WASHINGTON -- Researchers in Britain observing new Caledonian crows have determined that the female birds are not only capable of using tools but can modify them to assist their feeding, their study published Friday said.

The study in ***Science*** magazine tracked the crows' ability to use bent or straight wires to spear food in the bottom of a narrow plastic tube.

In 10 valid trials, with seven invalid ones interspersed, the researchers from Oxford's Zoology Department saw the captivity-raised female bird bend a piece of wire and use it to retrieve her food nine times, in a task she had never been taught nor been seen to perform.

The male bird used the straight piece of wire to stab the food and retrieve it once.

In all of the valid trials, it took each bird less than two minutes to retrieve its food, AFP reported.

Observations of the new Caledonian crows "raise the possibility that these birds may rival nonhuman primates in tool-related cognitive capabilities," said study co-author Alex Kacelnik. "Our finding, in a species so distantly related to humans and lacking symbolic language, raises numerous questions about the kinds of understanding of 'folk physics' and causality available to nonhumans."