17. Studies to evaluate the efficacy of glue stakes as a means of
 reducing bird damage to ricefields were continued. Numbers of birds,
 per 10-min interval, in test plots were similar (11.6 in treatment
 plots and 7.0 in reference plots) prior to treatment but dropped to as
 low as 0.2 bird per sampling interval in treated areas and increased
 to 17.1 birds per interval in untreated areas. Pretreatment surveys
 revealed 14.5 percent damage in treatment plots and 11.8 percent in
 reference plots. Although damage increased in both areas, as deter-
 mined by posttreatment surveys, the increase was slight in treated
 areas and quite large in reference areas (19.9 percent and,63.2 per-
 cent, respectively). The glue stakes lost their adhesiveness within
 3 days but the birds avoided the area for a full 8 days after
 treatment.

 18. A year-long study was conducted to evaluate the efficacy of
wax bait blocks for controlling rodents in coconut palms. Bait place-
ment in the palm crowns and deterioration of loose bait materials are
two difficulties which need to be overcome. Production records indi-
cate that the wax-block bait treatment provided effective rodent
control. Coconut production in the treated area was 2.2 times greater
than that of the reference plot.

 19. A study is in progress to determine whether anticoagulant
rodenticides may accumulate in ricefields. Although the possibilities
of biological concentration or secondary hazards are considered low
when these products are used according to manufacturers' recommenda-
tions, we plan to examine samples of paddy water, soil, rice plants,
and polished grain in two simulated "worst case" situations: (1) when
exceptionally high levels of bait (5 kg/ha per week, at manufacturers'
recommended concentration) are used throughout the growing season and
all bait is "spilled" into the paddy; and (2) when even greater levels
(50 kg/ha per week) are used, and all bait is "spilled" into the
paddy. Treatments were made in specially constructed paddies and
samples have been collected and submitted to DWRC for chemical
analyses.

 20. Evaluation of the efficacy of nonlethal electric barriers as a
means of reducing rodent damage to rice continued with a preliminary
field trial. Analysis of test results showed that the barrier was
effective in reducing rat damage. Damage in the plot bounded by the
barrier averaged 1.9 percent and damage in fields surrounding the test
plot averaged 8.6 percent. The reference plot suffered 18.8 percent
damage while the three fields surrounding it had an average of 11.9
percent damage.

 21. An examination of indirect (population suppression) control
efforts in Sudan revealed that such efforts are effective in killing
large numbers of birds and do provide some relief from damage on a