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.
We have left the nest where it is this fall, hoping the birds will return and claim it another year. It being of cotton, however, and having no threads to bind it in the crotch, we think the winter storms will wreck it.
It has been claimed by good authority that the cow-bird loves to deposit her eggs in the yellow warbler's nest. But this is of little avail to the cow-bird's trick, for Madam Warbler sees the point and the egg at a glance. She often builds above the intruder, imprisoning the alien egg, and so leaves it to its fate. A single bird is said to have built above the cow-bird's egg three times in succession, as the intruder persisted, until there were four floors to the nest, on the last of which the mother succeeded in laying her own eggs. If she becomes discouraged by the persistency of her guilty neighbor, she will leave the spot sometimes and search for another in which to carry on her own affairs in peace.