local basis. On a broader scale, however, such operations have rela-
tively little effect either in reducing populations or eliminating
damage. Quelea populations are currently maintaining themselves at a
very high and viable level. One reason for this is that population
suppression operations are currently directed at a small portion of
existing quelea nest and roost sites. As currently practiced, popu-
lation reduction campaigns are not the answer to the quelea problem.

 22. Reliable data on crop losses to birds in Sudan are scarce.
Project staff are continually accumulating information on the amount
of losses and the resultant economic impacts from a variety of
sources including literature reviews, personal interviews, and field
damage surveys. Many damage estimates for Africa as a whole are
probably very conservative based on the size of the quelea population.

 23. For logistics and economic reasons, some field testing related
to the Sudan quelea project is being conducted in Texas. A sorghum
variety (TX 623) similar to the Daber sorghum of Sudan and house
sparrows (same family as quelea) served as models in a field cage test
to determine the optimum concentration of methiocarb and adhesive for
field application. Results suggest that the acrylic resin, Rhoplex
AC-33, interferes with or masks the repellent properties of methio-
carb. Adhesives should probably be omitted from spray treatments in
very dry climates but if they are needed, concentrations of no greater
than one part methiocarb and ten parts adhesive are suggested.

 24. Field trials indicate that effective crop protection can be
achieved with relatively low levels of the bird repellent methiocarb.

 25. A survey of a new agricultural development project area
revealed a high potential for bird depredation problems in the future.
The area currently is not seriously affected but past history has
shown that agricultural schemes, both large and small, that are
located in prime quelea habitat, have suffered heavy depredation.
This new scheme (Blue Nile Integrated Agriculture Development Project)
is in prime quelea habitat.

 26. Arvicanthis niloticus and Mastomys natalensis are the two most
important agricultural rodent pests in Sudan. They cause significant
damage to a variety of crops including cotton, sorghum, wheat, ground-
nuts, and vegetables.

 27. Preliminary work began on the development of a toxicity pro-
file for gliftor, a rodenticide that is widely used in the Soviet
Union. A bioassay test using 1- and 2-percent concentrations of
gliftor revealed that it may be unpalatable at higher concentrations;
hence, bait shyness is a potential problem in the use of this product.