The blue jay that landed on the tulip poplar just outside my window earlier this week was quickly joined by another blue jay — a courting pair, I assumed. I couldn’t tell, though, which was male or female: A blue jay’s color pattern is the same, regardless of its sex.
That’s not true, however, of many other Georgia songbird species, which may have considerable plumage differences between male and female. An example is our common, year-round Northern cardinal. With its gleaming red feathers and black face, the male cardinal is one of Georgia’s handsomest creatures. The female, on the other hand, is one of our drabber birds, primarily brownish or grayish overall.
In several other songbirds, the plumage differences between the sexes is so striking that males and females of the same species appear to belong to entirely separate species. That is especially true for many of our migratory songbirds that will be returning from the southern tropics over the next several weeks to nest in North America.
As happens every spring, I can expect to hear from folks who believe they have a mystery bird in their yard — a bird they can’t identify because it’s not in their bird books. Or so they think.
The main problem, I find, is that they haven’t looked hard enough. They tend to pay most attention to pictures of the colorful male of a species and overlook the more somber-colored female. Indeed, many species — cardinal, painted bunting, indigo bunting, scarlet tanager, goldfinch, red-winged blackbird — are named for the vivid breeding colors of the males, even though the females lack those bold colors.
The rose-breasted grosbeak, for instance, is named for the male’s bright rose-colored patch in the middle of a gleaming white breast. It is one of our most beautiful spring migrants, eliciting a lot of oohs and ahs from folks when it stops at backyard feeders during migration. Little or no attention, however, may be paid to the dull, brownish, sparrow-looking bird accompanying him. This is the female rose-breasted grosbeak, whose feathers have not even a dab of rosy color.
Why such a huge difference? A major reason, bird experts say, is that a female’s dull plumage makes her less noticeable to predators when she is sitting on a nest.
IN THE SKY: The moon will be full on Wednesday — the “Windy Moon,” as the Cherokee peoples called this month’s full moon, said David Dundee, Tellus Science Museum astronomer. Mercury is very low in the east just before sunrise. Jupiter is high in the south just after dark. Saturn rises out of the east a few hours before midnight and will appear near the moon on March 29. Venus and Mars are too close to the sun for easy observation.
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