Benton Lake National Wildlife Refuge

Boom and Bust Cycles and Wildlife

The relative abundance of species and specific food and cover resources used by animals vary with the long-term dynamics of flooding and drying in the wetland basin and grasslands of the Refuge. Over 200 bird species from 12 different taxonomic orders have been documented on the Refuge during various seasons.

Breeding Bird Species During Boom (Wet Years) Cycle

Common breeding birds using the Refuge during boom years (wet years) include: eared grebe, mallard, northern pintail, gadwall, blue-winged teal, cinnamon teal, American wigeon, northern shoveler, redhead, lesser scaup, ruddy duck, Canada goose, American Coot, American avocet, Wilson’s phalarope, marbled godwit, willet, Franklin’s gull, white-faced ibis, black tern, common tern, Sandhill Crane, Forester’s tern, and black-necked stilt.

During these wetter periods of long-term precipitation and flooding cycles, many waterfowl, shorebirds, wading birds, gulls, terns, and other wetland-dependent species are present and production is high. Vegetation and invertebrate communities, as well as nutrient cycling, change when wetlands dry, re-flood, reach the peak flooding extent, and then begin drying again. Aquatic invertebrates reach peak abundance and biomass during wet periods of long-term water cycles in wetlands and include a rich diversity available to many wildlife species.

Wildlife Species During Bust (Dry Years) Cycle

During dry periods of the long-term hydrological cycle, fewer waterbirds breed at the Refuge and the smaller more concentrated and ephemeral nature of summer water reduces nesting attempts and success. During drier periods, extensive mudflat areas are available as surface water evaporates and recedes to deeper depressions. These mudflats attract large numbers of shorebirds that utilize the rich benthic and terrestrial invertebrate resources.  Drying wetlands concentrate aquatic prey for wading birds, and mammals utilizing the wetland basin.

The Refuge is home to many grassland birds throughout the boom and bust cycle. The Refuge has nearly 6,000 acres of intact, northern mixed-grass prairie. Grassland birds are one of the most imperiled groups of migratory birds in North America having experienced steeper, more consistent and more widespread population declines than any other avian guild. The native grasslands of the Refuge provide breeding habitat for Sprague’s Pipits, ferruginous hawk, upland sandpipers, long-billed curlew, marbled godwit, burrowing owl, short-eared owl, grasshopper sparrow, chestnut-collared longspur, Baird’s sparrow, sharp-tailed grouse, and bobolink.

Spring

Beginning in mid-March large numbers of pintails, mallards and tundra swans appear as ice leaves the Refuge and natural runoff from snow and rains accumulate. From several hundred to several thousand snow geese arrive and stay for a week or more. Bald eagles and peregrine falcons are often seen in the spring. Waterfowl in breeding plumage have paired off and begin to seek nesting sites. As the weather warms, more and more species arrive, with shorebirds the last to make their appearance. Canada geese with young may be seen in late April, and some duck broods may be seen in late May.  Pronghorn return to the refuge signaling the arrival of spring. Pheasants and sharp-tailed grouse begin breeding. Visitors may view grouse males on a lek, or dancing ground by reserving the free watchable wildlife viewing blind (fondly nick-named "The Grouse House") in April and May. Richardson’s ground squirrels can be seen on the Refuge roads and in the fields. An occasional muskrat can be seen swimming in the canals.

Summer

By June all birds that will nest at Benton Lake have arrived. With adequate runoff and/or artificial flooding, broods of ducklings, colonial nesting birds like eared grebes, white-faced ibis, and Franklin's gulls can be seen. As water recedes, a variety of shorebirds can be seen including, yellow legs, avocets, willets, Wilson's phalaropes, long-billed curlews, upland sandpipers, and marbled godwits. Songbirds, like chestnut-collared longspurs and western meadowlarks, are raising their young. Burrowing owls, which nest on the Refuge in limited numbers, may be visible. In the fields along the roads, badgers can be seen lying on their mounds sunning themselves. In the early morning, coyote can be seen scouting the Refuge. Yellow-bellied marmot are common among the rocks and roadways, but you must be quick, as they scramble when a car approaches. If you are patient, you may be lucky enough to view a long-tailed or least weasel in the grass near a dike before it dives into its hole. Pronghorn, white-tailed deer, and mule deer with their young of the year, can be seen in the grasslands of the Refuge.

Fall

With fall precipitation and surface water that holds over until fall, shorebirds and waterfowl numbers increase as migration peaks. Waterfowl that bred on the Refuge begin to stage in preparation for the migration further south. Bald eagles and peregrine falcons keen on following the migrating waterfowl flocks are frequently seen in pursuit of a meal. Tundra swans mark the beginning of the end of the fall migration. Deer and antelope become more wary after the beginning of hunting season, and become infrequent visitors to the Refuge’s grasslands. Jackrabbits change from brown to white in preparation for winter, but stand out against the golden grasslands. Golden eagles hunt the highest portions of the Refuge in search of rodents and birds.

Winter

The frozen and windy landscape provides a harsh living environment for most bird species. Great horned owls often move into shelterbelts this time of year and rough-legged hawks are common in most winters. Other hardy raptors seen occasionally include northern goshawks, gyrfalcons, and snowy owls. Northern shrikes, horned larks, and sometimes snow buntings are among the few song birds present. Ring-necked pheasants, gray partridge, and sharp-tailed grouse sightings are frequent as they gather to feed. White-tailed and mule deer re-appear in the open fields. Coyote and fox are easy to see against the white background of snow. White jackrabbits run across the fields and take cover in the shrubbery.