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Experimental evidence that egg color indicates female condition at laying in a songbird
The signaling hypothesis of eggshell coloration in birds is based on the assumption that females of species with blue-green eggs signal their phenotypic quality to their mates through deposition of
Egg colour reflects the amount of yolk maternal antibodies and fledging success in a songbird
It is shown that the intensity of blue–green colour of pied flycatcher Ficedula hypoleuca eggs reflects the amount of maternal antibodies in the yolk, a form of passive immunity crucial for offspring performance.
The results do not support the thermoregulatory hypothesis and show that certain measures of female health are related to nest-building effort in some years, probably depending on environmental conditions.
Egg colouration and male parental effort in the pied flycatcher Ficedula hypoleuca
This evidence is only tentative until experimental confirmation, but suggests that males are affected by the colour of their mates’ eggs, a possibility not considered hitherto in the study of sexual selection.
Evidence for the signaling function of egg color in the pied flycatcher Ficedula hypoleuca
The signaling hypothesis for explaining bright colors of avian eggs is supported, as mean within-clutch egg darkness was positively associated with both measures of female immunocompetence and better female condition was associated with colors tending away from intermediate and toward short wavelengths.
Nestling cell-mediated immune response, body mass and hatching date as predictors of local recruitment in the pied flycatcher Ficedula hypoleuca
Nestling immunocompetence as measured with the PHA assay is a better predictor of local recruitment probability than mass or hatching date in the study population, and should be considered in future studies of determinants of offspring survival chances and fitness in avian populations.
More colourful eggs induce a higher relative paternal investment in the pied flycatcher Ficedula hypoleuca: a cross-fostering experiment
Blue-green chroma in the pied flycatcher functions as a signal of female or clutch quality to males which respond by adjusting their relative investment with respect to total pair effort, which has positive effects on female fitness.
Female ornaments in the Pied Flycatcher Ficedula hypoleuca : associations with age, health and reproductive success
This work addressed the associations of these two ornaments with female age and with some health and breeding parameters in a Spanish population of Pied Flycatchers, finding that the white forehead patch characteristic of males and the larger wing patches may indicate some aspects of female quality.
Are eggshell spottiness and colour indicators of health and condition in blue tits Cyanistes caeruleus
Clear evidence of eggshell spottiness and general colour as indicators of general condition and stress in avian populations is presented for the first time.