With most species of our birds the nest is entirely built by the female. With the robin, the wood thrush, the phœbe, the oriole, the hummingbird, the pewee, and many others, the male is only an interested spectator of the proceeding. He usually attends his mate in her quest for material, but does not lend a hand, or a bill. I think the cock wren assists in nest-building. I know the male cedar-bird does, and probably the male woodpeckers do also. The male rose-breasted grosbeak assists in incubation, and has been seen to sing upon the nest. It seems fair to infer that he assists in the nest-building also, but I am not certain that he does, and I have heard another observer state that in a nest which he watched the female apparently did it all. My catbirds both worked overtime one afternoon at least, being on their job as late as seven o'clock. In three days the nest was done, all but touching up the interior. During the construction I laid out pieces of twine and bits of white paper on the bushes and wire netting, also some loose material from the outside of the old nest; all was quickly used. How much labor the birds would have saved themselves had they pulled the old nest to pieces and used the material a second time! I have known the oriole to start a nest, then change her mind, and then detach some of her strings and fibers and carry them to the new site; and I once saw a "chebec" whose eggs had been destroyed pull the old nest to pieces and rebuild it in a tree a hundred feet away. The male catbird is slightly brighter and fresher-looking than his mate, but we could easily tell her by her often simulating the actions of a young bird when she came with material in her beak; she would alight on a near-by post and slightly spread and quiver her wings in a tender, beseeching kind of way. She would do this also when bringing food to her first brood. When one of the parent birds of any species simulates by voice or manner the young birds, it is always the female; her heart would naturally be more a-quiver with anticipation than that of the male. On the fifth day the nest was completed and received its first egg. There was considerable delay with the second egg, but it appeared on the second or third day, and the third egg the following day. Then incubation began. In twenty days from the day the nest was begun, the birds were hatched, and in eleven days more they had quietly left the nest.