Measuring the exposure of Songbird Nestlings to Neonicotinoids in Natural and Agricultural Nest Sites

Neonicotinoid insecticides such as imidacloprid (IMI) have been under scrutiny for their damage on non-target invertebrates. However, recent literature suggests that grassland birds are experiencing population declines concurrently with increased IMI use. Field research was conducted to test the presence of IMI in Savannah Sparrow (SAVS) nestlings and their insect food supply at agricultural and non-agricultural nests. Using urine samples from Tree Swallows (TRES) dosed with IMI, an HP LC-MS was used to determine the concentration of IMI its metabolite 6-chloronicotinic acid (6-CN) at 0, 3 and 6 hours after exposure. Though no IMI or 6-CN residues were found in SAVS or their food, dosed TRES suggest birds can take upwards of 6 hours to excrete the parent compound and this was proportionate to the original dose. This will be a novel approach to neonicotinoid research on grassland birds and will serve as a guide to future research in this developing field.