Research Projects

Habitat Fragmentation | Modeling Mallard Productivity | Henslow's Sparrow Survey | Evaluation of Wetland/Upland Restoration

Fragmentation of Grassland Habitats in North Dakota

Sine 1996, I have participated in a collaborative study of predation on nests of grassland birds in the U.S. Prairie Pothole Region. We are examining predator foraging behavior, predation patterns, and nesting success. The other collaborators are Dr. William Clark (lead investigator) of the Department of Animal Ecology, Dr. Marsha Sovada, and Ray Greenwood, both of Northern Prairie Wildlife Research Center in Jamestown, North Dakota. This group, together with two graduate students, Mike Phillips (predators) and David Horn (nests), examined both the foraging behavior of major predators on nests of grassland birds and the nesting success of grassland birds on study areas in North Dakota.

There are theoretical reasons to suspect that habitat fragmentation contributes to low nesting success, but empirical studies of this relationship are rare for grassland species. Edge effects on nesting success have been documented in one Minnesota study of grassland passerines. The key missing information in previous studies concerns the process that links habitat pattern and nesting success, that is, foraging behavior of predators. Movement and foraging patterns of predators in fragmented landscapes are poorly known and have not been studied adequately while simultaneously examining nesting success. The goal of this study is to investigate these patterns and develop management recommendations that take advantage of knowledge of predator behavior. Results should be applicable to Iowa and other midwestern states, although the study areas are in North Dakota to take advantage of the diversity of nesting, grassland birds and to facilitate logistics. The group will radio-track striped skunks and red foxes and monitor nesting success of grassland birds on the same areas. The group has received funding for the project from the Institute for Wetland and Waterfowl Research (Ducks Unlimited). Field work on the predators and duck nests is complete and data analysis is proceeding. A progress report was in the Unit's most recent annual report.

Modeling Mallard Productivity in Northern Iowa

A progress report was in the Unit's most recent annual report.

Henslow's Sparrow Survey Techniques

I am developing survey techniques for Henslow's Sparrow in the Midwest with funding from the NBS Success with Species at Risk program (now the Biological Resources Division of USGS Species at Risk program) and the U.S. Fish and Wildlife Service. Henslow's Sparrow (Ammodramus henslowii) is rare or state-endangered throughout its range. The decline of this species is tied to its shrinking habitat base in the prairie ecosystem. Henslow's Sparrows nest in idle or lightly-grazed tall-grass prairie but will nest in fields of planted grasses that have suitable stature. Managers can therefore supplement prairie habitat with managed grassland.

In the 1996 and 1997 field seasons, we quantified singing rates during the daily cycle and during the nesting season. This will allow us to determine the best time of day/year to conduct surveys. We also took point-count data and made vegetation measurements to quantify habitat preferences. In the course of this work, we discovered two nests, which we have described, along with some literature survey on Henslow's Sparrow in Iowa, in Iowa Bird Life and in a web-accessible document. A short progress report was in our most recent annual report and a longer one was prepared in October, 1997. A Henslow's Sparrow Web Site, with resource links and distribution maps, is also being developed.

Evaluation of Wetland/Upland Restoration

This project is to start field work in 1998 and focuses on reproductive success of mallards. Associated work will be done with other birds.

Updated 7 November, 1997

This file: http://www.public.iastate.edu/~rkoford/research.htm

Return to Rolf Koford's Home Page

rkoford@iastate.edu