Redder is healthier in squawking birds

When barn swallow nestlings open wide and say “Ah,” parents may check their health much as human moms and dads peer anxiously down Junior’s throat.

Parents of barn swallows, however, may be looking for the healthiest throats so they can pop food into the youngsters most likely to survive, according to Nicola Saino of the University of Milan in Italy and her colleagues.