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Ring readings of Black-headed Gulls Larus ridibundus in Riga
City ChannelA.Kalvāns, [email protected]
E.Lediņš, www.ledins.lv
Everybody knows that Riga Old City Channel is a boring place with some ducks flippering around and some gulls making noise all the time..
History of city channel gull research
First Black-headed Gulls with colour rings E.Ledins observed here in Year 2002.
Several years we discussed that it would be a good idea to pay them more attention (we both work in old city)
Digital cameras became more popular in the meantime
First ring readings A.Kalvāns did in 2008, continued in 2009. and 2010.
In 2010 E.Ledins also started to look at those gulls..
What’s in the treasury of City Channel?
During 2 years we got 30 foreign controls
Readings of rings from 12 countries
Approximately the same number of rings we did not manage to read completely.
Number of identified rings 2009 2010
Finland 1 0
Estonia 0 1
Lithuania 1 0
Poland 3 2
Sweden 2 2
Denmark 3 1
Germany 0 2
Czech Republic 1 0
Belgium 1 2
Netherlands 3 2
UK 1 1
Spain 0 1
Total 16 14
About inside of the observations
Number of colour rings is smaller, but those are easier to read compared to metal rings.
A.Kalvāns is more successful ring observer, despite the fact that E.Ledins has a longer lens.
Authors have to say that research has not bee made very deeply and that we have spent more time in clubs and pubs nearby than for watching gulls.
Number of identified rings 2009 2010
A.Kalvāns 16 7
E.Lediņš 0 4
AKa and ELe 0 3
Total 16 14
Kind of rings 2009 2010
Colour rings 6 4
Metal rings 10 10
Total 16 14
Vēl par niansēm
Information from Ringing Centre in the first year is sent to observer for every second bird; during two years we have received it for almost all birds.
The right time to hunt the rings starts when first Black-headed gulls arrive in Riga, and last till end of April.
Until March, 2011 2009 2010
Received data from RC or from the ringer 15 6
Not received data 1 8
Number of identified rings 2009 2010
24.march - 31.march 4 5
1.April - 10.April 9 2
11.April - 20.April 3 3
21.April - 23.April 0 4
Total 16 14
Some facts:
Age of observed birds varies between 1 and 18 years (observed also 12, 15, 16 years old birds).
Largest distance - 2331 km – young bird ringer in Barcelona Zoo.
Most interesting life story is for an 18 years 9 months old bird (white ring LKW) - seen in 6 countries!
A bird ringed in Poland seen in Riga in 20.04.2009. and 21.04.2010.
Average time from ringing moment
2009 4 years 4 months and 4 days n=15
2010 5 years 11 months and 27 days n=8
Average distance, km
2009 873 n=15
2010 1117 n=7
Black-Headed Gull ringed in Barcelona, young bird.
White LKW – “best life history ever...” (Frank Majoor) 1) Ringed as nestling in Estonia 2) Another metal ring received in Poland 3) Estonian ring lost between 2003. and 2006. 4) Colour ring add in Netherlands 5) Seen in 6 countries!! 6) Last photo 02.03.2011. Mauritskade, Amsterdam, Ruud Altenburg –see on right side!
The same birds during migration period can be observed in Old City Channel, river Daugava and Getliņi rubbish damp (of course, number of ringed birds in Getliņi is much higher)
Even in one day the gulls in city channel can change completely – previous day’s observed rings can disappear and new ones observed. Birds seen here can be observed in Estonia or even in Sweden after some days.
Most of gulls gave been ringed as adult birds in wintering places; only two ringed as nestlings in Estonia and Lithuania.
Our special thanks to:
J.Ķuze and I.Austruma for participation in observations
Manager of Ringing Centre Juris Kazubiernis for his patience in data processing.
Our families for understanding, seeing us by the computer looking at pictures during hot nights of beautiful spring.
