Monday, 24 August 2015

Oxwich Marsh 23 August 2015: first swallow roost of the year

Another unsettled period of weather drew to a close yesterday.  However three days of heavy rain left its mark in the marsh, with water levels in the rides higher than at any time during the preceding winter.  

Despite this, however, we put out nets in the fen meadow to catch roosting swallows, and an additional (optimistic) three nets on a raised earth bund to see what was moving between the bracken on either side.  We only left these latter nets up for about an hour.

Sunset was around 20:20, but the swallows didn't come in until almost an hour later, and the flock took a long time to build.  The house martins that had been so numerous in the area when we arrived at 18:00 had long disappeared, but as usual there were a few sand martins mixed in.

The catch was as follows:

Species New Re-trapped Total
Sand Martin 4 0 4
Swallow 86 0 86
Wren 0 1 1
Sedge Warbler 1 1 2
Reed Warbler 4 1 5
Whitethroat 1 1 2
Blackcap 0 1 1
Blue Tit 0 3 3
Great Tit 0 1 1
Total: 96 9 105

Of 86 swallows captured, 15 were adults.  A few swallows came in early, and we took full biometrics on them, but after dark we only recorded detailed information from the adults (age, wing length, total tail, tail fork and weight).    The swallow flock was not as large as at this time last year, when the equivalent session resulted in 128 swallows and one sand martin being captured.  The sand martins are always a pleasant bonus: we had one adult and three juveniles during this session.  All the late swallows and the sand martins were over-nighted in purpose built boxes, and released at dawn the following day.

A second bonus was that the bund nets paid off with a little bit of warbler action.  Nothing unexpected, but enough to keep things interesting, with four new reed warblers alone making the effort worthwhile.  However, all silver linings have their cloud, and the capture of no fewer than six dor beetles and a common pipistrelle (which was duly extracted by a gloved Paul) along with the swallows provided it.  The beetles are very difficult to extract and frequently get very tangled.

A team tonight of Phil Mead, Heather Coats, Darren Hicks, Wayne Morris, Paul Aubrey and Keith Vaughton made the session go very smoothly.

Some pictures taken by Paul are below.

Owain Gabb
24/08/2015


L-R: Phil, Darren and Wayne, with Keith in the foreground

Taking a swallow wing length
One of the 72 young swallows ringed last night

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