Wild Life

With this issue, Charlotte Conservation Commission is very pleased to begin a new monthly column, Wild Life. These nature notes will be written by some of the many talented natural scientists and nature writers in our area. Topics will be as varied as the rich biological diversity on which they are based. All will be related to us in Charlotte, and feed our curiosity, awe and respect for the natural world. We hope readers will enjoy, learn and find ever more reasons to care about the exhuberant “wild life” in our landscape.

Grasslands Birds

Although most Charlotters drive, walk and bike past hayfields everyday, I’ll bet most are not aware of the wild life dramas unfolding there. These fields are alive with sex and cuckoldry, posturing and displaying, birth and death. These acts are played out each year May to August by a collective group of species known as grassland birds.
Grassland birds are habitat specialists, dependent on hayfields, pastures and fallow fields to successfully feed, roost and raise young. Common grassland birds in Vermont include the bobolink, meadowlark, Savannah sparrow and harrier. Less common are upland sandpiper, grasshopper sparrow, sedge wren, horned lark, vesper sparrow and short-eared owl. Specific habitat needs have led to development of complex behaviors, including extraordinary migrations (bobolinks migrate approximately 6,000 miles between North and South America twice each year), and unusual mating systems (a male Savannah sparrow can support up to three females on his territory).
Hayfields may seem like simple places, but in fact, they can be bustling with deception, intrigue and theatrics. Countless eyes (males!) are watching from perches atop tall blades of grass, and others’ ears (females!) are listening while buried deep in the grass, incubating four or five eggs snug in nests of dried grass. Yes, these eyes and ears are watching for predators. But they are also looking for mates —many mates. Male bobolinks, jet black with a bright yellow nape, and white tuxedo-like markings on their backs soar into the air, singing so wildly they almost seem confused, landing like they were butterflies. Sleek female bobolinks, golden and bronze with delicate stripes on top of their heads, like to test their mates and neighbors (who too could be a mate!), making a whine-like call and rocketing into the sky to see which male can keep pace. These behaviors, importantly, prove character and quality for all. The result is often mixed paternity. Remember, I started this article with the words sex and cuckoldry. That’s right, a bobolink nest of five young will often include one or more sired by a male other than the social mate.
Grassland birds help define the character of our agricultural landscape, but sadly their populations are declining faster than any other bird group in North America. In Vermont from 1966 to 2006, grasshopper sparrows declined eight percent per year, bobolinks and meadowlarks three percent per year, and Savannah sparrows 0.25% per year. For the last seven years, I have studied these declines and what we can do to reverse them.
Two main factors in Vermont contribute to their population decline. First, Vermont has been largely reforested, thereby decreasing the amount of available grassland habitat. Second, the processes of hayfield management have changed since the 1960s; hay is now cut earlier and more frequently. In the 1960s haying began in early July. Today, it often begins in late May in order to capture the higher protein content and thus increase dairy cow production. Hayfields that are cut early are cut more frequently, often in 35- to 40-day intervals.
These changes significantly affect breeding grassland birds. As ground-nesters, their nests are directly exposed to haying machinery. Consequently, 100% of nests active at the time of haying fail, with 80% destroyed by the machinery and 20% eaten by gulls, crows and mammals.
Much of Charlotte’s landscape is grassland. In 2005, Charlotte had 10,547 acres of potential grassland bird habitat. This gives Charlotters a unique and meaningful opportunity to support grassland birds through bird-friendly management practices in hayfields, pastures, and especially in residential open-space areas.
My research has focused on building grassland management plans that balance landowners’ economic objectives and birds’ reproductive needs. Past guidelines only encouraged delaying mowing until approximately August 1. Indeed, mowing in August and picking up the hay is the best way to manage for grassland birds. However, most hayfields are now harvested earlier in the summer. For intensive dairy farms the best bird-friendly management strategy is to cut as early as possible (before June 1, although cutting before May 25 is ideal) and delay the second harvest for 65 days. This provides enough time for birds to reproduce between harvests. For more information, including ways to offset costs associated with some of these practices, see the new Charlotte Conservation Commission publication, Grassland Birds in Charlotte: Our Role in Their Future (available at Town Hall and at Town Party on July 12). I also invite you to join me July 13 for a Charlotte Walk nature outing 7:30 to 9:30 a.m., when we will get an up-close look at these fascinating birds (call 425-5795 to sign up).
By incorporating grassland birds’ needs with other land management objectives, Charlotters can play an important role in stabilizing these species’ populations. Hopefully, in ten years I can write an article describing how the bobolink population increased rather than decreased another 3% per year, and thank Charlotters for leading the way.

Noah Perlut is a post-doctoral fellow and lecturer in the Rubenstein School of Environment and Natural Resources, University of Vermont.