Włodzimierz Meissner

Body shrinkage due to Arctic warming reduces red knot fitness in tropical wintering range

Consequences conferred at a distance Migratory animals have adapted to life in multiple, sometimes very different environments. Thus, they may show particularly complex responses as climates rapidly change. Van Gils et al. show that body size in red knot birds has been decreasing as their Arctic breeding ground warms (see the Perspective by Wikelski and Tertitski). However, the real toll of this change appears not in the rapidly changing northern part of their range but in the apparently more stable tropical wintering range. The resulting smaller, short-billed birds have difficulty reaching their major food source, deeply buried mollusks, which decreases the survival of birds born during particularly warm years. Science, this issue p. 819; see also p. 775 A warming Arctic decreases the fitness of migratory red knots in their distant wintering range. Reductions in body size are increasingly being identified as a response to climate warming. Here we present evidence for a case of such body shrinkage, potentially due to malnutrition in early life. We show that an avian long-distance migrant (red knot, Calidris canutus canutus), which is experiencing globally unrivaled warming rates at its high-Arctic breeding grounds, produces smaller offspring with shorter bills during summers with early snowmelt. This has consequences half a world away at their tropical wintering grounds, where shorter-billed individuals have reduced survival rates. This is associated with these molluscivores eating fewer deeply buried bivalve prey and more shallowly buried seagrass rhizomes. We suggest that seasonal migrants can experience reduced fitness at one end of their range as a result of a changing climate at the other end.

Levels of metals in blood samples from Mallards (Anas platyrhynchos) from urban areas in Poland

In this paper we present the studies conducted on blood samples taken from Mallards (Anas platyrhynchos). Birds were captured for ringing purposes (nxa0=xa043) in two small and two big towns (including highly urbanized areas). For comparison samples of blood from birds shot on fish ponds were used (nxa0=xa026). Based on the body mass all sampled individuals can be assessed as being in good condition. Levels of cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb) and zinc (Zn) in blood samples were measured with AAS. Concentrations of metals did not differ statistically between sexes and made up a following order: Fexa0>xa0Znxa0>xa0Cuxa0>xa0Crxa0≈xa0Nixa0>xa0Pbxa0>xa0Cd. Mallards from towns revealed lower concentrations of Zn and Cu but higher concentration of Fe. There was no difference in exposition to Pb between birds from towns and fish ponds.

Some Results of Long-Term Counts of Waterbirds Wintering in the Western Part of the Gulf of Gdańsk (Poland), with Special Emphasis on the Increase in the Number of Cormorants (Phalacrocorax Carbo)

Regular counts of waterbirds have been conducted in the western part of the Gulf of Gdansk since 1984. About 130 km of coastline were being surveyed within two days every month (September to April). The most common waterbird species (excluding gulls Laridae) are Tufted Duck (Aythya fuligula), Mallard (Anas platyrhynchos), Goldeneye (Bucephala clangula), Mute Swan (Cygnus olor), Coot (Fulica atra), Goosander (Mergus merganser) and Cormorant (Phalacrocorax carbo). The number of wintering birds of each species showed distinct fluctuations. Only Cormorants number has been rising continually, especially in winter (before 1990 less than 100 individuals, after 2000 more than 3,000). The highest number was recorded in autumn (10,953 in September 2003). In 1998 and 1999 non-breeders and post-breeders Cormorants consumed 300–900 t of fish per year. 73% to 80% of all taken fish were damaging for fishery and biodiversity: round goby (Neogobius melanostomus) and nine-spined stickleback (Gasterosteus aculeatus).

Seasonal age differences in weight and biometrics of migratory Dunlins (Calidris alpina) at Eilat, Israel

This study was undertaken to understand the migratory strategies of the Dunlins (Calidris alpina) caught in Eilat, Israel, before and after they accomplish the crossing of the combined ecological barrier of the Sinai, Sahara and Sahel deserts. Between 1999–2001, a total of 410 adults and 342 juveniles were banded. The significant difference in mean wing length between birds caught in autumn and spring reflects the degree of abrasion of the outer primaries during over-wintering in Africa. Dunlins caught in Eilat in autumn and early winter had a mean wing length 1.4–1.9mm longer than in the spring. The rate of body mass increase was comparatively high and the mean body mass of the heaviest 10% of Dunlin at Eilat was 56.2g (SE ± 0.6, N = 80). The heaviest birds from Eilat carried on average about 10g of fat with a lipid index (fat mass as a percentage of total body mass) of 18%. These reserves allow a flight of approximately 1 000km, which is probably sufficient for continued migration to more southerly wintering grounds.

