Cardinals at the feeder
For cardinals, who’s at the feeder is more important than what’s in it
Published: February 15, 2013
Prevailing wisdom dictates that when birds select what to eat, and where and when to forage, they weigh the benefit against the risk of predation and choose accordingly.
Intrigued by the notion that birds’ behavior may be more nuanced, researchers from Davidson College set up feeding stations around campus in January 2010. At each site, they filled one feeder with black-oil sunflower seeds and another with safflower seeds. Then they recorded which feeders were visited by Northern Cardinals.
Since sunflower contains more fat than safflower, the investigators expected the birds to prefer the sunflower, and as long as no other cardinal was present, they did.
But once the social situation changed, so did the foraging decisions. Females avoided feeders that were occupied by other cardinals, male or female, and they flew away when males arrived. Male cardinals also avoided feeders where males were feeding, but they approached feeders occupied by females, regardless of feeder contents.
Why would a male displace a female for a less-preferred food? “It seems likely that males may be under selective pressure to initiate contact with females before females are willing to reciprocate,” suggest the scientists. “Consuming a safflower seed for a male cardinal with regular access to a feeder containing sunflower seeds may be worth the opportunity to interact, however briefly, with a female.”
The researchers published their findings in the Wilson Journal of Ornithology.