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Using Sunflower to Decoy Birds Away From Sunflower

Tuesday, February 15, 2005
filed under: Birds

Could a sunflower decoy help keep birds away from the real McCoy? Researchers are looking at the concept of planting lure plots near commercial sunflower fields, with encouraging results.

Lowering blackbird damage in sunflower fields continues to be a significant hurdle for researchers and farmers. Farmers suffer field losses ranging from nothing to near total devastation. But often blackbirds tend to eat a portion of a field near a wetland or tree grove – about 20 to 30 acres. That lowers the overall yield of the field, but may not be enough to trigger an insurance claim – just part of the frustration of dealing with this pest.

Researchers at the USDA Great Plains Field Station of the National Wildlife Research Center and North Dakota State University have considered decoy plots over the years in an attempt to divert blackbirds to other feeding sites. However, there was never a lot of support for the concept with efforts directed to harassment and avicides. However, with those approaches having limitations, researchers took another look at decoy fields last summer.

George Linz at the Great Plains Field Station, Bismarck, N.D., coordinated lure plot fields with 16 growers in North Dakota last season. The concept was to plant 20-acre sunflower plots near a wetland that has a history of harboring significant blackbird numbers. Farmers were contracted to plant the sunflower plots as if it were a commercial field. Seventeen plots were planned but due to the wet and cool season, 13 plots were able to withstand the rigors of the season. Farmers were compensated $150 an acre.

Harvesting the decoy sunflower was not allowed, nor was the use of insecticides during or after the bloom period. Linz points out that head insects will help attract blackbirds and other bird species to the decoy fields. Plus, insecticides can have a diversion affect on birds. “It appears there are some insecticides that deter birds from foraging because of taste,” says Linz. Thus, there is no insecticide used on the plots nor are there any harassment techniques.

The key strategy of the lure plots is to keep blackbirds out of commercial fields as long as possible.

“Each seed eaten in the plot is one less seed eaten in a commercial field,” says Linz. “A decoy field gives the birds an alternative feeding site when farmers harass blackbirds out of their commercial fields. We know that blackbirds are going to eat sunflower since it is their preferred food in the fall…it is just a matter of where and whose field,” says Linz.

So maybe that field could be a decoy field, and one of the potential strengths of the lure plot concept is that it provides a feeding alternative for 'local' birds. These are blackbirds that are congregating in mid August into groups of several thousand, and are in the process of developing their flying feathers. “These birds are in really poor condition at that time of year and are very difficult to move out of fields, largely because they can't fly very well,” says Linz. It is these birds that really frustrate farmers, because they are not as easily harassed out of sunflower fields. These birds will minimize their flying time for feeding, so if a lure plot is nearby, they are very likely to use it.

By the time their feathers are fully developed in mid-September, the birds are also easier to harass, and are likely to begin their trek south. Thus, the lure plot might be able to play an important role in reducing that early damage which is almost uncontrollable, says Linz. Plus, about 70% of the damage usually occurs within the first 14 days after petal drop.

USDA and NDSU researchers observed the lure plots last season for desirable species as well as undesirable blackbird species. They also observed some of the plots for blackbird damage on a weekly schedule. Damage on the 13 plots ranged from 2 to 90%, with an average damage across all the plots at 39%.

There were 25 commercial sunflower fields within 1½ miles of the 13 lure plots. The USDA group conducted damage surveys of all of those sunflower fields. Damage ranged from less than ½ percent to a high of 24%, with an average of 2.7% across the 25 fields. There was one lure plot that was well utilized, yet five neighboring commercial fields averaged 10% damage. Obviously, here was a situation where another lure plot, or a larger lure plot, would have been helpful.

Roger Florhaug of Kensal N.D., had one plot next to a large shallow lake ringed with cattails. His plot was planted late because of the lousy spring conditions, but ended up with a good stand nevertheless.

“The bird pressure was intense and they literally cleaned out the plot. The birds definitely stayed in the plot until there was nothing left for them to eat,” says Florhaug. The closest commercial field was about one mile away, and they headed in that direction once the plot was consumed.

Florhaug thinks that the success of lure plots will be placement between a wetland and the commercial fields. In this case, the plot was too small – or there should have been two plots, because the size of the wetland is about 600 acres of open water and cattails. “The plots definitely have potential and I would do it again,” Florhaug says.

