Abstract
Laboratory studies were conducted, using a millet grain bait, to estimate the minimum concentration of 4‐aminopyridine (4‐AP) needed to produce abnormal behaviour and distress calls in house sparrows (Passer domesticus L.). Three concentrations (0.50, 0.75 and 1.0%) were tested and three doses (6, 18 and 30 mg) were administered by forcing birds to eat one, three or five treated grains. There were differences among the three concentrations in time from dosing to first distress call and in abnormal behaviour, but not in the duration and number of distress calls. At each concentration different doses had different effects. Males emitted more and higher pitched distress calls than did females. It is concluded that concentrations of 0.75 and 1.0% could be effective in reducing damage to cereal crops by house sparrows in Pakistan. The calculated LD50 was 5.9 mg/kg (4.5–7.7 mg/kg, 95% confidence limits).