Part II, Bobolinks

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 30^th 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 20^th, 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 23d^th, 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 5^th; and again on the 10^th.  Thereafter they were overhead only in 2s and 3s, perhaps birds in passage. A single Bobolink flushed from cover on  September 15^th.  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 20^th +/-.

-          - 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.