Sunday, September 18, 2011

Reprise

Saturday was spent watching for breaks in the rain, living in hope the forecast might change for the better; it did, so Will and I found ourselves at Out Rawcliffe again this morning, and hoping for a repeat of Thursday’s catch of 122 birds.

But we didn’t quite hit the same heights with today’s catch of 94 birds of 12 species, 93 new and a single recapture of a Chaffinch from recent weeks. New birds today, 48 Chaffinch, 29 Meadow Pipit, 3 Chiffchaff, 3 Blue Tit, 2 Goldcrest, 2 Coal Tit and singles of Great Tit, Goldfinch, Robin, Lesser Redpoll, Dunnock and Blackcap.

Chiffchaff

Goldcrest

Chaffinch – adult male

Lesser Redpoll

The throughput of Chaffinches from north to south was very marked today, with larger groups than of late and sometimes up to 10 or 12 individuals, which led to an overall count for the 6+ hour session of approximately 600 birds. The Meadow Pipit passage was slightly less than last Thursday with today’s count being 300+ birds, but again a mid-morning peak. There is a marked sexual difference in Meadow Pipits but one of today’s males was quite enormous, with a wing measurement of 90mm, significantly above the quoted range in Birds of the Western Palearctic (BWP). This bird just has to be of Icelandic origin.

We are now seamlessly into the swing of ageing Meadow Pipits, a process which is easier than determining their age in spring. However to accurately age any species it is essential to have a thorough knowledge of the moult and wear of those species’ feather tracts and a grasp of the general principles of ageing. If it is a species we don’t see in the hand very often a copy of “Svensson” or “Moult in Birds” are always to hand, books which give invaluable guidance. Both of the above mentioned books are actually invaluable to bird watchers who might want to spend time ageing species in the field through a telescope, but to bear in mind that some of the feather tracts or other features described may be invisible on a closed wing or tail.

”Svensson”

Moult in Birds

In the case of Meadow Pipits we have many years of experience with them to recognise the features of an adult’s complete post-breeding moult, or the partial moult of a juvenile bird where it replaces some only of its feathers. We also take into account the fact that in the north of their wide range an adult Meadow Pipit moult may take several days less than a typical UK Meadow Pipit, and in addition allow for the fact that Meadow Pipits may have two or more broods of young; the young birds could have been born anytime between the months of April/May and August, and depending upon their places of origin and date of birth, apparently identical juveniles may actually show quite differing amounts of feather wear and/or replacement.

The photographs below are from today, a recently fully moulted adult Meadow Pipit with the same age of feathers throughout the wing structure, and below that an image of a juvenile wing with a mix of recently grown adult type feathers and its retained juvenile “summer” feathers.

Meadow Pipit - adult

Meadow Pipit - juvenile

Once again our busy ringing session meant missing some of the visible migration, but we noted 37 Snipe, 20+ Skylark, 35+ Siskin in 3 separate groups, 20+ Lesser Redpoll, 3 Sparrowhawk, 180 + Swallows and 6 House Martin.

“Locals” included 2 more Sparrowhawks, 9 Buzzard, 2 Tawny Owl, 40+ Goldfinch, 20+ Linnet, 2 Kestrel, 3 Jay and 2 Great-spotted Woodpecker

7 comments:

Christian said...

Fantastic count of raptors and owls today Phil. In response to your comment on my blog, not one person as asked me about the LEO's whereabouts, so there has been no pressure to reveal the location, which is great. I haven't seen it myself since mid July, so I hope he/she is doing well.

Paco Sales said...

Un bello plumaje el que tiene el pinzon, un sábado de buenas capturas, el tiempo acompaño y lo aprovechastes, un abrazo Phil

Seasons said...

Hello Phil. The adult male Chaffinch and the Lesser Redpoll immediately caught my attention, certainly for their beauty. I would imagine, that close observation of flight pattern of certain species might help distinguish a juvenile from an adult. It's merely conjecture, and also a question. Thanks for yet another enjoyable post.

Phil said...

Hi Seasons and thanks for your appreciative comments. I am not certain to what you allude iro flight patterns but to all intents and purposes and at this time of year, juveniles and adults of many species can look superficially alike and it is only in the hand that they can be separated with any certainty.

EG Wow said...

A bird's wings are so beautiful when spread out!

Seasons said...

Phil, thanks for answering my vague question. I try to avoid long comments. Anyway, you understood.

Chris said...

So you got one of our mipits ;-)? Heye maybe you should give me its ring number ;-) Now pipits are gone from here but we do not stop to get new coming mgirants! Got three new species in two days ;-) Among which a northern parula this morning, that was gorgeous ;-)

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