Sunday 5 May 2013

The Crow's Nest

Spring has finally come, and my local patch is showing all the signs- loads of Skylarks singing, leaves popping out all over the trees and blackthorn blossom in the hedges, the first butterflies fluttering, plus the farmer's horrible oilseed rape field has bloomed and is wrecking havoc with my hayfever... yay for spring! My local patch is the site I watch wildlife at the most, I visit it once a week and record all birds seen on Birdtrack, the BTO's bird recording tool that helps them determine numbers of all species. It's a small arable farm, and doesn't have a particularly high species density, so everything I see there feels special.

All the species I see regularly are singing, or at least calling if they aren't really singers (Woodpigeons, I'm looking at you!) and I have been looking out for signs of nest building. I'm not sure many of the small birds are at the sitting on eggs stage yet, as they are still being seen in pairs, but one nest is definitely at that stage. My patch has a regular pair of Carrion Crows that are seen on practically every visit, feeding on the fields. Last Sunday I could only see one on the field, which was unusual, but then later I heard the sound of a crow calling from the top of a tree. Looking up, I could see a large bundle of sticks, and over the edge of it a tail could be seen. It was an occupied crow's nest!

I watched the male crow feeding on the field margin, and wondered if he was going to bring food to the female on the nest, but he seemed to be swallowing what he was finding. Then he flew a short distance along the field, and I noticed that the female was now on the field margin, and the male had been flying to her. She began to flutter her wings, then he put his beak to hers and regurgitated food for her. The wing fluttering is a gesture you usually see from newly fledged baby birds who want feeding, but in the breeding season you often see female birds doing it and receiving food from the male as a form of courtship and pair bonding. I have wondered whether the wing fluttering is just an understood begging gesture or if it is supposed to remind the male of baby birds to get him in the reproductive mood! Nature is very practical, after all. And I have heard female Blue Tits that are doing the begging gesture give quiet high-pitched calls that are quite unlike their normal contact call, as if they are imitating the sound of baby birds chirping. But I have no idea if my theory is on the right track.

I should think the male feeding the female was more for pair bonding than actual feeding, because they both fed on the field margin for 10 minutes or so before the female flew back to the nest. Incubating birds can leave the eggs for short times to eat and stretch their wings, so I should think that's what she was doing. I wondered if the calling from the tree was the female letting the male know she'd be joining him soon! When I visited today the female was on the nest again, and I realised I can only see the nest from one angle through the trees- even though it is large it is quite well concealed. I can't wait to see when the eggs will hatch! It will be easy to tell because I will see both crows again, no doubt rushing around to find food for their scrawny little bundles of joy. :D

A few weeks ago I was lucky enough to witness a fantastic piece of Buzzard behaviour. There were two Buzzards soaring in lazy circles together, and I wondered if they were a pair. Then one flew towards the other as if about to collide, but the other flipped upside down and swung its talons upwards so that it almost touched the other bird's talons. The behaviour didn't appear to be aggressive because they would then go back to soaring in circles around each other, and then they would flip their talons towards each other again.

The happened several times before another Buzzard appeared. It flew towards them and moved in close, as if to do the talon-swipe with one of the pair. At once the other member of the pair became aggressive, shooing the interloper away from its partner. The courtship display was broken up and sadly I didn't see who ended up where, but I did see a Buzzard flying away over the large field and I wondered if it was the interloping Buzzard getting out of the territory of the pair! I can't be sure because normal-plumaged Buzzards are very hard to tell apart. There is a very pale Buzzard with a boldly patterned head that is very distinctive and was a regular visitor to the farm during the winter, but I haven't seen him for a while. I wonder if he has formed a new territory elswhere? (of course he could be female, you can't tell the difference, but I've started calling him 'he' in my head, and given him the nickname of Osprey because of his bold head markings and pale plumage. This may confuse anyone who read my patch notebook, but the chances of me seeing a real Osprey on my farmland patch are pretty low!)

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