Allen on an Inadequate “Theory of Birds' Nests." 29 
spicuous tints,” “ in every case the females are less gay, and are most 
frequently of the very plainest and least conspicuous hues. Now,” 
he continues, “ throughout the whole of these families the nest is 
open * and I am not aware of a single instance in which any one of 
these birds builds a domed nest, or places it in a hole of a tree, or 
under ground, or in any place where it is effectually concealed.” As 
regards the North American representatives of these groups, there 
are frequent exceptions to this rule, as I have already shown, and 
that Mr. Wallace did not know of exceptions only shows that his 
examination of the subject must have been very superficial. As 
farther evidence of the imperfection and inexactness of Mr. Wal- 
lace’s knowledge of the subject concerning which he theorizes so 
boldly and speaks so emphatically, may be cited his remark about 
the Icteridce, or “Hangnests.” “The red or yellow and black plu- 
mage of most of these birds,” he says, “ is very conspicuous, and 
is exactly alike in both sexes. They are celebrated for their fine 
purse-shaped pensile nests.” As regards the facts of the case, there 
is no family of Passerine birds where the sexes, as a rule, are more 
widely different, the difference affecting not merely color, but also 
size, the females being not only much duller colored than the males, 
but much smaller. The instances in which both sexes are equally 
brilliant are the exceptions. 
To summarize the foregoing remarks, it has been shown, so far 
as the birds of North America are concerned (and the same could 
easily be shown for other equally extensive regions), that the spe- 
cies which breed in holes in trees, in burrows in the ground, or in 
„ domed, pensile, or covered nests, are as often dull, obscurely col- 
ored species as bright-colored ; that when the species are conspicu- 
ously colored, it is generally only the male that is attired in strik- 
ingly gay tints, the females having comparatively dull colors ; and 
that often species in which both sexes are clothed in bright and 
equally conspicuous tints build an open nest ; while the “ theory ” 
demands just the opposite of these conditions. In other words, 
that birds nest in holes, in open or in covered nests, without regard 
to whether the female is brightly or obscurely colored. F urthermore, 
that pensile and bulky covered nests are far more open to discovery 
than ordinary open nests, so that the advantage of having the con- 
tents concealed, be it eggs, young, or the female parent, is more 
* The italicized portions are as in the original. 
