Sunday, July 7, 2013

Bobolinks and Our Vanishing Grasslands

Male bobolink, McKnight Prairie, Goodhue County

The bobolink (Dolichonyx oryzivorus) is one of my husband Dave's favorite birds. Whenever we are in suitable habitat  -- grasslands -- his ears and eyes are open for them, and it's usually the ears that find them first. Bobolinks have a rich, varied, burbling, sometimes buzzing song. David Sibley, in his Field Guide to Birds of Eastern North America, describes it as "a bubbling, jangling, rising warble with short notes on wide pitch range." Roger Tory Peterson, in his Eastern Birds field guide, describes it as "ecstatic and bubbling, starting with low reedy notes and rollicking upward." Several samples of bobolink song can be heard here.

The Dennis Rodman of birds: Male bobolink, Rice County 

The male bobolink in breeding plumage is the only American bird that is black underneath and has white on its back (not just its wings). The straw-colored patch on the back of the head, which often looks thick and furry (but not always, as can be seen in the photo below), is usually the first thing I spot that tells me that I am seeing a bobolink. The female and the nonbreeding male are drabber and buffy in color. The bobolink is one of the Icterids (Icteridae), the songbird family that also includes the New World orioles, meadowlarks, blackbirds, cowbirds, and grackles. Its diet consists of seeds and insects.

Male bobolink, Rice County near New Prague

As grassland habitat has been lost, the populations of grassland-dependent birds, mammals and insects have dwindled. Meadowlarks and bobolinks are among the grassland birds that are harder to find than they once were. Bobolinks have the additional threat of being shot as agricultural pests in their wintering grounds thousands of miles to our south in central South America. Earlier hay mowing than in earlier times also threatens their reproduction; they nest on the ground in tall grass, so they are vulnerable when that grass is cut before the young birds leave the nest.

In Minnesota, less than two percent of the original (pre-European settlement) 18 million acres of native prairie, which covered one-third of the state, remains. What has been lost has been converted to row-crop agriculture and other human uses. The little that remains is scant and patchy, rather than forming large contiguous areas that provide the best habitat for those that depend on it. The enormity of this loss is displayed in this map from the Minnesota DNR, showing in yellow and tan the native prairie distribution in the second half of the 19th century, with the surviving remnants shown in red. It makes me want to weep.

This map can be seen on page 7 of the Minnesota Prairie Conservation Plan, published in 2011 by the Minnesota Prairie Plan Working Group, which included members from the Minnesota DNR, the U.S. Fish and Wildlife Service, the Nature Conservancy and other interested organizations. Click on the image above to see a larger version, and follow the text link above to learn more about a vision for prairie and grassland habitat acquisition, restoration and enhancement in Minnesota. 

The future of creatures like the bobolink depends on our doing what we can to preserve and restore the grassland habitat that is part of our great natural heritage.

Here are some additional resources:
Addendum: After posting this, I came across a blog post called Where Are the Bobolinks, published only yesterday on the excellent birding blog One Jackdaw Birding. I recommend it.

1 comment:

Hilke Breder said...

Thank you, Penny, for visiting my blog and leaving a comment! Your post offers lots of info and much insight! Grasslands are threatened everywhere by being turned into crop lands, broken up by highways, by suburbanization... I am thinking about writing a post about "nostalgia" birds, all those species that used to be plentiful but are no longer.