NLRG was formed in 1957 to help in the study of birds in the Lancaster and District Birdwatching Society area. There are currently 12 active ringers. Species currently being studied include: Pied Flycatcher, Bearded Tit, Sand Martin, Twite, Goosander, Oystercatcher and Grey Wagtail. Migration has been studied for 28 years at Heysham. We welcome anyone who wants to observe, help or perhaps wish to become a ringer. Photo: A Heysham-ringed Twite on the Mull of Kintyre (thanks to Eddie Maguire)

Saturday 20 October 2012

More on Coal Tits

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

No comments: