486 
LAMELLIROSTRAL SWIMMERS — ANSERES. 
meister cites it as having been noticed in varying numbers in all the easterly and 
northerly regions of La Plata, on the Rio Uruguay, and on the Parana as far up as 
Tucuran. This Duck — supposed by Leotaud to be the bicolor of Vieillot — is said 
by the former to occur in Trinidad, but to be found there chiefly as a bird of passage, 
visiting that island very irregularly. Occasionally it comes in considerable numbers, 
nests in the island, rears its young, and even has a second and sometimes a third 
brood before it departs. It then abandons the island, and is gone for several years 
without repeating its visit. Its habits, so far as Leotaud observed them, are pre- 
cisely the same as those of the a/utumnalis, and its flesh — like that — is also very 
highly esteemed by epicures. 
Colonel Grayson — quoted by Mr. Lawrence — gives very full notes of the habits 
both of this species and of the autunmalis, as observed by him in Western Mexico. 
Both species much resemble each other in their general appearance, as well as in 
their habits; and both are quite abundant in Western Mexico as far north as Sonora. 
The present species is the most numerous in that region. 
At the end of the rainy season, or in the month of October, this bird makes its 
appearance in the vicinity of Mazatlan in large flocks, inhabiting the fresli-water 
lakes and ponds in the coast region, or tierra caliente, during the entire winter, or 
dry months, subsisting principally upon the seeds of grass and weeds, and often, at 
night, visiting the corn-fields for grain. During these months Colonel Grayson has 
found it in the shallow grass-grown ponds in very large numbers, affording excellent 
sport to the hunter and delicious game for the table. Its flesh is white and juicy, 
and also free from the strong or rank flavor which Ducks not feeding exclusively on 
grain and seeds usually have. This bird is large and heavy, and often very fat. 
It is more easy of approach than our northern Ducks ; and Colonel Grayson states 
that he has often shot as many as fifteen with two discharges of his double-barrelled 
gun. When only winged, it is almost sure to make its escape, which its long and 
stout legs enable it to do by running and springing with extraordinary agility, ulti- 
mately eluding pursuit by dodging into the grass or nearest thicket. If the water is 
deep, it dives, and when it rises to breathe, raises only the head above the water, 
remaining concealed among the aquatic vegetation, where it baffles the hunter’s efforts 
to find it. 
Although its geographical range is almost entirely within the tropics, yet this 
species has its seasons of periodical migration from one part of the country to the 
other. During the month of April its well-known peculiar whistle may be heard 
nightly as northward-bound flocks are passing in apparently large numbers over 
Mazatlan. At first Colonel Grayson was not a little puzzled by this movement, 
especially as he had been assured that this bird is not seen north of the tropic, 
except as an occasional straggler ; but by frequent inquiries of the natives he was 
enlightened as to the point of destination of these Ducks, and was satisfied that 
they go no farther north than the Mayo and Taqui rivers, in Sonora, and the adja- 
cent lakes and lagoons, and that they breed there. Some, however, remain and breed 
in Sinaloa and in the adjacent region; and Colonel Grayson found, as late as Novem- 
ber, young broods near San Bias which were unable to fly. They doubtless raise two 
or more broods during the season; but he was never able to discover whether they 
nest in hollow trees, as the autumnalis does, or on the ground, among the grass. He 
was informed by the natives, however, that the latter is the case ; and they assured 
him that this bird lays from ten to fifteen pure white eggs. Though it inhabits the 
region near the sea-coast, this Duck is never met with on the sea, and very seldom 
in the estero, or salt-water lagoon, it being an exclusively fresh-water bird. 
