Waterbird Research Group KULING

Gdynia, Poland

Waterbird Research Group KULING

Gdynia, Poland

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Meissner W.,University of Gdansk | Kosmicki A.,Waterbird Research Group KULING | Niemczyk A.,Waterbird Research Group KULING | Fischer I.,University of Gdansk
Waterbirds | Year: 2017

Discriminant functions based on external body size measurements are widely used to sex different gull species with great accuracy. However, all of them have been derived for adult birds, which puts into question their usefulness for sexing immatures due to possible changes in size as birds mature. To address this issue, discriminant functions that allow sexing of Herring Gulls in immature age classes with an accuracy of 88-100% were developed. In total, 247 males and 111 females of wintering Herring Gulls, including birds in the first, second and third winter plumages and individuals in adult plumage, were measured and sexed in the region of the Gulf of Gdańsk (southeastern Baltic coast). In all age classes, total head length and bill depth were the best traits for sexing Herring Gulls. However, bill depth, but not total head length, increased with age. Hence, in the first and second winter plumages, total head length made a much higher contribution to the discriminant function than bill depth. In the third winter plumage, bill depth became more important. For individuals in adult plumage, however, the contribution of total head length and bill depth were nearly the same. Hence, using discriminant equations derived for adults resulted in erroneous sexing of 4.5-8.9% of immature males, which were identified as females, and illustrates the importance of deriving age-specific discriminant functions.


Meissner W.,University of Gdansk | Fischer I.,University of Gdansk | Bzoma S.,Waterbird Research Group KULING
Oceanological and Hydrobiological Studies | Year: 2012

Body mass and body composition of 27 adult Velvet Scoters (Melanitta fusca) were studied. These birds were collected from January to March in the Gulf of Gdańsk, Poland. Body mass, fat, and protein contents of both males and females decreased significantly between mid and late winter, possibly because of a physiological process or a result of worsening environmental conditions. In mid-winter, the mean body mass of males and females did not differ significantly, whereas in late winter the difference in body mass between sexes became prominent. There was no difference in fat mass between the sexes, but females had higher lipid indexes despite their smaller size. The lack of expected fat mass increase in late winter may be due to the spring migration strategy of Velvet Scoters which apparently opt to fly short distances rather than make long non-stop flights after departure from the Gulf of Gdańsk. Body mass was the best predictor of fat mass accumulated by Velvet Scoters wintering in the Gulf of Gdańsk. Copyright © of Institute of Oceanography, University of Gdansk, POL.


Grajewska A.,University of Gdansk | Falkowska L.,University of Gdansk | Szumilo-Pilarska E.,University of Gdansk | Hajdrych J.,University of Gdansk | And 7 more authors.
Environmental Science and Pollution Research | Year: 2015

The aim of this paper was to assess the influence of diet on the concentrations of total mercury (HgTOT) in the eggs of aquatic birds. Trophic level was determined using stable isotopes (δ15N, δ13C). Analysis was carried out on eggs (laid in 2010–2012) belonging to two species of terns nesting at the River Vistula outlet on the Gulf of Gdansk and on herring gulls nesting both in Gdynia harbour and on the Vistula dam in Wloclawek. The results show that seafood diet causes the highest load of mercury, that which is transferred into terns eggs. The amounts of accumulated mercury obtained were found to be different in the particular egg components with Hgalbumen > Hgyolk > Hgmembrane > Hgshell. In the herring gull eggs, three stages of embryo development with varying levels of mercury were determined. It was observed that mercury received from the albumen and yolk was most effectively removed when developing embryo into down. © 2015, Springer-Verlag Berlin Heidelberg.


Szumilo-Pilarska E.,University of Gdansk | Grajewska A.,University of Gdansk | Falkowska L.,University of Gdansk | Hajdrych J.,University of Gdansk | And 4 more authors.
Journal of Trace Elements in Medicine and Biology | Year: 2016

Aquatic birds occupy a high position in the trophic pyramid of the Baltic Sea. This means that they accumulate the greatest amount of harmful substances, including mercury, in their bodies. This element penetrates into their systems mainly via the alimentary canal. The amount of mercury absorbed from food depends on how badly the environment is polluted with this metal. The aim of this study was to discover the concentrations of total mercury (HgT) in the contour feathers, muscles, brain, lungs, liver, kidneys, heart and blood of four gull species Herring Gull (Larus argentatus), Common Gull (Larus canus), Black-headed Gull (Larus ridibundus) and Great Black-backed Gull (Larus marinus) and organic mercury (Hgorg) in the liver and brain of Herring Gull. The most important characteristic of the results obtained for the studied gulls was the statistically significant differences between the four species, probably resulting from their different diets-confirmed by stable-isotopes analysis (δ15N and δ13C). A logarithmic dependence was found between HgT in the blood and HgT in the brain of the Herring Gull. The authors suggest that among gulls burdened with the greatest mercury load, it is possible that the brain is protected by higher Hg accumulation in the muscles. The percentage share of Hgorg in the brain and liver of the Herring Gull depended on the concentration of HgT in these tissues and was always higher in the brain. In none of the cases, did the mercury levels assayed in the internal gulls' tissues exceed values associated with adverse health effects. © 2015 Elsevier GmbH.


Meissner W.,University of Gdansk | Bzoma S.,Waterbird Research Group KULING
Wader Study Group Bulletin | Year: 2011

This study compares the ringing recovery rate and resighting rate obtained using stainless steel rings and coloured numbered rings respectively in 828 Dunlins caught at a southern Baltic stopover site. Birds were colour-ringed between 25 Jul and 17 Sep 2010 and 41 had been resighted by 30 April 2011. The resighting rate was significantly higher than the steel ring recovery rate obtained from Dunlins ringed during 2008-2010. Both ringing recovery and resighting rates differed significantly among age groups, being much lower in adults. However in the case of steel rings the recovery rate of juveniles was eight times higher than in adults, but the difference in resighting rate of juveniles was only four times that of adults. Our study shows that even small colour plastic rings can be read in the field and adding them to the normal metal ring greatly increases the recovery rate. Using colour rings with individual codes facilitates more detailed studies of wader movements.

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