July, 1911 
NESTING NOTES ON DUCKS OF THE BARR LAKE REGION, COLO. 
123 
several species are omitted, as I have endeavored to include in these notes only such 
data as will add to the general fund of information on this subject. 
MALLARD (Aiids platyrkyuchos) 
During our numerous trips through the Barr Lake district we found the 
Mallard one of the commonest ducks. A very large flock wintered on the larger 
lakes; during spring and fall migration flocks of Mallards were always in evidence, 
and during the summer months pairs and single birds were quite common. It was 
therefore rather surprising that despite careful and persistent searching, we found 
but two nests of this species during three seasons’ work. Both of these, however, 
were quite out of the ordinary and are worthy of description. 
On May 11, 1907, while wading out from shore through a sparse, burnt-over 
Fig. 38. mallard's nest on musk-rat house, showing details of nest construction ■ 
growth of cat-tails, skirting asmall lake, a female Mallard flushed noisily from a large 
musk-rat house and revealed a beautiful set of eleven eggs deposited in a hollow, 
scraped in the dead cat-tails and debris forming the house, and well lined witli 
down. The house was very conspicuous, standing over two feet above the surface 
of the ivater surrounding it, and the nest was an open one as can plainly be seen 
from the accompanying illustration (Fig. 37). There was no apparent attempt at 
concealment. The female flushed when we were fully thirty yards from the nest, 
and the male swam about w^ell out of gunshot. 
A week later (on the eighteenth) we succeeded in approaching to within ten 
feet of the brooding female, who was in plain sight even from a considerable dis- 
tance. The nest was in much the same condition as on the preceding visit, but 
the downy lining was much less in evidence. On the twenty-fourth we found that 
