Sunday, 16 February 2014

Oxwich Marsh 16 February 2014

This morning saw the first ringing session at Oxwich Marsh for a month, following a sustained period of unsettled weather.  The rides were (predictably) almost knee-deep in liquid sludge, while an early covering of ice on the surface, made the experience like walking in a half frozen crème brûlée.  And to think I had been missing ringing ........

Male reed bunting
Although the feeders and bird table had been kept topped up, the catch was lower than in January.  The total of 37 birds was made up of the following: wren 1 (1), dunnock 2 (1), robin 1 (1), blue tit 13 (8), great tit 6 (5), chaffinch 1 (0), greenfinch 2 (0), goldfinch 1 (0) and reed bunting 10 (4).  The proportion of re-traps in the total for each species are indicated by the brackets.
 
The most pleasing element continued to be the numbers of reed bunting trapped.  Reed bunting is an amber-listed species of conservation concern in Wales due to a long term (moderate) decline in the Welsh breeding population.  There is a considerable data set held for the species for Oxwich Marsh.

The six new reed bunting trapped today, and the four re-trapped birds brought the total of new birds to 20 (only 36 new birds were ringed in 2013) and 'unique birds' to 26 in 2014.    As can be seen from the photos above and to the right, most male reed buntings are now starting to come into breeding plumage, with the striking black head feathers wearing through. 
 
Ageing reed buntings can be difficult, and a proportion should probably always be left un-aged - as educated guesswork just creates data noise.  Ageing is primarily on tail shape and wear, but both adult and juvenile tails can be very worn by February (this makes sense given the habitats they occur in), so tail shape is probably the more useful feature.  The shape of the tip of the fifth tail feather is suggested by Svensson as being the most reliable for separating 1st winter from adult birds (juvenile birds have a more pointed tip to the feather and a different shape to the final centimetre or so). 
 
Other than the reed buntings, it was good to continue to capture greenfinches, while a goldfinch was the first of the year to date.  Unfortunately, the pictures of the bird, and the features used to age and sex it were absolutely awful!

Thanks to Charlie Sargent for coming along.

Owain Gabb
16/02/2014.

No comments:

Post a Comment