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As the females and autumn birds almost invariably retain suggestions of 
the characteristic spring markings of the males the difficulty is really less 
than is generally anticipated. Of course, puzzling specimens occur which 
give even the experts some difficulty, but itis usually an alternative between 
two species, which can be settled by giving attention to one or more 
small details. In studying the warblers the observer is advised to first 
become familiar with the spring males. When the males of the common 
species are known, a comparatively easy matter with such strongly char- 
acterized forms, most of the females are recognized without much difficulty 
as they usually carry a subdued reflection of their mate’s brighter colour 
pattern. In the autumn, most juveniles resemble the females closely 
enough to make recognition not so very difficult. There are thus compara- 
tively few plumages besides the spring males that have to be learned 
individually. The Canadian Warblers represent twelve genera, seven of 
which are represented by single species only. Dendroica has sixteen species, 
Vermivora five, and three others are represented by three species each. 
The generic details of the most important will be discussed under their 
proper headings. 
Though called ‘‘ Warblers” their song should as a rule hardly be 
dignified by such a term. With few exceptions the songs are only insig- 
aificant little notes without much prolonged continuity, but as they are 
often specifically distinctive the student is advised to pay close attention 
to them, for when the great warbler migrations are on, the presence of a 
new or rare species is often first made known by a single unfamiliar sound 
directing attention from the many to the one that would otherwise escape 
notice. 
Economic Status. The Warblers are highly insectivorous. A few 
take more or less seed and a little fruit, the latter almost invariably wild, 
and no complaints have been made against any of the family. Their 
effect, therefore, is wholly beneficial. Being active they reach all kinds of 
insect habitats from the axils of highest flung leaves to between blades of 
grass on the ground, and as they are small they are satisfied to take insects 
and insect eggs that are too insignificant or too well hidden to receive the 
attention of larger birds. 
636. Black and White Warbler. BLACK AND WHITE CREEPER. FR.—LA FAUVETTE 
NOIRE ET BLANCHE. Mniotilta varia. L, 5-30. Plate XXXIX B. There is little 
plumage variation. 
Distinctions. A small black and white warbler which creeps about holes and branches 
like a woodpecker. In the autumn the colours of the young bird are similar to those of 
the adult but slightly veiled and have small washes of buff and less black on the throat. 
It is only to be mistaken in spring for the Black-poll but the white median stripe on the 
crown instead of all black can distinguish it from that species. 
Field Marks. Its creeping habits, strong black and white coloration with median 
ee stripe. In the autumn it is the only all black and white warbler to be seen in eastern 
fanada. 
Nesting. On ground at the base of a stump, log, or rock, in nest of strips of bark, 
grasses, etc., lined with rootlets and long hair. 
Distribution. Eastern North America; breeds in most of Canada north to well beyond 
the settlements. 
This is one of the earliest warblers to arrive in the spring and one of 
the easiest to identify at any time as it is always well marked and there is 
little difference in seasonal or sexual coloration. 
