vadu, romania

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lou bertalan
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Location: stuttgart, SW germany
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vadu, romania

Post by lou bertalan » Sat Oct 05, 2013 11:53 pm

hi,

there's no 'vadu'-thread in "other locations", so here is the beginning - although many birds have been posted from this location already. it's certainly a must for gullwatchers on the western black sea coast. but the beach is over 30 km long :)

first 20 new pics from september 1st uploaded here: http://www.lou.bertalan.de/gulls/m_newest.php
i had just little time, so i photographed many birds just passing by in 1,5 hours.

lou bertalan
Posts: 503
Joined: Tue Nov 03, 2009 2:43 pm
Location: stuttgart, SW germany
Contact:

location and statistics from 1.09.2013

Post by lou bertalan » Sun Oct 06, 2013 10:45 am

vadu is located just at the southern border of the lagunar area south of the danube delta. closeby in the lagoons there are some colonies of cachinnans (how many, how large?) while the breeding sites of michahellis on the roofs of constanta (large port city) are less than 30 km south of vadu. so, this is roughly the 'geographical' center of the limit between the breeding areas of the two species on the black sea coast.
https://maps.google.de/maps?q=Vadu,+Con ... 4nien&z=10

cachinnans breeds in a more or less continous areal from here on northwards with the core population in the north of the black sea.
michahellis breeds regularly at the western black sea coast from constanta on southwards, with the exception of small populations on crimea (where it might interbreed with cachinnans).

it is stunning how numeral dominant michahellis is from here on southwards and how dominant cachinnans is from here on northwards. even during migration which has well started at the beginning of september around constanta there are always much more michas while in the danube delta, north of the lagunar area michahellis is a very scarce appearance (around 1:100 to cachinnans).
both species seem to not interbreed on a larger scale in this region as they are well separated ecologically.

during 1:40 hours (from 14:15 to 15:55) on 1.09.2013 i photographed randomly passing by large gulls:

32 cachinnans and 21 michahellis ( 5-8 birds are not sure identified, sexing often tentative but in many cases very clear):

- 1cy male cach = 1
- 1cy female cach = 0
- 2cy male cach = 7
- 2cy female cach = 2
- 3cy male cach = 3
- 3cy female cach = 1
- ad male cach = 17 (32% of all birds, 53% of all cachinnans)
- ad female cach = 1

- 1cy male mich = 9 (17% of all birds, 43% of all michahellis)
- 1cy female mich = 5
- 2cy male mich = 2
- 2cy female mich = 0
- 3cy male mich = 3
- 3cy female mich = 0
- ad male mich = 2
- ad female mich = 0

cachinnans: male/female = 28/4 (87,5% / 12,5%)
michahellis: male/female = 16/5 (76% / 24%)
(well, in about 15% gender was not obvious enough to be sure).

it's noticeable to which extent males outnumber females (and not only this time; in sf. gheorghe where almost only caspian gulls occure the percentage of males is at least that high) - is it because they are more flexible due to their dominance?

lou

Ronald Klein
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Joined: Mon Nov 30, 2009 5:20 pm

Re: vadu, romania

Post by Ronald Klein » Fri Oct 11, 2013 7:14 am

Exactly the same we have found in the 1990ies.
http://gull-research.org/papers/gullpap ... 201996.pdf

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