How Iowa’s cows (and their healthy pastures) help Iowa’s birds

September 23, 2019 12:49 PM

Over 80% of Iowa’s landscape was once tallgrass prairie – an ecosystem comprising over 300 species of flowering plants maintained through regular fires and grazing by herds of elk and bison. This plant diversity resulted in an equally impressive assemblage of specially adapted birds that used the grasslands for raising their young each spring and summer. Today, many of these birds are still found in Iowa’s countryside but in reduced abundance because only about 11% of Iowa’s land is grasslands and these grasslands are quite different from the tallgrass prairie once found here.

Wildlife biologists and others concerned with the steady rate of decline among grassland breeding birds in Iowa and across the country are looking for ways to create more grasslands and to increase the diversity of existing grasslands to meet the habitat needs of more bird species. In their search for a way to regain some of the diversity that once defined Iowa’s landscape, bird lovers and biologists have found an unlikely ally; the cow.

Cows, through their variable preferences for forage plants and their tendency to trample plants they graze create diversity where they feed. This is especially true within the first few days of being introduced into a paddock. That is why research in Iowa and neighboring states has found that rotational grazing, where cows are moved among patches of forage many times a month, can host higher densities and more species of breeding birds than conventional, continuously grazed pasture.

Cattle in a rotationally grazed pasture.
Rotational grazing creates variable vegetation structure, which attracts a diversity of birds.

Research on cows and forage in rotational systems also shows that the farmer and cows win with rotational grazing. This is because the rotating periods of grazing and rest afforded the plants in the pasture allow them to recover from grazing and invest more energy in new growth and roots – a win-win for cows, birds, and the farm.

Another promising development in the emerging practice of growing birds and cows on the same acres is the recently authorized use of grazing in the management of fields enrolled in the Conservation Reserve Program (CRP). CRP acres are critically important for many of Iowa’s breeding birds, but many fields become so dense and low in plant diversity that they lose value to birds through time. Introducing grazing into these fields can help reinvigorate the grassland and create conditions for birds while also providing cattlemen access to important forage during the early spring or late summer. To learn more about new rules for grazing CRP acres, visit your local NRCS office.

Cattlemen and bird enthusiasts share a lot in common in their concern for the health and well-being of Iowa’s grasslands. There, through careful management of plant growth, diversity, and structure, we’re learning we can grow cattle and birds together on the same land that once grew birds and bison. This evolving recognition of how Iowa’s cows (and their pastures) can save Iowa’s birds is one sure to have lasting impacts on land, people, and local economies.


Adam Janke Associate Professor

Adam Janke is the statewide Wildlife Extension Specialist with Iowa State University Extension and Outreach. Adam is a trained wildlife biologist, having received a B.S., M.S., and Ph.D. in wildlife conservation and ecology from three land-grant schools in the Midwest.  He is also certified ...