Danielle Alberti

It starts with an e-mail—a notice of a rare sighting that lures streams of bird watchers to Colorado's open lands. A hybrid and two Snow geese have been spotted within an expanse of Canada geese.

Jessi Oberbeck, 24, and her mother Debby, 52, are two of the birders who made the trip to Stearns Lake to take a look.

"There they are," Jessi says, pointing to an adjacent field. "Let's get up on the dam and look down at them. Careful—don't flush them."

With those words, honks raise from the field as a woman and her dog approach. As the warnings sound, it becomes louder as each goose joins in. Finally, one bird takes flight, prompting the rest to follow. Jessi and Debby cover their heads as thousands of geese soar over them to land in the lake. After the obligatory clothing check, they scout the flock to find a bird that just doesn't quite fit in with the rest.

With a life list of 472, Jessi has seen almost every species found in the state of Colorado. Not that geography holds her back. She went birding in Pennsylvania, Texas and California in 2008. And over spring break, she is bound for Louisiana while her mother goes to Costa Rica.

"But we won't even talk about that," Jessi says. "She doesn't realize that she won't even be able to find the birds without a young pair of eyes to see them."

For this mother-daughter pair, birds are just a part of traveling. Every family vacation over the years proved to be an opportunity.

"That's the unique aspect about birding," says Debby. "No matter where you are, there are birds."

Jessi remembers the first addition to her life list. It was shortly after her fifth birthday, while visiting her parents' cabin in Grand Lake, Colo. Though she had seen many birds before it, the Townsend's solitaire was her first recorded sighting. While her passion went dormant with adolescence, it resurfaced in recent years when she spotted the Long-tailed duck—a rarity in Colorado.

"When you finally see a bird that you've been chasing for so long, it's really stinkin' cool," she said.

Jessi's commitment to birding becomes a little more apparent during the summer, when her tattoos come out. On her shoulder is a kookaburra—a testament to her time in Australia. Her ankle is host to the Ivory-billed woodpecker, an American woodpecker that may or may not be extinct. Though sightings have been claimed, its existence hasn't been confirmed in decades.

Spotting the hybrid, Debby laughs. "There he is! That's the funniest thing I've ever seen!"

Local birders speculate that it is a cross between a Canada goose, a Ross's goose and a Snow goose—a rare sight. Having found the hybrid, as well as both a Blue-morph goose and a White-morph goose, they decide to relocate to see what they can find.

As they drive past Broomfield's Lower Church Pond, they notice a higher activity level in the pond than usual. Suddenly, Jessi brightens.

"Pelicans? In winter? Mommy, we have to go there!"

Getting closer, it becomes obvious that the great white shapes aren't pelicans. Their necks curve in an unmistakable arc as they float gracefully on the water. Trumpeter swans—four adults and a juvenile.

"You know," Jessi says, nodding to me. "That's a great bird to start off your life list."