Catching a glimpse of a Henslow's sparrow, golden-winged warbler, cerulean warbler, short-eared owl, semipalmated sandpiper or wood thrush is rare in Pennsylvania, but without immediate conservation efforts it could soon be only a memory, according to birding groups.

Those half-dozen birds, which now breed or winter in the state or migrate through it, are on WatchList 2007, the latest listing by the Audubon Society and American Bird Conservancy of North American of birds facing an imminent risk of extinction.

The continental WatchList, based on a comprehensive analysis of population sizes and trends, distribution and environmental threats, includes 59 species on a "red list" of greatest concern, and 119 species on a "yellow list" because of a combination of rarity and steeply declining populations.

"All of us in Pennsylvania have an opportunity and responsibility to help protect our birds at greatest risk," said Tim Schaeffer, executive director of Audubon Pennsylvania. "We need conservation action now, while there is still time, and WatchList helps focus that action where it is needed most."

The WatchList, first issued by Audubon in 1996, is intended to call attention to bird species at risk before they require federal action as threatened or endangered, and serves as an early warning system for management agencies, land owners and the general public.

Birds can be affected by chemicals in the environment or lack of food, but the biggest threat to at-risk species is habitat loss caused by human activities, including development and farming.

The golden-winged warbler and Henslow's sparrow both breed in Pennsylvania and are "red list" birds because of the loss of suitable nesting habitat. The warbler, which favors dense shrubs and young saplings, has experienced a population decline of 98 percent in the state, while the sparrow population, which depends on declining grassland habitat, has declined by almost 70 percent in the past 40 years.

The semipalmated sandpiper, a migrant, and the short-eared owl, wood thrush and cerulian warbler, all of which breed in the state, are on the "yellow list" and have experienced severe loss of prime habitats.

To help preserve the at-risk species, Audubon has established 73 Important Bird Areas across the state to protect habitats like grasslands, forests and wetlands deemed critical to the birds' survival.

The closest to Pittsburgh are in Raccoon Creek State Park in southern Beaver County and Little Buffalo Creek basin, part of Audubon's Todd Sanctuary in southern Butler County.

Audubon has also urged individuals to help preserve bird habitat by planting backyard gardens, advocating for clean water programs and conservation funding initiatives, and establishing community green spaces.