Mmmm.... any idea what's changed, or gone wrong Mike?
I know I struggle to see Greenfinches round here now and Yellowhammers can be a bit patchy too.
Hi Delia,
I suspect poor breeding is one of the most important factors. I used to see loads of good sized family parties of lark and yellowhamer as I walked through crops in late summer. Now these parties are small. The parties are also few but that does not of itself say anything about breeding.
So why ? I notice far fewer invertebrates than we used to get, massively fewer than in the 1970s when everyone's kitchen needed flypaper in summer. So, far less chick food. In the last 15 years or so I have been establishing flower areas to try to reverse this. I thought this was working, with masses of beasties in them, loads of bumblebees. In 2015 we hardly had a bee and beasties seemed to have collapsed in numbers - but the swallows did really well so some things must have been OK.
Another factor might well be extreme rainfall during the breeding season. It seems to be quite common now to get really wet cold weather extending over a day. This year we had it twice in June - ~80mm rain in c.36 hours at the beginning of the month and ~100mm in c.36 hours at the end. Only one or two swallow nests had fledged by the end of June. Every nest failed, even the ones that were at egg stage, same for house martins and (first nest for several years) spotted flycatcher. What chance the birds nesting in the open ? I don't monitor them really as I don't have time to find them. This should have been the peak of the breeding season. The bad weather covered a large area, farmers in Ayrshire were complaining they had their worst June ever with over 180mm of rain (we had 227). So the effects would not just be local. Certainly this is my worst ever winter catching linnet, we have hardly caught any yellowhammer either, and the poor numbers might well tie in with this weather as they both breed relatively late. You may have noticed that I have had a very good winter for goldfinch and almost all of them are first year birds, so apparently not all species suffered the same.
I did find three early yellowhammer nests. Two certainly were predated (possibly stoat or weasel), one might have fledged. I am against predator control but it is easy for those in favour to whip up emotions against predators. Indeed, barn owl started predating swallow nests in a major way here in 2016 when small rodents seemed to disappear more or less completely. Though we have the rodents back, the barn owl know where there are easy pickings which doesn't help the swallows. More ammunition for the anti-predator brigade I suppose, but the problem arose not because of too many owls, but due to too few rodents. Oh, it also affected rats, so I suspect something like a virus but have no evidence. Who knows if it was driven by something humans had done.
Mike.