Murdoch on Migration of Birds. 75 



Their large size and the peculiarity of their markings, so different 

 from those of any Junco that I have ever seen, suggested a suspicion 

 that they might be the eggs of the Junco aikeni, but this Mr. Car- 

 ter docs not regard as probable. The nests of the first two present 

 nothing peculiar in their construction. They are saucer-shaped, 

 and are merely loose aggregations of grasses and stems of plants, 

 lined with fine material of a like nature. 



Mr. Carter is confident that he has never met with more than 

 three forms of Junco in Colorado, namely, caniceps, oregonus, and 

 aikeni ; the latter two he has known since 1859, when he first met 

 with them in large numbers near Central City, but his observations 

 have been mainly confined to the higher altitudes. He met with 

 aikeni in the greatest abundance on the eastern slope of the main 

 range, at an elevation of eight thousand feet, twelve years before 

 Mr. Aiken first brought it to the attention of naturalists. The lat- 

 ter's first specimens were procured in the lower and eastern limit of 

 their habitat, which will account for his speaking of their scarcity 

 and their straggling habits. The same winter (1871-72) Mr. Car- 

 ter, in his camp, a few miles west, and at an altitude greater by 

 some three thousand feet, met with these individuals every day, in 

 flocks of from a few individuals to those of a hundred or more. 



Mr. Carter is also quite sure that all the adults of this species, of 

 both sexes, are always found to possess the white wing-bands well 

 defined, and that it is only the birds of the first year, in immature 

 plumage, that furnish what has been mistaken for an intermediate 

 form between this species and the typical Junco hyemalis. Mr. 

 Carter has never, to his knowledge, met with oregomis or aikeni in 

 Colorado during the breeding season, but thinks that they all move 

 farther north to nest. 



EFFECTS OF THE WARM WINTER ON THE MIGRATION 



OF BIRDS. 



BY JOHN MURDOCH. 



It is well known that in ordinary winters all our summer resi- 

 dents and autumnal visitors have taken their departure from the 

 neighborhood of Boston by the month of December. From the 



