North American Crane Working Group

 

Date of this Version

1992

Document Type

Article

Citation

Davis, Craig A., and Paul A. Vohs. "The Ecology of Native Grassland Macroinvertebrates and Feeding Ecology of Sandhill Cranes.", In: Stahlecker D. W., ed. 1992. Proceedings of the Sixth North American Crane Workshop, Oct. 3-5, 1991, Regina, Sask. (Grand Island, NE.: North American Crane Working Group, 1992), 175.

Comments

Conference co-sponsored by the Canadian Wildlife Service, Saskatchewan Parks and Renewable Resources Department, and the Whooping Crane Conservation Association, Canadian Council. Proceedings used by permission of the North American Crane Working Group.

Abstract

The ecology of native grassland macroinvertebrates along the Platte River in central Nebraska and their role in the feeding ecology of sandhill cranes (Grus canadensis) was examined on 3 native grasslands along the Platte River during late winter-early spring, 1989 and 1990. Four hundred forty-four soil samples from the study area were sorted for macroinvertebrates. Environmental factors such as soil moisture, water table depth, soil texture, and plant species composition were recorded from each soil collection site. Fifteen sandhill cranes, observed feeding for 40 minutes, were collected from 1 of the study areas. Maeroinvertebrates were collected from 4 sites in close proximity to the location where each erane was feeding. In 1989, nearly all earthworms were found at sites with a water table depth > 60 em, whereas in 1990 earthworms were found at sites with water table depths s 10 cm of the surface; however, the greatest numbers were found on sites where water table depths varied between 50 and 60 em. The 1989 collections corresponded to severe drought conditions. Insect biomass was positively correlated with water table depths. Other relationships were documented. The dominant insect taxa found on the 3 study areas were scarab beetles (Scarabeidae), click beetles (Elateridae), Lepidoptera, crane flies (Tipulidae), and ground beetles (Carabidae). Aporrectodea spp. and Diplocardia spp. were the predominant earthworm genera. Scarab beetle larvae occurred in 58% oftbe erane esophagi, and snail shells and vegetation occurred in 50% of the crane esophagi. Otller food items included earthworms, crane fly larvae, and ground beetles.