HawkWatch International Inc.

Salt Lake City, UT, United States

HawkWatch International Inc.

Salt Lake City, UT, United States

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Robinson B.W.,Boise State University | Paprocki N.,Peregrine Fund | Paprocki N.,HawkWatch International Inc. | Anderson D.L.,Peregrine Fund | Bechard M.J.,Boise State University
Wilson Journal of Ornithology | Year: 2017

Nest collapse has been documented in many bird species, with little discussion of adult behavior following collapse. We present evidence of a partial collapse of a Gyrfalcon (Falco rusticolus) nest during the nestling period and the subsequent adult response. A nest camera captured the nest collapse and showed one adult Gyrfalcon holding a live nestling in its beak before leaving the nest. Later, we found the surviving nestling alive in an alternate nest 5 m from the original nest, presumably transported there by the adult. We believe this is the first report of an adult Gyrfalcon moving a nestling to a new location following nest disturbance. We place this observation into a context of Gyrfalcon nesting behavior described in published sources. The continued use of nest cameras may provide additional documentation and insight into this behavior and its prevalence in birds.


HawkWatch International and the University of Utah are partnering on two studies in the Horn of Africa: a new effort studying raptor migration over the Bab-el-Mandeb Strait in Djibouti, and a continuation of vulture extinction studies based in Ethiopia. Evan Buechley, a postdoctoral researcher at the University of Utah, will manage the two projects in conjunction with HawkWatch International scientists and University of Utah Biology Professor Cagan Sekercioglu. "Vultures are the world's most threatened group of birds and yet they provide critical ecological functions and benefit humans by consuming carrion and reducing disease," said Buechley. "There is growing evidence around the world that when vultures decline, populations of disease vectors like feral dogs, rats, and flies increase, leading to more human disease burden, particularly in developing countries. Ethiopia has the most diverse and abundant vulture community in the world--with seven species, all of which are threatened with extinction--and is a critically important location to target conservation actions and study how vulture declines impact ecosystems and human health." Buechley is surveying vultures throughout Ethiopia to estimate populations and distributions, track movements and key foraging and breeding sites, and to evaluate the human repercussions of vulture declines. More information can be found at http://www. . One of the critical sites to target conservation for vultures and other soaring birds is the Bab-el-Mandeb Strait, which is located between Yemen on the Arabian Peninsula and Djibouti in the Horn of Africa. An estimated 1.5 million diurnal raptors of at least 31 species, including eight species at risk of extinction, migrate each year between Eurasia and Africa. The geographic bottleneck is considered one of the largest, if not the largest, concentration of migrating birds in the world. However, very limited and no full-season data exist for this site to fully illustrate the ecological importance of the area. In order to better understand the diversity and magnitude of bird migrations over the Bab-el-Mandeb Strait in Africa, the group will conduct the first full-season bird migration count this fall (2017). HawkWatch International coordinates the largest raptor migration network in North America and helped launch the Veracruz, Mexico River of Raptors Project in 1991, which is now regarded as a world-renowned raptor monitoring, education, and conservation initiative. More information can be found at http://www. . "HawkWatch International has over 30 years of experience conducting raptor migration research and we are excited to be the first group to fully study the fall raptor flight at Bab-el-Mandeb and see how it compares to other major flyways around the globe," said Dave Oleyar, Ph.D., HawkWatch International Senior Scientist. Publications on these projects are anticipated for 2018-2019. HawkWatch International (HWI) has been in operation for more than 30 years and was the first organization to start long-term raptor migration monitoring in western North America. The data collected through their various research projects helps guide raptor conservation plans. HWI conducts public outreach and school education programs with live birds that reach more than 40,000 people annually, and coordinate more than 50 volunteers who help participate in citizen science research and education programs. More information can be found on their website at http://www. .


Paprocki N.,Boise State University | Paprocki N.,HawkWatch International Inc. | Glenn N.F.,Boise State University | Atkinson E.C.,Northwest College | And 2 more authors.
Journal of Wildlife Management | Year: 2015

