Hawks Act as Unwitting Muscle for Hummingbirds

Conservationists say nature is interconnected. Remove one species from an environment, and unrelated ones may suffer.

An invisible thread links hummingbirds and hawks. Black-chinned hummingbirds nest among northern goshawks and Cooper's hawks in Arizona. The small hummingbirds survive the giant raptors, but the Mexican jay, their nest predator, does not, and the birds seem to know this.

Ornithologists have long seen a strange gathering of hummingbird and hawk nests, but no one knew why. Scientists from Ecuador, the U.S., and Canada monitored hummingbirds, hawks, and jays in the Chiricahua Mountains for three nesting seasons to unravel the mystery.

They found a substantial association between hummingbird nesting success and hawk presence, which hummingbirds seem to seek seeking. Only 20% of the 342 humming bird nests the scientists identified were outside hawk nest range.

The scientists also found that hawks explain about one-third of jays' foraging behavior using a statistical model. Jays appear to actively change their food-finding techniques based on the chance of becoming hawk meal.