Northern Wisconsin advertiser. [volume] (Wabeno, Wis.) 1898-1925, 1907-10-24

rem. The red-winged blackbirds of
northern Texas migrate little, if any,
but those which nest in the Macken-
zie valley come all the way down to
spend the winter with them. So it
seems that, while there is a general
tendency in many birds to migrate
north in about the order in which
they spent the winter and to winter
IN about the order they occupied in
nesting time, there is no hard-and-fast
law concerning such order, and 1t is
not always possible to determine a
birds winter distribution by a knowl-
edge of its summer range.
The Spring Flight.
Then, spring migration differs ma
terially from fall migration. The So
called normal migration just re-
ferred to does not take place in
spring, since the birds of given spe-
cies do not hold the same relative po-
sitions throughout the entire north
ward flight. 1t Is supposed that in
the case of most species the first in
dividuals to appear in a given local
ity are those which nested there the
year before; that these are followed
by the individuals which nested in
the country Immediately to the north
ward, which are in turn followed By
those which nested still further to
the north. Then, since, in some
cases at least, the southern nesting
birds are the leaders both in the
spring and fall migrations there must
necessarily be a transposal of rela-
tive position between the time they
leave us in the fall and the time they
come back to us in the spring. It is
not yet known where or when this
change in relative positions occurs,
but this point will doubtless be set
tied by further observation. Possibly
the more southern birds remain In
winter quarters until the more north
ern birds start first, but very slowly,
since their country is still icebound,
and are passed by the fast-fying
southern birds, whose nesting grounds
are already open and waiting for
them. Later on, of course, another
transposal must occur; that is when
the southern birds have settled down
on their breeding grounds, and the
northern birds pass over them in the
wake of advancing spring.
Speed Of the Flights.
There has long been much specula
ton concerning the speed at which
birds perform their migratory jour-
neys and it has recently been ascer-
tanned that in many cases they travel
some parts of the journey very much
faster than others. Mr.. Cooke, treat
ing this subject in his government re-
port, states the migration of the
black-poll warbler nicely illustrates
this variation in speed. He says: at
winters in north central South Amer
lea and migrates in April across the
West Indies to Florida From here,
some individuals pass on northwest
to the Mississippi valley, thence
north to Manitoba, thence northwest
to the valley Of the Mackenzie, and
thence almost due west to western
Alaska. From the Gulf of Mexica to
Minnesota, a fairly uniform average
speed of thirty to thirty-five miles per
day is maintained; southern Indiana
and Missouri are reached the first
week in May, southern Iowa early in
The second week and southern Min.
nesota is entered by the middle o.
the month. Then comes a squirt;
within another week the black-polls
appear in the central part of the
Mackenzie valley and the following
week they arrive in northwestern
Alaska, many individuals undoubted.