52 THE CONDOR Vol. XXII 
ever, if the female is in the midst of house building, no better time can be 
found to locate her nest for, in spite of intruders, even at a distance of a few 
feet, she works with feverish activity and with a directness of flight that can 
scarcely escape the observation of even an untrained eye. Nevertheless, this 
period of construction is frequently interrupted by flights to the beach or along 
the cliff in search of insects, or for a period of song on some lofty point, or she 
too may dash out of sight far up the coast to return after a period of from five 
to thirty minutes. 
Another favorable time for the location of the nest is during the ineuba- 
tion period. Four nests under observation showed that the female remains 
Fig. 8. NEST oF ALASKA WREN; ABOUT ONE-HALF NATURAL SIZE, 
upon the eggs, whatever the character of the day or the stage of incubation, 
for a period ranging from eighteen to twenty-one minutes. She then feeds 
from two to five minutes. Here also her flight is relatively direct, in marked 
contrast to her usual journey along the cliffs, and is unmistakable after a brief 
experience. The recorded habits of several other birds indicate a fairly defi- 
nite daily program during the breeding season, but, so far as I know, none are 
so timed to the minute as the Alaska Wren. 
All of the nests discovered in 1918 were in the faces of cliffs anywhere 
from twenty-five to one hundred feet in height, and were placed at elevations 