There is widespread evidence that multiple drivers of global change, such as habitat degradation, invasive species, and climate change, are influencing wildlife. Understanding how these drivers interact with and affect species may be difficult because outcomes depend on the magnitude and duration of environmental change and the life history of the organism. In addition, various environmental drivers may be evaluated and managed at different spatial scales. We used a historical dataset from 1991 to 1994 and current information from 2010 to 2012 to examine whether occupancy patterns of wintering raptors were consistent with regional changes in distribution or habitat conditions within a local management unit, the Morley Nelson Snake River Birds of Prey National Conservation Area (NCA). We predicted that if local populations reflected regional shifts, then rates of raptor occupancy within the NCA would be higher compared to historical estimates and birds would use different habitats compared to historical use. Alternatively, if local populations were determined by habitat conditions, then we predicted that occupancy rate of raptors within the NCA would be lower compared to historical estimates and current habitat use would be consistent with historical use. Results support the hypothesis that northward distributional shifts influenced wintering raptor populations in southwest Idaho to a greater extent than local habitat conditions. Wintering raptors had higher occupancy rates in 2010-2012 compared to 1991-1994, whereas invasive grasses have increased and native shrubs have decreased suggesting that habitat suitability for raptors has declined over time. On the species level, changes in habitat use were associated with greater increases in occupancy rates in 2010-2012 compared to 1991-1994. Organisms flexible in their habitat use may be better able to respond to continental forces driving distribution shifts. Conversely, habitat or prey specialists may be poorly equipped to handle such rapid, large-scale global change. Further, Grinnellian niche models predicting species response to change by mapping current habitat use to forecasted vegetation maps should consider plasticity in habitat use and changes in the cost-benefits of life-history strategies. © 2015 The Wildlife Society.


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.


Freeman E.D.,Brigham Young University | Sharp T.R.,Brigham Young University | Larsen R.T.,Brigham Young University | Knight R.N.,U.S. Army | And 2 more authors.
PLoS ONE | Year: 2014

Exotic invasive species can directly and indirectly influence natural ecological communities. Cheatgrass (Bromus tectorum) is non-native to the western United States and has invaded large areas of the Great Basin. Changes to the structure and composition of plant communities invaded by cheatgrass likely have effects at higher trophic levels. As a keystone guild in North American deserts, granivorous small mammals drive and maintain plant diversity. Our objective was to assess potential effects of invasion by cheatgrass on small-mammal communities. We sampled small-mammal and plant communities at 70 sites (Great Basin, Utah). We assessed abundance and diversity of the small-mammal community, diversity of the plant community, and the percentage of cheatgrass cover and shrub species. Abundance and diversity of the small-mammal community decreased with increasing abundance of cheatgrass. Similarly, cover of cheatgrass remained a significant predictor of small-mammal abundance even after accounting for the loss of the shrub layer and plant diversity, suggesting that there are direct and indirect effects of cheatgrass. The change in the small-mammal communities associated with invasion of cheatgrass likely has effects through higher and lower trophic levels and has the potential to cause major changes in ecosystem structure and function.


PubMed | U.S. Army, HawkWatch International Inc. and Brigham Young University
Type: Journal Article | Journal: PloS one | Year: 2014

Exotic invasive species can directly and indirectly influence natural ecological communities. Cheatgrass (Bromus tectorum) is non-native to the western United States and has invaded large areas of the Great Basin. Changes to the structure and composition of plant communities invaded by cheatgrass likely have effects at higher trophic levels. As a keystone guild in North American deserts, granivorous small mammals drive and maintain plant diversity. Our objective was to assess potential effects of invasion by cheatgrass on small-mammal communities. We sampled small-mammal and plant communities at 70 sites (Great Basin, Utah). We assessed abundance and diversity of the small-mammal community, diversity of the plant community, and the percentage of cheatgrass cover and shrub species. Abundance and diversity of the small-mammal community decreased with increasing abundance of cheatgrass. Similarly, cover of cheatgrass remained a significant predictor of small-mammal abundance even after accounting for the loss of the shrub layer and plant diversity, suggesting that there are direct and indirect effects of cheatgrass. The change in the small-mammal communities associated with invasion of cheatgrass likely has effects through higher and lower trophic levels and has the potential to cause major changes in ecosystem structure and function.


Inzunza E.R.,Pronatura Veracruz | Inzunza E.R.,Dartmouth College | Goodrich L.J.,Acopian Center for Conservation Learning | Hoffman S.W.,HawkWatch International Inc.
Bird Conservation International | Year: 2010

Continental-scale bird population estimates are used as a decision-support tool in conservation plans. The calculation of these estimates includes the use of density values and survey data from one or multiple sources extrapolated to the geographic scale of interest. In this paper, we use migration count data from a migration monitoring project in Veracruz, Mexico, to revise existing North American population estimates of seven species of waterbirds, New World vultures, and diurnal raptors. In two species of waterbirds, we suggest that existing estimates are low and propose a mechanism to correct these figures. In the remaining five cases, we also determine present estimates are low, but use our data to provide new continental-scale values. We discuss the importance of refining population estimates using data from a diverse suite of field methods as a means to overcome the limitations of the single-survey-based estimates. Copyright © BirdLife International 2009.


