Northern Prairie Wildlife Research Center
Robert K. Murphy
|Main street in the town of Appam. Faded wooden placards identify the sites of merchants buildings that existed decades ago.|
Appam is more than a charming ghost town tucked away in northwestern North Dakota. It is also a special place for piping plovers. Each year they nest on the lake just north of town. Locals call it Alkali Lake.
There's at least one Alkali Lake in every county along North Dakota's Missouri Coteau, so we call this unique spot Appam Lake. It covers a bit less than a square mile and when the water level is just right, it offers five miles of salty, gravelly beaches suited for plover nesting.
Actually Appam appears to be a "boom and bust" proposition for nesting plovers. In the mid-1980s, roughly one-half of the lake basin held waters attracting about a dozen breeding pairs. Still fewer nested during severe drought in the late 1980s and early 1990s.
In 1993 many shallow bays began to refill and by 1996 the water level in Appam Lake appeared optimum for nesting plovers. Twenty pairs occurred in 1994 and 35 in 1995. In 1996 more than 105 adults - at least 50 pairs with nests - defended territories along Appam's shores. This likely represents an unprecedented breeding density for piping plovers in the Great Plains.
Abundance doesn't necessarily convey high quality habitat, however. We monitored production of young by a sample of plover pairs on Appam in 1996. We often observed plovers from a small boat about 30 yards offshore, to avoid disturbing birds while counting young. Twenty-one plover pairs fledged an average of: 0.9 young each, a little below an estimated 1.1 needed for a stable population; but slightly higher than plovers elsewhere in northwestern North Dakota (0.8) in 1996. Meanwhile, eight other plover pairs on Appam, protected by experimental predator barrier fences, fledged an average of 2.3 young.
|When the water level is just right. Appam Lake offers nearly five miles of salty, gravelly beaches suited for plover nesting. In the horizon, Appam's grain elevators tower over the surrounding plain.|
Coyotes may be an important predator of plover eggs on Appam. We routinely see coyotes hunting the beaches and seldom note other tracks of other mammalian predators. There are a few California and ring-billed gulls, but any large gull daring to fly over the lake is hastily escorted away by mobbing American avocets. Area raptors include northern harrier and ferruginous and Swainson's hawks, but these are also kept away by avocets.
Because Appam Lake hosts dozens of nesting plover pairs in some years, it is practical to manage it intensively for the threatened bird. High production of young on such areas can offset poor success elsewhere, and help reverse the species' population decline. Most of Appam lake is federally owned. Owners of adjacent, private lands have graciously supported management efforts.
Continued monitoring will help determine the extent, type, and location of management needed to boost net annual output of young plovers. Predator barrier fences will probably be main tools used to protect nesting plovers.
Like most resources in northern prairies, however, Appam is dynamic and may be nearly dry about two out of five years. In years when few plovers nested at Appam, efforts could be redirected to protect nesting plovers elsewhere.
Appam will be nominated as an IBA, or Important Bird Area in North America, because of its significance to piping plovers; it held four percent of the Great Plains breeding population in 1996. But it is more than a spectacular plover breeding site. White-rumped, Baird's, and pectoral sandpipers, ruddy turnstone, sanderling, semi-palmated plover, and other migrant shorebirds use the lake. About 60-100 avocets nest there.
In sparsly vegetated uplands adjacent to the lake, chestnut-colored longspur, Sprague's pipit, Baird's sparrow, and lark bunting are common breeding birds. Grasshopper sparrow, LeConte's sparrow, and even an occasional sharp-tailed sparrow also are there. Gadwall and shoveler loaf and feed in the salty water. Alarm calls of willets and marbled godwits add to the avocets' periodic, clamorous chorus.
Terry Rich, biologist for the U.S. Bureau of Land Management, surveyed plovers annually on Appam Lake during the 1980s. With a little poetic imagination, excerpts from his 1988 field notes aptly describe a hot summer day there:
"I had been walking around Alkali Lake all morning. The sun was hot...Myriad shorebirds objected to my presence. I had built a terrific thirst and my legs were beginning to weaken.
There were a number of piping plovers around the shoreline...As I tried to count them they ran ahead of me in bunches. I became confused. My head swam in the heat. I staggered back in bewilderment, becoming bogged in the salt-encrusted, sulfurous pudding. I squinted through my dusty sunglasses, trying to squeeze the perspiration from my eyes. They burned, but I was unable to relieve the pain. Horseflies tore my flesh and brought me part way back to reality..."
Appam may not be everyone's dream of a vacation at the beach, but to piping plovers-and lovers of the plovers-it's paradise!