Monday, 4 February 2019

Meisen Wood: At Last



January 25th 2019
Nets: 39m
Weather: -2C rising to 3C
Ringers: CS

Well, the weather here has been miserable since the New Year: consistent rain and drizzle occasionally punctuated by snow whose accompanying frosts have plummeted the temperatures to -9C; a typical dreary start to a new year on the north German Plain. 

Despite the persistent precipitation Meisen Wood has not been without avian interest.  Tawny and Eagle Owls have been regularly calling at sunrise and sunset; male Black Woodpeckers have started their territorial drumming on dead beech trees; and a host of passerines have started singing.  The activity around the feeding stations has been frenetic with the movement of tits, finches, nuthatches and woodpeckers being reminiscent of speeded up footage of aeroplane arrivals and departures at a major airport; a most welcome blizzard of colour on dreary grey days.

With the weather forecast indicating a minor respite in the gloomy weather for Friday, CS took the opportunity to stretch some nets for the first time this year.  And though unpredicted sleet brought an early close of play, the year’s first session was a decent one:

Species
Ringed
Re-trapped
Total
Blackbird
1

1
Blue Tit
2
9
11
Brambling
18

18
Chaffinch
1
2
3
Great Tit
4
11
15
Greenfinch
1
2
3
Long-tailed Tit

2
2
Marsh Tit

3
3
Nuthatch

3
3
Redpoll
1

1
Robin

2
2
Total
28
34
62

The ratio of new to re-trapped birds was on a par with previous years; though this year’s new ringed birds were bolstered by a good catch of Brambling.  Recently there have frequently been eighty to a hundred of these colourful finches at the feeders; and locally at least there seems to have been a small invasion of Brambling; though these numbers do not compare to those currently being recorded in central Europe where counts of five to ten million have recently been noted. 

Catching these northern finches is a pleasure at two levels: aesthetically because of their stunning colours; and scientifically as we often control birds from both ends of their migratory path – south west France and northern Scandinavia.  Despite their nomadism it is pleasing to know that Meisen Wood is on their migratory route.  The day’s Brambling data was interesting too in that most individuals had fat scores from two to four but quite a number had muscle scores of zero.  Potentially this indicates that these birds are not yet physiologically prepared to move on.

Of particular interest in today’s totals were several re-traps, particularly: two Greenfinch, and one each of the Long-tailed, Blue and Great Tits. 

Both the Greenfinches had been originally ringed in spring 2017, with one of them being re-trapped last spring.  Clearly, for this species, we are on their migratory route too; though quite where this route’s terminals are remains unresolved.  The German Migration Atlas shows many Greenfinch wintering in Belgium down to southern France; also these birds include German and southern Scandinavian breeders.  Several Greenfinch ringed by us have been controlled near Hamburg but whether these individuals were still on passage or breeding is unclear. 

The Long-tailed Tit had originally been ringed in September 2016 and has not been re-caught since.  Back then it had been aged as a 2.  This does not mean it was two years old.  The age code 2 means that ringers cannot say with certainty when that individual hatched.  Some ringers derisorily, and unfairly, describe this age code as a cop-out. Ageing birds is based on moult: when a bird moults; which moult strategy that species follows (of which there are several); and as a simple corollary to those points, the time of year.  Long-tailed Tit adults perform a complete post-breeding moult which is finished by late summer.  Juvenile Long-tailed tits undergo a complete post juvenile moult also finished by late summer.  Thus by early autumn there is no plumage difference between adults and juveniles so the ornithologist cannot say that the bird was born that year or in a previous year. That is not a cop-out but an honest recording of the in-hand observations.  So this re-encountered Long-tailed Tit was at least two and half years old, and possibly older, pretty impressive for such a small bird.

Two other birds extended the theme of being re-trapped for the first time since their initial ringing: a Great Tit and a Blue Tit.  Both had been ringed as nestlings in May 2015.  Their recapture the other day is interesting at several levels: it illustrates that mist netting, can be in certain circumstances, considered as a random sampling technique which gives strength to any statistical analysis through removing bias.  Also these two re-captures beg the question: where have these birds been in the interim years?  This question is a prime example of the fact that there is still much we do not know about the lives of birds, including common ones.  This, and other simple questions, will eventually be answered through ringing studies.

The weather forecast for the week ahead is mixed, mixed precipitation that is, with perhaps a small window of opportunity for ringing mid-week.  Fingers crossed!

Foot-note:  during Lynne and Johne’s visit in early November we captured a Swedish ringed Goldcrest.  We have just received notice that this individual was ringed nineteen days earlier at Hammaron Ringing Station, on Lake Vänern some 858km distant from here. 


Friday, 11 January 2019

December 2018 - Wilstone Reservoir



So to the end of the 2018. December could not match November for numbers and variety but we still had a reasonable amount. There were six new Chiffchaffs, one of which was retrapped, 42 Redwings and a single Fieldfare and a selection of the usual suspects (see table below).

Intriguingly, we did catch a Female Cetti's Warbler that seems to be choosing Wilstone as an over-wintering site. First ringed as an adult during the winter of 2013, she has been retrapped on at least one occasion every winter since. There has not been a territorial male at Wilstone for the intervening years so I think it unlikely that the female has been living in the reed bed all year round and just venturing into the study area in the winter.


