The route of the Pacific golden plover (_Pluvialis dominica fulva_)
is fully as interesting and as remarkable as the elliptical course
followed by its eastern cousin (_P. d. dominica_) (fig. 22). The
breeding range of the eastern golden plover extends through Arctic
America west to the northern coast of Alaska, where in the vicinity
of Point Barrow it meets the nesting grounds of the Pacific form,
which is really an Asiatic subspecies. It breeds chiefly in the
Arctic coast region of Siberia and merely overflows onto the Alaskan
coast, some of the birds probably migrating south along the coast
of Asia to winter quarters in Japan, China, India, Australia, New
Zealand, and Oceania, including the Hawaiian Islands, the Marquesas
Islands, and the Low Archipelago. Golden plovers in migration have
been observed at sea on a line that apparently extends from these
islands to the Aleutians, and it therefore appears certain that
at least some of the Alaskan birds make a nonstop flight across a
landless sea from Alaska to Hawaii. While it would seem incredible
that any birds could lay a course so straight as to attain these
small oceanic islands, 2,000 miles south of the Aleutians, 2,000
miles west of Baja California, and nearly 4,000 miles east of Japan,
the evidence admits only the conclusion that year after year this
transoceanic round-trip journey between Alaska and Hawaii is made by
considerable numbers of golden plovers.
[Illustration: B4761M
Figure 25.--Breeding and wintering ranges of the western tanager. See
figure 26 for the spring route taken by the birds breeding in the
northern part of the range.]
[Illustration: B4499M
Figure 26.--Migration of the western tanager. The birds that arrive
in eastern Alberta by May 20 do not travel northward along the
eastern base of the Rocky Mountains, as in that region the van has
then only reached northern Colorado. Instead the isochronal lines
indicate that they migrate north through California, Oregon, and
Washington, and then cross the mountains of British Columbia.]
The Pacific oceanic route probably is used also by the arctic terns
that breed in Alaska, and possibly by those from the more western
tern colonies of Canada. This species is of regular occurrence on
the western coasts of both the United States and South America,
indicating that the western representatives travel southward to the
Antarctic winter quarters without the spectacular migration features
that appear to characterize the flight of those from the eastern part
of the continent (fig. 15).