We soon discovered that in Argentina we were not at liberty to carry on our work in any place or manner that suited our purpose; in other words, there were game-laws, closed and open seasons, and it was necessary to secure permits from the owners of all lands on which we proposed to hunt. Of all these restrictions we were ignorant, and spent a blissful three days doing as we pleased; then a sergeant of police called and notified us that we were under arrest, and to call at headquarters as soon as convenient. I lost no time in going to see the chief, explained the nature of our work to him, and then acting on his suggestion took the next train to Salta to get a permit which entitled us to hunt anywhere within that province. All this was accomplished within a few hours. The various officials with whom I came in contact were most courteous and obliging. Our study of bird-nesting at Rosario de Lerma was confined largely to observing the parasitic habits of the black cowbird (_Molothrus b. bonariensis_), referred to by the Spanish-speaking people as the “tordo.” The bird usually called tordo, however, is a species of oriole, highly esteemed as a cage bird on account of its not unmusical singing ability. This bird is of slender, graceful build, about the size of a red-winged blackbird, and of a uniform glossy, purplish-black color except on the wings and tail, which have a pronounced greenish sheen. The female is of a dark, ashy-brown color. We saw flocks of them daily in the fields, on the backs of cattle grazing in the pastures, in the courtyards of houses, in corrals, and more particularly in the scattered trees, which were almost certain to contain at least one nest of the oven-bird (_Furnarius_) or of some species of brush-bird (_Phacellodomus_). Usually the flocks were composed of from ten to twelve individuals, the bright, glossy males outnumbering the dull, grayish females in the proportion of four to one. Azara gives the proportion of males to females as ten to one, but this disparity is too great for any part of the Argentine known to me. The birds are noisy, keeping up a loud chatter, especially where a flock is on the wing, or when preparing for the night’s sleep. The male bursts into a short, pretty song with frequency, dropping his wings and moving in a nervous manner while singing. Apparently the female does not sing. It has been said that the females of this species lay eggs during a period of three or four months; to know how many are laid by a single bird would be interesting, as the number must be very great in order to make allowance for the incalculable numbers that are wasted, and still provide enough to keep the ranks of the multitudes at their normal level. We did not find a single egg of _M. b. bonariensis_ on the ground, although Hudson states that in the vicinity of Buenos Aires these birds “frequently waste their eggs by dropping them on the ground.”