eS BREWSTER, Breeding Habtts of Golden-eye Duck. 209 
eggs of the Hooded Merganser are sometimes included in a set 
of the green, thin-shelled eggs of the Whistler. The whole bot- 
tom of the nesting cavity, be it large or small, is usually covered 
with eggs, and they are often piled in two layers or set on end, 
and packed so closely that it is as difficult to remove the first 
as to take a book from a tightly filled shelf. 
I used to suppose that in the cases of composite sets the labor 
of hatching the eggs and rearing the young was performed, how- 
ever unwittingly or unwillingly, solely by the original owner of the 
nest, or, in other words, that the Ducks which laid in the nests of 
other birds, whether of their own or of a different species, were 
simply parasitic, after the manner of the European Cuckoo and 
certain of the Cowbirds, but in 1897 I obtained evidence which 
seems to point to a different conclusion, at least as far as the 
Whistlers are concerned. Most of this evidence, as well as certain 
other observations on the breeding habits of the Whistler, is con- 
tained in the following notes, which I give nearly as I find them 
in my journal. 
May 30. We sailed the house-boat up the Lake to-day and an- 
chored near the edge of the flooded forest at the outlet where we 
intend spending a week or more. Soon after reaching this place 
we saw four female Whistlers flying together in a peculiar manner 
over the trees, now rising high in air, next descending and dashing 
among the trunks and branches, vibrating their wings rapidly and 
continuously as in ordinary flight, but describing circles about a 
remarkably tall stub with a shattered top. Around this they 
would pass a dozen times or more, gradually drawing nearer until 
one bird leaving the rest and pitching first downward, then sharply 
upward, would fly directly toward the stub and try to alight on 
itsjagged top. The attempt usually failed, when the bird, continu- 
ing its flight, would disappear among the trees, presently returning 
to begin circling again; but twice it gained a foothold and re- 
mained perched for several seconds, although it had to keep its 
Wings in constant motion to maintain its balance. Sometimes its 
flight was directed to a point near the top of the tree where there 
was a round, neat-looking hole, no doubt the entrance to a nest, 
for we afterward saw two Whistlers emerge from it in quick suc- 
cession. We thought that all four birds tried in turn either to 
