Eagle Nests Research Articles

Flushing Responses of Golden Eagles (Aquila chrysaetos) In Response To Recreation

ABSTRACT.— Disturbance because of human activity, including recreation on wildlands, can affect bird behavior which in turn can reduce breeding success, an important consideration for species of management concern. We observed Golden Eagles (Aquila chrysaetos) during the breeding season to determine whether the probability of flushing was affected by the type of recreationist, distance to encounter, eagle nest attendance, or date. We monitored eagles in 23 nesting territories from distant (600–1,200 m) observation points and recorded recreation activity within 1,200 m of eagles in the Owyhee Front of southwestern Idaho. In most (86%, n = 270) encounters, eagles did not flush in response to recreationists; however, whether an eagle flushed was affected by the type of recreationist and whether an eagle was at or away from the nest. Eagles were 60 times more likely to flush in response to recreationists that stopped a motor vehicle and transitioned to walking (11 of 17 passes) and 4.5 times more likely to fl...

Waterbirds of Arunachal Pradesh with Special Reference to High Altitude Rivers and Wetlands

Arunachal Pradesh, a state of India is one of the world's most difficult mountainous regions, extremely precipitous and highly jagged, measuring an area of about 83,500 km2. The NE India has the highest avian diversity in India, with around 900 species (Choudhury 2000; 2001a). Many of these are threatened. Of the 15 Critically Endangered species of bird listed in India, seven have been recorded in this region. Of the 18 endangered species of bird in India, 12 have been recorded in the North-east. Of the 53 vulnerable species of birds in India, 33 have been recorded in the North-east. Overall, 60% of the threatened birds in the country have been recorded in the North-east. Surveys were carried in Namdapha Tiger Reserve and National Park, Pakke Tiger Reserve, Eagle Nest and Sessa Wildlife Sanctuaries, Anini district of Arunachal Pradesh (part of Dihang-Dibang Biosphere Reserve, Mehao Wildlife Sanctuary and Tawang district of Arunachal Pradesh in 2005, 2006, 2009, 2013, 2014 and 2015 to find out the waterbird diversity with special reference to White-bellied Heron Ardea insignis.

An assessment of tree availability as a possible cause of population declines in scavenging raptors

Lack of suitable nesting trees is an increasingly common issue for avian conservation given rampant habitat and tree destruction around the world. In the African savannah, habitat loss and particularly tree damage caused by elephants have been suggested as possible factors in the decline of large bird species. Given the recent declines of vultures and other scavenging raptors, it is critical to understand if nest availability is a limiting factor for these threatened populations. Loss of woodland, partially due to elephant populations, has been reported for the Mara‐Serengeti ecosystem. Data on characteristics of trees used for nesting were collected for white‐backed, lappet‐faced, white‐headed vulture, and tawny eagle nests in Masai Mara National Reserve, Kenya. Nest tree characteristics were compared with the distribution of a random subsample of trees to assess nest preferences and determine suitability of available trees. Nearest neighbor distances were estimated as well as availability of preferred nesting trees to determine if tree availability is a limiting factor for tree‐nesting vultures. Tree availability was found to greatly exceed nesting needs for African vultures and tawny eagles. We thus conclude that on a landscape scale, tree availability is not a limiting factor for any of the species considered here (white‐backed, lappet‐faced, white‐headed vultures and tawny eagles).

Photo Observations Geraldine Harris – Wedge-tailed Eagle nest with two young

Photo Observations Geraldine Harris – Wedge-tailed Eagle nest with two young

Nest‐site characteristics, breeding success and competitive interactions between two recently sympatric apex predators

