Monday, 29 February 2016

Oxwich Late February Ringing: finches and a wisp of snipe

This week has seen relatively light easterly winds and settled weather.  As such, we managed to get in two short sessions.  During both of these we put a single sixty foot net adjacent to the feeders, while during the second session, on 28 February, we also put out some nets in an area used by day roosting snipe.

The combined catch is broken down in the table below:

Species
New
Recaptured
Total
Snipe
3
0
3
Great Spotted Woodpecker
0
1
1
Wren
1
1
2
Robin
1
0
1
Goldcrest
3
0
3
Coal Tit
1
0
1
Blue Tit
4
8
12
Great Tit
1
5
6
Chaffinch
13
4
17
Greenfinch
3
3
6
Goldfinch
8
12
20
Siskin
15
17
32
Reed Bunting
0
4
4
Total:
53
55

108


The features of the catch have been continued good numbers of finches and three snipe. We have seen an early influx of siskins to the feeders this year, and have already ringed 47 in 2016 (in 2015 we did not start catching siskins until April while in 2014 they started to be captured in March).  

As water levels have now dropped somewhat in the marsh, we were able to access one of the areas in which we have previously captured snipe, a rush-dominated freshwater marsh between an open area of water and the reed bed. 

Common snipe

Common snipe
Although the area had held at least 30 common snipe and three jack snipe the day before, during the ringing session the numbers were more modest, and we only captured three common snipe. We did so by walking through the area and flushing the birds into nets, which we erected along the reed bed edge.

After catching snipe comes the annual challenge that is attempting to age them.  Snipe can be aged on the basis of the pattern and edging of the median and lesser coverts and the degree of wear in the primaries (Prater et al., 1977).  Further illustrated information is available from a number of other sources, including the International Wader Study Group (Wlodarczyk et al., 2008).

Having scrutinised our birds, and concluded one was likely to be an adult and the others first winters, we considered how confident we were in our conclusions before fouring them all (i.e. noting them as being birds of unknown age but not fledged in the current calendar year).  As always, there is absolutely nothing to be gained by educated guesswork - we simply haven't seen enough of these birds to have become comfortable ageing them as yet, albeit we would hope to become more proficient over time.  It would be good to catch a couple of our ringed birds from previous years, both to begin to get an indication of the size of the local reference population and to see birds that we know are in adult plumage in the hand.

Thanks to all who have made it out for one or both of the last couple of sessions: Keith Vaughton, Heather Coats, Paul Aubrey, Wayne Morris, Emma Cole and Becky Phillips.

Owain Gabb
29/02/2016

Friday, 19 February 2016

Oxwich Marsh 18 Feb 2016: an eventful morning

A bright, clear, still day.  We put up a single net close to the feeders, as there remain few birds in the reed bed and ponies are currently grazing the open fields and have access to adjacent net rides.

The catch was relatively predictable, being dominated by finches with the odd locally resident tit and a dunnock thrown in.  Looking back at data for the last two years, we didn't start capturing siskin until March in 2014 and April in 2015, so capturing 39 unique birds to date (including recaptures from previous years) is great.  It will be interesting to see if we have an earlier first brood this year.

The day total was as follows:
Species
New
Recaptured
Total
Dunnock
0
1
1
Blackbird
1
0
1
Blue Tit
0
3
3
Great Tit
2
2
4
Chaffinch
10
3
13
Greenfinch
4
0
4
Goldfinch
13
6
19
Siskin
10
6
16
Total:
40
21
61

Following packing up, Darren's car refused to start, which was the eventful part of the day. An electrical wiring problem resulting in a lack of power to the battery was subsequently diagnosed and fixed by the AA four hours later (only three and a half hours later than they had promised to arrive). He spent the intervening period running between the gate to keep an eye out for the breakdown truck and his car, which the ponies had taken a liking to!

I will be delivering a talk, on behalf of Gower Ornithological Society on Ringing at Oxwich 2013-2015 at the Environment Centre, Pier St, Swansea on Friday 26 February at 19:00.  The cost is £1 on the door.  Everyone welcome.  

For more info about GOS events see: http://www.glamorganbirds.org.uk/gos-events.html

Some photos taken by Keith Vaughton are below.

Female greenfinch
Male chaffinch
Thanks to Keith Vaughton and Darren Hicks for running the session.

Owain Gabb
19/02/2016

Monday, 15 February 2016

Oxwich Marsh 14 February: an influx of finches

The first ringing session in a while, following a couple of weeks of rain and wind.  Over the past few days the wind had swung to the east, and although it was not as light as forecast, we were able to get a session in.  It was a cold, relatively bright morning with a light to moderate south-easterly breeze.

The catch of 70 birds was as follows:

Species
Ringed
Recaptured
Total
Dunnock
0
1
1
Blackbird
0
1
1
Blue Tit
2
2
4
Great Tit
3
4
7
Chaffinch
3
1
4
Greenfinch
2
1
3
Goldfinch
20
8
28
Siskin
17
4
21
Reed Bunting
1
0
1
Total:
48
22
70

The features of the catch were 21 siskin and 28 goldfinches, most of which were newly-ringed.  All of the birds were captured in a single 60-foot net.  It was nice to see a number of returning siskins from 2015, including the male (below).  We aged this bird as a 6 (hatched before last calendar year but exact year of fledging unknown) based on the criteria listed in Svensson (1992), some of which are illustrated in the photographs below.  IPMR Data later revealed that the bird was initially ringed as a 5 (a first winter / second calendar year) when first captured in the late winter of 2014/15.  

Siskin (male)
Siskin (male) showing relatively broad and largely unworn tail feathers typical of an adult as opposed to a juvenile.  The tertial tips are also visible at the top of the photo. In first winter birds the tertials are often unmoulted, and do not show the smart broad white fringes visible here.
Close up of the greater covers showing the uniformity in colouration across them
Most first winter goldfinches can be aged on evidence of moult limits in the wing (with the most straightforward to age having retained greater coverts), and the shape of / wear in the tail feathers. Some are challenging, however, such as the goldfinch shown in the following pictures.  This bird had moulted its tail completely, and showed rounded, unworn feather tips.  However, close inspection of the wing suggested that the alula feathers and primary coverts had been retained.  The bird had also moulted most of its primaries and secondaries, and moult of these feathers is more typical of adult than juvenile birds. However the three outer primaries had not been moulted (as is clear from the photo below); they were markedly shorter, bleached and also showed different tipping:

Goldfinch wing showing three retained primary feathers.  The bird also appeared to have unmoulted alula feathers and primary coverts.
Tail of goldfinch (no juvenile feathers present).
We concluded that this bird was aged 5 (a first winter bird), but had undergone an extensive post juvenile moult including some of the primaries and secondaries, but would be happy to hear any thoughts.  

Thanks to the team of Heather Coats, Wayne Morris, Emma Cole and Val Wilson for company and assistance yesterday.

Owain Gabb
15/02/2016