Winter Ecology of Common Ravens in Southern Wyoming and the Effects of Raven Removal on Greater Sage-Grouse Populations

My research focused on common raven (Corvus corax; hereafter raven) winter ecology and removal, and how raven removal aids Greater sage-grouse (Centrocerus urophasiansu; hereafter sage-grouse) populations. Raven winter ecology in the western US has not been described in detail. I researched raven use of landfills for foraging and raven use of anthropogenic structures for roosting, as well as dispersal of ravens in the spring. In all 22% of radio-marked ravens (n=73) used landfills during the day, and 68%(n=73) roosted at anthropogenic roost sites during the evening. Correlations between landfill and roost counts of ravens were stronger (0.4\u3err20 km. In the spring, ravens dispersed, on average, 38 km from landfills where they were caught. Large congregations of ravens at a few sites in winter may present opportunities to initiate raven population reduction methods to alleviate later problems. I analyzed raven survival and behaviour when USDA/APHIS Wildlife Services (WS) removed ravens using DRC-1339 during winter months. The number of ravens killed annually was 7-34% of the local population. Ravens did not avoid landfills, yet they switched roosts more frequently after an application of the toxicant. Raven removal improves sage-grouse nest success; however, data were not available to examine how raven removal improves sage-grouse abundance. I analyzed changes in raven density with regard to WS removal, and then related these changes with changes in sage-grouse lek counts the following year. Raven densities decreased by 50% from 2008-2014 where WS conducted removal programs. Sage-grouse lek counts improved in area where WS lowered raven abundance, in comparison to areas farther away, during the latter half of the study (2013-2015), when WS removal efforts intensified. Thereafter, a 10% decline in raven abundance was associated with a 2% increase in sage-grouse lek counts. Overall, ravens in souther Wyoming used anthropogenic resources during the winter, and removal of ravens at these locations, combined with removal in the spring, minimally impacted raven populations annually and was associated with increases in sage-grouse abundance

Winter Ecology and Spring Dispersal of Common Ravens in Wyoming

Numbers of Common Ravens (Corvus corax) have increased in western North America, and these high abundances are the source of problems throughout the species\u27 range. Little is known about the winter ecology of ravens. We studied a population of ravens in Wyoming during the winters of 2013–2015; our goals were to examine use of landfills for foraging and use of anthropogenic structures for roosting, as well as dispersal patterns of ravens from these landfills in the spring. On average, 22% of radio-marked ravens foraged at landfills on a given day and 68% roosted at anthropogenic sites (e.g. on buildings or underneath bridges) each night. Daily counts at an anthropogenic roost and at the nearest landfill were positively correlated. Decreased temperatures increased raven use of landfills and anthropogenic roost sites. In the spring, radio-marked and GPS-marked ravens (n = 56) dispersed an average of 38 km from the landfills where they were captured. Use of landfills and anthropogenic roost sites in the winter likely contributes to an increase in the number of ravens by improving survival and body condition of breeding-age birds. In the spring, ravens moved outward from these locations, and the area most susceptible to raven damage was localized within a 40-km radius of where ravens wintered

Common Ravens

Damage Management Methods for Common Ravens Type of Control -- Available Management Options Exclusion -- Often ineffective or impractical Fertility Control -- None available Frightening Devices -- Effigies • Pyrotechnics and propane cannons • Lasers and flashing lights Habitat Modification -- Bale and bury garbage • Install dumpsters with secure lids • Remove or bury dead livestock • Remove abandoned houses, sheds, and barns to eliminate nesting structures Nest Treatment -- Allowed with proper Federal and State permits; Egg oiling or addling and nest destruction Repellents -- Methiocarb (EPA Reg. No. 56228-33) • Methyl anthranilate (food-grade grape flavoring agent) Shooting -- Allowed with proper Federal and State permits; Requires use of non-toxic/non-lead ammunition Toxicants -- Compound DRC-1339 Concentrate (EPA Reg. No. 56228-29, 56228-63); May only be used by USDA Wildlife Services employees or people working under their supervision. Trapping -- Allowed with proper Federal and State permits; Live-trapping with modified soft-catch #1½, #2 or #3 coil-spring trap

Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world

Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic. Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality. Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States. Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis. Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection

