Henry David Thoreau wrote that the bluebird “carries the sky
on his back.” Although this poetic
description referred to the Eastern Bluebird, the meaning could just as easily
be applied to two other commonly seen, predominately blue birds that are found
throughout the southeast. The trio of
common “blue birds” in Mississippi includes the Indigo Bunting (Passerina
cyanea), the Blue Grosbeak (Guiraca caerulea), and, of course, the
familiar Eastern Bluebird (Sialia sialis).
If any of these three birds
has a claim to the distinction of carrying the sky in its plumage, it’s the
Indigo Bunting—the male of this species can seem to change hues as quickly as
the spring sky can fade from clear blue to a duller gray over the course of an
afternoon. Although any blue coloration
present in feathers is the result of light reflecting off of the structure of
the barbules, the Indigo Bunting’s appearance is especially changeable. The reason for this is that the feathers are
iridescent, catching different amounts of sunlight to appear any shade from
blue-black to bright turquoise. In
contrast to the male, the female Indigo Bunting is a much subtler brown, with
hints of blue in the wings; this more subdued coloration helps camouflage her
at the nest, which is generally placed in a small tree or shrub. In fact, thickets, woodland edges, and
overgrown fields are the favorite environments of this sparrow-sized member of
the cardinal family, and, like cardinals, it will come to backyard bird feeders
for sunflower seeds and white millet.
Its relatively thick, stout bill aids it in cracking hard seeds, but,
like many birds, it also feeds on insects. During the spring and summer, the excited,
up-and-down warbling song of the male bunting cues observers in on its
presence—helpful, considering how difficult it can be to catch a
glimpse of the vibrant blue bird when it is hidden in vegetation.
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| Singing male Indigo Bunting in the sunlight. |
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| Male Indigo Bunting on an overcast day. |
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Female Indigo Bunting
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The Indigo Bunting’s larger cousin, the Blue Grosbeak, lacks
the eye-catching iridescence of the bunting, but it is also a stunning
bird. The plumage of the male grosbeak
is a deep, royal blue with brown bars on the wings and a black “mask.” For the same reason as the female Indigo
Bunting, the female grosbeak is more cryptically colored: brownish gray, with a
touch of gray-blue on the wings.
“Grosbeaks” are aptly named—their dark-colored, conical beaks are very
stout and large, and point to their relationship with the well-known Northern
Cardinal, which also has a large bill.
They can be found in the same habitats as the Indigo Bunting, but
usually in much smaller numbers.
However, in spring and summer, it is not uncommon to see these striking
birds helping themselves to feeder offerings, bringing delight to observers who
realize that their backyard visitors are not simply oversized Indigo
Buntings. Once learned, the song of the
Blue Grosbeak is quite different from that of the Indigo Bunting; it is a
series of throaty, rolling warbles that befit this larger, less hyperactive
bird. Blue Grosbeaks may be less jumpy
than their smaller cousins, but anyone who has seen the males battling for
territory in the springtime, chasing each other through the underbrush, knows
that they are far from lethargic!
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| Male Blue Grosbeak |
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| Female Blue Grosbeak carrying nesting material! |
Nearly everyone has heard of or seen the bluebird, known to
some as the “bird of happiness.” Unlike
the other two “blue birds,” though, the Eastern Bluebird—washed with vibrant
blue on the back—has a rust-colored breast fading into a white belly. Female bluebirds have a similar pattern, but
with more subdued coloring. The
contrasting palette of colors makes this species difficult to confuse with
anything else, and the song—a short, lilting warble—is a familiar sound in
rural areas. Open woodlots, abandoned
fields, and pastures all provide habitat for Eastern Bluebirds, which nest in
rotting posts, snags, and the bluebird nest boxes constructed especially for
them. Bluebirds’ diet consists mostly of
insects and berries that they find in their natural habitat, although they will
also occasionally come to backyard feeders for suet, mealworms, and fruit. Unlike the Indigo Bunting and Blue Grosbeak,
the Eastern Bluebird is a member of the thrush family, which includes such
familiar birds as the American Robin and Wood Thrush. Because bluebirds—like robins—lack spots on
their breasts, they do not greatly resemble thrushes at first glance; however,
their slim, slightly curved bills, upright posture when perching, and tendency
to flutter their wings all point to this relationship. Interestingly, bluebird young look far more
like their thrush relatives. They have
streaked and speckled brown plumage, with blue only in the wings and tail.
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| Male Eastern Bluebird |
As for seasonal occurrence, the Eastern Bluebird can be
found year-round in the state, and the Blue Grosbeak and Indigo Bunting are
present during the breeding season. In a
way, we are fortunate that these three “blue birds” are common and widespread
across the southeast. About thirty years
ago, Eastern Bluebird populations were declining due to loss of nesting
cavities and competition with invasive European Starlings and House
Sparrows. Concern over the bluebird’s
plight led many people to construct nest boxes for them, which helped increase
the population to a healthy level today.
The Blue Grosbeak is also doing fairly well—it has even expanded its
range northward in recent years. The
Indigo Bunting is declining across many areas of its breeding range due to
habitat changes, but it seems to be maintaining relatively healthy populations regardless
of this fact. Because it does not use
heavily forested habitats, the bunting has fared better than many songbirds,
but both it and the grosbeak are at risk from destruction of habitat on their
wintering grounds in Central and South America.
Hopefully, measures taken to prevent habitat destruction in both North
and South America will ensure that these three species of “blue birds” continue
to thrive, bringing welcome touches of sky to the earthly environments that
they inhabit.
