X11 PREFACE. 
and White Creeper (Mniotilta varia) and the Black-throated 
Green Warbler (Dendreca virens). But the strangest example 
of this sort I have noticed I think was the case of an Oriole 
(Icterus Baltimore) that I heard at Ipswich last season. So 
different were its notes from the common notes of the Balti- 
more that I failed entirely to refer them to that bird till I saw 
its author.” 
‘Aside from such unusual variations as this, which we may 
consider as accidental, birds of unquestionably the same spe- 
cies, as the Crow, the Blue Jay, the Towhe!® and others, at 
remote localities, as New England, Florida, Iowa, etc., often 
possess either general differences in their notes and song, 
easily recognizable, or certain notes at one of these localities 
never heard at the others, or an absence of some that are else- 
where familiar. This is perhaps not a strange fact, since it is 
now so well known that birds of the same species present cer- 
tain well marked variations in size according to the latitude 
and elevation above the sea of the locality at which they were 
born, and that they vary considerably, though doubtless within 
a certain range, in many structural points at one and the same 
locality. In other words, since it is known that all the differ- 
ent individuals of a species are not exactly alike, as though all 
were cast in the same die, as some naturalists appear to have 
believed. 
‘*Certain irregularities in the breeding range of birds have 
also come to light. It is perhaps not remarkable that a pair 
of birds of species that regularly breed in northern New Eng- 
land should now and then pass the summer and rear their 
young in the southern part, as has been the case in certain 
known instances in the Snow Bird (Junco hyemalis), the Pine 
Finch (Chrysomitris pinus), and the White-throated Sparrow 
(Zonotrichia albicollis); but it is otherwise with the Snow 
Bunting (Plectrophanes nivalis), which rarely breeds south of 
Labrador, of which there is a single well authenticated instance 
10Tt is to be remarked that a variety of this bird has recently been found in 
Florida. 
