All those species that are liable at any time to become the victims of raptorial birds are very much beholden to this Swallow, as he is the most vigilant sentinel they possess. When the hurrying Falcon is still far off, and the other birds unsuspicious of his approach, the Swallows suddenly rush up into the sky with a wild rapid flight to announce the evil tidings with distracted screams. The alarm spreads swift as light through the feathered tribes, which, on all sides, are in terrified commotion, crouching in the grass, plunging into thickets, or mounting upwards to escape by flight. I have often wondered at this, since this swift-winged and quick-doubling little bird is the least likely to fall a prey himself. They possess another habit very grateful to the mind of every early riser. At the first indication of dawn, and before any other wild bird has broken the profound silence of night, multitudes of this Swallow, as if at the signal of a leader, begin their singing and twittering, at the same time mounting upwards into the quiet dusky sky. Their notes at this hour differ from the hurried twittering uttered during the day, being softer and more prolonged, and, sounding far up in the sky from so many throats, the concert has a very charming effect, and seems in harmony with the shadowy morning twilight. 30. ATTICORA CYANOLEUCA (Vieill.). (BANK-SWALLOW.) +Atticora cyanoleuca+, _Burm. La-Plata Reise_, ii. p. 479; _Scl. et Salv. Nomencl._ p. 14; _Hudson, P. Z. S._ 1872, p. 844 (Buenos Ayres); _Durnford, Ibis_, 1876, p. 158 (Buenos Ayres), 1877, p. 32 (Chupat), p. 170 (Buenos Ayres), 1878, p. 392 (Central Patagonia); _White, P. Z. S._ 1882, p. 596 (Catamarca); _Barrows, Bull. Nutt. Orn. Cl._ viii. p. 90 (Concepcion, Bahia Blanca); _Sharpe, Cat. B._ x. p. 186. _Description._--Above dark glossy blue; quills and tail-feathers black; cheeks and under surface of body pure white, the sides of the neck blue, descending in a half-crescent on the sides of the chest; sides of body and flanks brown; under tail-coverts black; bill and feet black: total length 4·7 inches, wing 4·05, tail 2·2. _Female_ similar. _Hab._ Central and South America.