WILD DUCKS OF THE BEAE EIVER MARSHES, UTAH. 
Species. 
Redhead 
Cinnamon teal 
Mallard 
Shoveler, or spoonbill 
Gadwall 
Ruddy duck 
Pintail 
Estimated 
number of 
breeding 
pairs. 
1,725 
800 
300 
250 
200 
175 
130 
Species. 
Green- winged teai 
Widgeon 
Blue- winged teal 
Scaup duck, or bluebill . 
Total 
Estimated 
number of 
breeding 
pairs. 
1 Not included in total. 
As a conservative estimate each pair of ducks may be expected to 
rear 5 young, and as the average brood varies from 7 to 12 indi- 
viduals this allows for considerable mortality among ducklings. 
Adding the survivors to the original pair, the total number of native 
birds on this marsh at the end of the breeding season should be 
approximately as follows : 
•pecies. 
Redhead 
Cinnamon teal 
Mallard 
Shoveler, or spoonbill 
Gadwall 
Ruddy duck 
Individ- 
uals. 
12,075 
5,600 
2,100 
1, 750 
1,400 
1,225 
Species. 
Pintail 
Green-winged teal 
Widgeon 
Blue-winged teal. 
Total 
Individ- 
uals. 
910 
350 
70 
70 
25,550 
In addition to the ducks, about 100 pairs of Canada geese breed 
on these marshes. Allowing 3 young as the average number brought 
to maturity by this species, there would be a total of 500 birds at 
the close of the season. The nesting season for these geese is prac- 
tically over by May 15, and their numbers were estimated from 
observations made before they disappeared in the lower marshes 
for their annual molt. 
The figures given above are approximations, but. it is believed 
that they are not far from the truth. From them it is learned that 
this marsh area produces between 25,000 and 30,000 ducks in the 
average season, as in 1916. The question may arise as to the pro- 
priety, in arriving, at a total, of adding the original pair of birds 
to the young produced. It is probable that a large part of the 
adult ducks that die from natural causes (as opposed to shooting) 
do so toward the close of the breeding season and during the molt 
that follows. Exhausted by the calls made upon their strength by the 
needs of the nesting season, they have not sufficient vitality to carry 
them through the annual molt that takes place as soon as they are 
freed from their parental duties. In the estimates, however, suffi- 
cient allowance has been made for mortality among the young to 
cover losses among the adults as well, so that the totals given should 
