Cliff Swallows Connect Geology and Ornithology

The basalt columns featured in today's picture were formed by molten magma oozing across the surface of the earth for millions of years. Cooling slowly, it contracted into hexagonal and pentagonal columns. Time, erosion and great floods plucked away blocks, leaving overhangs and ledges, protected homes for our tiny insect-eating summer residents. Here in force since early May, the Cliff Swallows are busily working on building their nests. Their technique is to scoop a mouthful, or rather a beakful, of mud from the shore of the river, fly to the basalt cliffs, deposit the miniature adobe-like brick, and repeat, over and over again. Each nest contains thousands of building blocks necessitating just as many trips to the river. Wings fluttering, they hover on tiptoes, pushing the ball of mud like a tiny snowball. Like an all-night disco, the action never stops on the bank of the Palouse.