616 REPORT OF NATIONAL MUSEUM, 1893. 



is, curiously enough, his only mellow expression. But his most com- 

 mon and renuirkable vocal performance is a cry beginning with a hol- 

 low-sounding internal note, and swelling into a sharp metallic ring; 

 this is uttered with tail and wings spread and depressed, the whole 

 l)lumage raised like that of a strutting turkey cock, whilst the bird 

 hops briskly ui)and down on its perch as if dancing. From its pufied- 

 out appearance, and from the peculiar character of the sound it emits, 

 I believe that, like the pigeon and some other species, it has the fac- 

 ulty of tilling its crop with air, to use it as a "chamber of resonance." 

 The note I have described is quickly and invariably followed by a 

 scream, harsh and impetuous, uttered by the female, though both notes 

 always sound as if proceeding from one bird. When on the wing the 

 birds all scream together in concert. 



The food of this species is chiedy minute seeds and tender buds; 

 they also swallow large caterpillars and spiders, but do not, like their 

 congeners, eat hard insects. 



I became familiar, even as a small boy, with the habits of the Scream- 

 ing Cowbird, and before this species was known to naturalists, but 

 could never find its nest, though I sought diligently for it. I could 

 never see the birds collecting materials for a nest, or feeding their 

 grown-up yonng like other species, and this might have made me sus- 

 pect that they did not hatch their own eggs ; but it never occurred to 

 me that the bird was i^arasitical, I suppose because in summer they 

 are always seen in pairs, the male and female being inseparable. Prob- 

 ably this is the only parasitical species in which there is conjugal 

 fidelity. I also noticed that, when approached in the breeding season, 

 the pair always displayed great excitement and anxiety, like birds 

 that have a nest, or that have selected a site on which to build one. 

 But year after year the end of the summer would arrive, the birds 

 reunite in i)arties of half a dozen, and the mystery remain unsolved. 

 At length, after many years, fortune favored me, and while observing 

 the habits of another species {Molofhrus hadius), I discovered by chan.ce 

 the procreant habits of the Screaming Cowbirds, and as these observa- 

 tions throw some light on the habits of M. badius, I think it best to 

 transcribe my notes here in full. 



Ai^air of Lenateros {Anumhius ucutkaudatuH) have been nearly all 

 the winter building a nest on an acacia tree 00 yards from the house; 

 it is about 27 inches deep, and 10 or 18 inches in circumference and 

 appeais now nearly finished. I am sure that this nest will be attacked 

 before long, and I have resolved to watch it closely. 



September 28. — To-day I saw a Bay- wing (J/, badius) on the nest; it 

 climbed over it, deliberately inspecting every j^art with the critical air 

 of a proprietor who had ordered its construction, taking up and rear- 

 ranging some sticks and throwing others away from the nest. While 

 thus engaged two common Cowbirds (.1/. bonariensis), male and female, 

 came to the tree. The female dropped on to the nest and began also to 

 examine it, peering curiously into the entrance and quarreling with the 



