Sunday, 15 May 2016

Oxwich Marsh 14 May 2016: fledglings and breeding grasshopper warbler

Despite consistent forecasts of very low wind speed on both the BBC and the Met Check websites all week, there was in fact a moderate south-easterly blowing throughout the morning. Overhead conditions were good (mainly cloudy), though, and we were able to put out a reasonable amount of net (780 feet in a mixture of scrub and reed bed habitats).

The marsh is typically quiet in May, with catches rarely approaching treble figures during a session, and the total of 57 birds today was about par. The catch broke down as follows:

Species
New
Recaptured
Total
Great Spotted Woodpecker
0
1
1
Wren
0
1
1
Dunnock
0
1
1
Robin
1
0
1
Blackbird
1
1
2
Song Thrush
0
1
1
Grasshopper Warbler
1
0
1
Sedge Warbler
4
1
5
Reed Warbler
3
0
3
Whitethroat
0
1
1
Blackcap
2
0
2
Chiffchaff
1
0
1
Blue Tit
0
3
3
Great Tit
0
3
3
Chaffinch
1
3
4
Greenfinch
5
3
8
Goldfinch
5
3
8
Siskin
5
1
6
Bullfinch
1
0
1
Reed Bunting
1
2
3
Total:
30
25
56

Juvenile greenfinch (Keith Vaughton)
The most interesting aspect of the catch was that fledglings of various species are now starting to come in. We had our first greenfinches, blackbird and robin of the year, with the former being the least expected (in 2014 the first fledged greenfinches were captured on 24 May and in 2015 on 30 May - so this is the earliest record by ten days). Siskin fledglings continue to visit the feeders, with the first recorded last week. More surprising, however, is that we are still catching un-ringed adult siskins, with the 135 different individuals processed in 2016 considerably in excess of the total for 2015 (58) and 2014 (62) already. If the birds are double-brooded again this year, we can expect them to stick around until July.

Juvenile blackbird (Owain Gabb). Note the ticks around the eye
The diversity of the catch was reasonable this morning, albeit the only notable species was grasshopper warbler. We captured 11 individuals in 2015, and are up to 3 so far in 2016. There have been regular reeling birds on site for some time now.. The bird we captured was a male, as it showed a cloacal protrusion, and it may be that this bird has taken up territory. We proved breeding in grasshopper warbler at Oxwich last year, through the capture of a male twice during the breeding season (if showed a cloacal protrusion when captured for the second time), a female with a brood patch, and finally recently fledged young. Hopefully we can do the same in 2016.

Thanks to this morning's crew of Heather Coats, Keith Vaughton, Cedwyn Davies, Wayne Morris, Emma Cole and Val Wilson.

Owain Gabb
14/05/2016

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