Why do birds cluster on telephone wires, and more specifically, why do they always cluster on the same part of the wire, year after year?
I’ve seen this everywhere I’ve lived that has overhead power lines. One section of wire is chock-full of birds in the day time, the rest are empty.
Is it like a vibration in the wire that the birds like? Is is habit? Is there a gang of birds and this is their turf?
Many birds flock together, especially in migration, and when resting they perch on high places so predators won’t get them. You often see tree swallows sitting on wires, and they tend to flock together. They are insect eaters and are awaiting their opportunity. Pigeons will do the same, waiting for homo sapiens to litter the street with food. Pigeons will often sit on roof tops and other high places, also. I usually see tree swallows on wires. I suppose because they are smaller birds and that’s what’s more comfortable to them. Starlings in migration will do the same, but I often see them on billboard signs, etc.
So the birds I see doing this are the insect eaters (tree swallows, etc.), birds in migration resting (starlings), and the ubiquitous rock doves.
Am with XPav here actually. Barbitu8 didn’t really explain why one sees pigeons on the same 50ft stretch of wire (like outside my office) and ONLY on that stretch of wire. The other two 50ft stretches of wire either side are definitely not occupied (except by a few stragglers who are obviously trying to get onto the prime real estate wires). My office is by a freeway and there are no garbage bins nearby. Explain that…
Sorry…just a follow up. It MUST be something to do with the fact that my car is situated underneath the only 50ft stretch of wire that they choose to perch on.
They have to perch somewhere on the wire, and since they flock together, it’s at the same area on the wire. I don’t see the problem. If they weren’t perched on that 50 ft, it would be another 50 ft. Perhaps they’ll getting a better bird’s-eye view.
An easy way to get free sneakers? 
But its always the same wire. There has to be some point at which there are no birds on that wire – so what makes the first bird come back and pick that wire?
I knew a guy years ago that used to go out to lunch and pick the same seat at the pub. If someone else was in his seat, he’d tell him, with no circumlocution, that that was his seat and to get his butt off. He was comfortable there. I guess birds are the same way.
Perhaps it’s the best place to watch for hawks or to see food.