Assessment of Woven Wire for Reducing Predation on Red-Winged Blackbird Nests

Red-winged blackbirds (RWBL) are a polygynous species, and disruptions to either territorial behavior or reproductive fitness of the males has potential to lower annual productivity of several females. A reduction in the number of fledglings produced per territory could ultimately result in lower damage to grain crops, at least on a local scale. It is thus feasible that socially acceptable nonlethal methods, including reproductive inhibition through either physical or chemical means, may accomplish a reduction in crop damage. Scientists at the USDA, Wildlife Services\u27 National Wildlife Research Center have shown that reproductive inhibition is an effective method for reducing local populations of some bird species. None of the studies, however, have had to meaningfully incorporate loss of statistical power through predation events on nests or eggs. We expect a crippling reduction in sample size (i.e., nests, eggs, nestlings, and fledglings) to occur over the course of any field experiment intended to measure the effects of reproductive inhibition on RWBL. Thus, developing a methodology to reduce predation of nests is a preliminary yet necessary step in the process of conducting any subsequent field-level tests. We assessed the efficacy of 2.54-cm x 2.54-cm woven wire cylinders (measuring 366- cm height x 183-cm diameter) for reducing mammalian predation on nests of RWBL. If effective at reducing nest predation, we will use these exclusion devices to enhance sample sizes in future experiments designed to assess effects of reproductive inhibition by chemical or physical methods on annual productivity of RWBL

Evaluation of Lorsban®-4E Aerially Sprayed on Sunflower Plots for Bird Repellency

Ripening sunflower fields in the northern Great Plains provide blackbirds with easily accessible sources of high-energy food. As many growers can attest, blackbirds can be nearly impossible to discourage from foraging in favored fields. To date, no single management method has been especially effective at consistently discouraging blackbirds

Evaluation of Bird Shield as a blackbird repellent in ripening rice and sunflower fields

Chemical repellents sometimes can provide a nonlethal alternative for reducing wildlife impacts to agricultural production. In late summer and autumn 2002, we evaluated Bird Shield™ (active ingredient: methyl anthranilate, Bird Shield Repellent Corporation, Spokane, Wash.) as a blackbird (Icteridae) repellent in Missouri rice fields and North Dakota sunflower fields. We selected 5 pairs of ripening rice fields in southeastern Missouri and randomly allocated treatments (treated and control) within pairs. The repellent was aerially applied by fixed-winged aircraft at the recommended label rate and volume (1.17 L Bird Shield/ha and 46.7 L/ha, respectively); 1 field received 2X the label rate. We observed no difference in average bird activity (birds/minute) between treated and control fields over the 3-day posttreatment period (P = 0.503). We used reversed-phase liquid chromatography to quantify methyl anthranilate residues in treated fields. The maximum concentration of methyl anthranilate in rice samples was 4.71 μg/g. This concentration was below reported threshold values that irritate birds. In North Dakota we selected 6 pairs of sunflower fields used by foraging blackbirds. We randomly selected 1 field from each pair for 2 aerial applications of Bird Shield at the label-recommended rate ~1 week apart. The remaining 6 fields served as controls. Daily bird counts, starting the first day of application and continuing for 5–7 days after the second application, showed similar numbers of blackbirds within treated and control fields (P = 0.964). We observed no difference in sunflower damage within treated and control fields (P = 0.172) prior and subsequent to the treatment. Bird Shield was not effective for repelling blackbirds from ripening rice and sunflower fields

Evaluation of Bird Shield as a blackbird repellent in ripening rice and sunflower fields

