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THE CONDOR 
Vol. XVI 
the nesting duck. Such a factor as weather is beyond our control. Others, 
such as predaceous animals, the market hunter, and encroachment of agricult- 
ure are within our control. At Los Banos we found that predaceous animals 
were destroying a very large percentage of ducks’ nests. The following table 
will make clear how great the destruction really was. 
Pintail Gadwall Cinnamon Fulvous Coot Killdeer 
Teal Tree-duck 
Undestroyed nests 1 3 1 47 4 
Destroyed nests 3 3 18 2 2 1 
In one locality where the water had lowered and allowed the approach of 
animals to what had been sedge-covered islets we found ten destroyed nests as 
a result of two hours searching. In most cases every egg had been broken into 
and the contents eaten. Of course the broken egg-shells made these destroyed 
Fig. 70. Raided nest of Pintail, the work of some predaceous 
mammal; Los Banos, May 24, 1914. 
nests infinitely easier to find, so that the relative number of destroyed and un- 
destroyed nests is doubtless somewhat exaggerated. Nevertheless, it clearly 
demonstrates the fact that large numbers of nests in this vicinity are destroyed 
by animals. In no other of the localities visited did we find a single nest which 
had been raided. 
We experienced no difficulty in distinguishing nests destroyed by preda- 
ceous animals from those from which the eggs bad hatched. In the former 
case the shells showed plain evidences of having been broken from the outside 
in, were usually more widely scattered about, and often contained a small part 
of the contents. Hatched eggs, on the other hand, had been fractured from 
the inside out and were usually broken up into small pieces or left in halves. 
Time and again on returning to a nest to photograph it we were disap- 
