NORWAY — For nearly 20 years, Mary Van Nest and her husband, Robert, have been participating in the annual migratory bird walk, but she’s seen the number of species decline over the past few years.

“I don’t know if it’s the weather or the climate changes,” she said.

The couple have organized the event at their 80-acre Pikes Hill Farm for years and have been birding together for about 40 years.

On Saturday, May 17, they will join others at the Roberts Farm Preserve at 64 Roberts Road for the two-hour migratory walk beginning at 7:30 a.m.

“Evening grosbeaks you just don’t see anymore,” Van Nest said. They used to be seen with an average of about 50 other species around the area during the bird watches. But they and certain warbler species seem to have disappeared from the area, she said.

“They’re lovely little birds,” she said of the warblers. “They’re so beautiful. We’ve always had them here until the last few years.”

Lee Dassler of the Western Foothills Land Trust, which is sponsoring the walk, said anyone who would like to participate should bring binoculars and bird books and dress for weather, bugs, walking and wet terrain. Refreshments will be available and donations are appreciated, she said.

In past walks, birders have identified black-throated green, yellow rump, black-throated blue, black and white, blackburnian, chestnut-sided, pine and Nashville warblers.

Other species identified included bluebird, blue-headed vireo, ovenbird, crow, tufted titmouse, tree swallow, black-capped chickadee, hairy woodpecker, redstart, least flycatcher, brown creeper, white-breasted nuthatch, yellow-bellied sapsucker, white-throated sparrow, hermit thrush, mourning dove, herring gull, goldfinch, rose-breasted grosbeak and robin.

Dassler said birders will also have a second chance to watch for birds from 8 to 10 a.m. Saturday, June 1, in Otisfield. John Gunn will lead the walk, rain or shine, at the Twin Bridges. The 252-acre woodlands is a proposed Community Forest for Otisfield. Bring binoculars, bird books, and dress for weather, bugs, walking and wet footing. Park at the Twin Bridges Rest Area on Route 117 at the Crooked River.

Donations are welcome. For more information about either event, call 207-739-2124, wflt@megalink.net.

ldixon@sunjournal.com