Late summer corvid flocks, green woodpeckers and horseshoe bats

Noted Sam's comments about corvid flocks with no obvious bare parts (where were the adults if they are rooks?). We also get large flocks of juv rooks in south Pembs. Currently there at least 500 or more feeding regularly on Castlemartin peninsula. Whilst there are some carrion crows in the flock, the vast majority are juv rooks (but often get reported as carrion crows).

There are adult rooks in the flock too but I have often noticed that somewhat scrawny juvs with black bills and lacking pale bare parts form by far the bulk of the flock - especially in a good breeding season like this year. Many rooks appear to have fledged this year - they certainly seem to have prospered in the "moist summer"!

I also wonder if, like choughs, adult rooks may be taking their offspring to good feeding grounds and actually encouraging them to join "young birds clubs" to assist their dispersal and survival. Makes some sense if you are an adult, wanting a quiet life after hectic and tiring breeding season, when now you need to moult and build up your strength again.

We know, from colour-ringing, that this is what can appear to happen with choughs. Young choughs join up with other young of the year and non-breeding older birds - forming a wandering flock gradually growing in size added to by newly dispersing recruits. This happens any time around now. By the beginning of August many surviving juvs will have dispersed from their breeding territories and may be roosting some distance away in flocks with 1-2 year olds.

Green woodpeckers - 1 juv noted at Stackpole - seen feeding out in the dune grassland with the male. I think quite a lot of holidaying visitors will have seen them as they are occasionally feeding near the coast path at present - lets hope passing peregrines are not hungry! We are hoping to do a repeat ant-hill density survey this autumn (last done 15 or so years ago) to see if we can detect any changes that may point towards reasons for a decline in green woodpeckers on the peninsula.

We have just started counting and marking baby greater horseshoe bats. (The thirtieth season running at Stackpole that the bat productivity has been monitored). This years breeding season is the latest, probably for at least 10 years of more. The first births are up to 10 days late and the "pups" are also very small at birth compared with usual births. This does not bode well for good autumn/winter survival!

The key problem for these bats almost certainly relates to the cold April this year, when insect food was scarce at a time the bats should have feeding well and putting on weight after coming out of winter roosts. Certainly moth numbers were poor then and numbers are still way down - judging by regular weekly standardised light-trapping reports around the country (plenty of typical species but generally lower numbers of moths being caught). I wonder if other edge of range insect-feeding specialists are being similarly affected?