We studied the autumn migration of the European robin (Erithacus rubecula) through north-eastern Poland. During the study period 2002–2004 we analysed a total of 2375 individuals: 1991 first-year birds and 349 adults. First-year birds had shorter wings than adults. Body condition was influenced by age, year of migration fat content and arrival time. Our results show that first-year birds arrived earlier, had low-fat levels and were in a comparatively poorer body condition to that of the adults and were less effective foragers. Stopover length decreased during the migration season for both age groups as a result of rush to their wintering areas because of winter approach. We found that adult females arrived later than adult males.
The test was carried out in the Central Poland, during the autumn migration in years 1997 and 1998, and the object was the Robin Erithacus rubecula. The aim of the study was the verification of the new field method for studying directional preferences in small Passerine migrants, proposed by Busse (1995). In total, 843 Robins were tested in "Busse's cage". Directions preferred by the tested birds were distributed in conformance with wintering areas and migration routes of the species known from literature. Robins with dark legs and grey plumage at flanks pointed at the directions according to the axis Scandinavia — the Balkans, which is in consistence with the literature data. Robins tested at daytime show stronger directionality than those tested at night. Birds tested with the sun visible expressed stronger directionality than those tested under overcast. The Robins tested at day more often pointed at the return direction — to the north and to the north-east. The activity of birds in the experimental cage increased at daytime with the lack of sun visible, and with overcast, and was higher in birds with smaller fat deposit, thus it reflected mainly the normal vital activity not associated with the migration.
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 relation between age, body parameters and the stopover behaviour of a small, short-distance, migratory bird during the season of autumn (August–October) was studied. Capture-recapture data of 1018 first-year and 89 adult European Robins migrating through central Poland (“Kaliszany” ringing station, 21°48’E, 51°05’N) in autumn between 1997 and 2005 were analysed. Body mass, length of wing and tail of young Robins caught and stayed at the stopover site showed significant seasonal variation. Immature Robins made longer stopovers (median = 4 days, 1–41) in the area than older ones (median = 3 days, 1–32). The stopover duration decreased continuously during the season. However, body mass changes at the staging site was not related to the age of birds. The birds migrating in the second half of autumn (late September–October) period accumulated fat faster than birds migrating in the early season. Our analyses confirmed that late migrants stayed for shorter stopovers and gained more body mass than early migrating birds due to a shift in migration strategy as an adaptation to time stress.
Acuaria subula (Dujardin, 1845) is redescribed by light microcopy (LM) and scanning electron microscopy (SEM) on the basis of specimens from its type host, Erithacus rubecula (Passeriformes, Muscicapidae), from Curonian Spit (Kaliningradskaya Oblast’, Russia) and Bulgaria. Acuaria skrjabini (Ozerskaya, 1926) is redescribed by LM and SEM on the basis of specimens from Passer domesticus (type host) and P. hispaniolensis (Passeriformes, Passeridae) from Bulgaria. Contrary to previous opinions recognizing A. skrjabini as a junior synonym of A. subula, the present study confirms that they are distinct species. They can be distinguished on the basis of the ratio between the length of cordons and the body length, the ratio between the length of muscular oesophagus and glandular oesophagus, and the ratio between the total length of oesophagus and the body length. In addition, the plates forming the cordons in these two species exhibit different morphological characters. Another difference between these two species is associated with the particular irregular mosaic ornamentation of the cuticle on the ventral and lateral sides of body around the region of vulva of A. subula and its absence in A. skrjabini. Data on their host and geographical ranges are surveyed. The type series of Acuaria buttnerae Chabaud et Petter, 1961, described as a parasite of Calandrella brachydactyla (Passeriformes, Alaudidae) in France, is re-examined; the latter species is recognized as a junior synonym of A. skrjabini (new synonymy).
We surveyed the prevalence of quill mites in wild passerines captured in Wielkopolski National Park, Poland. A total of 438 birds of 12 species were mist-netted during three consecutive spring seasons from 2006–2008. Eight bird species were infested with syringophilid mites: Erithacus rubecula (L.) (index of prevalence, IP = 16.2%), Turdrus merula L. (IP = 22.4%), T. philomelos Brehm (IP = 10.5%), Fringilla coelebs L. (IP = 36.2%), Coccothraustes coccothraustes (L.) (IP = 7.4%), Sturnus vulgaris L. (IP = 53.6%), Sylvia atricapilla (L.) (IP = 6.1%) and Troglodytes troglodytes (L.) (IP = 7.1%). In four cases, multiple infestation was observed, where one bird species was parasitized by 2–3 species of quill mites occupying separate niches in the plumage of the host.
During the studies on trematode fauna of birds from Lower Silesia, the rare species - Urotocus rossitensis (MÜHLING, 1898) - was found. It parasitized in the bursa Fabricii of Sylvia borin, Erithacus rubecula and Turdus philomelos, and in the cloaca of Turdus merula. All these birds are new hosts for U. rossitensis which was recorded for the first time in Poland. It is worth mentioning that the localization of this trematode in the cloaca of T. merula is nontypical, since the parasite has underdeveloped suckers. Morphological and biometrical data give us new information about variability of U. rossitensis. They allow the author to support WILLIAMS' (1960) proposition to include U. fusiformis MCINTOSH, 1935 and U. tholonetensis TIMON-DAVID, 1955 among the synonyms of Urotocus rossitensis (MÜHLING, 1898).