With an abundant supply of salmon, berries, ground squirrels, and carrion, the refuge provides excellent habitat for numerous brown bears. Bears use nearly all refuge lands, from mountain tops to the sea coast. Depending on weather conditions and food supply, bears usually leave their dens in April/May and return in October/November. Some bears will den much later, or not at all, if adequate food sources are available.

The northern Alaska Peninsula caribou herd is one of 13 major herds within the state. Herd size fluctuates naturally and has varied from 2,000 to 20,000 animals during the last half of the 20th century. The herd migrates up to 200 miles from spring calving grounds between Ugashik and Port Moller, to winter range extending from the Meshik Valley to the Naknek River.

Moose are relative newcomers to the Alaska Peninsula. They have been observed since the early 1900’s, but did not become abundant until the 1950’s. Moose travel seasonally to breeding, calving and wintering areas. Migration varies from a few miles to 50 miles during these periods. These huge deer stand 5-7 feet at the shoulder; with long legs that make movement through wet tundra, shallow ponds and limited snow relatively easy. Moose browse on vegetation, especially willow, birch and aspen. Although they appear harmless, moose can be very dangerous, especially females with young. Do not approach too closely or you may be charged.

More than 200 species of birds have been observed on or near the refuge, of which 45  bird species are year-round bird residents. The refuge provides important spring and fall staging areas and moderately good breeding habitat for many species. The cliffs, bays and poorly-drained lowlands provide abundant habitat for millions of birds, particularly seabirds, waterfowl, and shorebirds that use the Refuge primarily as a staging area during migration to and from nesting grounds in the Arctic. Seabirds also use the refuge for breeding. Numerous ponds, lakes, streams, and wetlands on the peninsula provide ample breeding habitat for a number of species. In the summer, migratory songbirds and raptors make use of the abundant shrub lands, tundra, and forest environments on the refuges.

Many of the salmon from the world’s most valuable sockeye salmon fishery (Bristol Bay) spawn in the streams that originate on refuge lands. The ecosystem of the refuge is fueled by massive runs of the salmon that enrich freshwater streams and lakes with nutrients from the ocean. All five species of Pacific salmon (king, coho, sockeye, pink, and chum) spawn in the streams and lakes on the refuge. The salmon runs begin in June and continue to September in Bristol Bay, and into December in the Chignik area.

The Alaska Peninsula Refuge contains many unique geologic and scenic features.  Indeed, the Alaska Peninsula Refuge is the most scenically diverse of the Bristol Bay refuges: the interplay of volcanic activity with shoreline erosion and glacial scour has created outstanding scenery. The Joint Federal-State Land Use Planning Commission listed Chiginagak and Veniaminof volcanoes, Castle Cape, and the Pacific Coast as one of the outstanding scenic complexes of Alaska. The Ugashik and Chignik Units of the Alaska Peninsula Refuge also provide pristine habitat to many significant fish and wildlife resources, and offer many subsistence and recreational opportunities.