Birds of a Prairie Community

With white man rapidly penetrating and disturbing the last remnants of pristine plant and animal communities on the North American continent, it is desirable to record the biological composition and dynamics of such communities before further modification takes place.Even now such studies often must be made, if at all, on areas where the plants and animals, formerly disturbed, have been allowed to return and re-establish somewhat limited natural relations.The present report concerns such a restored prairie community (fig.40) of approximately fifty acres situated next to the Iowa Lakeside Laboratory, near Milford, in northwestern Iowa, on the west shore of Lake Okoboji.The study covered the period from early June to mid-August, 1940.Vegetation.-The area is not entirely typical prairie.Formerly it was pastured, but parts of it were never plowed.For about the last twelve years it has been left alone, and two or three inches of dead grass debris have accumulated over the ground.As evidence of former disturbance, the Kentucky blue grass (Pea pratensis) is by far the most important species, constituting 25 to 100 per cent of the vegetation in various parts of the area.On the higher knolls, the vegetation approaches more nearly that of true prairie and consists of the grasses, Poa pratensis, Andropogon furcatus, A. scoparius, Sporobolus heterolepas, and Stipa spartea.Over sixty-five species of plants occur on the area, the principle forbs being an aster (Aster multiflora), a golden-rod (Solidago rigida), a lead plant (Amorpha canescens), a ragweed (Ambrosia artemisifolia), and a vervain (Verbena stricta).I am indebted to W. A. Anderson, State University of Iowa, for help with the plant taxonomy of the area.The vegetation is not entirely stabilized, although little yearly fluctuation is evident.The annual weeds have been largely eliminated by the Poa, and there is some evidence that the prairie grasses are expanding at the expense of Poa.There appears to be some invasion of box elder (Acer negundo) into the Poa grass along the south side.Small bogs and a kettle hole occur with aquatic vegetation, and in some of the ravines and along the shore of Millers Bay occur willows (Salix spp.) and cottonwood (Populus bakamifera).There are a few scattered clumps of buckbrush (Cephalanthus occidentalis) and weed patches with grape (Vitis sp.) along the boundary fence.This area is near the center of the True Prairie Association in the Stipa-Antilocapra Biome described by Clements and Shelford (Bio-ecology, 1939, John Wiley and Sons).It is surrounded by pasture and cultivated farmland, except on the south where it contacts a forest-edge of box elder, green ash (Fraxinus pennsylvanica Zanceolata), wild plum (Prunus nigra), and, farther back, bur oak (Quercus macrocarpa).This oak is the outermost representative of the Deciduous Forest Biome that covers the eastern part of the country.Climate.-Theonly climatic data available for the vicinity are from Lake Park, ten miles to the northwest, and information is available only for temperature and pre- [I651