Wheatlands Farm
Grassland Birds, 2013
Buffalo Gap, VA
Part II - Bobolinks
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At the beginning of the 2013 breeding season I was hopeful
that the flagship grassland birds – the Bobolinks and Dickcissels so elusive
here in the East – would again grace the grasslands at Wheatlands.
Because I am a cattle farmer, I was also optimistic that they would do their
business and depart with courteous dispatch so that Wheatlands and other farms in the
Shenandoah Valley could make the hay to feed their cattle through the coming
winter.
If I labor under myopic self-interest, I am comforted by the
understanding that presently in temperate North America cattle are the principal
reason for grasslands. On most farms subject to the economics of agriculture
the operative equation is: no cattle= no grasslands = no grassland birds.
Without today’s edition of the bison, the remaining grasslands in the East
would go back under the plow to grow commodity beans and corn – or commodity
pulpwood, or commodity subdivisions. I believe that the prospects for our grassland birds are linked closely to cattle farming.
My concern is with finding means which do not burden the
cattle farmer of accommodating the breeding needs of these marathon migrants.
Logic suggests that if we are to enjoy the delight and the biodiversity
afforded by the grassland migrants we need to seek ways to integrate them into
the grazing and haying regimes of the families still grinding out a living on
the cattle farms of the East and thereby still furnishing the nesting habitat
for Bobolinks and Dickcissels. I was
hopeful of finding that the breeding schedule would not preclude cutting a
prime stand of alfalfa and orchard grass for hay before it goes to seed and
before the briars and thistles take the stand. As we will see, that was optimistic.
You don’t just make hay any old time the notion overtakes
you. Hay has to be cut after the spring weather permits curing and before the
grasses and legumes divert their energy from growth to reproduction – to flowering
and making seed. That window is commonly as narrow as two weeks; some years it
never opens. In the Mid-Atlantic States the first cutting occurs mid-June at
the latest. There is hay to be cut to feed the cows in winter and there is also
the need to graze the cow herd through the growing season, April through
October. Ideally we could juggle pastures and hay ground to provide grazing all
year, but that gets tricky with the grass under two feet of snow. Therefore the
need for some hay is unavoidable where winter is a reality, as it can be in the
Shenandoah Valley with generous snowfall and occasional sub-zero temperatures.
It is not difficult to infer the success rate of nesting
attempts in a stand of grass cut for hay – zilch. If the herdsman forgoes a cutting of hay in
behalf of the grassland birds, he or she must buy replacement hay.
First-cutting hay carries a market value of about $500 per acre.
Allan
Strong, researching grassland bird nesting on farms in Vermont’s Champlain Valley,
used the USDA’s
EQIP
Program to compensate farmers for deferring their hay cutting until after
the nesting season (see Les Line’s account in
Audubon
Magazine ). Some plan for
compensating farmers for lost hay, perhaps patterned on Dr. Strong’s approach,
will have to be developed if grassland bird nesting is to be restored in the East
on a meaningful scale. We will also have to consider what Strong calls the
Bobolink’s “area sensitivity”, or requirement for large contiguous tracts of
grassland – up to 60 acres for a nesting group
(Allan M. Strong, Grassland and Successional Bird Conference, Smithsonian
Conservation Biology Institute , September 15, 2012).
A news account of the UVM program notes some of the issues
in the life of a Bobolink:
“They have flown across the Caribbean and the Amazon,” said
conservation biologist Roz Renfrew of the Vermont Center for Ecostudies. “They
have endured unbearable heat, been treated as pests in farm fields in South
America. They escaped trapping for the pet trade in the Caribbean and may have
survived hurricanes.”
But getting to North America in May to nest does not assure
safe harbor for the Bobolink because of conflict with farming schedules:
"A bobolink that nests in a field that is cut twice or three
times a summer faces zero chance of raising any young. Small wonder that surveys for the Vermont Breeding Bird Atlas found that bobolink numbers had
plummeted 75 percent from 1966-2007." Candace
Page, Burlington
Free Press, 4/13/13
The fortunes of the Bobolink, and other grassland endemics,
in Vermont may not differ materially from those in Virginia or in the lands
between. Researchers in Vermont have taken an interest in grassland bird
restoration so we rely on their findings. The Green Mountain folk and their
neighbors in Rhode Island have also fielded an inspirational community-based
restoration effort financed by local contributions called
The Bobolink Project . The undertaking funds the delay of hay cutting
to give the Bobolinks and other grassland breeders a chance to nest. The
project appeals to the obligation the citizens feel to support their wildlife
and their local farms, both of which contribute to the quality of their lives.
In 2013 the Bobolinks
arrived at Wheatlands Farm on April 30th and without delay the males
began their signature posturing and gurgling and sparkles of flight song. Because the males zip across hundreds of
yards from chummy bachelor groups to charm individual females on their (the
females’) territories, and because Bobolinks are polygamous and polyandrous, it
was difficult to get a count. How many?
A half dozen or more of both genders.
