Monday, 29 May 2017

Oxwich Marsh 28 May 2017: breeding groppers

The morning of 28 May was ideal for ringing; warm and virtually windless with overcast skies. We set a total of 720 feet of net in a mixture of reed bed and fringing scrub.

The day total was 65 birds.

Combined captures since 7 May, when the last blog post went up, are as follows:

Species
New
Recaptured
Total
Great Spotted Woodpecker
3
22
25
Wren
0
3
3
Dunnock
2
10
14
Robin
18
7
25
Blackbird
3
2
5
Song Thrush
0
1
1
Cetti's Warbler
1
2
3
Grasshopper Warbler
2
0
2
Sedge Warbler
3
8
11
Reed Warbler
2
4
6
Blackcap
1
0
1
Chiffchaff
1
3
4
Long-tailed Tit
3
2
5
Blue Tit
4
4
8
Great Tit
1
11
12
Chaffinch
11
11
22
Greenfinch
8
3
11
Goldfinch
11
5
16
Siskin
21
20
41
Bullfinch
1
0
1
Reed Bunting
0
4
4
Total:
96
122
220

The highlights have been:
  • The regular capture of great spotted woodpeckers. We have a minimum of 15 different birds visiting the feeders at present based on regular recapture data.
  • Better numbers of juvenile robins than were apparent at this time in 2016. 
  • Two grasshopper warblers, both on 28 May. The first, a female with an engorged brood patch was a fairly pale-looking brown bird, the second a buff-yellow type bird that did not show a brood patch or a convincing cloacal protrusion, and was not sexed. Reeling has been heard intermittently over the past month, but it was unclear whether a territory was present or whether passage birds could account for this. The female proves breeding for the third successive year.
  • A gradual increase in the number of reed and sedge warbler captured. Most of the ten and seven unique birds respectively have been returning individuals ringed in previous years.
  • Our first young blue tit, captured on 28 May. Following two years of poor productivity, numbers of blue tits are well down on previous years at present.
  • A continued steady trickle of siskins (many of which have been juveniles) and other finches. Fledged greenfinch and chaffinch were noted by mid month, and the last two visits have seen several fledged goldfinches captured.
Unfortunately a persistently singing lesser whitethroat avoided the nets all morning on 28 May.

May has been a better month in 2017 than in the past few years, with 339 birds (as opposed to 187 in 2016 and 216 in 2015) captured. It appears that early-breeding double or treble brooded resident species have had a relatively successful first attempt. It is hoped that single-brooded tit species have done better this year, and it will be interesting to see how numbers shape up over the next couple of months.

Thanks to Val Wilson for company and assistance yesterday, and to Heather Coats, Keith Vaughton, Cedwyn Davies, Emma Cole, Sarah Davies and Ed Stubbings for variously running and contributing to sessions over the past few weeks.

Photos are below.

Owain Gabb
29/05/2017.

Grasshopper warbler 1. A brown female with an engorged brood patch

Grasshopper warbler 2. A yellowish bird of unclear sex.

An adult female blackbird showing an element of leucism.

A second calendar year bullfinch with several retained greater coverts

Fledged siskins show considerable variation in colour. This bird was captured alongside the bird below.

Fledged siskin


Sunday, 7 May 2017

Oxwich Marsh: 7 May 2017 and the year to date

Perfect conditions for the first few hours today, with a very light north-westerly wind that gradually strengthened and veered to the south. Net rounds returned a steady flow of birds.

The catch was as follows:

Species
Ringed
Recaptured
Total
Great Spotted Woodpecker
0
7
7
Wren
1
3
4
Dunnock
1
9
10
Robin
2
0
2
Blackbird
1
1
2
Song Thrush
0
1
1
Sedge Warbler
3
0
3
Reed Warbler
1
0
1
Whitethroat
2
0
2
Blackcap
1
1
2
Chiffchaff
0
2
2
Blue Tit
0
2
2
Great Tit
0
10
10
Chaffinch
1
2
3
Greenfinch
1
0
1
Goldfinch
0
2
2
Siskin
7
8
15
Reed Bunting
0
1
1
Total:
21
49
70

The features were:
  • A control (bird ringed at another site and recovered a Oxwich) chiffchaff on BTO Tring (as opposed to London) number. We will await the information with interest.
  • Six juvenile siskins (following the first juvenile bird being captured last week).
  • The first reed warbler and sedge warblers captured in 2017 (despite both being present on the marsh for over two weeks)
  • Seven different great spotted woodpeckers, leading to bloodied / scratched hands for all present.
  • Good between year survival data on great tit in particular.
With reference to the table below, it can be seen that the year to date has been a little quieter than the previous two years, despite high levels of effort. Totals of unique birds by species between 1 January and 7 May inclusive in each of 2015-2017 have been as follows:

2017
2016
2015
Sparrowhawk
0
2
0
Water Rail
0
1
0
Jack Snipe
6
5
1
Snipe
22
6
2
Green Woodpecker
0
0
1
Great Spotted Woodpecker
11
4
4
Swallow
0
0
1
Wren
12
16
11
Dunnock
20
16
19
Robin
8
8
15
Blackbird
13
8
5
Song Thrush
5
3
1
Cetti's Warbler
4
0
7
Grasshopper Warbler
1
2
1
Sedge Warbler
3
6
3
Reed Warbler
1
2
2
Whitethroat
4
1
1
Blackcap
7
5
14
Chiffchaff
13
11
7
Willow Warbler
2
5
2
Goldcrest
4
10
6
Long-tailed Tit
5
2
10
Coal Tit
2
4
0
Blue Tit
54
98
124
Great Tit
39
51
44
Treecreeper
0
1
1
Magpie
0
1
1
Chaffinch
39
88
99
Brambling
0
1
0
Greenfinch
28
40
104
Goldfinch
194
200
162
Siskin
85
123
15
Bullfinch
7
0
8
Lesser Redpoll
0
1
1
Yellowhammer
1
0
0
Reed Bunting
18
44
30
TOTAL
608
765
702

The main differences between 2017 and previous years are:
  • Higher captures of common snipe, reflecting better (drier) conditions in the trapping area and greater effort in 2017
  • Lower numbers of blue tits than in 2016, which in turn represented a considerable decline on 2015.
  • A decline in chaffinch numbers (which were relatively consistent in the previous two years) and a continued decline in greenfinch totals
  • Lower numbers of siskin than in 2016 (when we started capturing birds earlier), but far more than in 2015
  • Fewer reed buntings captured than in both of the two previous years. 
Two years of poor productivity (fledging success) in blue tits is clearly reflected in the results from the year to date. There are simply less blue tits around to capture. This may also be the case for greenfinch and chaffinch, as trichomonosis has clearly affected the populations of both locally in recent years. For reed bunting the reasons for the lower numbers than in previous years are not apparent, while siskin seems to vary in terms of when birds start visiting feeders and the duration of capture between years. 2016 was the best year to date, but we are well up on 2015 when the annual total was just under 60 birds.

Thanks to Val Wilson and Natasha Dodds for company and assistance this morning, and to Keith Vaughton for running a session in the week.

Owain Gabb
07/05/2017.

The first fledged siskin of the year

The first whitethroat

The iris of whitethroats changes colour with age. Adult birds typically have a hazel iris.

The first sedge warbler of the year
Head of sedge warbler