Watch out! This colorful bird raises a nest of cannibals

It might seem wasteful, but many birds lay more eggs than will successfully hatch. Scientists have long believed these extra eggs represent a form of insurance, ensuring that at least some offspring ultimately leave the nest. But for the Eurasian hoopoe—known for its showy orange crest and the whooping cry that gives the bird its name—a new study suggests these extra eggs exist for a gruesome reason: to feed the youngest nestlings to older chicks. The “exceptional” study shows how sibling cannibalism can provide evolutionary benefits, says Michael Schaub, an ornithologist at the Swiss Ornithological Institute who wasn’t involved with the work. Researchers have observed siblings killing each other—siblicide—in many kinds of birds, including Verreaux’s eagles, ospreys, and blue-footed boobies. But chicks eating their siblings is a different ball game altogether, says Juan José Soler, an author of the new study and an evolutionary ecologist at the Experimental Station of Arid Zones in Spain. “Sibling cannibalism occurs only sporadically in birds,” he says, and typically involves “nestlings that were dead from other causes.” In an earlier study, however, Soler had shown that hoopoe mothers frequently feed younger chicks to older chicks. And he suspected that hoopoe mothers laid extra eggs with the intention of using the hatchlings as food. To explore that idea, María Dolores Barón, one of Soler’s graduate students, an...
Source: ScienceNOW - Category: Science Source Type: news