Bobolink:
Bobolinks are grassland specialists, relying heavily on local hayfileds
for their reproductive success. In the blackbird family, male bobolinks can be told by their striking plumage: black
bodies with white backs and yellow crowns. They are often seen in the summer hovering over hayfileds as their complex
song pours out (link below). Females are much more drab, streaked in browns much like a sparrow. Bobolinks are
one of our champion migrants, spending winters as far south as the plains of Argentina. Males arrive to our area in
early May and immediately begin setting up breeding territories in open fields. Female arrive shortly after, and by
early July their young will have begun to fledge from nests and disperse. Autumn sees large flocks of bobolinks roving
around the countryside, feeding in weedy fields and marshes.
Because bobolinks depend upon hayfileds for the majority
of their breeding success, they, along with many other grassland specialists, have been experiencing dramatic population declines
over the past few decades. The problem is that when these birds arrive to the breeding grounds they encounter what appears
to be prime habitat in our hayfileds. However, these fields are often cut as the breeding season is in progress, resulting
in year after year of zero reproduction from pairs using these fields. In effect, these fields become ecological sinks,
drawing in breeding birds who expend their energies throughout the breeding cycle, but are never actually able to fledge
young. This early cutting, along with habitat being lost to development and succerssion is having a severe impact on
our grassland birds.
But not all is lost, and with some adjustment, many
of our local hayfileds can be managed as agricultural grasslands: areas that are functional for both the hay farmer and the
birds that rely upon their fields. The first step is to consider the cut date. Of course later is better
for the birds, though many Bobolinks have fledged their young by the last week of June. Holding off the cut to the fourth
of July weekend will really go a long way toward turning around recent reproductive trends.
Another consideration is to harvest fields from the
inside out. Typically fields are cut from the outside in, in effect, rounding up all the animals into the middle of
the field where they are cut up in the blade's final pass. Cutting from the inside out simply drives animals to the
edge and away from the blade.
Finally, if the hay field is in fact a safe habitat
(delayed cut), steps can be taken to maximize its production. Essentially, the larger a field is, the more pairs and
the greater the pair density it will be capable of supporting. Such steps as removing hedgerows that divide fields will
create the contiguous open habitat that favors increased numbers of breeding grassland birds. If you have further
interest in creating agricultrual grasslands in your hayfields, please contact the East Quabbin Land Trust for further information
and advice.
Local examples of avian sensitive agricultural grasslands are EQLT's
Mandel Hill property at the intersection of Barre and Ridge Roads, Hardwick, and TTOR's North Common Meadows just past Petersham
center on route 32.
