MY LESSON Sight identifications of most students probably contain errors. On common species it's not important, as quantitatively they cancel out. But when a bird tripper, anxious to make a new record, wants me to help him decide he saw an exotic tern, I'm very careful--I've had experience. Rarities have to be checked on all points, not identified by elimination or on a few key characters. One of the best lessons of caution I had in New Guinea. It was in the mountains. Each morning I hunted in a forest where I'd found a new genus of bowerbird. Anything might occur, I thought. Then I saw flying through the treetops what could only be a magpie. A long-tailed, black and white bird, its pattern was unmistakable. There was nothing like it known from New Guinea. It would be an extension of range from Asia. Or it was a new and unknown species. Anyway I needed it as a specimen. But it was shy and eluded me. Morning after morning I haunted the forest. Finally I got the bird. And it turned out to be a partly albinistic specimen of a common, black, long-tailed bird of paradise. The abnormal white areas in its plumage had fooled me completely. But it helped teach me caution as to sight identifications. One of my Gary friends, Mr. Raymond Grow, who is a keen bird student, has the proper approach, as his identification of a winter duck showed. There were a number of unusual winter birds that season (1951-52): brown-headed chickadees, pine and evening grosbeaks, and red-breasted nuthatches, all from the North, were present. It was the sort of winter one expects other rarities from the North. DUCK CAUSES CONFUSION Mr. Grow had seen at the edge of Lake Michigan a duck he didn't know; it was boldly patterned in black and white, a big duck. An immature male eider seemed the only possibility. He came into the museum and we went over specimens, noting the difference in the shape of the head between the king and the common eider. He studied the descriptions and the plates. Nothing quite fitted. Unsatisfied, he went back to Michigan City, found the duck again, and suddenly realized it was a muscovy duck, partly albinistic, and escaped from someone's barnyard. It's not the first time a muscovy has caused confusion. Only a year or so ago we had a duck sent us from the Philippines that our correspondent wrote was shot swimming in a river with a Philippine mallard and surely represented a new species. But it turned out to be a muscovy whose original home is tropical American but has become domesticated and transported by man to far parts of the globe. Occasionally birds escape and take to the wild, even as this Philippine bird had done. GREEN HUNTING JAYS TURN BLUE [Illustration] Sometimes in "working out" a bird collection things get dull. In identifying the specimens, and writing down why they are this species, or that species, or subspecies, it seems routine; as though it were simply routine putting things in the categories ready for them.