You'll probably be asleep when autumn arrives at 5:51 a.m. Sunday. This first day of fall is known as the autumnal equinox. At this time of year, we have about 12 hours of daylight and 12 hours of night. The sun rises almost due east and sets due west.

Some reflections on the newly arrived season:

Corel photo library (ENLARGE)

Bluebirds, with their brilliant plumage, are very popular. Adult bluebirds soon will shed their breeding plumage and molt into a fresh set of feathers, making for a colorful autumn.

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"Autumn is a second spring when every leaf is a flower."— Albert Camus

"For man, autumn is a time of harvest, of gathering together. For nature, it is a time of sowing, of scattering abroad." — Edwin Way Teale

"No spring nor summer beauty hath such grace / As I have seen in one autumnal face." — John Donne

Convention for the birds

Everybody, it seems, loves bluebirds. But probably nowhere were the beautiful creatures more praised and adulated last week than at the University of Georgia in Athens, where the North American Bluebird Society was holding its 30th annual convention.

Scientists and amateur bluebird enthusiasts alike at the three-day conference pondered topics ranging from bluebird color patterns to how to help the birds survive the winter.

Why so much attention on bluebirds?

"They are gorgeous, remarkably sweet creatures," said Patricia Gowaty, a UGA associate professor of ecology, who was the conference's keynote speaker. The birds' tameness, brilliant plumage, warbling song and strong liking for nesting boxes endear them to bird lovers everywhere, she noted.

Scientists love them, too, because they are easy to observe and study as they forage in open landscapes and nest close to houses and other buildings. In addition, the sex of juveniles — not just adults — can be readily distinguished by differences in plumage color and pattern. This makes them a "model" species for studying mating behavior and interactions between parents and offspring, said Gowaty, who has spent more than 30 years tracking bluebirds in Georgia and South Carolina.

In her field studies, Gowaty helped dispel a once widely held notion about bluebirds — that pairs were mostly monogamous. She found that as many as half the nests contained young sired by multiple males. In other words, many female bluebirds "mess around," she said. Based on her landmark findings, other scientists found evidence of such activity in more than 90 percent of 100 species studied.

Reflecting on her findings, Gowaty concluded that female bluebirds who mate with several male partners may gain an evolutionary advantage — by producing babies with a variety of genetic makeups. The greater the genetic diversity, the better the chances of the offspring withstanding diseases and parasites.

Whatever their mating habits, Georgia's bluebirds have just about wrapped up their long nesting season, which began in early March. Many of them raised three broods. In some parts of the state, fledglings may still be leaving the nest.

As if to signal the end of their mating season, adult bluebirds soon will be shedding their worn-out breeding plumage and molting into a fresh set of spiffy feathers. Some folks say that adult bluebirds look their most brilliant in autumn because of the new plumage.

As cool weather sets in, bluebirds will gather in small restless flocks that rove through open country, feeding at the edges of woods or roadsides. If insect populations are low, they will eat fruits and berries.

Lumpy squirrels natural

A question that we often get this time of year concerns small, unsightly lumps protruding from underneath the skin of Eastern gray squirrels. Biologists call the lumps "warbles," which some folks mistake for tumors.

But biologists with the state Wildlife Resources Division say that warbles are a natural occurrence in squirrels this time of year. Although they cause some discomfort in the animals, the lumps are not life-threatening.

They are caused by the larvae of a botfly called Cuterebra emasculator. According to wildlife biologist Alex Coley, the flies lay their eggs on foliage, twigs or limbs, or directly on a squirrel. When the larvae hatch, they crawl into body openings and migrate underneath the squirrel's skin. There they grow for three to 10 weeks until they mature and exit, falling to the ground. The larvae then burrow into the ground to pupate.

In addition to gray squirrels, the botfly also parasitizes fox squirrels and chipmunks. The animals tend to recover quickly once the larvae depart.

Coley also has some good news for squirrel consumers: Even with warbles, squirrels "are perfectly safe to skin and eat," he says.

A full moon is rising

The moon will be full on Wednesday. Look for it to rise about sunset and set around sunrise, says Fernbank Science Center astronomer David Dundee. September's full moon is called the Harvest Moon because farmers once worked late into the night harvesting their crops under the light of the full moon.

Mercury is very low in the west just after sunset and sets about an hour later. Venus and Saturn shine brightly very low in the east just before sunrise. Mars rises out of the east at about midnight and appears near the moon Tuesday night. Jupiter sets in the west at about midnight.

You can reach writer Charles Seabrook at seabrk@comcast.net