Taste preference tests, with simultaneous presentation of treated and untreated food, were administered to 24 common vampire bats (Desmodus rotundus). The bats received brief exposures to four different stimuli representing sweet, salty, sour, and bitter tastes, each at four different concentrations. Despite a strong location bias, the bats significantly (P < 0.01) avoided the highest concentrations of the salty, sour, and bitter tastes. Consumption of the sweet stimulus at all concentrations was similar to that of the untreated standard. Vampires evidently can discriminate based on taste, although their ability is apparently poorly developed when compared with some euryphagous species such as the rat. Hence, taste is probably not a factor in host selection by the vampire.

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The methods of single stimuli and constant stimuli were used with a modified conditioned suppression technique to determine olfactory intensity-difference thresholds in White Carneaux and White King pigeons. While responding for grain reinforcement on a VI 2-min. schedule, conditioned suppression was established in the birds after several sessions by pairing amyl acetate odor at 7% of vapor saturation with electric shock. The degree of suppression to nonshocked lower intensities of this odor determined the DLs. Weber fractions computed, from these values ranged .6-7. Both psychophysical methods produced identical DLs. Olfactory nerve section abolished the 7% intensity response in all birds, showing that odor was the only cue utilized by the birds during preoperative discriminations.

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There is a continuing need to develop improved repellent formulations to protect buried cable installations fi-om damage by problem wildlife. We evaluated 2.0% mass/mass levels of capsaicin and denaton-i~~m benzoate in a polybutene carrier material (Indopol@) and an aboveground, rodent-deer plastic mesh barrier (\'exar@) for reducing gnawing by northern pocket gophers (Tho~not~lys talpnides) on communications cable (RG-8U). When treatments were applied as surface coatings, neither capsaicin nor denatonium samples were lower (P > 0.05) in measnres of cable damage compared to control (Indopol@ alone) or samples treated with \'exaP plastic mesh. When the test was repeated with a new group of 24 gophers ( n = G/group in each of 4 groups) bnt with the 2.0% capsaicin, 2.0% denatoniuin benzoate, and Indopol@ enclosed with electrical shrink tnbing, there was less damage for the capsaicin samples (P < 0.05) on mass, depth of cut, width, and volume of cable chewed when compared to samples treated with the Vexarm and Indopol@. Denatonium benzoate treatment also prodnced repellent effects ( P < 0.05) on the width measure when compared to Vexarm samples.In addition, the denatonium benzoate samples were damaged less than Indopol@ samples, although not significantly, as measnred by mass loss and depth of gnawing. Therefore, we concluded that although capsaicin and denatoneum benzoate appeared to be completely ineffective when applied as a surface coating to cable, the same agents became effective cable gnawing repellents when encased in electrical shrink tubing. This encasing procednre den~onstrated quite clearly that the means for applying the repellent agent are an all important aspect of de\.elopitlg effective prod~icts to control gnawing damage by northern pocket gophers. MANAGEMENT 63(4):1344-1349 JOURNAL OF WILDLIFE

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