Crop Damage Caused by Birds:
2008-2009 Report
Bird depredation of planted cereal grain is increasing in the US. Pesticides with avicidal properties have been reduced. This has contributed to three states with different bird species experiencing economic loss greater than 20% in planted corn. On a per acre basis, the loss is between $60 and $80, depending on the state. Avipel® is showing effective protection without toxicity to birds. Field experience with Avipel® for 2008 and 2009 is reviewed with mechanism of action and economics for the grower.
Avian Depredation to Planted Cereal Crops
Bird damage to planted corn, sunflower, canola and rice seed is growing. National statistics on the damage is not tracked by NASS (National Agriculture Statistical Service) or other government agencies, because birds have not been classified as an agricultural pest. Certain species are used, however, as monitors for pesticide safety by regulatory bodies. As a result of the extensive toxicity testing done on birds, several well known pesticides used to control insects have been removed from use because of avian toxicity (Measurol, Furadan®, Lindane).
Several states have monitored significant changes in bird damage. Wisconsin observed a direct correlation between increased corn field damage from cranes and cessation of Lindane use as an insecticide treatment. Crane populations continue to grow as a result of aggressive restoration of breeding flocks and habitat. Within one mile of a Wisconsin wetland where cranes feed in newly planted corn fields, 20% or more of the crop is being destroyed. Of the 3.5 million acres of corn planted in Wisconsin, 2.7 million acres are within the potential feeding range of cranes.
South Dakota is dealing with a pheasant population that continues to grow with successful habitat restoration. The cropland reserve program (CRP) has set aside significant land areas adjacent to corn fields. Cover and nesting sites have been provided in the process and with the loss of products containing Lindane, Furadan® and Measurol, crop loss has increased. Early spring does not offer birds much dietary diversity, and the liquid starch found in corn seed is essential to birds' reproductive health. In 2008, around 20% of the corn fields in South Dakota had noticeable bird damage that could vary from 5% stand loss to over 50%. Replanting in the Dakotas is a risky venture due to the short season. The economic impact of reduced stand is compounded by the necessity of additional weed control as well as yield loss. Using Avipel® is an effective way to keep planted corn seed off the pheasant's menu.
Mississippi has increased corn acreage substantially in the last two years at the expense of cotton. With over 750,000 acres in corn, migrating blackbirds, grackles, crows and cowbirds have found corn seed to be a very attractive source of starch for the energy needed during the migration north. The narrow planting window in the delta region happens to coincide perfectly with spring migration, and losses to birds have now been estimated by the state to be high. Twenty-five percent of the planted corn is experiencing from 10-15% stand loss and 5% of the corn is experiencing greater than 25% stand loss. Tillage practices plus narrow planting time work against any replanting in Mississippi, so crop yield is directly affected. As in South Dakota, increased weed control adds to the input cost of fields experiencing bird depredation.
Crop Loss Summaries for Representative States 2008-2009
Typical Examples of Bird Damage in the Field
In 2010, more data will be gathered on bird damage to rice, sunflower, canola, sorghum, and other cereal grains in addition to corn. Differentiating damage caused by birds from that of rodents can be difficult. The following photos can be used as representative samples of damage caused by different bird species.
Crane Damage, Wisconsin
This is a photo of typical crane damage. Notice how only one plant was missed in a row. Cranes seem to learn the planting distance of seed and often do not wait for the seed to sprout. With a large powerful bill, cranes have no problem penetrating any soil type to dislodge the seed, squeeze it, and swallow the soft endosperm. Discarded seed without the endosperm can often be found in the vicinity of the damage.
Pheasant Damage, South Dakota
This pictures damage commonly done by pheasants. Often a large hole is present where the pheasant has first dug for the seed with its claws prior to consuming the endosperm. Notice the damage continues down a row for some distance. Much of the pheasant damage occurs at the borders with CRP land, fence row and areas around pot holes. In cases where Avipel® was used only on the field's borders, pheasants went deeper into the field in search of untreated seed.
Blackbird Damage, Mississippi
As shown here, Blackbird damage often shows a lot of probing and breaking of the soil surface on either side of where the seed was planted. Blackbirds in great numbers will concentrate on patches of unprotected field. The dry Avipel® hopper box formulation has worked well to protect these fields.
Avipel's Mode of Action and Cost
Seed treated with Avipel® causes a gut reaction in birds. Birds learn quickly to avoid treated seed by observing other birds in a process called learned avoidance as studied in the early 1980's by Mason and Reidinger. Avipel® has been successfully used to protect seed in over a million acres of treatment in 8 states since 2006. The label is currently under emergency exemption Section 18 use; the full Section 3 label will be ready for submission to the EPA in early 2010.
The dotted line indicates treated and untreated sections of this test field; but, even without the line, it's easy to see where cranes have been feeding. The protected half of the field was untouched.
Retail per acre cost for Avipel® ranges from $3.79 to $5.37, depending on corn seeding rate and seed count per bag.