Evaluation of elevated bait trays for attracting blackbirds (Icteridae) in central North Dakota

Sunflower (Helianthus annuus L.) became an economically important crop in North Dakota in the 1970s, providing a major source of food for post-breeding blackbirds (Icteridae). Reducing local blackbird populations with rice grains treated with an avicide is one proposed alternative for reducing sunflower damage. In fall 2007 and 2008, we evaluated the idea of attracting blackbirds to rice-baited trays attached to wire cages supplied with live blackbirds. During our observations (1011 h), we saw 3888 birds, consisting of 25 species and 12 families, on the bait trays. Blackbirds made up 90.4% of the bird observations, whereas sparrows (Emberizidae) made up 1.6% of the birds observed. Overall risk to non-target species appeared minimal. The bait trays, however, attracted a small number of blackbirds compared to the source population feeding in nearby crop fields. Our results strongly suggest DRC-1339-treated rice used on bait trays is unlikely to be a cost-effective method of reducing blackbird damage to ripening sunflower.

► We attempted to attract blackbirds to baited trays attached to cages supplied with live blackbirds.
► During 1011 h of observation, we saw 3888 birds perch on the bait trays.
► Blackbirds made up 90.4% of the birds observed on the bait trays.
► Overall risk to non-target species appeared minimal.
► Bait trays attracted small numbers of blackbirds compared to the number feeding in nearby crops.