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Blackbird Project Focuses On Population Reduction

Sunday, December 1, 1996
filed under: Birds

The magazine article begins with these words:

“If Old King Cole was a merry old soul, it was probably because he had only ‘four and twenty’ blackbirds to contend with, and they were all out of commission. Participants in a meeting held at North Dakota State University in December were concerned with a much thornier situation — namely, how to keep a certain bird away from a highly desirable birdseed.”

No, that meeting didn’t take place in December 1996 — or even 1995. Those words appeared in the January 1978 issue of The Sunflower, reporting on a meeting involving NDSU researchers, representa-tives of the U.S. Fish & Wildlife Service and grower/directors of the just-established North Dakota Sunflower Council. Discussion centered on growers’ “rising concern over economic losses resulting from blackbird predation” and how to address the problem.

Despite the 19-year interval since that meeting, blackbird depredation in sunflower fields remains, for many Upper Midwest growers, a serious economic problem. In a 1990 grower survey conducted by the NDSU Extension Service, 16.3 percent of North Dakota respondents considered birds to be their worst problem in sunflower that year.

A 1994 survey — expanded to include additional states — found bird damage to be one of the three worst problems on 37.2 percent of North Dakota respondents’ sunflower acreage; on 35.6 percent of South Dakota respondents’ acreage; and on 17.4 percent of Minnesota sunflower acreage. It was judged as the single worst 1994 production problem on 13.1, 16.1 and 1.8 percent of respondents’ acreage in those three states, respectively.

While certain sunflower areas experience few if any problems with blackbirds, certain locales can expect significant economic losses virtually every year. Surveys conducted in 1994 and 1995 by the Animal Damage Control (ADC) unit of USDA-APHIS, for example, found that sunflower producers in North Dakota’s Stutsman County averaged more than $300,000 in damage from birds in each of those two years. On a statewide basis, ADC estimates place the cost of bird damage in sunflower at $3.5 million for North Dakota and $1.5 million for South Dakota in each of the ’94 and ’95 seasons.

The “blackbird problem” has spawned a host of responses over the years. Many of them have been akin to that expressed by a frustrated sunflower grower quoted in the 1978 magazine article. He indicated he’d tried “several methods — boomers, guns, repellents — but without significant success. ‘I’ve also,’ he said, ‘hollered at them, thrown rocks at them, swore at them — nothing seems to work.’ ”

Some growers in the late ’70s and early ’80s employed “Avitrol,” a chemically treated corn bait product which affected the nervous system of consuming birds — with the hoped-for result being that their shrieks would scare other birds into leaving the area.

During the ’80s, there was an expansive attempt to breed sunflower hybrids with morphological traits that made them tolerant or resistant to blackbird feeding. There also has been research into male bird sterilants, taste-aversion studies and even investigations into “bird psychology”. A federally funded program for hazing birds via fixed-wing aircraft, conducted from 1986 to 1994, covered about 22,000 hours in the air — but with limited, temporary success. Meanwhile, numerous growers have continued to employ propane-powered “boomers” in their fields. Many keep a shotgun or rifle in their pickup and, in a daily autumn ritual, fire round after round over the tops of their fields to unsettle feeding blackbirds. Tabasco-treated baits, scarecrow balloons, fireworks and a bagful of other low-tech approaches have also made the rounds.

Earlier this decade, USDA-APHIS-ADC invested considerable research into cattail management as a means of reducing blackbird habitat and thus diluting bird population concentrations. Compared to previous methods of bird control, this program — which uses a herbicide to kill blocks of cattails in choked wetlands — has had relatively good results and, in some areas, simultaneously enhanced waterfowl habitat. Interested producers in the two Dakotas can access federal funding for this purpose. Since 1991, a total of 823 private tracts and 78 tracts of public wetlands have been treated.

