Date of this Version
Blackbirds frequently use ripening sunflower (Helianthus annuus)as a food source in the northern Great Plains. In 1999 and 2000, the avicide DRC-1339 (3-chloro-4-methylaniline hydrochloride) was used experimentally on fall-ripening sunflower fields in North Dakota so researchers could evaluate its effectiveness for reducing crop depredations by blackbirds DRC-1339 was applied to rice and broadcast on the ground in a confined area within ripening sunflower fields. One objective of this study was to determine if nontarget birds, birds other than blackbirds, were eating rice and were exposed to DRC 1339. In 1999, 8 of 11(73%) sparrows collected by shotgun in sunflower fields treated with DRC-1339 had rice in their gastrointestinal (GI) tracts. In 2000, 5 mourning doves (Zenaida macroura) and 3 sparrows were collected by shotgun in sunflower fields treated with DRC-1339 Three doves had rice in their GI tracts, 4 doves and all 3 sparrows had measurable DRC- 1339 concentrations in their GI tracts, and 3 mourning doves and 1 savannah sparrow (Passerculus sandwichensis) exhibited histopathological signs of kidney damage. In April 2002, untreated rice was applied to corn stubble plots in South Dakota to determine which bird species ate rice. In 2002, 3 of 3 song sparrows (Melospiza melodia) collected by shotgun had rice in their GI tracts. Our results demonstrate that the use of DRC-1339 to control blackbirds in the northern Great Plains will likely expose nontarget birds to the DRC-1339 bait.