Lead isotope ratio measurements as indicators for the source of lead poisoning in Mute swans (Cygnus olor) wintering in Puck Bay (northern Poland)

Lead (Pb) poisoning is most commonly linked amongst anthropogenically-caused deaths in waterfowl and this is often associated with hunting and fishing activities. However, the exact identification of the source may be difficult with commonly-used techniques. We have studied isotope ratios using Inductively-Coupled Plasma Mass Spectrometry (ICP-MS) to investigate the source of Pb in the blood of Mute swans (nxa0=xa049) wintering in northern Poland. We compared the values of isotopic ratios from blood and ammunition pellets available on the Polish market. The mean Pb concentrations found was 0.241xa0μg/gxa0(w/w) and nearly half of the blood specimens had elevated Pb levels (higher than the cited 0.23xa0μg/gxa0w/w threshold of poisoning). Only the mean 208/206 Pb isotope ratio was similar in blood and pellet samples. Mean ratios of isotopes 206/204, 206/207 and 208/207 in swans blood and in pellets differed significantly. Moreover, coefficients of variation were higher in blood samples than in pellets. These discrepancies and significant differences in abundance of 204Pb and 207Pb isotopes in both materials indicated that pellets available today on the Polish market were not the source of Pb in the blood of Mute swans wintering in northern Poland.

Autumn migration of the Broad-billed Sandpiper Limicola falcinellus on the southern Baltic Coast

Broad‐billed Sandpipers Limicola falcinellus were counted and trapped in Puck Bay on the southern Baltic coast in autumn. The number of arriving birds varied greatly between years. The observed pattern was not completely convergent with data gathered at Ottenby, Sweden, 220 km north of Puck Bay. It seems that within years these two stop‐over sites might be used by different groups of migrants with the majority of birds that stopped in southern Sweden being able to fly over the Polish coast, making their next stop somewhere closer to the wintering grounds. Adult Broad‐billed Sandpipers migrated in the second half of July, and juveniles in August and the first half of September. There were no significant differences in biometrics between adults and juveniles. Morphometric variables were not correlated with date in either age group. Hence, the assumption of earlier departure of females from the breeding grounds was not supported. On average, Broad‐billed Sandpipers gained 1.6 g/ day in body weight, with a maximum value of 4.0 g/day (from 29 g to 33 g after one day). The theoretical flight range of Broad‐billed Sandpipers departing from the Puck Bay region ranged between 1,300 and 1,400 km. Thus, it seems that the majority of Broad‐billed Sandpipers are able to reach the northern Black Sea coast, which is one of the most important stop‐over sites, in one flight.

Low metabolic activity of biofilm formed by Enterococcus faecalis isolated from healthy humans and wild mallards (Anas platyrhynchos)

It is widely known that Enterococcus faecalis virulence is related to its biofilm formation. Although Enterococci are common commensal organisms of the gastrointestinal tract, the difference between commensal and pathogen strains remain unclear. In this study, we compare the biochemical profile of the biofilms formed by two groups of medical and two groups of commensal strains. The medical strains were isolated as pathogens from infections of urinary tract and other infections (wounds, pus and bedsores), and the commensal strains were taken from faeces of healthy volunteers and faeces of wild mallards (Anas platyrhynchos) living in an urban environment. The properties of biofilms formed by medical and commensal strains differed significantly. Commensal strains showed lower metabolic activity and glucose uptake and higher biofilm biomass than the medical ones. Consistent with glucose uptake experiments, we found that the glucose dehydrogenase gene was more expressed in medical strains. These results indicate that higher metabolic activity and lower protein concentration of E. faecalis cells within biofilms are formed during infections.