Bright Birds Make Good Mothers

Female blue tits with brightly coloured crowns are better mothers than duller birds, according to a new study led by the University of York.
 
Unlike humans, birds can see ultra-violet (UV) light. While the crown of a blue tit looks just blue to us, to another bird it has the added dimension of appearing UV-reflectant.

The three-year study of blue tits, which also involved researchers from the University of California Davis, USA and the University of Glasgow, showed that mothers with more UV-reflectant crown feathers did not lay more eggs, but did fledge more offspring than duller females. These brightly coloured mothers also experienced relatively lower levels of stress hormones during arduous periods of chick rearing.

Lees meer: ScienceDaily

Hue of Barn Swallow Breast Feathers Can Influence Their Health

A new study conducted at the University of Colorado Boulder and involving Cornell University shows the outward appearance of female barn swallows, specifically the hue of their chestnut-colored breast feathers, has an influence on their physiological health.

It has been known that in North American barn swallows, both males and females, those with darker ventral feathers have higher reproductive success than those with lighter colors, said Cornell Senior Research Associate Maren Vitousek, who led the new research while a postdoctoral researcher at CU-Boulder. Although there is evidence that breast feather color is significantly influenced by genetics, melanin-based plumage color like that in barn swallows also has been tied to social status and even to circulating testosterone, she said.

Lees meer: ScienceDaily