The bird-lover has many red-letter days in his calendar, particularly
when the birds are moving northward. The earliest arrivals, while snow
still covers the ground, give their own peculiar thrill of delight, and
waken in him new energy and great anticipations for the coming season
of bird study. But these early arrivals soon become a part of the
landscape and cease to lend any peculiar delight. Not so with the host
of warblers, for they are here one day and may be up and away the next,
not to be seen again for two or three months or even a year. One must
be on the alert during warbler time if he expects to catch a glimpse
of the passing host. But there are distinctively "warbler days" during
this warbler time. These vary in different years with the weather and
the advance of vegetation, from late April to the second or even third
week of May, in northern Ohio and central Iowa, and proportionately
later or earlier north or south of that latitude.
The subject of our sketch is not among the early migrating warblers
nor yet among the later ones. He usually travels with the second large
flight, and may then be expected late in April or early in May. The
earliest Oberlin, Ohio, record falls on April 27, 1896, and the latest
on May 10, 1897. Whether the birds arrive early or late they usually
remain in the vicinity two weeks, the males being present during the
first week and the females during the second. I have never found the
two sexes present on the same date. The species cannot be said to be
common even during the height of the spring migration, nor yet are
they rare. Few are seen during the fall migration at Oberlin, and
they during the last week of September and the first week of October.
Further west in the Mississippi valley the fall migrants seem greatly
to outnumber those of spring.
This is not a tree-top inhabiting species, but seems to prefer the
middle branches of the trees or the tops of shrubbery, often descending
to the ground and gleaning there much after the fashion of the Maryland
Yellow-throat. In the higher woods free from underbrush he seems to
prefer ground gleaning, but where low underbrush affords a place for
low gleaning he is seldom seen on the ground. In village parks he is
fond of a much higher perch, and must be looked for there well up in
the trees, even to the topmost branches, where he gleans among the
bursting buds and new leaves. On the Oberlin College campus he is a
regular spring visitor in early May, and here seems to appreciate
his environment and rare opportunities, for he sings his best to the
accompaniment of the medley of pianos in the Conservatory of Music
across the way, and the deeper tones of the great pipe organ in the
chapel hard by. Here I have heard him singing at all hours of the day,
while in the woods his song is less often given. One is at a loss to
assign a reason for the decided preference for the college campus,
which is in the center of the village activities. Rumbling wagons and
tramping feet cause the birds not the slightest alarm, but swiftly
moving bicycles act upon the birds' nervous system much as upon that of
an elderly woman.
The song of this warbler is variously rendered by the various writers
upon bird songs. None of these renderings seems to describe the song
as I hear it on the college campus. It is singing as I write: "_Tu euu
euu e-e-e-e-e!_" A variation sounds, "_C'weu, c'weu, c'wee-e-e-e_;"
sometimes "_c'weu, c'weu, c'w', c'w', c'wee-ee-e-e-e_." There is
also often a single phrase which sounds more like a scolding note
than a song. It is: "_Tw', tw', tw', tw', twee'e-e-e-e-e_," or even
"_Z-z-e-e-e-e_," rarely it may sound simply "_Z-z-z-z-z-z_." The song
is uttered in a spirited manner while the bird is feeding and flitting
about in the foliage, it interfering with the feeding only as a sort of
after-thought, causing a momentary pause as the bird raises his head
and straightens his body for the effort. It is one of the warbler songs
that are easily recognized and not readily forgotten.
Were it not for the white spot or patch on the wing of both male and
female at all seasons of the year and in all plumages, this warbler
would easily escape the notice of all but the alert ornithologist. His
black throat and breast, white belly and blue back and wings and tail
are not conspicuous in the trees and foliage.
The black-throated blue warbler spends the winter months in Guatemala
and the West Indies, and migrates north to Labrador and Hudson's Bay,
nesting there and in the northern parts of the United States. It ranges
west to the border of the plains.
The nest is placed in low shrubs or bushes from a few inches to two
feet above the ground, and is composed of dry fibrous bark, twigs, and
roots, lined with black rootlets and hair. The outside is often more or
less covered with cocoons. The thick swampy woods with an undergrowth
seems to be the favorite resort for the nesting birds. The four eggs
are buffy-white to greenish-white, rather heavily blotched with varying
shades of brown. They average about .69 × .50 of an inch.