Bioacoustics of Sporophila palustris

Early in February, 1880, two specimens of an unrecognized Finch were seen the the writer on the edge of a marsh at Concepcion where coarse grass is cut for thatching the houses of the humbler classes. One of these birds was secured and pronounced by Dr. Burmeister of the Buenos Aires Museum to be new to the fauna of the region, so far as he was aware. A careful lookout for other specimens was kept, but nearly ten months elapsed before another individual was taken. Resting one hot November noon in the scanty shade of a bush on the edge of one of the large marshes which border the lower Uruguay, my ear caught the notes of a song which seemed at first to be that of the common Goldfinch of the country ( Chrysomitris mugellanica ) but which, as it rambled on, developed a variety and sweetness far beyond the powers of that bird. An attempt being made to approach the bird, however, it developed other powers of a more practical and (to me) less satisfactory kind, and it was only after a half-mile chase through an indescribable mixture of land, water, and grass — the latter predominating — that a lucky third shot brought it down and a long hunt among the roots of the eight-foot grass brought to light this tiny Spermophila . Before the gun had been reloaded, or the bird wrapped up and put away, another male appeared, and in the course of an hour or two three ınore specimens, all males, were added to the first. Many more were seen and several killed, but the nature of the ground made it very difiicult to mark them down and find them, while their motions were so quick. and the grass so thick and high, that not one shot in three counted. No females were seen at this time, but within the next two weeks four more males and two females were taken. That they were nesting in the marsh there is little doubt, but that the nest escaped detection is not strange. The birds were never seen in flocks nor did they often associate with the “ Corbatitas. " The males were oftenest seen chasing each other over the marsh or pausing on the top of some tall grass stem or blighted bush to pour out their delightful song. Occasionally I caught a glimpse of a small bird in a flock of Sycalis luteiventris , which seemed to be unlike anything except this little Spermophila , yet may easily have been mistaken. Our little Finch is too fond of the open marsh, the society of the Wood Ibis and Courlan, and the rustling of the knife-edged giantgrass, to be found far from such haunts, and so long as he swells his snowy throat only in such company he need fear little from man.