a couple of terse paragraphs, you have beautifully summarized the essence of mobbing as well as some of the many questions surrounding this behavior. I agree entirely that the cues eliciting mobbing are probably quite generalized, so that it often occurs when the immediate benefits of the behavior, if there are any, are quite obscure. I would add that for some forms of mobbing, the frequency of the behavior increases during the non-nesting season. I've used screech owl recordings for a couple of decades to attract passerines, and my experience is that response to screech owl vocalizations nearly disappears when the parents are actively tending young in the nest, but then increases dramatically in mid-summer once young start to fledge, remains high during fall and winter, then declines dramatically in late winter/early spring when the adults begin to ready for breeding again. With respect to this particular form of mobbing (traveling some distance to seek out a vocalizing predator), I think there is a clear hierarchy of behavioral need and benefit; it only occurs when the more direct fitness benefits accruing from producing and taking care of vulnerable young is not a priority. It also suggests that education of naive young birds as to the identity of a potential predator is an important benefit. Certainly there is very little immediate risk of predation from a screech owl that happens to be exposed during daylight hours.
It's a fascinating behavior. I'd love to hear some of your observations and ideas about it in more detail.
I have watched and will look for photos of Crows and Red-tailed Hawks harassing each other.
I have seen Crows both as singles and multiples buzz a Hawk and in return I have seen the Hawk retaliate, after a single crow. It was rather an interesting display, it was like 2 kids fighting for the same piece of shore. Damage was not inflicted by either.
I have read that Crows like to "play" and will sometimes instigate events. This would seem to be the case when 1 Crow goes after a Hawk. Especially when there is not a nest in the vicinity.
This might be the exception to mobbing?
I have also seen Blue Jays after a hawk. And they continued to follow it as it tried to move away. Again there was no nesting nearby.
Sharon
Posted by Murray Feist on July 17, 2009 at 4:33 PM
Hello
Last year when out trying to sneak up on a mule deer buck, I jumped this hawk from his perch, who was soon beset upon by this smaller bird (Kingbird?). Like sharon I too will watch for fighting raptors (other than the eagle fighting over fish). On another note, this summer I missed catching a pair of fornicating red-tailed hawks on a tree branch (camera still in bag while driving.......) so would that count as harrasment or fighting ? :)
Posted by bill meikle on July 26, 2009 at 11:20 AM
Well I have seen birds mobbing various hawks and eagles and I am sure it is because of the threat that these birds pose to the smaller birds and their nests. I have a magpie's nest in my garden and i have seen a redtail diving right into the nest several times this season, always coming out empty handed and getting chased for miles by all the local magpies. Photo attached.
Discussion
9 replies- Luke
I'm not sure my explanation is much better, but mobbing behaviour by passerines of almost any or all raptors is extremely common - you'll see many songbird species go after owls, hawks and eagles. The most extreme form of mobbing that I've witnessed was a few years back when I watched an Eastern Kingbird riding on the back of a Red-tailed hawk (in flight) and pulling feathers from its back. Every explanation I've read in the ornithological literature comes down to the same thing - removal of the threat of predation by chasing the predator away from breeding and/or nesting territories.
Not sure this is particularly illuminating, but it seems to be the current explanation...
Brad
A raven isn't a blackbird but it is a black bird.
Adaptationists would say an organism engages in risky behavior like mobbing for reasons that include advertising their physical fitness and hence uncatchability (much like stotting behavior in gazelles), distracting predators from finding their offspring, warning their offspring, luring the predator away, allowing offspring to learn to recognize the predator species, directly injuring the predator or attracting a predator of the predator itself.
The much lower frequency of attacks between nesting seasons suggests such behavior may have evolved due to its benefit for the mobber's young. Behavioralist Niko Tinbergen argued that the mobbing induces confusion in gull chick predators, distracting them from searching for prey. A marauding Bald Eagle can only avoid incoming attacks by Mew Gulls by facing its attackers, which prevents it from locating its target.
I've watched multiple Ruby-crowned Kinglets, tiny, tiny little birds, mobbing a Bald Eagle, a species highly unlikely to raid a Kinglet nest. So I think it is a generalized reaction. Another puzzle is why mobbing birds from other nearby nests respond cooperatively to the "mobbing" call.
All of which is just another reason why birds are so interesting...
It's a fascinating behavior. I'd love to hear some of your observations and ideas about it in more detail.
I have seen Crows both as singles and multiples buzz a Hawk and in return I have seen the Hawk retaliate, after a single crow. It was rather an interesting display, it was like 2 kids fighting for the same piece of shore. Damage was not inflicted by either.
I have read that Crows like to "play" and will sometimes instigate events. This would seem to be the case when 1 Crow goes after a Hawk. Especially when there is not a nest in the vicinity.
This might be the exception to mobbing?
I have also seen Blue Jays after a hawk. And they continued to follow it as it tried to move away. Again there was no nesting nearby.
Sharon
Last year when out trying to sneak up on a mule deer buck, I jumped this hawk from his perch, who was soon beset upon by this smaller bird (Kingbird?). Like sharon I too will watch for fighting raptors (other than the eagle fighting over fish). On another note, this summer I missed catching a pair of fornicating red-tailed hawks on a tree branch (camera still in bag while driving.......) so would that count as harrasment or fighting ? :)