Blackbird Use of Wildlife Conservation Sunflower Plots

Blackbird (Icteridae) damage to ripening sunflower fields in North Dakota ranges from $5-10 million and has probably forced many growers to abandon this crop. From 2004 to 2006, USDA, APHIS, Wildlife Services cost-shared Wildlife Conservation Sunflower Plots (WCSP) with sunflower growers. The objective of the WCSP was to provide blackbirds an attractive nearby alternative food source to reduce damage in commercial fields. From 2004 through 2006, sunflower damage in the WCSP\u27s was 39%, 32%, and 60%, respectively. In comparison, damage in nearby commercial fields was 5%, 4%, and 18%, over those years. In 2006, drought in the region may have concentrated blackbirds into more permanent wetlands, contributing to higher levels of local damage. Conversely, the lower levels of damage in both 2004 and 2005 may have been a consequence of better water levels in more ephemeral wetlands, which dispersed the birds among more roost sites. We believe that avian use of WCSP was influenced by the nearness of shelterbelts, cattail-dominated wetlands, and contiguous blocks of commercial sunflower. We speculate that WCSP can reduce bird damage in nearby commercial fields