Magdalena Remisiewicz

The Primary Moult of Curlew Sandpipers Calidris ferruginea in North-Western Australia Shifts According to Breeding Success

Barshep Y., Minton C., Underhill L.G. & Remisiewicz M. 2011. The primary moult of Curlew Sandpipers Calidris ferruginea in North-western Australia shifts according to breeding success. Ardea 99: 43–51. The population moult parameters, yearly onset of moult and sex-specific schedule of moult in relation to breeding success, and pattern of feather mass growth were examined in a population of Curlew Sandpipers Calidris ferruginea that migrate to northwest Australia. The mean start date of moult was 18 September, and it lasted on average 129 days. No significant variation in duration of moult was detected and feather mass was deposited at a constant rate. The yearly onset of moult was positively correlated with the proportion of first year (juvenile) birds: the mean start date of moult in good breeding years was 25 September, ten days later than mean start date of moult in poor breeding years, being 15 September. Males generally started moult five days earlier than females. The mean moult start date of males was five days earlier in poor breeding years compared to good breeding years, while the moult of females was 11 days earlier in poor breeding years compared to good breeding years. In Curlew Sandpipers the timing of post-breeding migration is advanced in bad breeding seasons, which explains the observed correlation between breeding success and the timing of moult in non-breeding areas.

Synchronisation of the autumn mass migration of passerines: a case of Robins Erithacus rubecula

Abstract. The pattern of autumn migration of the Robin was studied through an analysis of daily dynamics for the birds caught in the years 1984–1997 at four ringing stations (two on the Baltic coast and two in inland Poland). In a given year, migration dynamics was found to be distinctly similar at all stations. It showed conspicuous consistence (± 2 days) in the dates with peak numbers. This could be explained by assuming that Robins take off at the same time across a large breeding ground, and arrive almost simultaneously at stopover sites located over extensive areas. Moreover, migration dynamics from year to year at a given station was also remarkably similar, though this phenomenon was more distinct at the inland stations than at the coastal ones. Day-to-day fluctuations in numbers were on an average the highest at the coastal station most exposed to variable weather, the lowest at the inland stations, and intermediate at the more “sheltered” of the coastal station. The paper discusses the extent to which such results can reflect the influence of weather conditions on passage, or else a precise internal (physiological and genetic) mechanism responsible for the timing of migration.

The Migration System of Common Snipe Gallinago gallinago on Autumn Passage Through Central Europe

The Common Snipe Gallinago gallinago migrates in large numbers through central Europe towards its wintering grounds in western Europe. Over the past 20 years more than 12 000 Common Snipes were ringed at seven ringing stations in Poland during their autumn migration. Birds migrating along the Baltic coast tended to spend the winter in more northern areas than those that used southern Poland as stopover sites during migration. This pattern supports the hypothesis of a parallel autumn migration exhibited by Common Snipe. Additionally, snipes passing through Poland at the beginning of the autumn migration (originating from near breeding areas) overwintered further north than later migrants (known to originate from more northern areas), which is consistent with a leap-frog migration pattern. Our results suggest that the migration pattern of the Common Snipe is more complex than previously thought, because these birds use a combination of two different non-exclusive migratory patterns.

Seasonal fluctuations in population size and habitat segregation of Kittlitz's Plover Charadrius pecuarius at Barberspan Bird Sanctuary, North West province, South Africa

Seasonal fluctuations in population size reflect breeding patterns and movements of birds, but distinguishing residents from itinerant birds is difficult with partially migratory species such as Kittlitzs Plover. We determined changes in the size of Kittlitzs Plover populations in two microhabitats (Goose Point and Sandy Beach) at Barberspan Bird Sanctuary, North West province, South Africa, where we ringed waders between February 2008 and May 2010. Using a Bayesian model, we estimated the population of this species at these two sites from capture–recapture data gathered in eight 3- to 12-day collection periods. The estimated adult population at Goose Point peaked at 161 in October 2009, but decreased to about 40 in March 2009 and March 2010. The immature population peaked at 119 in January–February 2010. This, along with observations of nests and chicks, suggests that residents bred at Goose Point from September to March. The estimated number of adults at Sandy Beach increased from 48 in March 2010 to 380 in April 2010. Adults captured there in April 2010 formed feeding flocks and were heavier than the resident birds at Goose Point. These results suggest that Barberspan Bird Sanctuary supports resident and itinerant populations that are partially segregated in different microhabitats.

Investigations of sexual dimorphism in live Kittlitz's Plover Charadrius pecuarius from inland South Africa

Charadrius plovers generally show little sexual or seasonal dimorphism in size and coloration, but most published measurements come from museum specimens. We aimed to determine sexual size dimorphism in live Kittlitzs Plovers Charadrius pecuarius, based on measurements of 96 males and 112 females ringed at Barberspan Bird Sanctuary (North West province, South Africa) between February 2008 and October 2009 and sexed by DNA analysis. The females were significantly heavier than the males in September–October, but their mass decreased significantly from September to the end of March (b = −0.10, t = 3.82, P = 0.0002), likely because of egg laying. Body mass has limited utility for sexing, because heavy birds with high fat scores of both sexes, possibly itinerants, occurred in all months. Tarsus-and-toe length differed between sexes (P = 0.066). Wing length of birds with old primaries decreased in September–October (ANCOVA, F1,153 = 8.84, P = 0.003), but did not differ between the sexes (ANCOVA, F1,153 = 0.23, P = 0.626). Wing length for birds with fresh feathers, total head length, bill length, tarsus length and height of the white forehead patch did not differ between sexes. We attribute this lack of any clear sexual dimorphism to the species’ monogamous mating system and shared parental care, and to its simple terrestrial displays, which would likely result in weak intersexual selection.