All these divergent approaches to controlling blackbirds have had one thing in common: They’re designed to disperse, not reduce, the bird population. While one grower’s persistence may move the birds out of his sunflower field, the avian marauders don’t “disappear into thin air.” They move to the next available food source — often a neighbor’s field. So on a macro level, the problem has simply been transferred, not solved. (Continued)

A new approach now being researched by USDA takes a decidedly different tact. For the past five years, Dr. George Linz has been investigating the use of an avicide — “DRC-1339” — to reduce red-winged blackbird and common grackle populations and, as an ultimate goal, help cut sunflower growers’ losses to birds.

Linz, based in Bismarck, N.D., is a wildlife biologist with ADC’s Denver Wildlife Research Center. He now has completed three years of baiting research in east central South Dakota, an area where the last large concentrations of blackbirds are located in the spring prior to moving north and spreading out across their breeding sites. Current state and federal permits allow him to kill up to 250,000 blackbirds per year in the course of his research, which continues in 1997.

(The National Sunflower Association Board of Directors — which has been a strong supporter of the 1339 research — would like to see the permit increased to one million birds per year, but that is subject to approval by the South Dakota Game, Fish & Parks Department. Such a request may be made this winter.)

Weather permitting, the spring treatment period runs from the third week in March through the third week of April. DRC-1339 is applied to brown rice at a rate of one “hot” bait per 25 untreated baits. Using ATVs, Linz and his co-workers spread about 26 pounds of product per acre. The avicide has a three-day activity period, losing its efficacy if not ingested within that period. One treated rice particle will kill the consuming blackbird, with death occurring from one to three days following ingestion.

(Linz also has fall-baited with DRC-1339 in mature sunflower fields in North Dakota, but that approach hasn’t worked well thus far. The birds preferred to dine on the ripened seeds, he reports, rather than go to the ground to pick up the treated bait. It’s presently uncertain whether the fall-bait research will continue in 1997.)

“The spring-bait research focuses on suppressing the breeding population,” the USDA scientist explains. “When you kill birds in the spring, you’re trying to reduce them at a time when their population is at its lowest point — just prior to breeding.”

Results to-date clearly indicate the approach works. “Each year we’ve had a permit for 250,000; and we’ve come real close to killing 250,000 a year,” Linz reports. Those numbers have been confirmed through extensive searches of the areas in and adjacent to the South Dakota baiting sites.

While there’s little doubt about the efficacy of DRC-1339, its success in Linz’s controlled research trials leads into two critical questions: (1) Can killing a given number of blackbirds (e.g., one, two or three million) translate into noticeably reduced damage in the region’s commercial sunflower fields? (2) Along with blackbirds, is the avicide also killing nontarget species — especially pheasants?

The verdict is still out on both questions. “So far, we’ve been concen-trating on baiting strategies and on environmental effects — especially in terms of nontarget birds,” Linz notes, “not on whether we kill enough birds to reduce sunflower damage. We’re not sure at what level we’d be able to show that.”

Larry Kleingartner, executive director of the National Sunflower Association, concurs with that assessment. He and Linz also agree that even if expanded permits are received for the use of DRC-1339, the avicide will not be a one-stop solution for producers battling blackbird depredation. “Our hope is that the combination of cattail control, frightening devices and the good old high-powered rifle — coupled with lowered blackbird populations — is going to reduce damage,” Kleingartner remarks.

Lou Huffman, in charge of the ADC’s operations program for North Dakota, holds a similarly cautious view. “Every-one would like to think there’s a ‘silver bullet,’ ” Huffman observes. “But there just isn‘t one.” It’s not realistic to expect any single method to draw down blackbird populations to where there’s never an economic problem, he says. So regardless of whether DRC-1339 eventually does impact region-wide breeding numbers, the average affected sunflower producer “is still going to need his ‘bag of tricks,’ ” Huffman remarks.

The other question — whether nontarget species are at risk when DRC-1339 bait is spread in a given area — is a touchy one, especially in a state like South Dakota where the pheasant is of such great importance to the economy as well as the state’s general image and environment.