The hoopla continued
unabated until, on June 20th, it quit. It was as if the entire
rollicking company had decamped overnight, not a Bobolink to be seen or heard. Everybody else was in place; the Dickcissels
(we’ll get to them), the Grasshopper Sparrows, the Meadowlarks, the Savannah
Sparrows. I saw no conclusion other than that the Bobolinks had abandoned their
nesting efforts and so reported to the Virginia
Working Landscapes
coordinator whose associates were conducting a breeding bird census at
Wheatlands.
I would learn later that in
2012 the coordinator, Amy Johnson, a doctoral candidate in grassland
ornithology, had experienced a similar Bobolink outage on another Shenandoah
Valley farm 75 miles to the north of Wheatlands. In both instances the birds vanished
(or so it seemed) in the third week of June and reappeared a month later.
I first
(re)noticed them on July 23dth, rolling waves of adults of both
sexes (some males in molt) and skinny juveniles with stubby tails. The females
were carrying food. The young were able to fly but they gaped and panted and
were plainly still on light duty. Over the next month males completed molt, the
juveniles gained flesh and stamina, the mamas did the heavy lifting and by
early September they all looked alike. Occasionally
I could get a count as flocks came and went and on August 11th saw 84 Bobolinks
pitching into 16 acres of my weedy, uncut hay (uncompensated, by the way). I am confident that number is
conservative.
So, Kim Kaufman,
Executive Director of Black Swamp Bird Observatory at Oak Harbor, Ohio (www.bsbobird.org/ ) did the Bobolinks leave in mid-June, complete their breeding elsewhere,
then return in July?
“I doubt it. Those juveniles with the stubby tails would not
have been capable of travel. The birds probably bred where you saw them.“
Combining Kim’s
assessment with Amy’s observation from 2012 suggests that after the eggs hatch,
perhaps even at the time they are laid, the Bobolinks go under the radar, stop
displaying and move in stealthy feeding forays. When the fledglings are mobile
a month later the entire tribe resurfaces in force. In 2013 at Wheatlands they spent another four
weeks foraging intensively on the natal grounds, socializing, recruiting,
and training for the trek to Uruguay -- at 12,000 round-trip miles, one of the
longest known migrations of any land bird breeding in North America. Flocks of
up to 50 birds shuttled between weedy stands of uncut hay, flashing mustard in
the late sun, chiming their flight call. Sixty birds pitched into the main
breeding paddock on September 5th; and again on the 10th. Thereafter they were overhead only in 2s and
3s, perhaps birds in passage. A single Bobolink flushed from cover on September 15th. Entonces se fueron hacia las pampas.
(My) Bobolink conclusions
from Wheatlands observations, 2013:
- - The
raucous displays of flight song cease at about the time of hatching, June 20th
+/-.
-
- The birds haven’t left; they are just lying low, foraging in cover. The males have
quit singing.
- - An
attractive breeding field might invite Bobolinks from nearby breeding areas to
aggregate there after fledging for the resources needed to mature the juveniles
and prepare the cohort for migration.
This neighborly interaction might explain how the dozen or so adults on this
farm at the beginning of breeding grew to scores by early September.
- - Experience
here in 2013 suggests a breeding stand can be grazed moderately (but probably not
mobbed) after the Bobolinks fledge without detriment to the birds. In fact, the
cattle shared the stand with the
84-member Bobolink flock. The key to integrating grassland bird conservation with cattle farming practice will be to find a way for cattle and birds to co-utilize the stands after fledging. Light, rotational grazing (not continuous grazing) appeared to offer promise on this farm in 2103. Rotational grazing is labor-intensive; it does not happen by accident. We must consider also that
- - The
Bobolinks need six weeks on the nesting ground after fledging to raise the young and build strength for the
journey to southern South America.
If the last observation withstands
more field scrutiny, we might reconsider the adequacy of a schedule which gives
the Bobolinks use of the natal grounds only through fledging. If the stand is
cut just after fledging the breeding group may lack the resources to mature the
juveniles. My observations at Wheatlands in 2013 suggest the post-fledging
grow-out period is no less essential to the Bobolinks’ breeding success than is
the nesting opportunity. Their chances are likely better if they are not forced
from the breeding field by a July mowing.
We cannot forget the
cattle and the farmer in this equation.
Rather than viewing them both as irritants, as some conservationists
occasionally let slip, we might consider that we will have but few grassland
birds in the East without the private
grasslands, typically in active use as pasture or hay ground for cattle. The
cattle take vigilante action at woody intrusion in their pastures, and the
farmer mows hay and clips pasture for weed control and both actions suppress
woody succession. Some public grasslands,
such as those planted on reclaimed landfills, provide active grassland bird
conservation opportunities ; others, especially lands in hunting programs, commonly
grow up in autumn olive for lack of funds to arrest the succession process, an energy-
and labor-intensive endeavor.
In the private realm,
maintaining the grasslands is part of the accepted economics of cattle farming. Forgoing cuttings of hay is not. If the
public good suggests that grassland ecosystems with their appealing birds are
important, then we should discuss public policy which recognizes the need to
integrate their conservation with the realities of farming. Allan Strong and
Amy Johnson are among those who are leading research which could support public
discussion of conserving our grassland birds.