Autumn Migration of Waders (Charadrii) at the Reda Mouth (N Poland)

Autumn Migration of Waders (Charadrii) at the Reda Mouth (N Poland) The migration of waders was investigated at the Reda mouth (Polish Baltic coast) between 1996 and 2001. During the study 496 counts were conducted in the period between 5 July and 5 October. The most numerous species observed were: the Lapwing (Vanellus vanellus) - 39.5% and Dunlin (Calidris alpina) - 29.8% of all waders. Because of a variety of habitats in the Reda mouth region, among the waders staging numerously in the Reda mouth there were species typical both for coastal and inland habitat. It was shown that birds from tundra zone migrated later than those from more southern breeding areas, which was caused by much later beginning of egg laying in northern latitudes. Moreover, in the species from tundra zone, e.g. the Knot (Calidris canutus), Little Stint (C. minuta), Curlew Sandpiper (C. ferruginea), the migration of both age classes were well separated, whereas in those from more southern areas, e.g. the Little Ringed Plover (Charadius dubius), Common Sandpiper (Actitis hypoleucos), such difference was less pronounced and the period of common passage of adults and juveniles was much longer. A comparison of the obtained data on migration pattern with some other sites in Poland where regular counts were conducted showed several similarities and some discrepancies, which are discussed in the paper.

Results of Fieldwork of Wader Research Stations Working in Poland in 2004-2005

Results of Fieldwork of Wader Research Stations Working in Poland in 2004-2005

Sexual dimorphism in adult Little Stints (Calidris minuta) revealed by DNA sexing and discriminant analysis

Background The sex of an individual organism plays such an important role in its life cycle that researchers must know a bird’s sex to interpret key aspects of its biology. The sexes of dimorphic species can be easily distinguished, but sexing monomorphic bird species often requires expensive and time-consuming molecular methods. The Little Stint (Calidris minuta) is a numerous species, monomorphic in plumage but showing a small degree of reversed sexual size dimorphism. Females are larger than males but the ranges of their measurements overlap, making Little Stints difficult to sex in the field. Our aim was to develop reliable sexing criteria for Little Stints in different stages of primary moult during their stay on the non-breeding grounds in South Africa using DNA-sexed individuals and discriminant function analysis. Methods We caught 348 adult Little Stints in 2008–2016 on their non-breeding grounds at Barberspan Bird Sanctuary. To molecularly identify the birds’ sex we used P2/P8 primers and DNA isolated from blood samples collected in the field. We used Storer’s dimorphism index to assess the degree of sexual size dimorphism. Then we divided our sample into two groups: before or during and after primary moult. For each group we developed two functions: one using wing length only and the other a combination of morphometric features including wing, tarsus and total head length. Then we used a stepwise procedure to check which combination of measurements best discriminated sexes. To validate our result we used a jack-knife cross-validation procedure and Cohen-kappa statistics. Results All the morphometric features we measured were bigger in DNA-sexed females than in males. Birds with fresh primaries had on average 2.3 mm longer wings than those with worn primaries. A discriminant function using wing length (D1) correctly sexed 78.8% of individuals before moult, and a stepwise analysis showed that a combination of wing length and tarsus (D2) correctly identified the sex of 82.7% of these birds. For birds with freshly moulted primaries a function using wing length (D3) correctly classified 83.4% of the individuals, and a stepwise analysis revealed that wing and total head length (D4) classified 84.7%. Discussion Sexual size differences in Little Stints might be linked to their phylogenetics and breeding biology. Females are bigger, which increases their fecundity; males are smaller, which increases their manoeuverability during display flights and hence their mating success. Little Stints show an extreme lack of breeding site fidelity so we did not expect a geographical cline in their biometrics. Sexing criteria available for Little Stints in the literature were developed using museum specimens, which often shrink, leading to misclassification of live birds. The sexing criteria we developed can be used for studies on Little Stints at their non-breeding grounds and on past data, but should be applied cautiously because of the overlapping ranges.

Primary moult of continental Black-tailed Godwits Limosa limosa limosa in the Doñana wetlands, Spain

ABSTRACT Capsule: Most Continental Black-tailed Godwits Limosa limosa limosa using the Doñana wetlands during post-breeding migration appear to begin moult before they arrive and suspend moult before they migrate onwards to West Africa. Aims: We aim to describe the primary moult strategies and patterns in the Continental Black-tailed Godwits using the Doñana wetlands, a major passage and wintering area for waterbirds in southern Spain. Methods: Individual godwits were captured, marked and their primary moult was scored in Doñana during the non-breeding season (June–March) in 2011 and 2012. Data from resightings of colour-marked godwits and birds equipped with satellite transmitters were used to estimate stopover duration during post-breeding migration (June–September) to determine if godwits move to West Africa before completing their primary moult. Results: Average primary moult duration was estimated to be 84 days ± 9 se, during 29 June–21 September and did not differ between sexes. Only 2% of individuals were observed with suspended moult. We estimated stopover duration in Doñana to be 13 days ± 2 se before migrating to West Africa. Conclusions: Most godwits stage for about two weeks in the Doñana wetlands during southward migration, moult their primaries and appear to suspend moult before crossing the Sahara. Others may complete their primary moult in Doñana, or elsewhere in Europe and overwinter in Doñana where increasing numbers of godwits have been detected in recent years. A few individuals may finish the moult in Doñana and migrate to West Africa late in the post-breeding season.