REPELLENT POTENTIAL OF VEGETABLE TANNINS ON QUELEA QUELEA

In many developing nations around the world. pest birds are a serious threat to human food supplies. In the Sahelian zone of Africa, red·billed quelea (Quelea quelea) is of greatest concern. Cereal grain crops within the range of quelea are subject to severe depredations. Therefore, a wide variety of approaches have been taken to alleviate these losses. In 1972 Magor and Ward reported that during the past 20 years, hundreds of millions of birds have been killed by explosives, flame throwers, and lethal chemicals used to control birds assembled at night in roosts and breeding colonies. Despite this huge control effort, there were no long-term reductions in quelea populations (Crook and Ward, 1968). The high cost, possible contamination, and low successes of such operations led to suggestions for a more ecological approach (Jackson and Park, 1973). Crop protection rather than simple population reduction became the goal (Fumilayo and Akande, 1979; Ward, 1979). . In nature, secondary plant substances (many nonlethal) have protected a wide variety of plant species from vertebrate consumption (Rogers, 1978). For example, astringent tannins in some sorghums successfully deter birds (Harris, 1969). Recent studies at the Denver Wildlife Research Center (DWRC) on bird-resistant sorghum (Bullard et aI., 1980; Bullard et aI., 1981) led to the consideration of testing commercial tannins for possible utilization as repellents in topical applications to cereal grain crops. The following studies were conducted to determine tannin efficacy in the laboratory