Two years ago a pair came to the house grounds, the first we had seen so near. We wondered what they would nest with first, knowing their disposition to take the material close at hand. We knew they strip the down from the backs of the sycamores in the mountain cañons, and gather bits of wool fiber from tree trunks, or ravel lint from late weed stems in the arroyos. So we anticipated and shook loose cotton-batting in a bush. No sooner did father yellowbird spy the fluffy, white stuff than he brought madam, and she was delighted. This cotton could be pulled by beakfuls, and an afternoon or two would make the entire nest. And they used it, not getting another thing save some gray hairs from a lady's head, which in combing had escaped, and were saved on purpose for the birds. The nest was placed in the crotch of a pepper-tree, just out of reach of tiptoe inquirers. Just one pinch of cotton above another until the cup was deep and true to the shaping of the mother's breast, she turning round and round after the manner of nest-builders. Through the layers ran separate hairs which held the cotton in shape. It was a beautiful thing, that nest, even after it had served its purpose, and we took it down when the birds had flown. That was a mistake of ours. It was before we had come to know it is better to leave old nests undisturbed. Many birds love to return the coming season and repair last year's structures. When the following summer came, and the yellowbirds returned from their winter in Mexico, they went straight to the same old tree. They crept up and down the trunk, peering into all the crotches, and criticising every place where a nest might have been. Perhaps a single speck of the cotton had 'remained and served for "a pointer"; anyway, the birds located the exact spot and went to work without more ado. Exactly as though they remembered, they went also to the supply counter where we had placed more cotton in advance of their coming, and with it they built exactly the same white nest in the very crotch of last year's happy history. It was a pretty sight to see the mother take the cotton. It looked sparklingly white against her breast and dripping from her beak. And all the time she was arranging it in the nest to suit her experienced mind, her mate sang, warbling his sympathy, darting through the leaves, and running up and down the branches. This running up and down the boughs, so like their cousins, the creepers, makes this bird look graceful of form and motion, as indeed he is, anywhere and at anything he does. On this account he is often called the gem-bird, his brilliant grace suggesting some precious and coveted stone. These warblers of ours did not feign lameness, if we came near the nest, as some of the family are said to do. From daily companionship they came to know and trust us. Had the nest been a little lower we should have succeeded in taming them completely, as we have many of the wild birds at nesting-time.