EFFECTS OF FENITROTHION ON MEMORY FOR CACHE-SITE LOCATIONS IN BLACK-CAPPED CHICKADEES

The effect of fenitrothion on food caching in the black-capped chickad ee was investigated. Oral doses of fenitrothion calculated to produce peak brain inhibition levels of 50 to 60% had no effect, or possibly e ven improved the ability of the birds to retrieve existing food-cache memories when administered after cache locations had been memorized. I n the more extreme cases, birds were able to remember cache sites even when their physical abilities were still visibly impaired. The same d ose of fenitrothion administered to the birds before they were allowed to cache improved cache-recovery performance. This result is consiste nt with results we obtained at lower brain ChE inhibition levels with physostigmine (reported elsewhere). It is inconsistent with studies th at indicate that dosing with anti-ChEs typically gives rise to a U-sha ped response with impairment at the higher dose levels.