Just north of Eureka, Montana lie the Tobacco Plains, a sea of grass surrounded by coniferous forest. Within this sea is a remnant prairie “island” known as Dancing Prairie Preserve. This island contains a complex mosaic of native prairie grasses growing in the gravelly soils deposited by receding glaciers.
Natural History of the Preserve
The Tobacco Valley is sandwiched between the Purcell Mountains and Kootenai River (Lake Koocanusa) to the west and the Whitefish Mountain Range to the east. This valley is part of a larger geologic feature called the Rocky Mountain Trench that extends from northern British Columbia south into Montana.The mountains on either side of this valley consist almost entirely of Precambrian sedimentary formations, the Belt rocks. During the last glaciation period, the great Rocky Mountain Trench glacier covered this area to as far south as the southern Swan valley. Here, at the Preserve, the ice was deep enough to bury the majority of the mountains as an almost continuous ice cap. To this day, one can see many remnants of this glacial time including drumlins, kettles and moraines.
Drumlins appear as long, streamlined hills covering vast stretches of the valley floor which originally formed from deposits of glacial till molded beneath a large glacier. These drumlin fields in the Tobacco Valley are the only large fields of drumlins in Montana.
Kettles are a depression in the ground surface that are formed by a large block of ice melting after it has been covered and surrounded by glacial drift (rock and dirt deposited by glaciers). The depression that remains often contains a lake or pond. An example of a kettle can be found in the north west corner of the Preserve surrounded by Ponderosa Pine trees.
Moraines are deposits of glacial till, which is sediment dumped directly from glacial ice movement.
A Missing Piece
The Conservancy began acquiring land for the preserve in 1987 as a means of protecting one of the last sites in Montana where Columbian Sharp-tailed grouse came to perform their elaborate mating dance. The site of their gatherings The arrival of the birds, which once blackened the skies in parts of the west, was a true herald of spring in this area. Sadly, our efforts weren't enough, and the Columbian Sharptail is no longer found in the state.
This decline of the sharp-tails in the Tobacco Plains was most likely due to a combination of factors, including the loss of winter habitat along the Kootenai River. In the winter deciduous trees and shrubs provide both food and cover for the grouse. During the remainder of the year, the birds require standing grass or other vegetation for cover on the dancing grounds, as well as in nesting and brood rearing areas. Among other things, this cover provides protection from both ground and aerial predators for both adults and young.