Tachycineta thalassina May 7 - San Joaquin Experimental Range, alt. 1000', Madera Co., Calif. one (or 2?) adults were carrying nest material in small wisps into a cavity on the under side of a horizontal limb of Quercus douglasii about 15 feet up. The bird(s) would swoop in thru branches of tree canopy and past the bigger limbs & out again when we were too close; but several times one was seen to go directly into the hole without perching at the rim: limb of tree We could not reach the cavity & do not know how extensive it was within the limb. It was undoubtedly of woodpecker origin, as were 4 or 5 other holes higher up on main, nearly vertical trunks of tree.