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Truth or Consequences, NM, United States

Wallace Z.P.,Oregon State University | Kennedy P.L.,Oregon State University | Squires J.R.,U.S. Department of Agriculture | Olson L.E.,U.S. Department of Agriculture | Oakleaf R.J.,Eagle Environmental Inc.
Journal of Wildlife Management | Year: 2016

Studies of anthropogenic impacts on wildlife may produce inconclusive or biased results if they fail to account for natural sources of variation in breeding performance and do not use probabilistic sampling at a scale functional for management. We used stratified random sampling and generalized linear mixed models to test hypotheses on relationships of daily nest survival rate (DSR) and fledgling production with anthropogenic and environmental factors that influence reproduction in the ferruginous hawk (Buteo regalis). We conducted the study across ferruginous hawk range in Wyoming, USA, 2010-2012. We performed extensive field surveys of prey, vegetation, and nest substrates, and used spatially explicit data to quantify weather, and the most widespread forms of anthropogenic infrastructure (i.e., roads, oil and gas well pads) in ferruginous hawk territories. We found strong evidence that DSR and productivity were greater for nests on anthropogenic structures (i.e., artificial nest platforms, gas condensation tanks, abandoned windmill platforms, power poles) compared to natural substrates (i.e., trees, cliffs, rock outcrops). Additionally, ferruginous hawks produced more fledglings at territories with greater shrub cover and fewer severe storms during the June brood-rearing period. Amount of oil and gas development and prey was not associated with either measure of breeding performance. Our results suggest that artificial nest platforms are an effective tool to improve breeding success of ferruginous hawks and nesting on anthropogenic structures does not constitute an ecological trap for this species. Although ferruginous hawks nested in some areas with very little vegetative cover, territories with greater amounts of shrub cover produced more fledglings. The negative impact of severe spring storms on fledgling production illustrates the importance of including future weather scenarios in management planning for this species because storms are predicted to increase in frequency and intensity as a result of climate change. Published 2015. This article is a U.S. Government work and is in the public domain in the USA. © Published 2015. This article is a U.S. Government work and is in the public domain in the USA. Source


Wallace Z.P.,Oregon State University | Wallace Z.P.,Eagle Environmental Inc. | Kennedy P.L.,Oregon State University | Squires J.R.,U.S. Department of Agriculture | And 2 more authors.
PLoS ONE | Year: 2016

Grassland and shrubland birds are declining globally due in part to anthropogenic habitat modification. Because population performance of these species is also influenced by nonanthropogenic factors, it is important to incorporate all relevant ecological drivers into demographic models.We used design-based sampling and occupancy models to test relationships of environmental factors that influence raptor demographics with re-occupancy of breeding territories by ferruginous hawks (Buteo regalis) across Wyoming, USA, 2011-2013. We also tested correlations of territory re-occupancy with oil and gas infrastructure-a leading cause of habitat modification throughout the range of this species of conservation concern. Probability of re-occupancy was not related to any covariates we investigated in 2011, had a strong negative relationship with cover of sagebrush (Artemisia spp.) in 2012, was slightly higher for territories with artificial platforms than other nest substrates in 2013, and had a positive relationship with abundance of ground squirrels (Urocitellus spp.) that was strong in 2012 and weak in 2013. Associations with roads were weak and varied by year, road-type, and scale: in 2012, re-occupancy probability had a weak positive correlation with density of roads not associated with oil and gas fields at the territory-scale; however, in 2013 re-occupancy had a very weak negative correlation with density of oil and gas field roads near nest sites (≥500 m). Although our results indicate re-occupancy of breeding territories by ferruginous hawks was compatible with densities of anthropogenic infrastructure in our study area, the lack of relationships between oil and gas well density and territory re-occupancy may have occurred because pre-treatment data were unavailable. We used probabilistic sampling at a broad spatial extent, methods to account for imperfect detection, and conducted extensive prey sampling; nonetheless, future research using before-aftercontrol-impact designs is needed to fully assess impacts of oil and gas development on ferruginous hawks. Source


Delong J.P.,Eagle Environmental Inc. | Delong J.P.,HawkWatch International Inc. | Delong J.P.,University of Nebraska - Lincoln | Cox N.S.,Rio Grande Bird Research Inc. | And 5 more authors.
Condor | Year: 2013