New
Retrap
Total
Blackbird
2
2
4
Blue Tit
2
2
4
Bullfinch

1
1
Cettis Warbler

3
3
Chaffinch
2

2
Chiffchaff
6
1
7
Dunnock
2
1
3
Fieldfare
1

1
Goldcrest
3
3
6
Goldfinch
1

1
Great Tit
3
1
4
Kingfisher
1

1
Long Tailed Tit
7
10
17
Redwing
42

42
Reed Bunting
2

2
Robin
1
2
3
Siskin
2

2
Song  Thrush
1

1
Treecreeper

1
1
Wren
3
4
7




Total
81
31
112

Meisen Wood: Year’s End



Date: December 2018
Ringers: CS and EB

After Lynne and Johne’s enjoyable visit in early November little ringing was done until December.  This is usual in November when we typically lose two or three sessions because of The Fall – a wonderfully apt Americanism.  If we were to ring during this period the majority of the time would be consumed with the tedium of extracting gorgeously coloured leaves from the nets.

Despite the dearth of ringing, Meisen Wood is a delightful place to be during this period. The meadow is briefly quilted with rich yellow, gold, brown and scarlet leaves.  The upper woodland paths become thickly carpeted with a plush layer of golden-brown larch needles.  While on the frequent damp, overcast days, the incandescent blotches of golds and reds from the trees not yet stripped of their leaves is accentuated.  This is also a fungally rich time with earthstar constellations, dripping inkcaps, scarlet agarics, rich red-brown boleti and various sulphur coloured toadstools.  Meanwhile the red squirrels are actively burying seeds, nuts and acorns in the meadow; and increasingly birds are coming to the feeders. 

Above all this obvious avian migration continues: with skeins of White-fronted Geese and noisy flocks of Cranes winging their way towards their wintering grounds.  And this year we have observed a major movement of Brambling, on one morning more than two thousand flew over. Two ringing sessions at November’s end, few leaves needed extracting, and the figures (not shown) reflected this Brambling movement with 36 ringed.  The final November session was notable as being the first since early September when the number of re-trapped Great Tits outnumbered new Great Tits.

This autumn we have ringed 413 new Great Tits, such a large number being a consequence, in part, of serendipity.  Inexplicably one of our sound systems slipped to playing Great Tit calls and with the adjacent net containing many of those tits a change in tactics ensued.

The Great Tit captures are intriguing at several levels.  Most Autumns, for two or three weeks, we capture males with notably longer wing lengths of 81 to 83mm compared to the normal 78 – 79mm range; this cohort contained some of the larger winged males.  Thus, according to Bergman’s Rule, these individuals could potentially be migrants from more northerly latitudes.  An intruding caveat to this theory is 63% of the captures were juvenile females which the scientific literature indicates as being dispersal: males stay on territory and unpaired females disperse.  Though many Baltic Ringing Stations this autumn ringed large numbers of Great Tits, therefore do these captures indicate a migratory or an irruptive movement? 

Given the literature’s somewhat equivocal stance and Nature’s delightful capacity to not be easily categorised, the numbers probably reflect a mixture of migration, dispersal and irruption.  Further the Devil’s Advocate’s hand would state: there has always been a Great Tit passage through Meisen Wood but because you did not play the appropriate sound lures you were oblivious to its intensity!  Um, a good point, to be examined in future years!

By Advent we have normally resumed our standardised ringing effort and this year was no exception, December’s totals are shown in the table below:



Species
Ringed
Re-trapped
Control
Total
Blackbird
3
3

6
Blue Tit
59
36
1
96
Brambling
58
6

64
Chaffinch
23
4

27
Coal Tit
12
9

21
Crested Tit

2

2
Goldcrest

1

1
Great Tit
19
81

100
Greenfinch
44
4

48
Long-tailed Tit
1


1
Marsh Tit
1
20

21
Nuthatch
2
2

4
Robin
1
2

3
Treecreeper

1

1
Willow Tit

1

1
Total
223
172
1
396

Good numbers of Brambling, Chaffinch and Greenfinch acquired rings.  Normally throughout the winter we catch a dribble of Chaffinch, a smattering of Greenfinch and it is noteworthy if we see a Brambling before March.  Various sources report a Brambling invasion this winter which is reflected in our catches and observations.  And, superficially at least, it would appear that there has been a good movement ot the other two finch species too.

Entering the year’s final data into the Heligoland data system allows for reflection on some of the data we have collected; or not as the case maybe. 

With 3636 newly ringed birds this has been, for us an outstanding year’s ringing; that figure is more than double our yearly average.  Within that figure it was pleasing to note that we ringed a good number of Blue Tits this year, who unlike in 2017, seem to have had a good breeding season.  A situation reflected across much of northern Europe with high numbers of Blue Tits being ringed in Scandinavia and in the Baltic States; one of which, wearing a Lithuanian ring, we caught in the year’s penultimate session.  The German Ringing Atlas shows many Blue Tits originating from the Courish Spit (shared by Russia and Lithuania) migrating to western Germany and the neighbouring Netherlands.

Sadly our figures show some apparent breeding failures.  During 2018 we hardly ringed any Wrens, Dunnocks or Chiffchaffs!  Within Meisen Woods we found two predated Wren nests.  Despite two Chiffchaffs chiff – chaffing all spring and summer we captured no females or juveniles during the breeding period.  At the time we commented on how long the two males were singing; did they both fail to attract mates?

The 3636th bird was, appropriately, a resplendent male Brambling whose head feathers were already wearing away to their stunning dark head plumage of summer.  Now with each day getting fractionally longer this Brambling, hopefully, augers well for a good ringing year ahead. 

Happy New Year!