Why Do We Manage Grasslands With Delayed Mowing?

ArrayMarch 22, 2018 at 10:06 am

[caption id="attachment_2785" align="alignright" width="463"] Male (Left) and Female (Right) Bobolink (Dolichonyx oryzivorus). Photo courtesy of National Audobon Society[/caption] By Natural Resource Manager Daniel H. Hill Did you know that managed grasslands and hay fields are important, intricate ecosystems found throughout the State of Maine? Did you know they were in decline? Numerous wildlife species utilize hay fields and grassland habitat, particularly several songbird species including the Eastern meadowlark (Sturnella magna) and bobolink (Dolichonyx oryzivorus), both listed as Species of Greatest Conservation Need (SGCN). These two species are in decline and habitat loss is one of the largest contributing factors. Bobolink populations in Maine were down 2.8% between the years of 1966-2010, and more recent numbers estimate a 3.3% decline from 2000-2010. Delayed mowing is extremely important for the nesting success of this songbird species. I learned that in my previous work at the Bureau of Parks and Lands and in my current role at MDIFW. The call of the male bobolink can be described as a metallic, bubbly, rambling song with a mixture of sharp high notes and buzzy low pitches.  It is something truly unique, that captures the essence of a hayfield or grassland in the spring and throughout the summer. [caption id="attachment_2787" align="alignleft" width="426"] Bev Chapman Wildlife Management Area (Before Late Mowing). Photo Courtesy of IFW wildlife biologist Amanda demusz[/caption] [caption id="attachment_2786" align="alignleft" width="424"] Bev Chapman Wildlife Management Area (After Late Mowing). Photo Courtesy of IFW wildlife biologist Amanda Demusz[/caption] Bobolink require a 65-day period to successfully build a nest, incubate their eggs and raise their young. Unlike other song birds, the bobolink has a difficult time successfully brooding a second time in the same season. If there is nest failure for any reason, the success rate on the second nest is significantly less. Most hay fields without song bird management are harvested two or more times annually to produce a feed quality hay in Maine. The first cutting is usually in June, the second by mid to late July, and possibly a third into August depending on the growing season.  This is where agricultural practices and the biological timeline of the song bird conflict. At MDIFW, fields and grasslands designated and managed for nesting song bird habitat by cannot be cut prior to July 1 to minimize impacts to nesting birds. The Bureau of Parks and Lands (BPL) restricts mowing until after August 15. Breeding bird surveys at these locations reflect nesting success with fledgling young which reinforces these important management efforts. Delayed mowing practices were refined through collaborative efforts involving biologists, land managers, private landowners and the public to enhance nesting and breeding conditions for these birds.  There are cooperative programs in place to work with private landowners to set up mowing schedules, develop bird survey opportunities, and even provide cost-share funds to offset added cost of late mowing activities.  If you are interested in more information on these management efforts, you can contact the Department or your local County Soil and Water Conservation District or Natural Resource Conservation Service center to receive more information.