Sunday, November 15, 2009

Displacement Activities of Common Ravens

Displacement activities is a fancy phrase that I heard somewhere and found again in "The American Crown and Common Raven" by Lawrence Kilham. Kilham was a doctor and professor of medicine as well as a very devoted and methodical birdwatcher.
Typical displacement behaviour includes twig pulling, pebble tossing, beak cleaning, grass pulling and preening. Sometimes it appears the birds are bored or trying to pretend that they are not interested in something. Other times they may be nervous.
Today I watched a raven perching (remember, ravens are the largest of the perching birds (passeriformes) on a cut down tree. It looked around, it scrapped its beak and it grabbed and pulled off twigs.
I suppose the displacement refers to displacing nervousness or fear or boredom into some kind of basically harmless activity. I got a few shots of the activity and put them together in a composite.
Getting that composite where I wanted it made me remember something. I uploaded it to a website and found that it ended up far away from the component shots. I sort images on that site by date taken. The composite shot had been put together in a blank image in Photoshop and so had no date taken. The solution, which I should have remembered, was to open a shot from the sequence, open the composite and paste it on top, flatten the image and save. That way the composite had the same data taken as the pictures in the sequence.

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