MANCHESTER, NH—In a welcome sight heralding the end of another winter and the arrival of spring, United Parcel Service men across the nation are breaking out the shorts.

UPS driver Luis Tendero breaks out the shorts in Eugene, OR.

"Look!" said Manchester, NH, cashier Brenda Cosgrove, staring out the window of the yarn shop where she works. "There goes another one! That's three today!"

Across the U.S., signs of the change of season abound, as daffodils poke out of the ground, the songs of the robin are once again heard in the trees, and leaves bud on the branches. For millions of Americans, however, there is no more beloved harbinger of spring than the sight of a UPS man's sturdy calves in the open air after months hidden away beneath heavy brown fabric.

"Between the long winter and this cold rain we've been having, it felt like it was never going to warm up," said Hugh McCaskill, a St. Cloud, MN, real-estate agent. "But then I saw a pair of UPS shorts on the street while driving to work this morning, and my heart soared. There's nothing quite like that first sighting of the year."

"I had a hard time concentrating on work today," said Aberdeen, MD, insurance-claims adjuster Jim Freund. "Seeing those UPS guys in their short pants made me want to run home, grab my baseball glove, and head over to the park. As thanks, I think I'll stop off at my local UPS office and send a five-pound parcel to Hagerstown at the two-day shipping rate."

Even if the grass is green, many citizens say spring has not truly arrived until the first pair of knees are seen just below the conservative hemline of those somber brown shorts.

"The temperature can be in the mid-70s, the cherry trees can be in full bloom, and the calendar can say June," said Washington, D.C., resident Cathy Anderson. "But until [UPS delivery man] Bill [Plevekis] comes to my door in those brown shorts with the socks hiked all the way up, I don't feel like winter has truly ended."

Though scientists are not certain what evolutionary instinct, complex set of genetically coded chemical signals, or UPS corporate policy tells the delivery men when to shed their long pants, the switch to shorts has a powerful emotional resonance with many.

"Ever since I was a kid, I haven't been able to stop wearing my down jacket until I see a UPS man in shorts," said Virginia Bourne, who, as office manager for a Buffalo law firm, signs for packages daily. "This year, I still haven't seen one, but something tells me today might be the day. [UPS delivery driver] Russ [Zorn] should be doing a drop off/pick up around 3 p.m., and I've got a good feeling."

The year's first sighting of a pair of UPS shorts is always a media event, and last Monday was no exception. When Yakima, WA, legal secretary Lynn Harrison phoned Today weatherman Al Roker to report a pair emerging from a UPS van in front of her neighbor's house, she touched off a deluge of similar calls to news outlets nationwide.

"I always smile extra big when I think about the UPS shorts," said Roker, who adds miniature pairs of brown shorts to his weather map each spring until every state has reported a sighting. "There's just something about those UPS men and their little shorts that brings out the spring feeling in me."

The delivery drivers are well aware of the feelings they evoke when they cast off their bulky winter trousers each year.

"My shorts symbolize rebirth. They give people hope for new beginnings," said New York City UPS delivery man Greg Gullicksen. "Also, I got a lot more freedom of movement when I'm getting in and out of the truck."