Sunday, 31 May 2015

Oxwich Marsh 30 May 2015: fledglings and a new species for the site

A light north-westerly breeze and open skies at dawn, with intermittent cloud during the morning.  Not bad conditions for ringing at all, so we attempted to get a good amount of net up - 860 feet in total.

The catch was a good one: a hundred birds of 21 species.

Species New Re-trapped Total
Great Spotted Woodpecker 1 2 3
Wren 0 8 8
Dunnock 0 4 4
Robin 3 1 4
Blackbird 2 2 4
Song Thrush 2 0 2
Mistle Thrush 1 0 1
Cetti's Warbler 0 1 1
Grasshopper Warbler 1 0 1
Sedge Warbler 0 3 3
Reed Warbler 1 0 1
Whitethroat 0 1 1
Blackcap 0 2 2
Blue Tit 2 3 5
Great Tit 6 3 9
Treecreeper 1 0 1
Chaffinch 6 4 10
Greenfinch 3 2 5
Goldfinch 12 8 20
Siskin 3 3 6
Reed Bunting 2 7 9
Total: 46 54 100

The highlights were: our first fledgling goldfinches, greenfinches and chaffinches of the year; juvenile song thrushes, blackbird and robin; a female grasshopper warbler with a well defined brood patch; a good session for reed buntings with 9 trapped; and, the star bird of the day (having not been captured on site previously), a mistle thrush.

The grasshopper warbler was caught in the same net as a male of the same species last week.  In the previous weekly blog post, it was noted that the male was in breeding condition (it had a cloacal protrusion) and was a bird initially ringed on the marsh a month or so before, so it seemed reasonable to assume breeding.  The presence of a female with a brood patch removes any residual doubt that breeding is taking place on the marsh.

Very few mistle thrush are ringed in Wales annually.  In 2013 the total was 10 birds (including 2 pullus).  Over the past year or two, we have started to catch the species relatively regularly however.  This is largely due to the efforts of Cedwyn Davies and Chris Newberry at Margam, but we recently also trapped the species on the Contant Effort Site at WWT Penclacwydd, and yesterday saw the first capture of the species at Oxwich.  The bird, a recently fledged juvenile, was trapped in a ride we created in the spring, and which runs through a mixture of semi-natural scrub and rhododendron next to the main channel through the marsh.  It had a wing length of 152mm and a weight of 102.2g.

It was also good to get a relatively high catch, as the weather appears to have been a real factor in limiting capture rates in recent months.  Overall, the total of unique birds captured is now similar to this time in 2014, albeit we have completed a good number more sessions.

Thanks to Heather Coats, Keith Vaughton, Charlie Sargent, Lyndon Jeffrey and Dan Rouse for company and assistance yesterday.

Photos of the mistle thrush, taken by Keith, are below.

Owain Gabb
31/05/2015
Juvenile mistle thrush

Juvenile mistle thrush

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