Aerial spraying of quelea

Abstract

More than 10 000 ha of roosts and nesting colonies of quelea are sprayed with avicides every year in Africa. The avicide the most frequently utilized is Queletox. Since 1959 the dose of avicides has decreased from 5.5–39 kg a.i. to 0.6–2.4 kg a.i. per ha. The droplet diameter decreased from 250 to 50–150 microns. However, to avoid contamination of the environment and ensure a rapid mortality of quelea it is recommended to use the doses between 2.5 and 4 kg of a.i. per ha. Spraying of avicides should be done in the evening when all quelea are in the site. The dose should be so high that the sprayed birds die during the night and within the limits of the sprayed area. The droplet diameter should be chosen according to the weather conditions during spraying so as to reduce the drift of avicides. Spraying of sites containing non‐target species should be prohibited. More studies are necessary about the impact of spraying on the non‐target species. It appears also that the avicides presently used are too persistent after spraying, and act too slowly on quelea. Further optimization of the dose of avicides and droplet diameter will be possible if more data are available on droplets, the impaction efficiency, the body capturing surface and mode of intoxication. More data are also necessary on quelea behaviour during and after spraying.

Keywords:

• quelea
• avicides
• aerial spraying
• noxious birds
• pest birds

Notes

Present address: 5352 Coolbrook, Montreal, QUE H3X 2L4, Canada.