°i8q7 1 Chadbourne, Spring Phoudgc of the Bobolink. ^43 



The buff edging of the breast feathers was never more than a 

 narrow line, evidently owing to the absence of the long fugacious 

 tips, which are so characteristic of the newly developed feathers, 

 and it is therefore probable that spring males showing much buff 

 suffusion beneath, have recently passed through a ' spring moult,' 

 or at least through a partial 'feather-change.' 



The dealer from whom I bought the bird told me, that " last 

 fall he (the Bobolink) lost lots of feathers"; and added: "In 

 spring Bobolinks don't often lose any feathers to speak of. 

 Sometimes I don't believe they lose any feathers at all ; and you 

 can't see any pin-feathers either while they are getting black. 

 But in autumn the pin-feathers stick out all over them. Once in 

 a while though, I've seen one have a regular moult, just as they 

 do in fall." The above was written verbatim at the time, and is 

 further proof that because one individual of a given species has 

 ' moulted^ it does not necessarily follow that all individuals of that 

 species ' moult ' also. 



Turning next to the series of skins : — The only early spring 

 material is from Corumbti, Brazil. The male already referred to 

 (Coll. Amer. Mus. Nat. Hist., No. 32783,) taken March i, shows 

 new feather-growth in a marked degree ; and as was pointed out 

 by Mr. Chapman, ' moulting ' was in full progress. It is however 

 quite another matter to prove that no color-change was also going 

 on simultaneously in any of the feathers ; for though zoithout the 

 loss of old feathers from the tracts concerned., ■ — or in other words, in 

 the absence of ' moulting.,' — an alteration in color must be due to a 

 color-change in the same feathers ; yet it does not follow., on the other 

 hand, that because a bird is ' moultifig,^ a color-change in the individ- 

 ual feathers — be they old or hew — is thereby excluded. In fact the 

 CorumbA bird itself furnishes conclusive proof that just the 

 reverse is the case ; and on careful examination one finds here 



the Corumba specimen, and Dr. Allen says nothing of any similar coloring 

 among the birds seen by him. When we call to mind the fact, — to be referred 

 to later, — that the black of the Bobolink is really due to brown, instead of 

 black coloring matter, — it is at once clear that the excess of chestnut and white 

 show a lack of the normal quantity of pigmented matter ; and it seems almost 

 sure that in the Corumba bird, we have not a normal example, but a partial 

 albino ! 



