There’s an intersection I pass every morning where there are usually a few dozen birds clustered together on the utility wires on one corner. Why is this? The corner has a suburban park on it (softball diamonds, playground; not much brush), and there’s a golf course on the opposite corner (with some brush where they might nest). The other two corners have small stores and businesses (dry cleaner, etc.).
My theory is that it’s warmer there, with heat from the idling cars – but would that heat be enough to make a difference to the birds when it’s, say, 40 degrees out? And why always on the one corner?
A given location may be better than other similar locations based on food availability (feeders, etc), safety from predators, amount of sun exposure, etc.
There is a particular section of wire near a Kroger’s they like here.
Maybe the thermals are better, naybe there are more bugs, maybe folks through their hamburger buns out at the stop light. Perhaps you can see the hawks coming.
I wonder why a few guys come and go, and suddenly a large mass of birds will take off, fly around in a circle and sit back down. Did a particularly juicy bug fly by? Did someone fart?
Yeah, and why is there always one lone bird off from the rest of the group? Is he the stinky one? Do they all make fun of him and not let him sit with the “in” crowd? Is he shy, maybe?
It is possible that there is wearing in the insulation of the wires, and where they cluster is actually slightly warmer than it ought to be. Not shockingly so, but enough to allow the vinyl jacketing of the wires to become warm.
My guess is its scent. For whatever reason at some point a bird lands on a particular spot on a wire leaving something and its picked up by later arrivals. That combined with the tendency of birds flocking together reinforces the behavior of repeatedly landing in the same area.
I don’t know what science says about this idea, but that’s my guess.
I’ve been paying attention to them since the OP, and they tend to sit near the pole.
The wire swings in a greater arc further away from a pole. Maybe they like a seat that doesn’t blow in the breeze.
Birds in general (there are a few exceptions) have a very poor sense of smell. It is unlikely that this is the explanation.
From the description, it sounds like that particular spot might provide the best viewpoint for the detection of approaching predators. On the other hand, depending on the kind of bird the park might offer more food than the other corners of that intersection.
Aside from this, birds will often tend to perch near one another as a defense against predators. More eyes offer more vigilance. Also a bird sitting by itself is more vulnerable to being picked off. (A hawk, for example, risks injury by plunging into a flock, whereas it can easily pick off a single bird.)
Hanging out en masse to discourage predators makes sense – I’ve seen a lot of hawks in that immediate area. It could just be coincidence that I noticed them there three or four mornings in a row; there’s no telling how many mornings they haven’t been there. (For instance, I didn’t notice them this morning – but I caught the light, so I wasn’t sitting there staring at the wire, waiting to make my turn.)
A herd (not the right collective noun, but I don’t know the correct one) of pigeons sit on a telephone wire above where I sometimes play tennis. Red-tailed hawks feast on pigeons and I saw one catch a pigeon one day; however, often these pigeons take off in unison, fly around, and return to the same spot in a matter of a minute or two. I’ve never seen a predator when they do this, but apparently they have. I think the reason they’ve chosen that spot is to watch the tennis matches. Even pigeons need comic relief every now and then.
Whoa, very interesting article, Colibri – thanks for linking it! I’ve read a little on emergent behavior – it makes sense that flock movement would be an example of it.
