BLACKBIRD USE OF WILDLIFE CONSERVATION SUNFLOWER PLOTS

Authors

George M. Linz, USDA/APHIS/WS National Wildlife Research CenterFollow
Jonathan M. Raetzman, North Dakota State University, Fargo
Heath M. Hagy, North Dakota State University, Fargo
H. Jeffrey Homan, USDA-APHIS-Wildlife Services
William J. Bleier, North Dakota State University, FargoFollow

Date of this Version

February 2007

Comments

National Sunflower Association Research Forum. Online at http://www.sunflowernsa.com/research/

Abstract

In North Dakota, annual blackbird damage to sunflower ranges from $5-10 million. Blackbird damage to ripening sunflower has forced some growers to plant alternative crops. From 2004 to 2006, USDA-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 to commercial fields. A secondary benefit of WCSP was to provide a safe-haven for other wildlife that frequently use shelterbelts and wetlands along the edges of sunflower fields. In 2004 (n=13), 2005 (n=21), and 2006 (n=25), sunflower damage in the WCSP’s was 39%, 32%, and 60%, respectively. Damage in nearby commercial fields was 5% in 2004, 4% in 2005, and 18% in 2006. In 2006, dry conditions may have concentrated blackbirds into bigger roosts in the larger and deeper wetlands, contributing to higher levels of sunflower damage compared to 2004 and 2005. Lower levels of damage in 2004 and 2005 may have been caused by the greater availability of wetlands, which dispersed the flocks. 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. Based on these data, additional large-scale field tests appear to be warranted.