Chemical repellents sometimes can provide a nonlethal alternative for reducing wildlife impacts to agricultural production. In late summer and autumn 2002, we evaluated Bird Shield™ (active ingredient: methyl anthranilate, Bird Shield Repellent Corporation, Spokane, Wash.) as a blackbird (Icteridae) repellent in Missouri rice fields and North Dakota sunflower fields. We selected 5 pairs of ripening rice fields in southeastern Missouri and randomly allocated treatments (treated and control) within pairs. The repellent was aerially applied by fixed-winged aircraft at the recommended label rate and volume (1.17 L Bird Shield/ha and 46.7 L/ha, respectively); 1 field received 2X the label rate. We observed no difference in average bird activity (birds/minute) between treated and control fields over the 3-day posttreatment period (P = 0.503). We used reversed-phase liquid chromatography to quantify methyl anthranilate residues in treated fields. The maximum concentration of methyl anthranilate in rice samples was 4.71 μg/g. This concentration was below reported threshold values that irritate birds. In North Dakota we selected 6 pairs of sunflower fields used by foraging blackbirds. We randomly selected 1 field from each pair for 2 aerial applications of Bird Shield at the label-recommended rate ~1 week apart. The remaining 6 fields served as controls. Daily bird counts, starting the first day of application and continuing for 5–7 days after the second application, showed similar numbers of blackbirds within treated and control fields (P = 0.964). We observed no difference in sunflower damage within treated and control fields (P = 0.172) prior and subsequent to the treatment. Bird Shield was not effective for repelling blackbirds from ripening rice and sunflower fields

Stroke genetics informs drug discovery and risk prediction across ancestries

Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries

Evaluation of Registered Sunflower Insecticides as Candidate Blackbird Repellents

Blackbird damage to ripening sunflower is forcing some growers to plant alternative, albeit less profitable, crops. Currently, only Bird Shield® (a.i., methyl anthranilate) is registered as a bird repellent on ripening sunflower. However, field experiments with Bird Shield showed no consistent differences in damage levels between treated and untreated plots. During September and October 2003, we screened five insecticide formulations for feeding repellency using individually caged red-winged blackbirds. The tested insecticides are registered and currently available for use on ripening sunflower. They were Asana® XL, Baythroid® 2, Lorsban®-4E, Scout X-Tra®, and Warrior® T

Bird Damage to Corn and Sunflower in North Dakota

The last comprehensive field surveys of bird damage to sunflower in North Dakota were conducted in 1979 and 1980. Average economic damage across years was slightly over US $5.0 million. Sunflower prices have appreciably increased since these monetary losses were calculated. As corn acreages in North Dakota have increased, so have complaints from growers about blackbird damage to corn. Quantitative surveys of blackbird damage to corn, however, have never been conducted in North Dakota. The goal of our multi-year study is to quantify blackbird damage to sunflower and corn crops in the Prairie Pothole Region, the principal corn and sunflower growing area in North Dakota (Fig. 1)

Comparison of Lorsban®-4E and Caffeine Aerially Sprayed on Sunflower Plots for Bird Repellency

Ripening sunflower fields in the northern Great Plains provide blackbirds with easily accessible sources of high-energy food. As many growers can attest, blackbirds can be nearly impossible to discourage from foraging in favored fields. Repellents sometimes can be effective feeding deterrents, especially if alternative foraging sites are readily available

Assessment of Bird Damage to Sunflower and Corn in North Dakota

North Dakota is the top sunflower-producing state in the United States, annually harvesting about 404,686 ha (1 million acres). Since the early 2000s, corn also has become a major crop within the state due to increases in corn prices. Blackbirds (Icteridae) can cause significant damage to both ripening corn and sunflower. The National Sunflower Association considers blackbird depredation to be a key factor in the reduction in sunflower acreage in the Prairie Pothole Region (PPR). In order to better quantify the amount of damage caused by blackbirds, we assessed blackbird damage to ripening sunflower and corn in 120 randomly selected plots during 3 growing seasons, 2008–2010. On average, damage to sunflower was more intense than damage to corn, with sunflower in the southeastern region experiencing the greatest levels of damage. Further analysis will determine possible landscape characteristics associated with this damage

Site Use of European Starlings Wintering in Central New Jersey

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 = 78% of days tracked), stayed closer during daytime wanderings (x = 2 km), and roosted onsite. In contrast, starlings in the urban-suburban mosaic showed less fidelity (x’s = 10% and 36%), wandered farther (x’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 \u3e6 km from a bait site are probably on a direct bearing between the bait site and roosting site