INTRODUCTION. 85 



study these seeming distinctions, and decide if tliey are 

 constant. 



Specific characters are, I believe, sufficiently tangible 

 and constant in nature, and never need be mistaken ; this 

 will hereafter be illustrated. I would, however, first speak 

 strongly in disfavor of the growing belief in the hybridism 

 of birds. I do not believe that, generally speaking, hybrids 

 occur ; there are a few cases, but they are exceptions. In 

 many instances the so-called hybrids are but abnormal con- 

 ditions of plumage, that can be accounted for on entirely 

 natural gi-ounds. But sometimes the ornithologist, in his 

 haste to make new species, has divided the two opposite 

 stages of color in one species, calling each by a difterent 

 specific name, and has afterwards found specimens that 

 in their peculiar plumage, size, etc. naturally form con- 

 necting links between the two ; in his perplexity as to 

 which of these to refer it, he has hit upon the fortunate (1) 

 expedient of calling it a "hybrid." Would it not have 

 been much better, if, at first, he had taken a large num- 

 ber of specimens, and, studying them, seen what the sup- 

 posed hybrids really were 1 



A species consists in a bird's being so organized that it 

 always reproduces young which are like itself; or, if they 

 differ, the variation never exceeds fixed points. More- 

 over, I believe that a true species will seldom mate with 

 others having different characteristics; or, if such a union 

 occurs, the offspring are always infertile; thus, by 

 these never-varying laws, species are kept from an^alga- 

 mating. Take, for an illustration, the Robin, a bird that 

 since its discovery has never had a single variety or local 

 race called a "new species" (at which I marvel greatly, how- 

 ever). The typical specimen has a clear red breast, black 

 head, and immaculate slate-colored back and wings, which 

 at once distinguish it from all others of the Turdince. 

 "We also have a Robin that is very light-colored, with the 



