Birds of a Different Feather Sometimes Flock Together
It is exceedingly rare to see birds of different species socializing, but birders will occasionally witness interspecies preening, in which one species grooms another, usually picking at parasites in the process. Now ornithologists are trying to explain the unusual behavior.
Texas birder Lora Reynolds captured images of the phenomenon in San Antonio’s Phil Hardberger Park, where she spied a black vulture preening a crested caracara. Both birds are carrion eaters, but the caracara is also a raptor in the falcon family. Raptors are generally not the friendliest of neighbors.
Ecology and Evolution
Biologist Lori Boies saw the preening pics Reynolds had posted on social media and realized she had witnessed similar behavior of the same two species, about a mile away from the park the year before. Boies and a couple of colleagues wrote up her sightings in a report published this year in the journal Ecology and Evolution.
The bird experts call it “interspecific allopreening,” which, among birds of the same species, is a common social behavior that helps maintain feather health, reduce parasites, and build relationship bonds. The cross-species behavior has, until now, only been recorded in rural areas in Texas and in Central and South America. The San Antonio sighting is the first to be seen in an urban environment.
“This supports the theory that human-modified landscapes can promote wildlife interactions and reveal behavior rarely seen in rural habitats,” the authors conclude in the study.
Boies and colleagues suggest that urban green spaces like the park in San Antonio, a small green oasis in the middle of suburban development (and not far from the airport), forces bird populations to share territory. Rather than fight over it, they appear to be just trying to get along.
Of course, it could also be the case that the concentration of birds and humans in one area simply increases the odds of observing the weird behavior.
Photo credit: Lora Reynolds-Shaw / Phil Hardberger Park Conservancy
