We always know summer is coming straight away when we see the warbler, just as we know winter is here by the first snowflake. And as soon as they arrive nesting begins. For that very purpose they come, of course. As to the nests, they are very beautiful. The one in the picture must have been built deep in the woods, where grasses and dried leaf tatters were plenty. But there is no set pattern to go by, when nests are made. That is, there is no particular building material allowed, as with the swallows and some others. The yellow warbler loves best to use things that mat together readily, so the nest cup will be compact and thick, like a piece of felt cloth--so different from the nest of the grosbeak, transparent and open, like basketwork. To get this cloth-like substance, the birds visit the sweet-fern stalks of the pasture sides, pulling off the woolly furze bit by bit, until a beakful is gathered. Then they make a trip to the brooks, especially in early spring, where they wake up the catkins on the pussy-willows and get loads of the soft fur. Oh, the secrets the pussy-willows know, about bird and bat and butterfly cocoon, and other winged people that frolic in their shadows! They could tell you exactly how many beakfuls of pussy fur it takes to weave a crib blanket for a yellow warbler's nest. Whole nests are made of it sometimes; for the warbler loves to gather one particular kind of material for a nest if sh& comes across enough of it in one spot. That is why they build so rapidly, always getting it done in a hurry. They love big loads of anything, and the male shows his mate where she can find it with the least trouble. In places where sheep pasture, rubbing against trees and catching their sides into thorns and sticks at every turn, the yellowbird gathers the wool. She likes this particularly, as it is light and clings to itself, and she can carry large quantities at one trip. The happy boy or girl who has a pasture near by home is rich. There is nothing like a pasture to study nature in, especially birds. A wood lot with trees of all sizes in it, a cranberry bog, a huckleberry patch, a maple grove, a sweet-fern corner, with snake vines running at random among young brakes--ah! this is the spot of all the world for nature-lovers and birds. One can part the bushes and find a warbler's nest most anywhere. One can peer up into the treetops and find another. In the treetops the nest is fastened securely, be it where the winds have a habit of blowing through their fingers when it isn't necessary. But birds and winds are fair play-fellows and seldom interfere with one another. Here, in southern California, we have little wind, if any, in the days of the summer yellowbird. So nests are often set in a crotch without a bit of fastening.