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

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