6:25 Went with my friend on to check out Mills pond area on a whim. As we walked through we quickly noticed a flock in roosting in a tree and performing the “paired dive bombing dance”. Eventually they moved further east to the roof top that they had occupied the previous time I witnessed them out there, then off out of sight.
I have fashioned a hypothesis on the paired flight that fits what I know about flocks. To the best of my knowledge members of a flock are not in any sort of pair bond or actively mating. While they could possibly have ‘friends’ it seem unlikely that this has anything to do with that. The flights also don’t seem like proper fights because they begin spontaneously and end just the same. Also multiple birds, if not every bird in the flock at some point, engage in this behavior. My speculation is that it is a form of social jockeying or perhaps even more specific, jockeying for a perch. One bird will initiate the chase to challenge a bird for their perch and if the challenged bird pulls out of the chase their perch is forfeit. This is just a hypothesis, so I need to get more footage of the event to solidify things.
[Updated] Bernd Heinrich described a behavior similar to this displayed in ravens in his book “Mind of the Raven”. He chalks the behavior up to play rather than any direct social or survival function.
10:00 I could see one crow atop G1. He flew off to westward over my building then returned and landed in parking lot. He quickly saw me and took off perched in N1.
1:39 top of N1 single crow giving calls in medium length 4’s 3’s and then 2’s. I could hear a crow to the west responding only in 2’s. Crow on N1 flew off to the north.
2:00-2:30 Went down to Mills pond and saw three crow. one landed on the ground and poked around for a while, that was it.
On my weekend I traveled about 60 miles north. I happened to spot a crow chasing another unknown bird as I was walking through down. I have to marvel at these crows that will so readily chase something twice their size.
10:56 Single crow perched on G2 giving long 2’s and 3’s in even pace with mild downward inflection. Remained perched for 1-3 minutes before flying off to another tree, then to the wooden fence. Second crow joins and they look over the north side of fence. Newcomer is likely one giving calls in 3’s similar to before. First crow gives short high 3’s in a sort of kek-kek-kek fashion. during this another crow flies overhead. Second crow jumps down behind fence followed by first. I run around the block to get a better view. from my view at home I can only see the outer side of the wooden fenced in area. from around the block there is a building in the way. A sign says beware of dog on a gate to the fenced in area. One of the crows jumps back up on the fence. Just then I notice a white and black cat sauntering along and watch him slip under the gate and enter the fenced in area. Loud long rapid calls probably in 5’s but really not grouped, erupt from the fenced in area and one crow flies up over the roof and back to perch on a nearby tree with the other crow. Undoubtedly this is an example of alarm calls. The key features as I can tell are the rapidity and the lack of grouping.
12:36 One crow perched in G1 giving long 3’s another unseen crow to northwest gave short high 3’s “Kek-kek-kek”. Two perched on tree just above wooden fence and gave series of low calls in no particular grouping. one flew off to east, other left unseen.
1:42 single crow on SE1 giving long 4’s. flew off to N3 then out of sight northbound.
2:48 flying west to east with something in its bill
3:15 perched on tree above wooden fence cawing pretty much incessantly until retreating some minute later to N3, then N1 then to G1 to eat some small piece of food carried over from at least G3 if not near the wooden fence. Ate food in several bites, ruffled feathers then moved further east to another tree. hopped around that tree for a few seconds then made off towards the east out of sight.
4:04 individual on G1 giving medium length calls in rapid succession in 6’s or more. flew over behind gas station, then to N3 then off westbound.
4:18 flew in from east, perched on N3
4:30 Complete confusion. I could see a single crow perched on G2 then other crows fly in from east. One Crow flies through the area between N1,N3,G1,G2 as if being chase but I cannot see any other birds. A Crow perches on N3 and gives some calls, then flies over to tree above wooden fence and gives the old long-short-short call. Some noise can be heard from neighbors but nothing can be seen. Yet another crow flies through and the crow perched above the wooden fence takes off. Next I saw a crow perched in G2 hopping around a bit. A Squirrel, probably surprised by the crow, was doing its best to remain motionless. Eventually it tried to make it’s way back up the tree. At just that moment the crow jumps over and picks of something in beak and flies away to the east.
6:30 My friend and I put together a board with measured markers on it to see if we could get some measurements on the crows that flock at Mills pond. Before we could even set up we spotted two crows in the marsh grass picking around. I attempted to see what they were picking out but could only get sight of a partially open bill holding something small. Wat ever it was it was no bigger than a marble and could be picked out of the ground and eaten readily.
We set up the board and placed three plastic cups containing salted peanuts, unsalted peanuts, and regular ruffle potato chips in front. We then moved about 20 meters away and waited in the grass. Absolutely nothing came to take the bait. A couple crows flew over head, and There was possibly even a small flock perched in a tree to the west, but that was the extent of it.
9:40 perched on E1 for at least 15 minutes, didn’t move around much
10:30 perched on tree next to E1 grooming and ruffling feathers, flew off north.
6:02 I heard calls but could not get a visual on any birds before they went silent. As I looked around I saw something, possibly a cat, move around the corner of the wooden fence and out of sight. I ran around the block to see if I could ID it but it was gone. On my way back a single crow flew over head from the north east and perched low on N1. I watched it for about a minute then moved around to the other side of the tree to get a better look. The crow moved up a branch or so and proceeded to ruffle his feathers and preen. I was close enough I could see how drenched this bird looked. It is a bit of a reminder that these birds have to rough the worst of the weather with no protection at all.
8:00 Saw two crows flying in from the west. One of them perched on a low branch of E1. Eventually three, though I’m not sure where the other two came from, took off to the south east. I followed through the park and then further south. I found a good grouping of them roosting in a tree, probably 20-50 birds. There where some vocalizations ranging from low to high among different birds, but most calls where in groupings and seemed pretty tame and undirected. Some of the birds surprised me with their shear volume.
A loud noise from down the street startled the whole flock and they all took flight at once. They moved westward as I did my best to follow them. The flock diverged and formed two groups that perched on either side of the street I was in. Slowly single crows would make their way back and forth, and at times whole trees with up to a dozen would empty out. they moved progressively northwest over the course of 5 minutes. They moved into an area that was inaccessable from the road. It appears that this was their final roost as they did not move from this spot for some time.
another pass by the mills pond area gave no sign of any crows, so it does not seem that the flock that has frequented their was around tonight.
Not to make the assumption that only one bird can perch on a given tree, but I do believe that its a good guess that the bird that perches on E1 is a repeat character. If that was the same bird that perched their tonight and then joined the flock, that would confirm that this bird is unattached and not one of the local mating pairs. This is circumstantial, but its all that I have to go on for now.