Ultralight video cameras fastened to the tail feathers of crows have shown the birds to be versatile tool-users in the wild.
The first-of-its-kind study reveals that wild New Caledonian crows use a greater variety of tools and foraging techniques than had previously been thought, researchers say.
So far, research on captive birds has demonstrated the species' remarkable cognitive and tool-making abilities.
And field studies of remnants left by tool-making birds—such as leaves that had been bitten into strips to serve as probes—had also suggested that tool use is common in wild populations.
But researchers had few direct observations of crows making and using tools in a natural setting, due to the difficulty of actually watching their behavior in the birds' dense forest habitat.
New Caledonian crows live in mountainous forests on islands in the South Pacific. In the wild the species is highly sensitive to disturbance by human observers.
A research team led by Christian Rutz of the University of Oxford in England solved this problem by mounting tiny cameras on the tails of individual birds.
The 13-gram (0.5-ounce) cameras—slightly heavier than two U.S. quarters—provide the closest thing yet to a bird's-eye view of behavior in a natural setting.
"The lens is pushed forward through the central tail feathers and peeks through the bird's legs," Rutz said. "You have a shot showing part of the crow's belly and whatever appears in front of the bird."
Rutz and colleagues describe their bird-mounted video cameras in this week's edition of the journal Science.
Unexpected Behaviors
Although their pilot study was intended primarily as a demonstration of the new technology, the researchers gained important new information about the crows' life in the wild.
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