Quantitative assessments of bird damage to lowland sorghum (Sorghum bicolor) were made annually from 1976 through 1979 in the major growing areas associated with the Awash River Basin. Results indicated that the red-billed quelea (Quelea quelea) can be an important limiting factor in the overall production of this cereal, and that damage can be locally severe. Lethal control of quelea breeding colonies found along the Awash River and at Lake Zwai was undertaken in September/October of both 1978 and 1979. Subsequent assessments showed substantially less bird damage in both years and overall losses were minimal.

Ultrasonic or high-frequency sound-producing devices are marketed as a scaring or frightening method for bird control. Although inaudible to humans, most birds also do not hear in the ultrasonic frequency ranges of above 20,000 Hz, thus the credibility of advertised claims raises questions. A review of efficacy studies conducted and published by a number of researchers fails to demonstrate the usefulness of such bird control devices.

The use of trained falcons and hawks for dispersing pest birds has been mainly limited to airports in Europe and, to a lesser extent, in North America to prevent bird/aircraft strikes. The peregrine falcon (Falco peregrinus) and the goshawk (Accipiter gentilis) are the raptors used most often. These trained birds can effectively disperse gulls (Larus spp.) and a variety of other pest bird species, although other bird-scaring methods are often equally or more effective and economical. Because of the scarcity of trained raptors and handlers, their use is limited to special situations such as airports where the incidence of bird strikes is potentially high and all possible measures must be taken to assure aircraft safety.

Scarecrows and raptor models are fairly common traditional methods of attempting to frighten unwanted birds. Their effectiveness depends on the conditions under which they are used and the unwanted bird species involved. Best results are obtained from those that are most lifelike and have motion. When coupled with loud startling sounds or recorded distress calls their effectiveness is generally enhanced. Habituation by at least some birds is inevitable so the duration of effectiveness diminishes with time. It is essential to know what works best in a given situation so those methods can be employed to achieve maximum efficiency. An understanding of the limitations of these devices will temper expectations to a realistic level.