During July 1804, Lewis and Clark traversed up the middle Missouri River valley, through a region that is now part of northwestern Missouri. On July 12, near the mouth of the Big Nemaha River, they observed some “artificial mounds” representing the locations of ancient Native American graves. There they also saw many Canada geese families along the river. Now, 200 years later, the Big Nemaha River is a tiny, muddy remnant of its once 80-yard width, and all traces of the burial mounds are gone. A small town, Mound City, has developed near here along the eastern edge of the valley, and a stream with the anachronistic name of Squaw Creek provides critical water for Squaw Creek National Wildlife Refuge. And, from late fall through early spring, upwards of a million or more birds stop at this refuge while on their migrations north and south, arriving from breeding grounds as far north as Canada’s high arctic tundra and heading toward wintering grounds as far south as southern South America.
Squaw Creek N.W.R. is located at the eastern edge of the Missouri River Valley, about two miles south of Mound City, Mo., reached via exit 79 off Interstate I-29. It was established in the 1930s after early 20th-century efforts to farm the frequently flooded bottomlands failed, and the land reverted to the federal government. By using a series of low dikes and water-control structures, nearly half of the refuge’s approximate 7,400 acres is maintained as shallow marshland, with the rest being deciduous woodlands, pastures and croplands.
The refuge is flanked to the east by steep, forested “loess hills” that are over 150 feet high, and were formed by deep deposits of silt blown in from the west and deposited along the river valley during late Pleistocene times. The nearby Missouri River is no longer the mile-wide shallow and snag-strewn river known intimately by Lewis and Clark. Since the 1940s, it has been diverted, diked, dredged and dammed, the results of 70 years of spectacularly unsuccessful efforts by the Corps of Engineers to prevent flooding and to keep the channel deep enough to support today’s nearly nonexistent barge traffic. Now it is a biologically degraded waterway, confined regionally to a 600-foot-wide channel and a consequent rapid stream flow that is prone to periodically catastrophic floods.
In this region the Missouri Valley’s north-south orientation, its historically rich bottomland farms and its extensive marshes provide a powerful magnet for migrating waterfowl, shorebirds and other water-dependent migrants. The adjacent wooded hillsides provide natural migratory guidelines for hawks, vultures and eagles using updraft winds on which to effortlessly soar and glide during migrations, and tree-dependent songbirds also use these forested hillsides as migratory corridors and brief stopover sites.
Shortly after arriving in Nebraska in 1961 I sought out this famous refuge, and thereafter have never missed a migration season without visiting it at least once. Even as early as the 1960s the refuge supported fall populations of several hundred thousand snow geese, out of a continental population of then perhaps two million birds, as well as large numbers of other waterfowl. During subsequent decades, the national snow goose population has progressively increased, and Squaw Creek’s migrant population has continued to thrive. From the years 2008 through 2011, for example, the maximum yearly numbers of snow geese at the refuge have ranged from about 390,000 to 1,425,000 birds. Peak numbers depend on the onset of winter weather, but during normal years, the largest numbers are likely to be seen in late November or early December, and again in early March. Some 20–25 percent of the Missouri valley geese are mostly brown-plumaged “blue geese,” a color variation that is the result of a genetic mutation of unknown survival significance. There are also many variably intermediate plumages produced by the mating of snow and blue plumage types, confounding easy field identification.
In recent years some Ross’s geese, miniature relatives of the snow goose that are little larger than mallards, have also been increasing. These tiny geese are often overlooked among the much larger snow geese, but an all-time maximum of 440 were observed in 1987. A few hybrids between snow geese and Ross’s geese have also been reported, further complicating field identification.
Because of commercial and private waterfowl hunting around the refuge’s perimeter, large numbers of snow geese are shot each fall. Some of the birds that are only wounded manage to make their way back to the refuge limits, gradually resulting in a small flock of flightless or nearly flightless birds. This supply of variably incapacitated geese produces a rich bounty of prey for raptors, especially bald eagles. The eagle population has increased over the past several decades in parallel with that of the geese. A record number of 476 eagles were observed on the refuge in 2001.
During the first full weekend of December, when eagle numbers are likely to be near their maximum, “Eagle Days” are celebrated at Squaw Creek. It is not uncommon then to see more than 100 bald eagles during a single trip around the refuge’s 9-mile perimeter road. Some might be perched on tall cottonwoods near the road but are more likely to be standing on muskrat “houses” in the middle of the marsh. Often an eagle will take flight and fly above the massed geese, causing a pandemonium and offering the eagle an opportunity to detect any birds that are weak fliers or are otherwise vulnerable. Eagles in adult plumage cause more panic than do immature birds lacking white heads and tails, suggesting that the geese recognize that adults pose a greater risk than do young ones, which tend to be scavengers rather than effective predators. After the species had recovered from the pesticide poisonings of the mid-1900s, bald eagles first nested successfully at the refuge in 1997. They have since been regular breeders, with two nests usually active.