Prey selection of migrating raptors has been documented only rarely. Here we used a genetic approach to identify avian prey of Sharp-shinned Hawks (Accipiter striatus) migrating through central New Mexico. we identified species by comparing profiles of a section of the 16S rRNA mitochondrial gene extracted from feathers of prey of known species to profiles from feathers of prey found on the feet and beaks of migrating hawks. we also quantified prey availability along the migration route with multi-year sampling by mist net at two sites near the raptor-sampling site. Sharp-shinned Hawks took most prey species in proportion to their availability, but they took some species, particularly medium-sized species, more frequently than expected. This pattern may indicate selection for energetically rewarding prey, or the pattern also could arise from differences between our sample of potential prey and the potential prey as viewed by the hawks themselves. The co-occurrence of migrating predators and their prey suggests interesting feedbacks that likely influenced the evolution of migration strategies of both hawks and songbirds in this area. © The Cooper Ornithological Society 2013. Source


Millsap B.A.,U.S. Fish and Wildlife Service | Harmata A.R.,Montana State University | Stahlecker D.W.,Eagle Environmental Inc. | Mikesic D.G.,Navajo Nation Zoo
Journal of Raptor Research | Year: 2014

We reviewed band encounter data for Bald Eagles (Haliaeetus leucocephalus) and Golden Eagles (Aquila chrysaetos) to estimate natal dispersal distances for both species in the coterminous United States (U.S.). We filtered band recovery data to focus on individuals banded as nestlings, encountered at ages old enough to be breeding, and encountered at times of the year when they may be at or near breeding or prospective breeding sites. Our final data set included 96 Golden Eagles and 878 Bald Eagles. Distances between banding and subsequent encounter sites for both species were lognormally distributed. We employed both traditional and Bayesian methods of analysis, and obtained similar results from both approaches. Bayesian analysis of banding data suggest a median natal dispersal distance of 69.2 (95% highest density interval HDI = 63.5-73.1) km for Bald Eagles and 46.4 (HDI = 36.0-55.2) km for Golden Eagles. Median natal dispersal distance for female Bald Eagles 78.3 was (HDI = 35.4-128.6) km greater than for males; we lacked sufficient data to analyze natal dispersal distance by sex for Golden Eagles. Median Bald Eagle natal dispersal distance did not differ among eight regional populations, but there was evidence of a trend toward increasing natal dispersal distance from east to west across the coterminous U.S. Our findings are compatible with natal dispersal data in the literature for both species. The U.S. Fish and Wildlife Service uses estimated natal dispersal distance of Bald and Golden eagles to set one of the geographic scales at which the effects of permits that authorize the "take" (removal from the wild) of eagles is evaluated. Our analyses suggest that choice of a natal dispersal value in the range of the 50th-90th quantile of the distribution as an effect-area for modeling or effect-assessment for both species of eagle is reasonable. For Golden Eagles, this range is 46-175 km, and for Bald Eagles 69-346 km. © The Raptor Research Foundation, Inc. Source


Stahlecker D.W.,Eagle Environmental Inc. | MacKERROW E.P.,New Mexico Consortium | Batkin J.P.,129 West Zia Road | Foy B.R.,214 Spruce Street
Western Birds | Year: 2014

To better understand the status of the Boreal Owl (Aegolius funereus) at the southern extremity of its North American range, we conducted audio playback surveys between late July and mid-October 2012 at seven of the nine northern New Mexico locations where the species had been documented between 1987 and 1993, as well as four additional locations 10-15 km from sites of previous detections. All survey locations were in subalpine conifer forest at elevations >3000 m above sea level. In total, we called in at least 12 individuals (6 adults and 6 juveniles) at or near six of the seven historical locations and at least three adults at two new locations. Of the eight locations with confirmed Boreal Owl detections, two were in the San Juan Mountains, two were in the Jemez Mountains, and four were in the Sangre de Cristo Mountains. Recently fledged owls were seen at both San Juan Mountain sites and photo-documented at one site. Adult owls were photo-documented at the other six locations. Detection of Boreal Owls at six of seven historical locations confirmed the species' long-term residency in New Mexico's three northern mountain ranges. While Boreal Owls have likely been present in New Mexico since the Pleistocene, climate change appears likely to threaten their high-elevation habitat, particularly since more frequent and larger fires are predicted in the future as the forest dries. Source

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