Monday, 25 December 2017

Between the Glühwein

Meisen Wood: various December dates.
Nets: varied between 18m and 39m.
Sound: Crested and Coal Tit (on two occasions).
Ringers: CS, EB and JL (visiting from England).

Species
Ringed
Re-trapped
Total
Blackbird
5

5
Blue Tit
10
21
31
Chaffinch
5
1
6
Coal Tit
1
13
14
Crested Tit

1
1
Dunnock

1
1
Great Tit
18
26
44
Greenfinch
1

1
Long-tailed Tit
1

1
Marsh Tit
1
4
5
Nuthatch
1
3
4
Robin
1
1
2
Total
44
71
115


The continuous dreick weather of November, the snow of December combined with family commitments in northern England and elsewhere in Germany have limited the ringing in Meisen Wood for several weeks now.  A situation deliciously compounded by visitors (including a ringer) from England, who like us, enjoyed the pleasant atmosphere of local Weihnachtsmärkte and the compulsory glugging of numerous Glühweinen along with other traditional, alcoholically laced beverages.  Between these fine indulgences a few short ringing sessions were run and the table shows the combined results.

For JL, who normally rings few passerines, the sessions were rewarding in several ways.  His joyful whoop on a net round in finding a re-trap Crested Tit was quite delightful.  He then processed the bird which was his first ringing encounter with this species.  He was pleasantly reacquainted too, on four occasions, with Marsh Tits; a species he believes he has not handled for eight or nine years.  While his comments on the weights of the Great Tits and Blue Tits are best summarised by the English idiom: little fat ________! 

Throughout the winter we record fat and muscle scores.  We find that Great Tit, Blue Tit, Greenfinch and Chaffinch pile on the fat with the fat scores rising during the day thus, late on, they are usually high up the obesity index.  Contrastingly we find Coal and Marsh Tits have low or even zero fat scores but their weights do increase during the day.  Coal and Marsh Tits caught late in the day typically being 10% heavier than those caught in the early net rounds; presumably their energy reserves are being stored elsewhere in the body e.g., the liver.  This winter fattening/weight gain is a clear physiological adaptation for the birds to survive the long winter nights and is unrelated to migration.   

Our Coal Tit numbers this year are 135% higher than previous years.  The Coal Tit (in Germany at least) is considered to be a partial migrant and irruptive consequently this would appear to be an irruptive year.  One of the re-trap Coal Tits was originally ringed in December 2015 and aged, then, as a 4.  This was the first time it has been re-caught thus making it at least three years old which is above the typical two year life expectancy for the species.

Nuthatches, according to many Belgian and Dutch studies, are strongly territorial and sedentary species exhibiting nest site and mate fidelity; with a change in mate only occurring when one of the pair dies.  Coming onto our ringing site are three territories with a fourth bordering the very south-eastern edge of Meisen Wood.  Consequently we catch few new Nuthatches and thus are wondering which of the six we regularly re-trap has possibly died?  Though given that they too have an average life expectancy of two years then ringing an occasional new nuthatch simply reflects the dynamic nature of wildlife.

Looking at Christmas and New Year family commitments, and the weather forecast this is probably about it for ringing in Meisen Wood for 2017.  So on that note:

Frohe Weihnachten und ein gutes neues Jahr euch allen!

(Happy Christmas and New Year to you all).


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