Do birds avoid cotyledons coming from imidacloprid-treated seed?

Insecticides applied to seeds before sowing may present a toxicological risk to seed-eating birds. Non-buried treated seeds and cotyledons from treated seeds of soybean can be eaten by birds. To evaluate if the avoidance behavior (rejection of treated food) limits the exposure and consequently the risk for birds, three fields of the Paraná Agriculture Experimental Station were sown with soybean. Equal parts of each field were sown with non-treated and insecticide treated seeds (imidacloprid 60% w/v). The amount of non-buried seeds and the number of missed cotyledons/linear meter were measured by systematic sampling, beginning at random. Birds were surveyed using point counts from field-edge. The amount of non-buried seeds/linear meter was not significantly different between the sowing and 48 h after of sowing. The difference of missed cotyledons/linear meter between control and treated plots was significant in the three fields, with the amount of missed cotyledons/linear meter 51, 37 and 26% being lower in the treated plots than in control plots in the three fields, respectively. As a function of published studies, approximately 50% of the surveyed birds in this field experiment eat seeds. Due to the high percentage of seed-eating birds, although the chemical shown a repellent effect, determining if this effect prevent the intoxication will be necessary.