THE OOLOGIST 



41 



narrow coarse grass belt, I would en- 

 counter her, sometimes swimming 

 about, under manifest agitation and 

 quite as often winging, hysterically, 

 over-head. 



Determined, one day, to learn the 

 reason why, my quest led into deep 

 masses of marsh-growth, where mud 

 and water were full three feet deep. 

 Almost had I become tempted to give 

 up the wearisome quest when, finally, 

 the glint of something whitish amid 

 the luxuriant grasses, aroused my 

 deepest interest. And then, upon a 

 bog, I found a deep, down-lined nest, 

 with a slide into the water on the 

 south side. In the nest were eight 

 eggs, some of them clay color, some 

 of them green, and in the water were 

 other eggs, all of them red-head eggs. 

 The red-head eggs were incubated; 

 the canvas-back, liresh. No question, 

 then, as to which bird had been the 

 usurper. In the magazine files the in- 

 terested student will find sundry simi- 

 lar settings down of curious composite 

 "sets" of red-head, canvas-back, scaup, 

 buffle-head, ruddy, eggs. 



Of course, we all know much about 

 the freaks engendered by cow-bird in- 

 trusions. Some of us, perhaps, have 

 found evidence of arrant stupidity on 

 the part of cowbirds. I once took a 

 set of towhee eggs, in Northern Min- 

 nesota, only to find, two days later, 

 two eggs of the northern cowbird in 

 that otherwise empty nest. I have al- 

 so found, quite counter to what some 

 of the wise men have said, a very few 

 host-nests containing eggs of the host 

 that were nearer to hatching than 

 those of the parasite. Most of us are 

 aware that some of the larger specie 

 of smaller birds are more frequent 

 cowbird hosts than others. Is this, 

 one wonders, a matter of tempera- 

 ment, of a larger, more good-natured 

 toleration? 



Again, ho^ many of us have noted 



that the Song Sparrow never seems 

 to lose any of its own eggs, as a rule, 

 even upon the intrusion of two, or 

 even three, cowbird eggs into their 

 nests? (The same is sometimes true 

 of the common towhee). A conspicu- 

 ous example of the greater frequency 

 with which the nests of some one 

 species of host is intruded upon, than 

 others. I have found in the case of 

 observations made by a correspondent 

 of mine, a high-bred Hollander, who, 

 poor fellow, went the way of all 

 tubercular flesh, after a sojourn in 

 Oaxaca, Mexico. He found the local 

 form of the red-eyed cowbird almost 

 uniformly parasitic upon the local 

 towhee, Pipilo rutilis. Every set of 

 these beautiful eggs, as I now remem- 

 ber, was accompanied by one or two 

 eggs of the red-eye. 



Akin to the parasitic habit is that of 

 co-nesting. This is a habit prevailing, 

 apparently, with but a few species. 

 Of course, it is not strange that it 

 should be found, occasionally, main- 

 taining with domesticated species, 

 as when, for instance, I once found 

 amicably side by side on fourteen eggs, 

 my two young hen-turkeys sitting. 

 Of the same purport, that of co-opera- 

 tion, is the rare habit evinced by, for 

 example, the hawk owl, both birds of 

 a devoted pair sometimes incubating 

 side by side. One would greatly like 

 to urge upon younger bird students an 

 awakened and a persistent habit of in- 

 trospective study of these, and of 

 kindred phenomena in the great bird- 

 world. Just as soon as we shall have 

 found ourselves interested in the eco- 

 nomic and social relations between 

 various species of birds, and shall 

 have become fascinatingly absorbed in 

 the study of bird-psychology, as most- 

 strikingly manifested in the reproduct- 

 ive period, we shall then, and then 

 only, have found the great, delicious 

 secret of super-interest. And when 



