Attractive Great Tits Raise Healthier Babies, Even If They’re Not Genetically Related

With their bumblebee chest and bright white cheeks, great tits are lovely little birds. And those white patches indicate not only how healthy a particular bird is but how healthy the children she raises will likely be—even if they’re not her own.

According to new research, there’s a correlation between a mother tit’s black stripes and her chick’s weight, and white cheeks correspond to a chick’s immune strength. In the latter case, though, the underlying factors behind the older bird’s plumage influenced both genetically-related chicks’ and adopted chicks’ health.

To arrive at these conclusions, researchers from the Palacky University in the Czech Republic studied great tit parents and chicks in around 85 nests over a period of several years. The researchers studied the chicks’ weight, size and immune strength as the young birds matured. In some of those nests, they swapped chicks, so that great tit parents were taking care of babies that were not genetically related to them.

The team found a correlation between a chick’s weight at two weight and the size of its genetic mother’s black breast stripe. This suggests that nature, rather than nurture, may play a stronger role in a chick’s size.

But the immaculateness of a mother’s white cheek patch, they found, corresponded to her chick’s immune strength, regardless of whether the baby was her own or a foster chick. This suggests that nurture as well as genetics plays a role in how strongly a chick’s immune system develops, the researchers explain in a statement.

The male great tit’s stripes and white patches, the researchers found, had nothing to do with how their offspring turned out.

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Rachel Nuwer | | READ MORE

Rachel Nuwer is a freelance science writer based in Brooklyn.