Találati lista | Tudóstér

001-es BibID:	BIBFORM018803
Első szerző:	Pap Péter László (ökológus)
Cím:	Increase of feather quality during moult : a possible implication of feather deformities in the evolution of partial moult in the great tit Parus major / Péter L. Pap, Zoltán Barta, Jácint Tökölyi, Csongor I. Vágási
Dátum:	2007
Megjegyzések:	Here we investigate the change in feather quality during partial post-juvenile and complete post-breeding moult in great tit Parus major by measuring the change in the number of fault bars and feather holes on wing and tail feathers. Feathers grown during ontogeny usually are of lower quality than feathers grown following subsequent moults at independence. This is reflected by higher number of fault bars and feather holes on juveniles compared to adults. Fault bars are significantly more common on tail and proximal wing feathers than on the distal remiges, indicating a mechanism of adaptive allocation of stress induced abnormalities during ontogeny into the aerodynamically less important flight feathers. On the contrary, feather holes produced probably by chewing lice have a more uniform distribution on wing and tail feathers, which may reflect the inability of birds to control their distribution, or the weak natural selection imposed by them. The adaptive value of the differential allocation of fault bar between groups of feathers seems to be supported by the significantly higher recapture probability of those juvenile great tits which have fewer fault bars at fledging on the aerodynamically most important primaries, but not on other groups of flight feathers. The selection imposed by feather holes seems to be smaller, since except for the positive association between hatching date, brood size and the number of feather holes at fledging, great tits' survival was not affected by the number of feather holes. During post-juvenile moult, the intensity of fault bars drops significantly through the replacement of tail feathers and tertials, resulting in disproportional reduction of the total number of fault bars on flight feathers related to the number of feathers replaced. The reduction in the number of fault bars during post-juvenile moult associated with their adaptive allocation to proximal wing feathers and rectrices may explain the evolution of partial post-juvenile moult in the great tit, since the quality of flight feathers can be increased significantly at a relatively small cost. Our results may explain the widespread phenomenon of partial post-juvenile moult of flight feathers among Palearctic passerines. During the next complete post-breeding moult, the total number of fault bars on flight feathers has remained unchanged, indicating the effectiveness of partial post-juvenile moult in reducing the number of adaptively allocated fault bars. The number of feather holes has also decreased on groups of feathers replaced during partial post-juvenile moult, but the reduction is proportional with the number of feathers moulted. In line with this observation, the number of feather holes is further reduced during post-breeding moult on primaries and secondaries, resulting in an increase in feather quality of adult great tits.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Journal of Avian Biology. - 38 : 4 (2007), p. 471-478. -
További szerzők:	Tökölyi Jácint (1984-) (biológus) Vágási Csongor István Barta Zoltán (1967-) (biológus, zoológus)
Pályázati támogatás:	OTKA T046661 OTKA NF061143
Internet cím:	DOI Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon:

001-es BibID:	BIBFORM013320
Első szerző:	Pap Péter László (ökológus)
Cím:	Variation in haematological indices and immune function during the annual cycle in the Great Tit Parus major / Péter L. Pap, Csongor I. Vágási, Jácint Tökölyi, Gábor Á. Czirják, Zoltán Barta
Dátum:	2010
ISSN:	0373-2266
Megjegyzések:	We investigated seasonal variation in haematological indices and immune function in the non-migratory Great Tit Parus major over a complete annual cycle. The haematocrit value showed a marked reduction in spring and summer, reaching a lowest value during moult, after which it increased to reach a maximum in winter and spring. The peak in the heterophil to lymphocyte ratio (H/L) during July indicated that Great Tits were the most stressed during the first half of the moulting period. The increase in heterophils and H/L ratio, concurrent with a reduced number of lymphocytes during the breeding season, probably reflected the cost of reproduction in terms of physiological stress and immune suppression. After breeding the number of heterophils and the H/L ratio decreased, reaching a lowest value during winter. The concentration of immunoglobulins followed the seasonal pattern in the number of heterophils, though highest values occurred somewhat later, in July?September during the second part of the moulting period. Our observations indicated large differences in activity throughout the year of different components of the immune system. This suggests differences in function among the components and possibly differences in susceptibility to stress, parasitism and hormones during the annual cycle. When juveniles became independent of their parents, the immunoglobulin concentration increased, whereas other immune measures did not show a significant change. This indicates a rapid increase of at least one component of the immune system after the young fledge.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Ardea. - 98 : 1 (2010), p. 105-112. -
További szerzők:	Vágási Csongor István Tökölyi Jácint (1984-) (biológus) Czirják Gábor Á. Barta Zoltán (1967-) (biológus, zoológus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
Borító:
Saját polcon:

001-es BibID:	BIBFORM030386
Első szerző:	Vágási Csongor István
Cím:	Correlates of variation in flight feather quality in the Great Tit Parus major / Csongor I. Vágási, Péter L. Pap, Jácint Tökölyi, Edina Székely, Zoltán Barta
Dátum:	2011
Megjegyzések:	The most important function of moult in birds is the renewal of deteriorated feathers. Worn and holey remiges may incur fitness costs, yet little is known about the factors responsible for the degree of feather wear and sources of variation in feather hole incidence. Here, we report results on variation in feather quality based on a study of three consecutive annual cycles of a Great Tit Parus major population. We found that month, age, sex, weight and the presence of feather holes are the main sources of variation in degree of wear. Juveniles and individuals with lower feather quality (measured through rachis diameter) and with fault bars present had higher feather hole loads. Feather abrasion peaked in the breeding season and was higher in females probably due to higher workload. The lower feather quality of juveniles compared to adults probably arises because of fast ontogeny in contrast to adults' prolonged moult. Our results indicate that feather deformities are positively interrelated and can be used as proxies of feather quality. Our findings on the correlates of feather holes seem partially contradictory with the widespread view that holes are feeding marks of chewing lice. We propose that feather holes are instead minor feather handicaps, at least in Great Tits.
Tárgyszavak:	Természettudományok Biológiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban annual cycle fault bar feather deformities feather hole feather wear flight feather quality Parus major
Megjelenés:	Ardea. - 99 : 1 (2011), p. 53-60. -
További szerzők:	Pap Péter László (ökológus) Tökölyi Jácint (1984-) (biológus) Székely Edina Barta Zoltán (1967-) (biológus, zoológus)
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat
Borító:
Saját polcon: