Allen on an Inadequate "Theory of Birds' Nests." 29 



8picuous 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 iu 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 

 further 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 Icterido?, 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 Avhich 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. Furthermore, 

 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. 



