Effects of Prescribed Burns and Bison (Bos Bison) Grazing on Breeding Bird Abundances in Tallgrass Prairie

Grassland birds have declined more than any other avian assemblage in North America, with nearly every species showing negative population trends. In the Flint Hills of Kansas, the largest remnant of the tallgrass prairie biome, annual spring burning of rangeland has recently replaced burning every 2–3 years. I examined effects of different burning and bison (Bos bison) grazing regimes on June abundances of seven bird species using a 23-year data set from the Konza Prairie Biological Station. Fire significantly affected the abundances of six of the seven species. Effects varied among species but, notably, four grass-dependent species—Grasshopper Sparrow (Ammodramus savannarum), Henslow’s Sparrow (A. henslowii), Dickcissel (Spiza americana), and Eastern Meadowlark (Sturnella magna)— and the shrub-dependent Bell’s Vireo (Vireo bellii)—were least abundant or absent at sites in the breeding season immediately following burning. Upland Sandpipers (Bartramia longicauda) were most abundant at sites in the season following burning, whereas Brown-headed Cowbirds (Molothrus ater) exhibited no significant response. Bison grazing increased abundance of Upland Sandpiper and Grasshopper Sparrow, nearly eliminated Henslow’s Sparrow, and (in combination with recent fire) lowered the abundance of Dickcissel. Although fire and grazing are natural forces that maintain tallgrass prairie, their action was, until recently, intermittent and patchy, providing grassland birds with a variety of levels of disturbance. If the vast Flint Hills prairie is to serve as a grassland bird stronghold, the region-wide practice of annual burning with intensive grazing must be replaced with alternatives that restore heterogeneity to the landscape. Efectos de las Quemas Programadas y del Pastoreo de los Bisontes sobre la Abundancia de Aves Reproductivas en Praderas de Pasto Alto

The nature and consequences of mother–daughter associations in naturally and forcibly weaned bison

Bison (Bos bison) mothers and daughters have a stable association that may persist beyond weaning, whereas no such extended relationship exists between mothers and sons. The practice of forced weaning of bison in Antelope Island State Park, Utah, provided the opportunity to experimentally investigate the nature and consequences of postweaning mother–daughter associations. Forced weaning changes the early social environment of calves and may disrupt social organization by eliminating mother–daughter associations. We compared the mother–daughter associations of forcibly weaned female yearlings, following release back into the population, with those of naturally weaned female yearlings. Yearlings that had been forcibly weaned as calves did not reassociate with their mothers following winter separation. Forcibly weaned yearlings spent no more time with their mothers than with randomly chosen adult females. Naturally weaned yearlings had a significantly stronger association with their mothers, were displaced less often by other herd members, and spent more time in the centre of groups than forcibly weaned yearlings. We were unable to detect benefits to naturally weaned daughters in terms of growth and age at first reproduction. Mothers of naturally weaned yearlings did not differ from mothers of forcibly weaned yearlings in subsequent mass change or reproduction.

Zooarchaeological Evidence of Prairie Taxa in Central Missouri during the Mid-Holocene

Previous studies report that remains of prairie taxa are common in western Missouri archaeological sites. There is no reported evidence of prairie taxa, such as Bos bison, from sites within the northern Ozark Highlands of Missouri. New data indicate that prairie taxa inhabited the area during the warm and dry mid-Holocene (8500–5000 14C yr B.P.). Evidence suggests prairie taxa were farther east and south than previously documented in central Missouri and underscores the importance of biogeographic data in studies of prehistoric environments.