Common Ravens

Damage Management Methods for Common Ravens Type of Control -- Available Management Options Exclusion -- Often ineffective or impractical Fertility Control -- None available Frightening Devices -- Effigies • Pyrotechnics and propane cannons • Lasers and flashing lights Habitat Modification -- Bale and bury garbage • Install dumpsters with secure lids • Remove or bury dead livestock • Remove abandoned houses, sheds, and barns to eliminate nesting structures Nest Treatment -- Allowed with proper Federal and State permits; Egg oiling or addling and nest destruction Repellents -- Methiocarb (EPA Reg. No. 56228-33) • Methyl anthranilate (food-grade grape flavoring agent) Shooting -- Allowed with proper Federal and State permits; Requires use of non-toxic/non-lead ammunition Toxicants -- Compound DRC-1339 Concentrate (EPA Reg. No. 56228-29, 56228-63); May only be used by USDA Wildlife Services employees or people working under their supervision. Trapping -- Allowed with proper Federal and State permits; Live-trapping with modified soft-catch #1½, #2 or #3 coil-spring trap

Effectiveness of the Toxicant DRC-1339 in Reducing Populations of Common Ravens in Wyoming

Common raven (Corvus corax) populations have increased several-fold in the western United States during the past century; these birds cause problems when they kill new-borne lambs and calves and depredate nests of greater sage-grouse (Centrocercus urophasianus). The toxicant DRC-1339 is used by U.S. Department of Agriculture/Animal and Plant Health Inspection Service Wildlife Services to manage common raven populations and reduce the severity of these problems, but it is difficult to determine how many ravens are killed by an application because carcasses are rarely found. We examined the effectiveness of DRC-1339 applications for preventative control of ravens at 3 landfills and 5 nearby roosts in Wyoming, USA, from 2013 through 2015. Wildlife Services removed 23%, 34%, and 7% of the radiomarked sample of ravens in southwestern Wyoming during 2013, 2014, and 2015, respectively, according to Kaplan–Meier survival estimates. During the 3 winters, 235 of 240 raven carcasses that we collected died from DRC-1339 poisoning. The following year, raven fecundity and immigration had offset most, but not all, of the mortality produced by the DRC-1339 program. Raven population estimates declined 9% from the 2013 winter to the 2014 winter and 12% from the 2014 winter to the 2015 winter, based on telemetry data and roost counts. Ravens did not avoid landfills after they were treated with DRC-1339 probably because few ravens died there. Estimated mortality rates from DRC-1339 applications based on carcass counts underestimated the actual rates by 79% and landfill counts of ravens underestimated it by 49%. Roost count estimates of mortality were within 15% of the actual mortality rate. © 2016 The Wildlife Society

Adult Sage‐grouse Numbers Rise Following Raven Removal or an Increase in Precipitation

Weather and lethal control of common ravens (Corvus corax; hereafter, ravens) can affect the nesting success of greater sage‐grouse (Centrocercus urophasianus), but implications of these effects in terms of the subsequent size of the breeding population are unknown. We used generalized linear mixed models to assess the effects of weather and raven removal on sage‐grouse lek trends within Wyoming, USA, from 2008 to 2015 by counting male sage‐grouse at leks within 8 circular sites each with a 16‐km diameter and 4 circular sites with a 24‐km diameter. We compared sites where U.S. Department of Agriculture/Animal and Plant Health Inspection Service Wildlife Services (WS) removed ravens the previous year (removal sites) with other areas where they did not (nonremoval sites). Wildlife Services intensified removal efforts beginning in 2012; and, 1‐year later, WS started removing ravens to benefit sage‐grouse (i.e., raven removal was conducted near prime nesting habitat for sage‐grouse). Raven densities decreased 50% from 2008 to 2014 in removal sites, but increased in nonremoval sites by 42% based on 6,255 point counts conducted at 1,154 random locations. We hypothesized that adult sage‐grouse numbers would be greater at the 30 leks in removal sites compared with the 28 leks in nonremoval sites. The top AICc model showed that the percent change in raven numbers, minimum temperatures during the brood‐period, and precipitation during the brood‐period were informative predictors of lek counts during the next year. Fewer ravens, cooler temperatures, and more precipitation were associated with more adult males on leks. Cooler temperatures and more precipitation probably increased the survival of sage‐grouse chicks indirectly by increasing their forage, while a decrease in raven numbers may have increased nest success rates. This study was one of the first to demonstrate a positive correlation between these variables and changes in the number of adult male sage‐grouse on leks in the subsequent year