Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 5

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  migratory behaviour
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
1

Relation between stopover length and time and body parameters of European Robin Erithacus rubecula [L., 1758] during autumn migration [Central Poland]

100%
Polak M., Szewczyk P.
Polish Journal of Ecology
|
2007
|
tom 55
|
nr 3
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.
2

Migratory behavior of young sturgeon, Acipenser oxyrinchus Mitchill, in the Oder River drainage. Preliminary results of a radio telemetric study in the Drawa River, Poland

80%
Fredrich F., Kapusta A., Ebert M., Duda A., Gessner J.
Archives of Polish Fisheries
|
2008
|
tom 16
|
nr 2
The movements of individual juvenile sturgeon, Acipenser oxyrinchus Mitchill, during their first stage of downstream migration were observed in the Drawa River, Poland. Two groups of 10 sturgeon each (9 months old, reared in closed recirculation systems) were tagged with internal radio-transmitters. The first group of sturgeon (119-184 g) were tagged with Holohill BD-2N transmitters (weight 0.43 g, operational life 14d) and released on May 7. Fish from the second group (143-206 g) were tagged with BD-2 (weight 1.2 g, operational life 56d) and were released on May 24. The releases took place in the Drawa River below Kamienna Dam, 33 km upstream from the river’s confluence with the Noteć River. All of the fish moved downstream, but migration speeds differed. Seven sturgeon from the first group reached the confluence with the Noteć River, approximately 30 km downstream from the release site, during the first 18 days, which indicated there had been staging intervals in pools. Within four days, six fish from the second group had moved downstream the Drawa River and were located 20 km downstream from the confluence with the Noteć River. The downstream migration speed of the fish correlated with fish size and increased with water temperature.
3

Blackcaps Sylvia atricapilla on migration: a link between long-term population trends and migratory behaviour revealed by the changes in wing length

80%
Ozarowska A., Zaniewicz G., Meissner W.
Acta Ornithologica
|
2016
|
tom 51
|
nr 2
Recent climate change has a major impact on the sizes and distribution of bird populations, the phenology of their breeding/migration and migratory behaviour (migration distance, migration strategy). We documented changes in the numbers of juvenile Blackcaps migrating in autumn through the S Baltic that were paralleled by changes in wing length of captured individuals during a 43-year study period (1967-2009). We suggest that the observed trends may indicate changing population composition of migrating birds. In the Blackcap, wing length distinguishes among different populations and increases with increasing migration distance of a given population. Available published data show that long-distance and short-distance Blackcaps pass the study region. Hence, we assumed that shorter-winged birds are short-distance migrants wintering in the southern Europe, and that longer-winged individuals are long-distance migrants wintering in the sub-Saharan region. It seems that in 1967-1980 most Blackcap populations declined, but, as wing length slightly increased, the rate of this decline has been higher in the shorter-winged/short-distance Blackcaps. Over the subsequent 24 years alongside with rapidly growing numbers of birds, we noted a remarkable decrease in wing length. This indicates a pronounced increase in the number of short-distance individuals compared to long-dis- tance migrants. Both groups may benefit from improved conditions at their breeding grounds, but the shorter migration route and favourable conditions at wintering sites north of Sahara could favour short-distance migrants over the longer distance and longer-winged Blackcaps.
4

Migratory behaviour of Blackcaps Sylvia atricapilla wintering in Britain and Ireland: contradictory hypotheses

80%
Busse P.
The Ring
|
1992
|
tom 14
|
nr 1-2
5

Wing to tail length ratio in European Blackbirds [Turdus merula L.] of different age

80%
Wysocki D., Kiriaka B.
Polish Journal of Ecology
|
2007
|
tom 55
|
nr 1
Urban European Blackbird (Turdus merula L.) population was studied in 1997–2004 in two city parks of Szczecin (NW Poland), based on observations of colour-ringed birds. Biometric studies involving numerous bird species showed that the wings of individuals in their second year of life are shorter than those of birds older than two years; the causes of the differences are, however, unclear. The wing length of the individuals observed the year following the ringing was similar to that of the individuals that were not observed that year (probably non-survivors) –127.2 vs. 127.5 mm for young birds, 129.9 vs. 128.3 mm for old birds, respectively. Therefore, the hypothesis assuming increased mortality of shorter-winged individuals has to be rejected. In opposition to the expected differences between the wing to tail length ratios in the young and older birds (1st year – 1.43, 2nd year – 1.40, older – 1.39) one has to reject the hypothesis that the young individuals benefit from higher maneuverability of shorter wings. On the other hand, the greater wing length of those individuals captured in their second year of life and recaptured one year later (127.2 vs. 129.7 mm respectively) allows to accept the hypothesis of better nutrition as the cause of longer wings in the older blackbirds.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 1 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.