Cowart's Common Room
Twisty Turny Lark

On my walk along the river this afternoon I came to a spot where a flock of house martins were wheeling and dealing. Yet I am no sure what they were doing. I could see no insects, nor were the birds making those little swerves that you see insectivores make to catch an insect. So what were they doing?

But certainly they do catch insects normally and it set me wondering yet again how a bird can fly fast - like a martin - and set its eyes to focus on little insects which must be very hard to spot unless in focus and the focus must be changing all the time. While doing this and focussing on insects, the bird, flying fast has to avoid the ground, trees, humans, cows etc and while doing this it has to avoid colliding with another martin. In a lifetime I have never seen two birds collide despite their unpredictable flightpaths, twisting and turning. Look how often humans bump into each other! And this afternoon there must have been 20 martins in the space of not much more than a good sized room. Answers on a postcard, please.Very HappyVery Happy

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Posted at 8th Jun 2018 - 05:46PM   Posted by Fennie   Twisty Turny Lark Comments: 3

Re:
Camilla's Avatar Thank you for posting Fennie, we used to have a lot of House Martins under the eaves to the roof in one of our other houses we lived in here in Norfolk. Are the birds over your house Fennie? if so perhaps they have their nest there although I would have thought baby birds would have fledged by now.Very Happy

Posted by: Camilla on 9th Jun 2018 at 10:25AM

Re:
Fairy Nuff's Avatar But the birds are only fast to us and we are lumberingly slow to them...
Why you can't take a Pigeon to the Movies

It would be like us watching a snail or vice versa.

Posted by: Fairy Nuff on 9th Jun 2018 at 10:49AM

Re:
Fennie's Avatar Most interesting FN. I wonder if it is the same in dolphins, or whether they are more like us. Comparative biology focusses on structure, not on function.

But I still would like to know how your martin or swift can scan the sky for a small insect that may be close or distant (and therefore would require different focus in the eye) and then latch on to it. If my own focus is six feet I can see insects six feet away but not seven or five. Do birds have a very long depth of focus, I wonder? Or keep one eye for close vision and one for distant? It must be the same for fish that can focus on something moving swiftly either towards them or away and therefor needing a change of focus. Light levels are much poorer in water which must exacerbate the problem.

But at least now thanks to you I know not to present Faith's pigeons with a film to keep them entertained in the aviary, though I still feel they would respond to music. Very HappyVery Happy

Posted by: Fennie on 9th Jun 2018 at 02:28PM

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