Re: Size bias
Ive wondered about bird brains for a while now.
We have a couple of peanut feeders outside our kitchen window. I spend quite a bit (probaby far too long - I should be doing a jigsaw puzzle) watching the antics of the Blue Tits, Great Tits, Robins and Sparrows that frequent them.
First. How did they locate the feeder in the first place and how did they know it was a source of food?
Second. There is a third feeder attached to the kitchen window. This contains Flutter Butter (other peanut butter based feeds are available) How did they work out that this thing attached to a sheet of glass also contained food. (they love it by the way and can empty a pod in almost the same time tha the squirrel can empty the nut feeder.)
Interestingly the Tits tend to queue to use it. The Robin won't come to it if there is a Tit feeding. If it's free then it will come and sit on it and hog it for a while.
The Sparrows won't come anywhere near it - perhaps they're chicken.
There's anorher feeder for Finches. We haven't seen a finch all year - but not one of the other birds will touch it.
What has intrigued me most is the birds' reaction time. That and their communication.
Example, two House Sparrows sitting on the fence about 20cm apart. With no obviously link between them they took flight as one and flew away as a pair in the same direction side by side.
A slo-mo film might have detected a difference in their launches, but I couldn't see it.
The Tits (both varieties) are very acrobatic when feeding. It's always intrigued me that they land on the feeder (a vertical stainess steel tube with holes spaced for they to get at the nuts) without making mistakes. Their feet are always in the right place to get the peanuts nearest to top of the tube. If the squirrell has been lunching and the nuts are now only at the bottom, they instantly switch to an upside down position. Again, lightning fast. The Robin on the other hand took two or three weeks before he could land on the feeder like the Tits do.
I watched a Sparrow today trying to imitate a Humming Bird, trying to get a peanut while in hover mode. He could only manage about 3 seconds before giving up. He did manage to get his beak in the feeder but couldn't maintaing the hover long it enough to pull a nut out out.
There are other occasional visitors with their own quirks and tricks but I think I have rambled on long enough now.