Smith J.P.,HawkWatch International Inc. | Smith J.P.,983 University Avenue | De Long J.P.,HawkWatch International Inc. | De Long J.P.,Yale University | And 4 more authors.
Journal of Raptor Research | Year: 2012

Knowledge of the migration geography of Flammulated Owls (Otus flammeolus) is limited. We combined data from multiple studies in the western United States to evaluate patterns of variation in Flammulated Owl morphometrics. Measurements from autumn migration study sites in New Mexico, Nevada, and Idaho followed a geographic cline from southeast to northwest across the species' range. Our objectives were to: (1) describe age- and sex-specific variation in the morphometrics of Flammulated Owls captured at the three sites, and (2) discuss the implications of this variation for understanding the species' migration geography. Based on a hierarchical series of factorial two-way ANOVAs, we discovered significant overall sex-specific differences in wing chord, exposed culmen length, and hallux length, and a consistent pattern of site-specific differences for most measurements. Most measurements increased from southeast to northwest, consistent with previous data on clinal variation in the species. Evidence of significant variation in the morphometrics of owls captured at the three migration sites suggests little longitudinal mixing of migrants in the region. © 2012 The Raptor Research Foundation, Inc.


Slater S.J.,HawkWatch International Inc. | Smith J.P.,HawkWatch International Inc.
Journal of Wildlife Management | Year: 2010

In sagebrushsteppe and other open habitats, power lines can provide perches for raptors and other birds in areas where few natural perches previously existed, with potential negative impacts for nearby prey species, such as greater sage-grouse (Centrocercus urophasianus). Between September 2006 and August 2007, we used driving surveys, behavioral-observation surveys, and prey-remains surveys to assess the ability of perch-deterrent devices to minimize raptor and common raven (Corvus corax) activity on a recently constructed transmission line in southwestern Wyoming. All survey methods demonstrated that activity was significantly lower on the deterrent line compared with a nearby control line; however, deterrent devices did not entirely prevent perching. Considering use of cross-arms or pole-tops alone, we sighted 42 raptors and ravens on the deterrent line and 551 on the control line during 192 driving surveys of each line. Golden eagles (Aquila chrysaetos) and ravens were the species most commonly observed successfully overcoming deterrent devices. Smaller rough-legged hawks (Buteo lagopus) regularly avoided deterrents by perching on conductors (i.e., wires). We documented much off-line activity near both survey lines and suggest that fewer birds near the deterrent line likely reflected reduced availability of nearby alternate perches. There was a pronounced winter peak in on-line perch use, with the effect more evident on the control line. Behavior surveys corroborated our driving-survey results but were otherwise unproductive. During 549 prey-remains surveys of each line, we found 9 single and 60 grouped prey items near deterrent-line poles, compared with 277 single and 467 grouped items near control-line poles. We observed few sage-grouse in the study area but did witness a likely power linerelated, raptor-caused sage-grouse mortality. Overall, our results suggest that perch-deterrent devices can reduce raptor and raven activity on power-line structures, but to determine their utility on entire power-line segments, we suggest managers consider 1) what level of reduction in perch activity is worth the cost, and 2) the availability of alternate perches in the surrounding landscape. © 2010 The Wildlife Society.


Farmer C.J.,Acopian Center for Conservation Learning | Smith J.P.,HawkWatch International Inc.
Journal of Raptor Research | Year: 2010

Long-term monitoring is important for ensuring effective conservation of raptor populations. Raptors also can serve as indicators of biodiversity and ecosystem condition. Therefore, effective monitoring of raptor populations yields the added benefit of helping to evaluate the status of ecosystems. Spring counts of migrating raptors at concentration points may contribute to these goals, particularly by providing insight into the vital demographic rates underlying population trends. Although much is known about the monitoring value of autumn migration counts in North America, little research has addressed the value of spring counts. We compared counts at seven spring watchsites to those at seven autumn watchsites matched by region (Southwest, Great Lakes, and Northeast) to assess the value of spring counts for population monitoring. Our analyses suggested that population indexes derived from spring migration counts provided estimates of population change that differed overall from autumn migration counts in the same region. The concordance of spring and autumn trends was higher in the Southwest and Northeast than in the Great Lakes region, suggesting greater variation in the seasonal representation of populations in the latter region. The average precision of spring trend estimates was better than for autumn estimates in the same region in two of three regions, and the estimated rates of change often were lower in spring. Spring counts enhanced the ability to estimate population trends for species that are less common in autumn counts, including the Rough-legged Hawk (Buteo lagopus) and Red-shouldered Hawk (B. lineatus). To realize fully the value of spring counts, we recommend the establishment of additional spring watchsites in areas that concentrate migrants in autumn, but do so to a lesser extent in spring, as well as additional research to define the populations sampled by autumn and spring counts. © 2010 The Raptor Research Foundation, Inc.

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