The bird looks like a northern spotted owl -- the threatened dweller of old-growth forests of the Pacific Northwest -- only bigger. It also resembles a barred owl -- a species common across the continent. But on closer inspection biologists say it is a cross between the two.

Discovery of the hybrid, one of only two to be confirmed, was made near Mount Baker in the northern Cascades Range of Washington. It suggests the dwindling species may be threatened not just by loggers destroying its habitat but by hybridization draining its gene pool. The two species belong to the same genus.

Like a barred owl, which is known for a call that sounds like maniacal, human laughing, the hybrid has similar markings on the back of its nape and head. Its breast looks more like a spotted but has a larger white area and a bigger buff patch below its neck. Where the spotted owl has round spots on top of its head, the hybrid has rectangular bars. Its facial coloring is between that of the parent species. The bars on its tail resemble a spotted owl's, they are farther apart.

Biologists say the male hybrid has been paired with a barred female for two seasons, but it is not known whether the pair have reproduced. Another hybrid has been confirmed near Medford, Ore., and it is rumored that two others may exist in the Northwest.

"We don't want to blow this out of proportion because we don't really know what this means," said Don Utzinger, a wildlife biologist in the Mount Baker ranger district of the Mount Baker Snoqualmie National Forest. "We have a few isolated cases of hybrid owls and we have lots of people out in the woods and they're going to be keeping their eyes open to see what else there is."