In southern Wisconsin, rolling hills and family farms go hand in hand. We sometimes get questions from farmers about how to make sure their practices support birds, as well as the livestock and crop needs of their farm. Here is the answer to a question we hear from farmers: when can I hay my fields so grassland nesting birds can raise their young?
Carolyn Byers, director of education with Southern Wisconsin Bird Alliance, provides the answer here:
"I did my M.S. work on grassland birds nesting in the Driftless area of WI, and it's one of my favorite things to talk about. We wrote a blog series about grassland bird nests a few years ago, if you're interested. It's wonderful to hear that you farm and want to work with the birds. By delaying harvest you're providing really important habitat for them.
The general recommendation is to avoid harvesting/mowing/grazing from May 15 - July 1. These birds need a week or two to build nests and about a month to raise young. If their nest gets disturbed/eaten early in the season, they will try renesting. An early July harvest would still disrupt some nests, but many of the nests will have finished by then.
Eastern Meadowlark on turned up soil. Photo by Arlene Koziol
A male Bobolink on grasses. Photo by Kelly Colgan Azar
Some quick facts about Eastern Meadowlarks / Bobolinks
Average Spring arrival date: Late Feb - March / late Apr- late May
Days spent building a nest: 3-18 / likely the same as meadowlarks
Incubation (keeping eggs warm): 13 - 15 / 10 - 13
Days until fledging (leave the nest): 11 - 12 / 10 - 14
When they fledge, they're not fully flighted or fully independent. This is the stage that scientists know the least about, since the birds move around a fair bit and are hard to track. They are probably fully flighted about 1 week after leaving the nest, and probably hang around with a flock of mixed-age birds until they leave in the fall.
Since Eastern Meadowlarks get back to Wisconsin earlier than Bobolinks, they're able to better time their nesting efforts with the insect hatch each spring. They begin nesting as early as weather permits—this year was probably pretty early. Bobolinks come back a bit later, and begin nesting as soon as they're here. Delaying until July 1 would benefit both species. If you need to harvest earlier, Eastern Meadowlarks would likely have more nests finished but Bobolinks would still be raising young. If one of your fields has more Bobolinks in it, you might consider delaying harvesting that one longer.
A Wisconsin pasture. Photo by SandyWeisz
Some good resources to check out:
Managing Habitat for Grassland Birds, A Guide for Wisconsin by Sample & Mossman. It's available on Amazon and our office has a copy if you'd like to look at it.
Thank you to the producers who support birds in Wisconsin! We are grateful for your work!
Written by Carolyn Byers, Southern Wisconsin Bird Alliance
Cover photo: Eastern Meadowlark nest by Carolyn Byers
