POEEST :a;nd steesm 
659 
I December, 1919 
The Canvas-back 
narrow head. Marilas are stockilv built, 
with a short neck and a rounded head. In 
“fresh-water” ducks the wings are long 
and slender, tapering gradually to a point, 
while in Marilas the wings are compara- 
tively shorter, broader, and either com- 
ing abruptly to a point or what is loosely 
termed rounded. In flight, another ex- 
cellent character is the way the wings are 
used. Marilas flap their wings much 
more rapidly than most “fresh-water” 
ducks, and always the tip of the wiug 
describes a narrower arc in space. This 
is a somewhat difficult point to follow, 
and in figures the statement amounts to 
this, that if we assume that a black duck 
flaps its wings 100 times in a minute, a 
canvasback would flap its wings 150 
times, as each flap takes less time. This 
Is the explanation of the rapid flight 
of a green-winged teal which can outfly 
even the large and powerful canvasback. 
It flaps its wings just as rapidly, but over 
a greater space as in other “fresh-water” 
ducks, thus getting extra power and speed. 
There is one other interesting point 
about the Marilas that is connected with 
their ranges and migration habits. Why 
i.s the scaup common on the coast of Mas- 
sachusetts and the canvasback rare? Per- 
secution is not an absolutely conclusive 
answer. The true answer is a difference 
of breeding range and of migration route. 
The nesting area of the Marilas is, gen- 
erally speaking, the central prairie lake 
region of the continent from the Dakotas 
north through Canada. From this com- 
paratively small area the migrating birds 
scatter in a huge fan embracing nearly 
the whole of the United States. As far 
as the Atlantic States are concerned it is 
obvious that the migration route is a diag- 
onal to the south-east. But as the coast 
runs northeast to southwest, it is appar- 
ent by glancing at the map that Virginia 
and Long Island are almost equidistant 
from the breeding grounds. This is the 
reason why canvasback arrive in Chesa- 
peake Bay and Curritick Sound at about 
the same time or even earlier than they 
appear on Long Island, a fact which has 
caused astonishment to many. As a mat- 
ter of fact, there is more to it even than 
this. Flathead Lake, North Dakota, 
V and Western New York are twm excellent 
places for canvasback, both nearer the 
breeding grounds than Long Island or 
Currituck Sound. But they do not reach 
there any earlier either. This can be ac- 
counted for by the habits of the bird. Its 
migration is purely a question of cold 
weather and open water, and it does not 
leave its breeding grounds in any large 
numbers until the season becomes unfa- 
vorable. With comparatively few excep- 
tions each canvasback has its particular 
winter feeding grounds. It is highly un- 
likely that a canvasback wintering in Cur- 
rituck Sound one year will winter in 
Western New York the next. So when 
the time comes for it to leave its nesting 
The Red-head 
grounds it makes for its winter feeding 
grounds, and in most cases gets there, 
with no stops on the way. So now we can 
see why the canvasback is so rare a bird 
except in places v/hich answer its tastes. 
The scaup duck breeds much farther 
north in numbers. Its southeast diagonal 
consequently brings it much farther north 
along the Atlantic States in numbers. 
Here we have the answer to our question 
about the comparative abundance of the 
tv/o birds on the Massachusetts coast If 
w'e go still farther north to Labrador, we 
get entirely outside the normal diagonal, 
with the result that all Marilas are casual 
stragglers to that coast. The ringnecked 
duck’s migration route is the most south- 
erly and the least easterly of them all, so 
that with the exception of a very few 
birds from Virginia southward it never 
reaches the Atlantic Coast at all except a 
few stragglers which clubs take pride in 
mounting and pointing out to visitors. 
Ludlow Geiscom. 
Bills of drake lessen and 
iiatural size 
Pliolofirnijiii; courtesy of American Museum of Natural Histori 
;rcr.:er staups (known also as little and big broadI)ill or bluebill), and riagnecked duck (left to right). 
These thri-e species have black heads. The scaups differ from the ringueck in having a 
white itripe in the wing, and from another in size, especially of the bill. 
