Monday, 7 July 2014

Oxwich Marsh 5 July 2014: a couple of six year olds

The weather forecast had not given cause for optimism, but in the event there were light winds and we lost only 45 minutes to a prolonged heavy shower.  This, and strong sunlight late morning resulted in a reduction in the catch to a total of 87 birds (124 were caught during the previous week).

The catch was as follows:

Species New Re-trapped Total
Wren 2 1 3
Dunnock 5 0 5
Robin 2 3 5
Reed Warbler 3 1 4
Whitethroat 1 0 1
Blackcap 5 0 5
Blue Tit 7 6 13
Great Tit 6 9 15
Chaffinch 12 2 14
Greenfinch 4 3 7
Goldfinch 8 2 10
Reed Bunting 4 1 5
Total: 59 28 87

The birds were predominantly fledglings, but we also had a few old stagers: a reed warbler and a reed bunting first ringed as adults in August 2009 (so at least 6 years of age by next month) were trapped, as was a blue tit that was initially ringed (as a first winter) in October 2009 (and therefore likely to be just over 5 years of age). 
 
The most welcome other features of the catch were juveniles: a whitethroat, five blackcaps, three reed warblers and four reed buntings amongst them.   Many of the young birds were in entirely juvenile plumage, and were given the age and moult code 3JJ, with some of the tits and robins (in particular) having recently begun their post juvenile moult (age and moult code 3JP).   '3' refers to a young bird hatched during the calendar year.  'J' indicates they are predominantly in juvenile plumage, with the second 'J' confirming the plumage is entirely juvenile.  If the second J is replaced by a P ('3JP') this indicates some post juvenile moult has started.
 
All blackcaps were in entirely juvenile plumage bar one.  In this bird the post juvenile moult was very advanced: it was moulting its greater coverts, the crown was black (indicating a male), the tail and wings were fresh and the feathering of the tail was narrow and pointed.  This combination of features indicated it was a young bird reaching the end of its post juvenile moult, and therefore must have fledged some time before the other young birds we trapped.  Pictures are below:
 
The gap in the greater coverts is visible here. The primaries are fresh, with the outers already having a small amount of wear.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

The bird was clearly a male.  It retained a couple of brown flecks on the head, and various feather tracts on the body were also being moulted.
 
 
 
 
 
 
 
 
 
This was the day we went over 1000 new birds for the site in 2014 (over 1600 birds have now been trapped in total at Oxwich in 2014).  Thirty-one species account for this total.  A breakdown is below:
 
Species New Re-trapped Total
Sparrowhawk 1 0 1
Woodpigeon 1 0 1
Kingfisher 2 0 2
Great Spotted Woodpecker 8 19 27
Swallow 1 0 1
Wren 16 19 35
Dunnock 20 26 47
Robin 26 26 52
Stonechat 2 0 2
Blackbird 7 7 14
Cetti's Warbler 3 4 7
Grasshopper Warbler 1 0 1
Sedge Warbler 8 2 10
Reed Warbler 17 4 21
Whitethroat 3 0 3
Blackcap 66 2 68
Wood Warbler 1 0 1
Chiffchaff 13 0 13
Willow Warbler 10 7 17
Goldcrest 2 1 3
Long-tailed Tit 1 1 2
Coal Tit 3 0 3
Blue Tit 117 127 244
Great Tit 66 93 159
Magpie 1 0 1
Chaffinch 84 25 109
Greenfinch 192 50 242
Goldfinch 220 53 273
Siskin 60 55 115
Bullfinch 3 3 6
Reed Bunting 87 60 147
Total: 1042 584 1627
 
The personal highlights, half way through the year, have been the first wood warbler trapped at the site, the two stonechats, the numbers of finches (particularly the goldfinches and greenfinches), a French-ringed reed warbler, a spring grasshopper warbler, and the good numbers of reed bunting we have trapped.  The biggest year for reed bunting at Oxwich was 2009, when 160 new birds were ringed.  It is looking like we might get to that sort of number in 2014.
 
Autumn warbler migration is almost on us, so other target will be to beat the 122 reed warbler and 65 sedge warbler trapped in 2013.  Seems like a long way to go at present, but a few good sessions change things very quickly!
 
Thanks to Heather Coats, Charlie Sargent and Keith Vaughton for their company and assistance on Saturday.
 
Owain Gabb
07/07/14

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