Saturday, 19 April 2014

Oxwich Marsh 18 April 2014

As there had been an influx of migrants over the previous few days, we decided to try and put out a bit more net than usual.  In addition to 160 feet of net in scrub / around the feeder, we put 180 feet of net into the reedbed and a further 240 feet of net along a bund running alongside one of the main channels (580 feet of net in total).  The weather during the morning was very pleasant, albeit a bit bright for ringing - the nets became very visible within the first few hours.

Female kingfisher
The dawn chorus was encouraging: both reed and sedge warbler had arrived in the reed bed in some numbers, a grasshopper warbler was reeling close by, there were occasional bursts of song from (the resident) Cetti's warblers, and as the morning went on we heard both whitethroat and cuckoo.  Willow warbler and blackcap song provided the backdrop, with both being abundant in nearby scrub.  Small flocks of finches remain at the marsh (mainly siskin and goldfinch), and these birds were also regularly heard commuting over, with the siskin occasionally bursting into chattering song.

The catch was relatively varied, with sixteen species trapped.  The breakdown was as follows:

Species New Re-trapped Total
Kingfisher 1 0 1
Great Spotted Woodpecker 0 1 1
Wren 2 1 3
Dunnock 1 0 1
Cetti's Warbler 1 1 2
Sedge Warbler 2 0 2
Reed Warbler 1 1 2
Blackcap 4 0 4
Willow Warbler 1 0 1
Blue Tit 1 1 2
Great Tit 0 3 3
Chaffinch 4 3 7
Greenfinch 6 5 11
Goldfinch 19 13 32
Siskin 9 9 18
Reed Bunting 4 6 10
  56 44 100

The highlights of the catch were the migrant warblers.  Two reed warbler and two sedge warbler were trapped: one of the reed warblers was a returnee from 2013 (having wintered in sub-Saharan Africa).  None showed significant residual fat deposits.  In addition, we captured a few blackcaps and a very nicely marked willow warbler.


Reed warbler
Sedge warbler
 

The showiest bird was a kingfisher.  This is the second bird to be caught at the site since ringing recommenced in 2013.  The bill colouration indicated that it was a female (approximately two-thirds of the lower mandible is orange in females - in males at least two-thirds is black).
 
Finches continued to proliferate, accounting for 68 of the total of 100 birds trapped.  Many were showing cloacal protrusions or brood patches, and it will be interesting to see how much longer they hang around.  The variation in the extent of post juvenile moult in siskins is very interesting - one bird had retained all of its greater coverts, with 2-4 retained greater coverts and retained tertials being normal, and the odd first winter bird retaining only its alula feathers and primary coverts.  The reed bunting total keeps ticking.  The target is 202 birds (including retraps), captured by Barry Stewart at the marsh in 2009.
 
The overall totals for the marsh for 2014 is shown in the table below:
 
Species New Re-trapped Total
Kingfisher 1 0 1
Great Spotted Woodpecker 1 3 4
Wren 3 6 9
Dunnock 5 10 15
Robin 1 6 7
Stonechat 2 0 2
Cetti's Warbler 2 3 5
Sedge Warbler 2 0 2
Reed Warbler 1 1 2
Blackcap 5 0 5
Chiffchaff 5 0 5
Willow Warbler 5 0 5
Goldcrest 2 1 3
Blue Tit 65 95 160
Great Tit 14 40 54
Chaffinch 37 6 43
Greenfinch 126 20 146
Goldfinch 166 32 198
Siskin 33 10 43
Bullfinch 3 2 5
Reed Bunting 66 34 100
Total: 545 269 814
 

Nearly all the birds were trapped in the scrub, with only 4-5 in the reebed and 2 in the bund nets.  We are still learning how to work the site most effectively!
 
Finally, we recently heard back about a great tit controlled at the marsh in late February.  While most tit recoveries tend to involve birds moving a few km, this bird (originally ringed in Briton Ferry) had moved approximately 25km (the straight line distance between the two areas).  While we would hope to record more significant 'controls' in 2014, this is of some interest nevertheless.

Many thanks to Cedwyn Davies, Charlie Sargent and Keith Vaughton for a very enjoyable session yesterday.

Owain Gabb
19/04/2014

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