When using DRC-1339 Concentrate, applicators have sometimes found that blackbirds will not feed on standard grain baits. While the search for more attractive baits has generally focused on alternate grains, fruits, and occasionally processed foods, a first-rate candidate may be insects. To our knowledge, no feeding tests using red-winged blackbirds have been conducted to measure consumption rates among various commercially available insects. Our results indicated that large-sized mealworms were the best bait for red-winged blackbirds during fall, whereas crickets were favored over small-sized meal¬worms and waxworms in summer. We speculate that choice was based to some extent on the quantity of fat available among the different foods. We plan to conduct similar feeding trials with European starlings.

The National Sunflower Association has identified blackbird damage as a key reason for growers to abandon sunflower. In the 1980s, National Wildlife Research Center scientists showed that “decoy” plantings of sunflower can significantly reduce bird damage to nearby commercial sunflower fields. For a variety of reasons, largely logistical and economic in nature, decoy sunflower fields did not become wide-spread. Over the last decade, new federal farm programs have placed more emphasis on wildlife conservation. Thus, decoy sunflower fields planted to ameliorate blackbird damage and establish habitat for wildlife might garner broad support from both agricultural and conservation groups. We present preliminary data on avian use of ripening sunflower fields that support the notion of “Wildlife Conservation Sunflower Plots” (WCSP) as a broad-based dual-purpose wildlife management strategy. We also outline research plans designed to refine the concept of WCSP.

Cattail stands provide roosting and staging areas for large congregations of blackbirds in North Dakota in late summer and early fall. Since 1991, the U.S. Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services (WS) program has conducted a cattail management program in North Dakota to alleviate blackbird damage to ripening sunflower. To extend the capabilities of the program, a geographical information system (GIS) will be incorporated to help WS personnel find blackbird roosts more effectively. We will use the GIS to construct field maps showing the association between areas of moderate to high sunflower damage (>5%) and cattail-dominated wetland basins >2 ha. Buffer distances comparable to the distances blackbirds typically travel to forage will be placed around sunflower planting areas susceptible to high damage. This will help WS personnel focus their efforts on locating cattail-dominated wetlands that should be enrolled in the management program and improving current and future blackbird damage management programs.

Managing European starlings with DRC-1339 near urban and suburban areas can lead to adverse publicity resulting from encounters by the public with dead and dying birds. Collectors could retrieve the birds, if the likely sites of mass mortalities were known. In December 2009, we radio tagged 50 starlings at 3 sites in central New Jersey and studied their movements and behavior. Two of the sites were ensconced in a mosaic of suburban and urban habitats, whereas the other was in a rural setting. The sites were selected from a list of agricultural producers that had requested assistance from the Wildlife Services program in New Jersey. Starlings using the rural study site showed strong site fidelity (x-bar = 78% of days tracked), stayed closer during daytime wanderings (x-bar = 2 km), and roosted onsite. In contrast, starlings in the urban-suburban mosaic showed less fidelity (x-bar’s = 10% and 36%), wandered farther (x-bar’s = 6 km and 4 km), and seldom roosted onsite. No study sites were visited by members from the other radio-tagged cohorts. Major roosts in the urban-suburban mosaic averaged 10 km (n = 4, SE = 1.4) from the study sites. We predict that most starlings will remain within 6 km of the site during daytime. Poisoned starlings may become lethargic and seek refuge in dense vegetation (e.g., evergreens) near the baited site. Birds >6 km from a bait site are probably on a direct bearing between the bait site and roosting site.

We radio tagged and tracked 50 European starlings between December 2008 and January 2009 at 3 feedlots in the northern Texas Panhandle. Daily fidelity to sites of capture (home feedlots) was different among the 3 radio-tagged cohorts. Cohorts from Sites A and C were recorded at home feedlots on 48 and 59% of tracking days, respectively. The Site B cohort was at its home feedlot 95% of days. There were qualitative differences in use of home feedlots between cohorts A and C. The former were nearly obligate in their use of concentrated animal feeding operations (CAFO), whereas the latter tended to balance their use between CAFO and a nearby urban center. Six birds (12%) used either one or both of the counterpart home feedlots. Of these, 5 permanently switched from their home feedlots and used counterpart home feedlots; one bird captured at Site B alternated between Sites A and C after abandoning its home feedlot. Use of roost sites depended on habitat composition surrounding the study feedlots. Urban habitats were used as roosts by several birds from Sites A and C, whereas birds using Site B roosted at a petroleum refinery and a reservoir. Some Site B individuals used both roost sites during the study period; however, the reservoir was the preferred roost site. Daily activities in habitats away from the home feedlot generally occurred ≤5 km from the home feedlot. For birds from Sites A and C, offsite habitats were mainly urban areas and small CAFO. Increased habitat heterogeneity, as exemplified in our study by urban habitats and CAFO near Sites A and C, seemed to reduce rates of daily use of home feedlots. Heterogeneous environments can complicate management strategies that use DRC-1339 Concentrate for reducing starling numbers at infested CAFO. First, starlings may be erratic in their daily use of a CAFO in complex environments. Secondly, urban areas, when present, may be used as refuges by poisoned birds, leading to adverse public exposure.