| dc.description.abstract | The effects of exposure to rain and sunlight on the efficacy of 4-Aminopyridine (4-AP) as a frightening agent for blackbirds (Icteridae) was measured in terms of the ability of the exposed bait to induce abnormal behaviors in cowbirds (Molothrus ater). Two-way analyses of variance (types of exposure x amount of bait eaten) and Duncan's multiple range tests were used to examine differences in manifestation, duration, and total times involved in the reactions of the birds to 4 bait treatments: 1.27 cm rain, 8.89 cm rain, 2 weeks sunlight, and control. Chi-squared tests were used to compare treatments with regard to the frequency of occurance and the average length of occurance of 6 behaviors: hovering flight, muscular incoordination, trembling, convulsions, vocalizations, and regurgitation.
There were statistically significant differences between the duration and total times of the birds fed 8.89 cm-rained bait and the control, and in the total time involved between the 1.27 cm-rained bait and the control (P<0.05), but the actual values were relatively small. Qualitative differences in behavior between treatments are of more importance than the quantitative differences: the treated baits produced reactions which were more frequent, but of shorter duration, than the reactions observed in the control group. Also, these reactions were quieter and less visible than the reactions of birds fed fresh bait, implying a possible reduction in the effectiveness of the 4-AP as a frightening agent | en |
