134 Notice of Audubon’s Birds of America. 
In his history of the chestnut-sided wood warbler, our author 
says: ‘‘ Where this species goes to breed I am unable to say, for to 
my enquiries on this subject I never received any answers which 
might have led me to the districts resorted to by it. I can only 
suppose, that if it be at all plentiful in any part of the United 
States, it must be far to the northward, as I ransacked the borders 
of Lake Ontario, and those of Lake Erie and Michigan, without 
meeting withit. I do not know of any naturalist who has mee tt 
more fortunate, otherwise I should here quote his observations.” 
The writer is somewhat surprised at this, as the bird, although 
rare, is still occasionally to be found breeding in Massachusetts. 
He has known of several nests having been discovered in the 
vicinity of Boston, and is under the impression that he furnished 
Mr. Audubon, by letter, with a description of a nest and its eggs, 
which were five in number. Both were very similar to the nest 
and eggs of the summer yellowbird, Sylvia @stiva, and he re- 
grets that as the egg of the bird is still in his possession, he was 
not aware of the desired information in time to furnish it for the 
text of the present work. 
In his account of the Sylvia astiva, so universally and so fa- 
miliarly known in this portion of the country as the summer yel- 
lowbird, Mr.Audubon speaks at some length of the ingenuity . 
so often displayed by individuals of this species, in evading the 
burthen of the cow bunting. Although not a summer passes 
that we do not hear of several instances of the remarkable fact, it 
does not seem to be so generally known as so interesting a display 
of instinct would seem to deserve. 'To escape the burthen, both 
of hatching the eggs and rearing the young of the cow blackbird, 
' Ieterus pecoris, the bird displays the surprising ingenuity narrated 
in the following extract: “Mr. Nuttall was the first naturalist 
who observed the very curious method in which it contrives to 
rid itself of the charge of rearing the young of the cowbird. ‘It 
is amusing,’ he says, ‘to observe the sagacity of this little bird 
in disposing of the eggs of the vagrant and parasitic cow troopi 
al. The egg deposited before the laying of the rightful tenant, 
too large for ejectment, is ingeniously incarcerated in the bottom 
of the nest, and a new lining placed above it, so that it is never 
hatched to prove the dragon of the brood. "Two. instances of 
this kind oceurred to the observation of my friend, Mr. Charles 
Pickering ; and last summer I obtained a nest with the adventl- 