Linz does not believe there is a significant risk to the pheasant population or other nontarget species. He says that despite many hours of searching during their three years of South Dakota research, he and his associates have yet to come across a pheasant (or other nontarget bird) killed by the avicide in the treatment areas. Of course, he adds, there is the possibility ill birds have hidden under dense cover before dying — or that they left the treatment area after ingesting treated bait.

“We’re not overly concerned,” Linz concludes. “But it is a question for which we need good answers.”

As director of the Wildlife Division of the South Dakota Game, Fish & Parks Department, Doug Hansen has a definite concern about the potential impact of the avicide on nontarget species in and near the treatment areas.

While his department is clearly less enthusiastic about the use of an avicide than is the National Sunflower Association (a major promoter of the project), Hansen says the big concern is not over killing 250,000 or even a million blackbirds. Rather, he ventures, it’s a matter of making sure the nontarget species — pheasants in particular — are not at risk. “As with any toxic chemical being used in the environment, it is the responsibility of the industry using it to assure its safety to humans and nontarget animals,” he notes.

At the urging of, and in cooperation with, the National Sunflower Association and USDA-APHIS-ADC, the South Dakota Game, Fish & Parks Department is in the preliminary stages of developing a study to determine what effect, if any, the use of DRC-1339 will have on wild pheasants.

If approved for funding by the U.S. Fish & Wildlife Service, the study likely will be conducted through South Dakota State University’s Department of Wildlife & Fishery Sciences. It would involve penned bird trials and larger field trials, probably including some radio telemetry (tracking of bird movements). Whether the study begins this coming spring or in the spring of 1998, a completed report would be expected by not later than the fall of 1999, according to Hansen.

Hansen says his agency is not trying to be either an advocate for or a hindrance to the possible adoption of DRC-1339 on a widespread basis, but “is willing to try to answer some of the questions that will inevitably be asked.” The National Sunflower Association has hoped the pheasant study would begin this coming season (1997), with USDA then over-lapping some of its own environmental assessment work on top of that. Hansen says the starting date remains uncertain as yet, pending funding approval. When the 1339 program becomes operational, it is people like Lou Huffman and his counterparts in other states who would ultimately implement an approved avicide treatment program on blackbirds. Only qualified ADC personnel, or contractors under the direct supervision of ADC, would be permitted to carry out the baiting.

NSA’s Kleingartner adds that the North Dakota ADC operations office already has a qualified bird biologist on staff. “The biologist used to work with Dr. Linz and has a great deal of blackbird experience,” he says.

Before any operations program could occur, however, compliance with the National Environmental Policy Act requires a full environmental assessment. Data on DRC-1339’s impact on nontarget species would be a critical part of that assessment — and that’s why the NSA and others are so anxious for the South Dakota pheasant study to get under way.

“This is not just a regional sunflower problem; its a national problem,” says NSA’s Larry Kleingartner. Blackbirds are a major headache in the rice fields of Louisiana, for corn growers in a number of states, and for blueberry and other fruit crops, Kleingartner notes — in addition to urban areas, “especially in the South, where the birds overwinter.”

NSA has developed liaisons with other commodity organizations to better address the blackbird problem. The communi-cation line has been especially active with rice growers in Louisiana, where DRC-1339 is already used under a Section 24-C state label.

“DRC-1339 has been granted a full Section 3 EPA label,” Kleingartner emphasizes. “This is a tremendous development which opens the door for operational programs.

“Too much emphasis is being given to nontargets such as pheasants,” asserts the association executive. “Three consecutive years of field research have not resulted in any evidence of pheasant mortality — and neither have ADC caged studies.

“It is time to move on to the next stage in using this tool to hopefully provide some relief to growers experiencing significant dollar losses from blackbirds,” he concludes. — Don Lilleboe
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