Despite the satisfactory results obtained with the original equipment,
major problems of data acquisition, reduction, and analysis plagued
this earlier study. Efficient handling of large volumes of data was
difficult, and use of a single-bait (no-choice) test limited inter-
pretation of these data.

Recently, we purchased an improved system for automatic, continuous
measurements of rodent feeding patterns. This system consists of:
(1) four 200-g electronic balances, (2) one Horizon II microprocessor,
 Sone multiplexer-scanner, and (4) one teletypewriter. All data
acquisition is under the control of the microprocessor; the minute-by-
minute bait intake by rats from two choice cups is automatically
transferred and stored on permanent 75 mm X 75 mm X 1.6 mm magnetic
disks.

A series of studies are planned to assess the effects of different
rodenticides and rodenticide concentrations on bait intake patterns
of ricefield rats as well as other species. Automatic recording and
analysis of data will permit evaluation of changes in feeding behavior
induced by sublethal doses of toxic baits. This information will make
possible the development of improved bait formulations for both new
rodenticides as well as those currently in use.

Drug-induced taste aversion in ricefield rats (R. r. mindanensis):
factors affecting drug effectiveness and feasibility of use for
reducing crop damage

If a rat is exposed to sufficient levels of ionizing radiation or
given certain drugs within a short time after tasting a novel sub-
stance, subsequent intake of that substance is reduced. This effect
is termed "conditioned taste aversion" and it is currently being pro-
posed as a nonlethal method for control of agricultural damage by a
variety of vertebrate species (e.g., bear damage to apiaries, rat and
bird damage to grain or fruit crops, and coyote predation on sheep).

Despite repeated laboratory demonstrations of the conditioned taste
aversion effect, a number of factors can affect generalizations from
laboratory to field situations. Laboratory use of deprivation
regimens, intraperitoneal injection or gavage administration of drugs,
and controlled presentation of novel taste stimuli serve to optimize
the effect. Our current work is designed to: (1) clarify several
factors likely to influence field applications of drug-induced aver-
sion and (2) assess the feasibility of drug-induced taste aversion
for reducing crop damage by the ricefield rat (R. r. mindanensis). To