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Relationships between territory quality and carotenoid-based plumage colour, cell-mediated immune response, and body mass in Great Tit Parus major nestlings

100%

Galvan I., Diaz L., Sanz J. J.

Acta Ornithologica

2009

tom 44

nr 2

Plumage colour is classified as pigmentary or structural, depending on whether it is caused by pigments or by feather microstructure. However, recent findings indicate that carotenoid-based plumage colouration also reflects at UV-blue wavelengths and that the underlying structure is related to the reflectance properties of the yellow feathers. Thus, yellow plumage is based on interactions between structural and pigmentary components. This study investigated the relationships among the vegetation structure of breeding territories, both components of plumage colour, T-cell- mediated immune response and body mass of nestling Great Tits Parus major. By using a model of avian visual perception, we found that, while plumage yellowness was associated with mature vegetation, plumage brightness and UV- blue reflectance were related to immature habitats in territories. We noted considerable variability in the development of carotenoid-based colour components under different environmental conditions, as plumage yellowness, but not brightness or UV-blue reflectance, depends on the availability of carotenoids, which is assumed to be high in mature territories with high food abundance. Territorial features denoting mature territories were also related to high body mass and immune response in nestlings, but none of the colour components were related to these variables of the vegetation structure, suggesting that habitat quality is related to nestling body mass and immune response through mechanisms different from those through which it is related to colour.

Seasonal variation of singing activity and relative effect of the advertising behaviour of males with different plumage colour in the Pied Flycatcher Ficedula hypoleuca

100%

Ilyina T. A., Ivankina E. V.

Acta Ornithologica

2001

tom 36

nr 1

From late April to the second 10-day period of June 1994—1999, in 76 unmated males the time-budget was measured during 304 hours in a 6.6 km2 area of mature mixed and coniferous forests near Moscow. In 1999, territorial males were counted at least once per pentade throughout the breeding season in a 35 ha plot with 180 nest-boxes. Dark (grades 2-3 on Drost's scale) and pale (grades 5-7) males had similar levels of singing activity, but in cold weather the former had higher song rates than the latter. The singing activity of all the males was relatively low at the beginning of the season (by the mid-May). Dark males sang mainly from open perches (67.6% of songs, compared with 23.2% for pale males). In dark males visual stimulation compensated for the relatively low acoustic activity in early spring when trees were still lacking leaves. The immediate vicinities of nest-boxes occupied by dark males were visited by females significantly more frequently than those of pale ones.

Ograniczanie wyników

2 Acta Ornithologica

1 Diaz L.

1 Galvan I.

1 Ilyina T. A.

1 Ivankina E. V.

1 Sanz J. J.

1 2009

1 2001

Wyniki wyszukiwania

Relationships between territory quality and carotenoid-based plumage colour, cell-mediated immune response, and body mass in Great Tit Parus major nestlings

Seasonal variation of singing activity and relative effect of the advertising behaviour of males with different plumage colour in the Pied Flycatcher Ficedula hypoleuca