NORTHWESTERN MEXICO. 313 



Fam. Anatid^. 



270. Anser gambelii Hartl. 

 Mazatlan, Grayson. 



" From the month of September until February in considerable flocks ; appear to migrate up and down the 

 southern gulf shores." 



271. Bernicla canadensis var. occidentalis Baird. 

 Durango, Grayson. 



" I met with this species in flocks, on the I'oad to Durango, between tlie Sierra Madre mountains and the 

 city of Durango, in the montlis of February and March. But I have never seen or heard of one west of the 

 Cordilleras in this locality." 



272. Dendrocycjna ftdva (Gm.). 

 Mazatlan, Grayson. 



"There are two species of this remarkable genus found in Western Mexico, considerably resembling each 

 oilier ill their general appearance, as well as in their natural habits. They .are both natives of the Tropics, 

 and are quite abmnlant in Western Mexico, as far north as Sonora. Our present species being the most nu- 

 niei'ous ill this locality, I will fiist treat of. 



"At the conclusion of the rainy season, or the month of October, they make their appearance in the vicinity 

 of Maz:itlan, San Bias, and soutliward, in large flocks ; inhabiting the fresh water ponds and lakes in the coast 

 region, or tierra caliente, during the entire winter, or dry months, subsisting ])rincii)ally upon the seeds of 

 grass and weeds, and often at night visiting the corn-fields for grain. During these months I h.ave found them 

 in the shallow grass-grown ponds in very large numbers, affording excellent sport to the hunter, and a deli- 

 cious game for the table ; their flesh is white, juicy, and feeding upon grain and seed, is free from the strong 

 or rank flavor of most other ducks ; they are rather heavy or bulky, and usually fat. They are more easy to 

 a]iproach than our northern species; I liave shot as many as fifteen with the two discharges of my double- 

 barrel. When only winged tliey are almost sure to make their escape, which their long and stout legs enables 

 them to do, running and springing with extraordinary .agility, and ultimately eluding ]iursuit by dodging into 

 the grass, or nearest thicket ; if the water is deep they dive, and as they rise to breatiie, having only the head 

 above water, and that concealed among the water plants, they are soon abandoned by the hnntei-. 



"Althougli its geograpliical range is confined within the limits of the Tropics, yet this si)ecies has its seasons 

 of periodical migrations from one part of the country to the other ; during the month of April their well- 

 known and peculiar whistle may be heard nightly as they are passing over Mazatlan in ai)parently large flocks, 

 going northward. At first this phenomenon puzzled me not a little, as I well knew that they are not often 

 found for north of the Tropics, except an occasional str.aggler. But I was at length enlightened as to their 

 point of destination ; by frequent enquiiies of the natives, I was satisfied that tliey went no farther north 

 than the Mayo and Yaqui Rivers, in Sonora, and the adjacent lakes and lagoons, where tliey breed. Some, 

 however, remain and breed in the State of Sinaloa, and the adjoining localities. I found young broods near 

 San Bias that were unable yet to fly as late as the inontli of November. They doubtless rear two or more 

 broods during the season. I never have been able to discover their nest, nur liave I been s.atisfied as to 

 whether they nest in hollow trees, as its near ally does, or whether it forms a nest on tiie ground among the 

 grass, which latter su]iiiosition, I have been infinaned by the natives, is the case; the natives also tell me they 

 lay.teii to fifteen pure white eggs. It inhabits the region near the seacoast, lint is never met with in the sea, 

 and very seldom in the estero or salt water lagoons, being entirely a fresh water duck." 



273. Dendrocygna autumnalls (Linn.). 

 Mazatlan, Grayson, Bisclioff". 



"The habits of this sjiecies are no much like its preceding near ally (D./iiliyi) as to leave but little room 

 for any addition.)! reniaiks. It is, however, more nocturnal in pursuit of subsistence, visiting the dry corn- 



MEMOIRS BOST. Sue. NAT. HIST. VOL. II. 79 



