At no other time is there such concerted singing among the song-sparrows as in these first days of the arrival of any considerable flocks. From bare fields and brown hedgerows arises this simple and spontaneous expression of joy, a primitive invocation to the goddess Spring, fresh and clear and innocent as the morning itself. As they hop about among the dry weeds, one will now and then pick up a straw and hold it meditatively a moment with some premonition of the nest. Presently they will be flitting among the still leafless brambles and briers with an air of secrecy and importance. Some bright morning in March there comes to the listening ear the song of the purple finch--a wild sweet strain with the abandon of gipsy music, which thrills with its very wildness and unrestraint. Anon Phoebe arrives with dry little voice and familiar swoop after the first incautious fly. Every season has its characteristic song. More than all others is the voice of the hyla, essentially springlike and to be associated with no other time. For several days there has been an occasional desultory chirp from the woods, when of a sudden, some clear evening, there comes out of the stillness that wonderfully sweet piping of little frogs. Fresh and ringing as child voices, it has, at a distance, a certain rhythm, a soothing cadence, which lulls the ear like the musical patter of rain-drops in summer showers. Put your ear close to one--if you can find him--and the sound is deafening, so loud and shrill it pierces to the very marrow. The small creature sits in some low shrub in the swamp, grasping a twig on either side as with tiny hands, while it inflates its air-sac from time to time and sings the love-song of its race. Heard afar, how soft and pleasing are these answering calls of the hylas which are the very voice of the evening itself. About the time the hylas begin to sing in chorus, you may look for the appearance of the leopard-frog. He is to be heard at midday in his pond uttering a most deliberate and prolonged snore, evenly and smoothly drawn out, as if his sleep were dreamless and content. Presently there is an answering snore, full as deliberate and serene, from across the pond, followed by long intervals of silence. Very different from this somnolent song of the leopard-frog is the shrilling of garden-toads. Not every one would recognize the solemn and dusty toad of the flower-beds, that flops from under the feet in the dusk, in this brighter colored creature, floating at full length in the shallow water, his air-sac inflated before him like a parti-colored bubble. The shrilling of toads fills the air; they are under a spell, a witchery, which has set them all to chanting this single strain--high-pitched and subdued--with a sort of mild frenzy.