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530 ORNITHOLOGY AND OOLOGY. 
feet of the bird. They are very thick-shelled, and, when 
struck together, sound almost like balls of ivory. They are 
more spherical in form than the eggs of any other duck that 
I have seen, and are but little more pointed at one end than 
at the other. Their dimensions vary from 2.50 by 1.75 
inches (the longest and narrowest specimen in a large num- 
ber in my collection) to 2.10 by 1.80 inches (the shortest 
and broadest specimen in the same): the usual size is, on 
the average, about 2.13 by 1.70 inches. I am not aware 
that any nest of this bird has been found south of Lake 
Umbagog. 
When the nest of this species is approached, the female 
remains quiet, and flies off only when alarmed by blows on 
the trunk of the tree on which her nest is built. She then 
flies silently, and alights in the lake, near which the nest is 
usually built, and watches the intruder from a safe distance, 
without making any outcries or disturbance. If the tree is 
surrounded by undergrowth so thick that she cannot see the 
intruder from the water, she flies silently over and around 
him, always at a safe distance. The male never shows him- 
self on such occasions; and I think it likely that he separates 
from his mate at the commencement of the period of in- 
cubation, and remains by himself until the young are able 
to provide for themselves. 
When living in the neighborhood of fresh water, this bird 
has many of the habits of the other Mergansers, and then 
feeds on aquatic insects and their larvae, and is an expert 
fisher and diver. 
When the female is suddenly surprised, while with her 
young in a stream or pond, she gives a guttural, chattering 
ery, when the whole brood dives and swims off under water 
to the shore, where they conceal themselves in the aquatic 
herbage. While they are thus retreating, the mother simu- 
lating lameness, almost exactly like some of the shore-birds 
on the beach, flutters before the intruder, using every arti- 
fice to decoy him from the neighborhood of her young, 
