Cooper’s Hawks Update 4: Pre-flight

The last image I have of the smallest chick is from Tuesday the 21rst a bit after 2 p.m. It wasn’t doing well, sleeping much, not appearing terribly successful in the food scrums, and suffering from some sort of wound on the back of the neck. For the previous week or so, it didn’t seem to be growing as the others were. Four days later, I’m sure it’s no longer in the nest. I am frustrated that the camera didn’t catch its demise, which likely happened on Wednesday, a day I couldn’t keep the cameras in the tree due to rain.
I did see this chick pecked by the largest of the birds, and it may be that this is where the wound came from. Another possibility is that this wound was actually a tick. I am very curious about whether the siblings had a role in what happened, as I suspect these Coopers may be a bit more aggressive to one another than the literature suggests. I was hoping I might recover the carcass when that bird succumbed, which would have given some useful information. Ellie and I searched the base of the tree on the off chance it could be found, but one would expect the adult female to either have carried it off or butchered it. I will say that there is a profusion of bugs flying in a small swarm around the nest. It could be that the dead chick is just crammed at the bottom of the nest bowl. untitled_16-06-23_9512

You may remember that we started with 6 chicks. There remain four seemingly hail Cooper’s hawk young now, with their rapidly filling feathers making them seem suddenly enormous. This is that very short period of days when chicks move up in size more than would appear physically possible.

The diet has taken a turn to the birds, with chipmunks and squirrels seemingly in shorter supply. At right
is what I think is a northern flicker being dismembered for the hungry crowd. You can see the woodpecker-style tongue sticking up out of the beak.

The young continue to posture, and at times even appear to attempt to injure one another. I have images of chicks with what look like scratches extending from their nostrils to their jaw joints.  untitled_16-06-23_7617

Other offenses include stomping and a strange sort of peck that lasts between 4 and 8 seconds of continued pressure into the side or neck of the victim. Here is a stomping example, at left. Now that the young are starting their hopping/branching/flapping stage, it is hard to determine what is calisthenics and what is a dominance display. One thing we can look to, however, are the reactions of the siblings, which may be more indicative than the dramatic actions themselves. I’ve been thinking about this for some time. Here is another of the bumptious flappings, about an hour lateruntitled_16-06-23_6796

Notice that there appear to be two different sorts of reactions from the other birds. There is what appears to be an incensed imitation of the flapping (at right); or there is a studied lack of notice taken (above), with the birds looking away. For the life of me, I can’t quite make sense of this because I haven’t been able to reliably identify the different chicks as individuals. If I were able to color code them, I suspect we’d see a relatively consistent divergence of behaviors depending on the individual displaying and the individual observing. There may be a method of doing this by looking at scale patterns on the legs.

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Grip development

The young are branching a bit further (below), and doing little hopping test flights. They are also testing the grip of their talons. Here is one of the young (left) figuring out how to make a better grip, perhaps doing a little strength testing of the grip that a Cooper’s hawk must use to kill prey.

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And then there are the little oddities that probably mean nothing, but for which I keep records, in case a pattern develops over years. An example: one of the young opted to pick up a leaf or hemlock bark piece from the nest bowl. The others thought this was the very strangest of behaviors and observed it closely (below).

I started to place game cameras out on the “butchers block trees” that last years batch of fledglings used as central loitering hubs and places for parents to transfer prey to them. The hope is that untitled_16-06-25_5277-2these new birds, once fledged, will frequent the same haunts and provide very close up images.

 

The full Cooper’s series:

First Hatching

The Brood

Winnowing‎

Pre-Flight

Flight!

Epilogue

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