Saturday, November 13, 2010

Puerto Rican parrot twilight behavior, sleeping clumped in a bunch.

This is the only photo of this behavior ever taken, you can see a parrot ready to fly away at the bottom
As the leader of the captive propagation program of the Puerto Rican parrot I spend time, probably than anyone on its right mind should, observing parrot behavior. I also read the notes of previous aviculturists about the parrot’s behavior in captivity to look for context for my observations. But there is a gap in the information about this parrot’s behavior, there’s an absolute absence of writings on what the parrots do after dark. In fact most people seem to assume that as soon as night falls the parrots go to sleep and that’s that. To say the truth this inference is largely true, however in the period of twilight before complete darkness the parrots do things that have been missed, as far as I can tell, by other observers.

The reason for missing these behaviors is very simple, after the daily work shift ends the personnel goes to their houses, to do errands, to take a nap, to eat, and hanging around the parrot cages is the last thing in (including me) anyone’s mind. But one day I noted that the period of twilight was marked by an inordinate amount of calls coming from a relatively small area in the cage, the calls denoted intense socialization at a time that I had always assumed the birds were setting down to sleep. This piqued my curiosity and I decided to see what was happening.

What I found is that sometimes, instead of sitting on the many perches on the cage, the parrots will cluster together to sleep in the wire forming a mass that resembles a grape bunch. I have never read this reported, and it doesn’t seem like they sleep in this way in the wild. The birds arrange themselves in a very tight bunch, literally side by side in a degree of intimate contact that I would have thought inconceivable between adult parrots that are not pair bonded. The forming of the bunch is accompanied by much squawking and I suspect this is caused by birds jostling each other for position on the bunch. I have never set out to watch the formation of the bunch since this would probably disrupt its formation but I have on rare occasions witnessed its dissolution. Also most of our flight cages have, by design but this is a matter for another post, odd asymmetrical shapes that limit line-of –sight viewing.  What I found most interesting about this clumping behavior is that the PR parrots, which can be quite picky with who they associate during the day, seem to lose their selectivity as night falls and join together in relative amicability and closeness that they don't show during the day.

I suspect the birds clump as a form of protection from predators. I make this inference because of what happens when the clump is disturbed. When the birds are startled the clump explodes like a grenade with birds flying in all directions. I have just a single photo of this clumping, it was taken when I had to feed the flock very early before dawn because we were doing some special work with the wild birds and I wanted the captive birds to be all fed by first light in the morning. In the photo you can see only part of the clump as a number of the birds had flown away the moment they detected movement near the cage. Nevertheless the photo shows the way the birds arrange themselves on the wire. Previously I always thought that only mated pairs slept this way.

It is unclear what triggers this behavior as some birds are quite content to sleep in perches.  For the moment being this behavior remains a curiosity observed from time to time.

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