Sunday, 26 June 2016

Oxwich Marsh 25 June: more fledglings

A still but overcast morning with rain forecast to come in late morning, and a small team left us putting up less net than usual, restricting ourselves to 400 feet in the reed bed and 60 foot in the scrub near the feeders.  A northerly breeze stiffened through the morning, and nets were down by 11:00am.  With rain falling on the drive out of Gower, we’d made the right decision.

Species
New
Recaptured
Total
Great Spotted Woodpecker
2
1
3
Wren

2
2
Robin
2

2
Blackbird
1

1
Cetti's Warbler
1

1
Grasshopper Warbler

1
1
Sedge Warbler

1
1
Reed Warbler
2

2
Blackcap

1
1
Chiffchaff
4

4
Willow Warbler
2

2
Blue Tit
4

4
Great Tit
18
4
22
Chaffinch
13
7
20
Greenfinch
6

6
Goldfinch
13
3
16
Siskin
1
1
2
Reed Bunting
3
2
5
Total:
72
23
95

Grasshopper warbler
We opened the reed bed nets to the sound of a Grasshopper Warbler reeling close by, so it was of no surprise that the first bird extracted was a retrap, perhaps proving this species is again breeding in the Marsh.

The features of the catch were the high proportion of juveniles of most species processed during the morning.  This included the first young Cetti’s Warbler of the year.  Cetti’s is a species we hear regularly with its characteristic song burst while skulking in the scrub and reeds around the Marsh, and it’s rewarding to once more prove breeding.  Juvenile finches were ever present at each net round, with a good number of young Chaffinches of note.  Of the Great Tits trapped, only one was an adult.

Of the juveniles caught, most were coded as 3JJ indicating that they were yet to commence their post-juvenile moult.  In contrast, two adult Willow Warblers processed at the same time showed differing moult scores, looking very different in appearance in the hand.  One was yet to commence moult having severely abraded primaries.  The second bird was in main moult, replacing flight and body feathers.  Willow Warbler is the only British species that undertakes a full moult twice a year. Adults moult soon after breeding, with the new feathers grown not being of very high quality and adults and first-years undergo a complete moult in Africa. This ‘winter’ moult occurs just before the birds start spring migration north.

Willow warbler
Both our birds were dark-legged and not especially green or yellow in appearance.  Wing formulae and supercilium length aided identification, but highlights the need for caution when attempting to separate Willow Warbler and Chiffchaff in the field without any auditory or behavioural cues to help.

The retrapped Blackcap was a male and aged as code 5, i.e. a bird hatched in 2015.  It had a black cap, one retained old greater covert and worn and pointed tail feathers, yet to be replaced.

A rewarding session, with a good total considering the nets erected and duration. 

Thanks to Darren Hicks for keeping the feeders stocked during the week.

Today's team was comprised of Heather Coats, Paul Aubrey, Val Wilson and Wayne Morris.

If you would like to understand what it takes to become a ringer and/or are interested in joining the Group, please leave your contact details in the comments box at the bottom and we will get back to you in due course.

Wayne Morris
26 June 2016

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