Several people have commented on the vast numbers of Coal Tits about this autumn locally. Today I decided to ring in the garden with a single 9 metre net to see just how many Coal Tits there are using the garden. In 3 hours this morning and a further hour and a half this afternoon I caught 58 birds. The catch totals were:
Dunnock - 1
Blackcap - 1
Goldcrest - 1
Long Tailed Tit - 1
Coal Tit - 11 and 9 retraps
Blue Tit - 5 and 2 retraps
Great Tit - 7 and 4 retraps
Chaffinch - 8
Greenfinch - 3
Goldfinch - 4
Bullfinch - 1
Over one third of the catch being Coal Tits is pretty stunning however 4 of the retraps were 'same days' which I always record as doing population estimation is much easier with them. Ringing and Migration volume 4 page 225 has a really handy table for population estimation and taking the numbers I have suggests there are about 40 coal tits using the garden today. My captures for October (33 individuals encountered, 11 re-encountered) suggest a population of around 70. Although the sample sizes are small such different estimates could suggest quite a bit of turnover within the garden.
The Bullfinch is the first I've seen in the garden since September. Another one was present although not caught. The goldcrest is a new species for the garden although I've seen and heard some before there.
Perhaps the highlight was the Blackcap which weighed in at a massive 24.4g. Looking through the group's records of Blackcap only 5 have been heavier out of over 1,500 that have been weighed. All the previous ones have been at Heysham on autumn passage.
Richard
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