MOLOTHRUS RUFOAXILLARIS. 87 



The Screaming Cow-bird is larger than the allied species. The 

 female is less than the male in size, but in colour they are alike, the 

 entire plumage being deep blue-black, glossy, and with purple reflec- 

 tions ; and under the wing at the joint there is a small rufous spot. 

 The beak is very stout, the plumage loose, and with a strong, musky 

 smell ; the oesophagus remarkably wide. 



It is far less common than the other species of Molothrus, but is not 

 rare, and ranges south to the Buenos-Ayrean pampas, where a few 

 individuals are usually found in every large plantation ; and, like 

 the M. badius, it remains with us the whole year. It is not strictly 

 gregarious, but in winter goes in parties, never exceeding five or six 

 individuals, and in the breeding- season in pairs. One of its most 

 noteworthy traits is an exaggerated hurry and bustle thrown into all 

 its movements. When passing from one branch to another, it goes by 

 a series of violent jerks, smiting its wings loudly together ; and when 

 a party of them return from the fields they rush wildly and loudly 

 screaming to the trees, as if pursued by a bird of prey. They are not 

 singing-birds ; but the male sometimes, though rarely, attempts a song, 

 and utters, with considerable effort, a series of chattering unmelodious 

 notes. The chirp with w T hich he invites his mate to fly has the sound of 

 a loud and smartly-given kiss. His warning or alarm-note when 

 approached in the breeding-season has a soft and pleasing sound ; it is, 

 curiously enough, his only mellow expression. But his most common and 

 remarkable vocal performance is a cry beginning with a hollow-sounding 

 internal note, and swelling into a sharp metallic ring ; this is uttered 

 with tail and wings spread and depressed, the whole plumage raised 

 like that of a strutting turkey-cock, whilst the bird hops briskly up and 

 down on its perch as if dancing. From its puffed-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 faculty of filling 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 chiefly minute seeds and tender buds ; they 

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

 geners, eat hard insects. 



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

 Screaming Cow-bird, 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 