Many other raptors migrate through the area each fall, especially the slow-flying and soaring hawks called buteos, which use updrafts from the slopes of the loess hills to gain lift for their flights south. The most common buteos are red-tailed hawks, which among counts farther north in southern Iowa comprise about 40 percent of the raptors, and are likely to winter not much farther south than Oklahoma and Arkansas. A small percentage of these are dark-plumaged (Harlan’s race) red-tails, which have probably migrated from the Yukon drainage of northwestern Canada or Alaska, but the majority of birds are more likely to consist of more extensively white-plumaged individuals (eastern race) coming out of southern Canada and the northern states.
Among the buteo hawks, Swainson’s hawks are probably second only in numbers to red-tails and are very early fall migrants. They usually migrate in large flocks while on their way to southern South America, a trip of about 8,000 miles from central Canada and one that may require more than two months. Turkey vultures are also very common early migrants and closely follow the hilly eastern edge of the river valley for maximum soaring efficiency. Turkey vultures banded in Kansas are known to have migrated as far as northern South America.
Several trends in waterfowl numbers have been evident in recent years at Squaw Creek. Other geese, including Canada geese and greater white-fronted geese, are now common. Like the snow goose, the Canada goose has been increasing nationally for several decades, at least in part because of a greatly expanded food source provided by intensive Great Plains corn farming. Until about the year 2000, maximum numbers of Canada and white-fronted geese on the refuge rarely exceeded a thousand each, but between 2008 and 2010 maximum numbers of Canada geese averaged about 15,000, and those of greater white-fronts averaged about 16,000.
Squaw Creek N.W.R. also attracts great numbers of migrant ducks. Mallards are the most abundant, with maximum 2008–2011 numbers between ranging from nearly 13,000 to nearly 102,000, the numbers usually peaking in late November. Northern pintails have a migration schedule similar to mallards, with peak yearly populations of about 7,000–33,000. Green-winged teal are also late fall and early spring migrants; their 2008–2011 peak numbers have ranged from about 3,000 to 17,000. Blue-winged teal are abundant early fall migrants, with peak recent populations of about 3,000–20,000. Northern shovelers and gadwalls are the most common of the other surface-feeding ducks, with recent maximum yearly numbers respectively ranging up to about 18,000 and 24,000 birds. The only relatively common diving duck using the refuge is the gradually increasing ring-necked duck, whose yearly maximum numbers have recently reached as high as 25,000 birds.
As part of an international effort to increase the population of the once-endangered trumpeter swan, several Canadian provinces and northern states have started trumpeter swan reintroduction programs. These efforts have been highly successful, and now this world’s most magnificent and largest swan can be seen in many parts of the northern Great Plains. First noted at Squaw Creek in 2000, trumpeter swans have been present with increasing regularity and numbers. The maximum number seen in 2008 was 78, but between 2009 and 2011 a peak average of 148 trumpeter swans were present. The adults and newly fledged young arrive in early fall and usually reach peak numbers by early December or early spring. A few somewhat smaller tundra swans on their way to Atlantic coast wintering areas are sometimes also seen among the trumpeters.
Shorebird migrations at Squaw Creek are also impressive. Species that are common to abundant during both spring and fall include the killdeer, lesser yellowlegs and the spotted, semipalmated and least sandpipers. During spring, the semipalmated plover, greater yellowlegs, long-billed dowitcher and white-rumped, Baird’s and pectoral sandpipers are all common. Many of these species use very different fall migration routes and are much less common then.
Other notable water-dependent birds using the refuge include the American coot, common gallinule and the Virginia and king rails, all of which have been found to be nesting. Additional wading birds reportedly nesting include the American bittern, least bittern, cattle egret, green heron and the yellow-crowned and black-crowned night herons. Great blue herons, great egrets, snowy egrets and little blue herons are also regularly seen.
All told, at least 310 bird species have been documented or less formally reported on the refuge. This total places the refuge among the most bird-rich locations in the upper Great Plains region and represents the largest number of bird species reported from any national wildlife refuge in Missouri.
Squaw Creek N.W.R. is a natural jewel, offering a small reflection of what the Missouri Valley’s wildlife might have resembled in Lewis and Clark’s era. The refuge is open sunrise to sunset daily and has a modern interpretive center that is open weekdays all year, and also on weekends during migration periods. Information is available from the refuge headquarters: P.O. Box 158, Mound City, MO 64470; phone (660) 442-3187.
Image Credits: Paul A. Johnsgard