Basis for estimates of cereal grain losses to quelea in Africa

Crook and Ward (The Problems of Birds as Pests) estimate the continen-
tal population of quelea to be between 109 and 1011 individuals and
suggest that 90-100 percent of the quelea diet is comprised of the
seeds of wild grasses. Laboratory studies indicate the average food
consumption of quelea approximates 3 g/day. If we use the lower esti-
mate of 109 individuals and assume that 10 percent of the food con-
sumption of the entire bird population during a 30-day period each
year, when mature grains are present, accounts for total damage, the
total amount of grain consumed by this population is 90,000 metric
tons per year. Conservatively assuming a field value to small farmers
of $100 per metric ton, the value of this loss amounts to $9 million.
If we use the estimate of 1011 for the quelea population and make the
same assumptions, the result is a calculated annual loss of $900
million. Statements of losses as "more than $100 million per year"
are based on a midpoint population estimate and a recognition of the
conservative figures used in these assumptions.

Summmary of major bird damage problems in the Sudan

A summary of the major bird damage problems in the Sudan is given in
Table 5.