Ornis Polonica 2012, 53: 165–174
Density of males of the Corncrake Crex crex in selected areas in Poland
Michał Budka, Paweł Ręk, Tomasz S. Osiejuk, Krzysztof Jurczak
Abstract: In 2007–2011, 12 localizations in Poland were controlled each once. In total, 238 surveyed 1 km² UTM grid squares fulfilled two requirements: (1) the observer could have heard each potential bird from the distance of less than 500 m, and (2) spent more than 40 minutes within square. In total, 441 calling corncrake males were recorded. Birds inhabited mainly cultivated and uncultivated meadows. Rarely, birds were observed in the fields, pastures and forest plantations. The average density of calling males varied from 1.3 to 6.6 per 1 km² of potential habitats, depending on the localization. However, local densities were considerably higher: up to 10–25 calling males per 1 km². The average distance between a territorial male and its nearest neighbour was 316 meters, but 67% of males had the nearest neighbour in the range of 50–300 meters. Within the hearing distance, which was assumed here as a 1 km, territorial male had 6 calling individuals on average. Single males were observed in less than 4% cases. Results of this study suggest that the corncrake can reach high densities in suitable habitats. There was a tendency of males to cluster in loose groups, which consisted of few to more than ten males. Such groups were observed even in large, homogenous habitats. Such behaviour of males may increase mating success and indicates irregular distribution of the females. In this study, possible interpretations of the results of the corncrake surveys, in the view of the current knowledge, are discussed.
Ornis Polonica 2012, 53: 175–187
Occurrence of the Bean Goose Anser fabalis subspecies in the Łódź region during spring migration in 2011
Łukasz Krajewski, Tomasz Janiszewski, Tadeusz Musiał
Abstract: The paper reports first results of the Bean Goose subspecies counts in the Łódź region during spring 2011. From over 58,300 Bean Geese observed during 21 counts in 7 different locations, 7,088 individuals were identified to the subspecies. The percentage of the Taiga Bean Geese A. f. fabalis in the Bean Goose flocks was bigger in the Warsaw-Berlin proglacial stream valley (average 32.7 %, range 0–87%) than at the Jeziorsko reservoir (average 15.3%, range 3–32%), which could be explained by different habitat preferences between subspecies. The peak of the Taiga subspecies migration fell about 2 weeks earlier than that of the Tundra subspecies A. f. rossicus. The percentages of Bean Goose subspecies in the Łódź region differed from the pattern known from Poland. Apart from the differences in the geographical distribution routes of Taiga and Tundra Bean Geese, and the different proportion of subspecies in the Łódź region may be affected by various stopover strategies – the Taiga Bean Goose spends more time at the stopover sites compared to the Tundra Bean Goose.
Ornis Polonica 2012, 53: 188–201
Occurrence of the Red-breasted Goose Branta ruficollis in Poland
Łukasz Ławicki, Tadeusz Stawarczyk
Abstract: By the end 2011, 220 records (ca 383 individuals) of the Red-breasted Goose Branta ruficollis in Poland were made. Until the late 1980s the species was recorded only 11 times, but since 1990 it has been recorded annually with a clear increasing trend. Median number of observations in 1990–2005 was 4 records per year (range 1–12) and a significant increase occurred after 2005, when the median was 20 records per year (range 13–41). Most of the records was in western Poland (87%), mainly from Silesia (99 records) and Wielkopolska (40). The Red-breasted Geese were recorded in 125 places, mostly in the Barycz River Valley (47 records), Biebrza River Basin (13), Mietków Reservoir (11) and the Warta River Mouth NP (10). Red-breasted Geese were most frequently observed in autumn, with the peak in the third decade of October and the first decade of November. In winter, they were observed in small numbers whereas in spring the highest numbers fell in the second and third decade of March. Most observations concerned single (75%) and adult (59%) birds. Red-breasted Geese were most frequently observed on fishponds (28%) and in farmland (27%), somewhat less frequently in river valleys (22%) and at dam reservoirs (18%). The large increase in numbers of the Red-breasted Geese noted in Poland in recent years is likely due to more numerous occurrence in Western Europe and higher observers activity in search of rare species in flocks of geese.
Ornis Polonica 2012, 53: 202–208
Genetic riddles of specialization in the Common Cuckoo Cuculus canorus
Summary: Reproduction of Common Cuckoo Cuculus canorus involves parasitizing broods of other species. Previous studies allowed to identify host-specific gentes (races). Each of them aims in imitating background colour and spot pattern of host eggs. Molecular studies had shown that races appear to be limited to female lineage with cross mating males keeping the cuckoos as one genetic species. The differences are reflected in variation on the level of mtDNA, suggesting that only females are host-specific and genes responsible for this situation may be located on chromosome W. Other work reveals nuclear microsatellite differentiation indicating the possibility that mate choice is not random, but biased towards specific host preference for both males and females. Still, there is not enough evidence to establish solution to the problem. Article gives up to date summary of what is known in the topic.
Ornis Polonica 2012, 53: 209–221
The ratio of the heterophils and lymphocytes as a stress indicator in birds
Summary: The ratio of the heterophils and lymphocytes (H:L ratio) is known as a reliable stress indicator in free-living birds. It is considered that H:L ratio allows to assess body reaction to long-term stress caused by ecological and physiological factors. Results of studies of many authors indicate that particular factors can influence the stress index of young and adult birds in a different ways. The H:L ratio is affected by physiological mechanisms of the stress reaction. The level of corticosterone and heat shock proteins result in increase in the H:L ratio. A change in the H/L ratio is detectable within hours following exposure to a stressor. Thus, in contrast to corticosterone (its level increases 2–3 minutes after capture), the H/L ratio is not affected by handling or blood sampling stress what is advantageous in the field studies.
Ornis Polonica 2012, 53: 222–226
Numbers and distribution of the Corncrake Crex crex in Białystok in 2011
Paweł Mirski, Adam Zbyryt
Summary: . The paper presents results of the Corncrake census in Białystok city (NE Poland, area of 102 km²) in 2011. The Corncrake surveys were performed at night, twice at each place. The population of the Corncrake was estimated at 38–43 calling males. Density was estimated at 0.37–0.42 male/km² of total area and 1.25–1.42 male/km² of open landscape. Corncrakes occurred in 23–30% of 1×1 km squares. The highest densities were found in the valleys of the Biała river (western part of the city), Dolistówka river (north-eastern part of the city) and in the Dojlidy Górne district (south-eastern part of the city). The number of the Corncrake in Białystok is higher compared to other major cities, such as Poznań, Łódź, Warszawa or Olsztyn. The probably reason for this fact is high attractiveness of the abandoned agricultural landscape, such as meadows, fields etc., on relatively large area in the administrative boundaries of the city.
Ornis Polonica 2012, 53: 227–229
Next records of the Cory’s Shearwater Calonectris diomedea in Poland
Michał Polakowski, Michał Skakuj, Sergiusz Niziński, Piotr Zientek, Gerard Bela
Summary: On 15th September and 1st October 2011, two Cory’s Shearwaters were observed and photographed on the Vistula Spit near Piaski and Krynica Morska, Bay of Gdańsk, respectively. Both observations were accepted by the Polish Avifaunistic Commission and represent the fourth and fifth records for Poland, respectively.
Ornis Polonica 2012, 53: 230–231
Mystery bird 68: Pallas’s Grasshopper Warbler Locustella certhiola