Sept., 1914 
SURVEY OF BREEDING GROUNDS OF DUCKS 
237 
pointed to find that it had been destroyed. Let me cite several instances. We 
marked a Cinnamon Teal’s nest containing five eggs and a Gadwall’s nest 
containing nine eggs. On returning we found both of them raided and every 
egg destroyed. A Pintail’s nest found one day, when examined the next morn- 
ing was found to have been raided and all but four eggs destroyed (see fig. 
70). On one occasion we found a Cinnamon Teal incubating three eggs, while 
around the nest there were evidences that several other eggs had been de- 
stroyed. On returning to the nest later we found that two other eggs had been 
removed and the bird had deserted her nest. A Fulvous Tree-duck’s nest con- 
taining twelve eggs and well concealed on a weed-covered island was raided 
during our stay and every egg broken. 
Our attempts to find out the particular species of animal doing the work 
proved unavailing. In most instances nests were placed in a growth of grass 
or sedge where no tracks were discernible. In other cases the soft mud at the 
bottom of the shallow water did not permit tracks to remain long in evidence. 
Raccoons were extremely common, and in some places near clumps of tules 
paths were found where their foot prints were plentiful. The fact that in some 
cases the animal had to wade through water to reach the nest which we found 
destroyed, also lends support to the theory that coons were largely responsible 
for the depredations. A number of weasels were seen during our stay, and 
coyotes were said to be common. It is possible that these two predaceous ani- 
mals also took part in the destruction of nests. 
Irrigation as praticed at Los Banos is also responsible for the destruction 
of many nests. Mr. Paul J. Fair, who has worked in this vicinity for some 
time, told me that he found many inundated nests. In some places the water 
was clear enough for him to see nests and eggs completely submerged a foot 
below the surface of the water. Dr. Frank M. Chapman, when visiting this 
locality in the summer of 1903, found similar conditions. He states: “Evi- 
dently the abnormal and sudden rise of the water, as well as the equally un- 
usual fall, prevents many birds from rearing young. I found numbers of 
flooded nests in May, which had been built when the water was still rising, 
while disappearance must have been even more disastrous.” Water is contin- 
ually rising or lowering. The rising of the water floods the nests and the low- 
ering allows the approach of predaceous animals to the nesting sites. 
Still another factor is found in the large herds of cattle which are pastured 
here. We found two nests which had been trampled by cattle, and Mr. Fair 
tells me that he also found several nests which had been destroyed in like man- 
ner. 
A rather remarkable state of affairs therefore exists in this locality. The 
nesting grounds were made available by the formation of pasture land out of 
originally arid plains, and yet the same factor, irrigation, instrumental in cre- 
ating these excellent grounds, is responsible for the destruction of many nests. 
The reclamation, even of swamp land, does not always entirely destroy the 
nesting grounds of ducks. A letter from Mr. Wm. N. Dirks dated May 18, 
1914, records the discovery of two nests of Mallard, one of Pintail and five of 
Cinnamon Teal. These were uncovered while the grain was being mowed on 
a ranch at Alvarado, Alameda County, California. On Lower Klamath Lake 
Ave were told by a rancher that he had found several Mallard’s nests in his rye 
field earlier in the season. Other ranchers told us that Mallards and Teal com- 
monly nested in grain and alfalfa fields. It is certain, therefore, that some 
of our ducks adapt themselves to changed conditions. 