Lure plots in 2005

USDA plans to expand the number of plots this year to about 30 to 40 in North Dakota and South Dakota. “We need further assessment of damage reduction to commercial fields, decoy field placement, size and the number and type of desirable species that use the plots,” says Linz.

Linz is hoping that bird and other environmental organizations will have an interest in these decoy plots. He points out that there are many desirable bird species that use sunflower fields throughout the season for protection and feeding. The big leaves and closed canopy of sunflower fields provide good protection for many species. And pheasants love to feed on unharvested sunflower heads throughout the winter, according to Linz.

According to Linz, 43 different species were identified in the plots during the season. In addition to blackbirds, the most common were a host of sparrow species, goldfinch, horned lark and American pipit.

Mike Clemens, a farmer and member of the NSA board of directors, hopes that birding groups or environmental groups might financially support the concept of decoy plots.

“It appears that the decoy plots might be a ‘win win’ situation for both farmers and birding groups,” he says. “We know that a lot of different bird species use sunflower fields. The key for us is to lower damage on our commercial fields with these plots. Farmers have been feeding blackbirds for a generation now and it has been devastating to farmers and the entire sunflower industry.”

Clemens anticipates that the interest in plots will increase if they indeed lower damage and if cost sharing is available. Bird groups could help a great deal in financially supporting the plots and thereby supporting other species.

“Obtaining additional federal dollars for a program like this is becoming more difficult. Private sector dollars will be needed if the program expands significantly,” Clemens says.

Clemens would also like to see rules requiring feed plots in CRP with established wetlands. Again, sunflower is the near perfect food and that might help in dispersing blackbirds in the fall. – Larry Kleingartner

Get Details on ’05 Cattail Control Program

USDA’s Wildlife Services has been spraying cattails on private and public lands for 10 years, averaging about 6,000 acres per year between North Dakota and South Dakota.

Removing thick stands of cattails in standing water has proven effective in dispersing blackbirds. Removing cattails also makes it more difficult for certain blackbird species to establish successful nesting in the spring. USDA prefers cattail sloughs of 10 or more acres with a history of harboring lots of blackbirds. Opening these wetlands provides better habitat for ducks and geese.

USDA uses approved aquatic herbicides such as the glyphosate-based Rodeo®. The spraying usually takes place between July and the first freeze to gain the best results.

Up to this point, USDA has sprayed 70% of the cattails in a stripping configuration. Leaving smaller strips of cattail apparently resulted in an agreement with the Fish and Wildlife Service. The Service promoted the strips for protection for some species. However, farmers have found that leaving 30% of the cattails can still provide significant blackbird habitat.

USDA will now allow the land owner/renter to pay for the final 30% of the control program. The option will be placed right on the application. For a 15-acre wetland, the cost to the farmer for treating the remaining 30% of cattails would be about $300. The benefit will be better bird dispersal, and the wetland should remain clear of cattails for four years and longer.

For applications or further information about the cattail control program, call USDA Wildlife Service at 701-250-4405 in North Dakota and 605-224-8692 in South Dakota.

Evaluating dispersal agents

George Linz and others at the USDA Wildlife Services Great Plains Field Station have been looking at potential products that could be used to keep blackbirds out of sunflower fields. Linz has been testing all of the insecticides that are already labeled on sunflower. The concept is that if a producer is spraying for head insects such as seed weevil, that the farmer may as well use an insecticide that has more blackbird repellency if birds are a potential concern.

With the help of NSA funding, he conducted field studies last year. Linz placed 8x8 ft cages in a sunflower field, and an aerial applicator was contracted to spray an insecticide over the field. Blackbirds were placed in the cages after the application. There were differences between the control (no insecticide) and the insecticide treated cages. So far Lorsban® appears to function best; the strong odor of the insecticide may be a deterrent.

Results remain very preliminary, and the experiments will be repeated again next season. Linz will be combining insecticides with Bird Shield® and other potential repellents. Linz will be testing caffeine as well. He reports that there has been some success with using caffeine as a bird repellent in rice country.

At the end of the day, we need to have multiple approaches to controlling bird damage in sunflower, because there is no single magic bullet in anyone’s arsenal at this point, according to Linz.
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