A happenstance meeting at a western Minnesota pharmacy launched the career of one of Minnesota's most prolific birding pioneers.

Mae Nisbit Peterson banded more than 15,000 birds from 120 species in a 27-year span — logging 286 different birds on her so-called life list.

The daughter of a carpenter and his Scottish bride, she was born in Rochester in 1876 and graduated from high school there in 1893.

She studied nursing, then shifted gears — graduating with a pharmacy degree from the University of Minnesota and landing a job at a drugstore in Ortonville on the South Dakota border in the early 1900s.

Mixing more than compounds, she married her pharmacy co-worker, Charlie Peterson, in 1905 and they purchased a drugstore 30 miles away in Madison, Minn. — the Lac qui Parle County seat.

Peterson's Drug Store would serve as an anchor in Madison's business district until Charlie died in 1938. The fateful meeting that sparked Mae's birding passion happened there in 1924, when she was raising two sons in her late 40s.

Dr. Thomas Roberts, the curator of the University of Minnesota's Museum of Natural History, stopped by the Madison drugstore with a pair of associates. They were working on a diorama depicting prairie habitat and asked if anyone knew about nesting sites of western Minnesota prairie birds.

" 'Charlie' Peterson, as everyone knew him in Madison, said that his wife had just inherited some bird books and that maybe she could help him. Thus began her interest in birds," according to Goodman Larson's loving memorial, written when Mae died, in a 1960 issue of the Flicker — the newsletter of the Minnesota Ornithologists Union.

Larson, a childhood neighbor of the Petersons, grew into a birding luminary after Mae gave him his first bird book.

"The outgoing warmth of her personality and interest in people was a two-way charm — opening the eyes of the uninitiated to the wonders of nature as revealed through an interest in birding," Larson wrote in 1960.

"How many times has the door of her friendly white house opened to the timid knock of a freckle-nosed child carrying an injured Robin or the report of a strange warbler that evaded identification?"

Peterson wasn't always sweet. During the Dust Bowl days of 1934, she identified Arctic towhees, which she figured grew disoriented in a dust cloud. Her findings — a first in Minnesota — drew skepticism from Roberts at the Natural History Museum in Minneapolis. So Peterson purchased a sparrow trap, captured a male and female towhee and sent them to Roberts, who was compiling his book, "The Birds of Minnesota."

"While she's a lovely lady, to prove that she was right, she'd squeeze [the specimen] until it died and send it to him," Larson said.

Many of Peterson's rare bird sightings happened at a little-known lake straddling the South Dakota border near tiny Marietta, Minn. (pop. 155). Known fittingly as Salt Lake, the 312-acre body of water has the most salty alkalinity of any water between the Atlantic Ocean and Utah's Great Salt Lake.

Considered one of Minnesota's top birding spots, "Salt Lake first came to the notice of the birding community as a result of reports" from Mae Peterson, according to the Audubon Society's website.

A sign remembering Peterson is perched on the shores of Salt Lake, where she spotted many rare birds, including marbled godwits, eared grebes, snowy egrets and the black-throated gray warbler.

It's no coincidence that the Minnesota Ornithologists Union held its first meeting 55 years ago (1963) in Madison, starting traditional springtime treks for birders to Salt Lake. In 1973, 13 years after her death, the Minnesota Department of Natural Resources began acquiring more than 700 acres of land around the lake to preserve nesting habitat.

"It was through her early interest that this lake was preserved," according to one 2003 book. "She brought the place to the attention of naturalists who would later rescue it from becoming a dumping ground for farm machinery and general junk."

Thanks to Mae Peterson, Salt Lake now attracts birders from around the globe to catch unusual glimpses of avocets, tundra swans and phalaropes.

"She was known as the Bird Lady," said Barb Redepenning, curator of the Lac qui Parle History Center in Madison. One of Peterson's bird traps is among the items on display in the museum.

In his 1960 memorial in the Flicker, Goodman Larson recalled "the joy one could find watching birds from her back porch."

Her home in Madison, he wrote, felt like a Scandinavian cottage — and was punctuated with items from her birding.

"Birds' nests mounted on the wall, a pair of well used binoculars hanging from a peg, souvenir bird images sent from faraway places by bird loving friends," he wrote.

Her meticulous notebook was often open, and a house for purple martins was perched on her garage roof.

"Through the window of her porch you could see what was a veritable bird sanctuary," Larson wrote, "the lilac hedges hiding the town from view while giving nesting sites and privacy to the Brown Thrashers as they dipped into her bird bath."

Curt Brown's tales about Minnesota's history appear each Sunday. Readers can send him ideas and suggestions at mnhistory@startribune.com. His new book looks at 1918 Minnesota, when flu, war and fires converged: tinyurl.com/MN1918.