An influential period in avian life‐cycles is the annual breeding season, when competition over suitable nesting sites and territories is a key factor that can determine fitness and distribution, especially for species that are highly selective in their nesting habitats. We analysed nest‐site characteristics, breeding success and competitive interactions between two apex predator populations. Whereas the Short‐toed Eagle Circaetus gallicus has nested in the Judean Foothills (Israel) for a long time, the Long‐legged Buzzard Buteo rufinus has only invaded the nesting habitat of the Short‐toed Eagle during their breeding season in the last two decades. These two recently sympatric species have similar nesting ecology and frequently use the same nests. They are therefore expected to compete over nesting sites and territories. We analysed interspecific interactions between these two species by combining information from comprehensive observational, experimental, GIS analysis and remote sensing data, deriving 65 variables to characterize the nest‐sites used and the breeding success in 381 breeding attempts over four consecutive breeding seasons. To assess interspecific and intraspecific territorial behaviour and aggressiveness, stuffed Long‐legged Buzzards and Short‐toed Eagles were presented close to nests. Nest‐site characteristics overlapped substantially between species, and Long‐legged Buzzards occupied 21% of all Short‐toed Eagle nests. Intraspecific aggression rates among Long‐legged Buzzards were higher than their interspecific aggression rates with Short‐toed Eagles and also higher than intraspecific aggression among Short‐toed Eagles. Long‐legged Buzzard and Short‐toed Eagle breeding densities (1.59 ± 0.11 and 2.96 ± 0.11 pairs per 10 km2, respectively) are likely to be the highest across their respective breeding distributions, with a maximum productivity of 0.96 ± 0.01 and 0.56 ± 0.05 (young fledged/breeding pair) for Long‐legged Buzzard and Short‐toed Eagle, respectively. Intraspecific interactions among both species play an important role in determining their breeding success and the spatial distribution of nesting sites. Our results suggest that interspecific competition over nesting sites and territories between both species, and the potential dominance of Long‐legged Buzzard, has both direct and indirect impacts on the spatial and demographic distribution of Short‐toed Eagles due to the recent establishment of Long‐legged Buzzard territories in the Judean breeding area.

Ecological analysis of faunal complexes western region of Ukraine

The paper present result of research on the ecological analysis of faunal complexes of the Western region of Ukraine. The animal world of this region is distinct from the other zones. The variety of the landscape determines the variety of the animal world. Ukrainian Carpathians are one of the last area in continental Europe to support viable populations of large carnivores. Established that the endemic to the Western region of Ukraine are carpathian squirrel, carpathian newt, spotted salamander, golden eagle. The most rare animals are: bison, brown bear, lynx, golden eagle, white-tailed eagle, common muskrat, european gopher, forest cat. The Brown bear population in the Ukrainian Carpathian reach approximately 150–200 individuals. The lynx population is officially estimated to be about 350–400 individuals. In Ukraine there are about 300 species of bison. Only 33 nimals left in Ukrainian Skolivsky Beskydy. We can also find noble deer, roe, wolf, moose, hare, squirrel, wild cats and pigs, hamster, field mouse and so on. Some fur animals (nutria, mink, silvery-black fox, muskrat, stone marten, badger) were brought in from afar, and they acclimatized themselves well to the environment. The diverse habitats in the Carpathians support a wide variety of bird species, using the region for nesting, migrating and wintering. Overall, more than 300 species are found in the Zakarpattia. Bird life includes golden eagles and black wood peckers, carrion eagle, black griffons, white-tailed eagle, sparrow, titmouse, owls, gulls, partridge. The golden eagle nests in all the major mountains of Europe, in the Ukrainian Carpathians – 10–15 pairs. The rivers and lakes are home to ducks, geese, storks, swans and cranes. Rivers, lakes and manmade reservoirs of the Western region of Ukraine are inhabited with perch, bream, zander, pike, crucian carp, sazan, carp, sturgeon, trout. Among reptiles, one can come upon vipers, grass-snakes, and lizards. The spotted salamander and three types of tritons are entered in the Red Book. It was found that the most Red species are in Zakarpattia (168) and the least – in Rivne (85 species). The main factors of influence on the biodiversity of the Western region of Ukrain are identified. It is shown that poaching, anthropogenic and recreational activities have the most influence on faunal complex studied region.

The First Black-and-Chestnut Eagle (Spizaetus isidori) Nest Discovered in Argentina Reveals Potential Human–Predator Conflicts

Fil: Araoz, Rodrigo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigaciones y Transferencia de Jujuy. Universidad Nacional de Jujuy. Centro de Investigaciones y Transferencia de Jujuy; Argentina. Universidad Nacional de Tucuman. Instituto de Ecologia Regional. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Tucuman. Instituto de Ecologia Regional.; Argentina

Improving bald eagle nest monitoring with a second spring survey

Failure to account for observation error can cause bias in estimators of variables important for wildlife management and conservation, such as abundance, occupancy, and species composition. Therefore, long-term monitoring programs need to evaluate sources of bias to ensure that objectives of the program can be met. Although trend estimation is possible using biased estimators, population status, and management decisions can be sensitive to random and systematic heterogeneity in the observation process. For example, standard methods used to monitor reproductive attempts at bald eagle (Haliaeetus leucocephalus) nests fail to quantify observation error. We used bald eagle nest surveys from 3 national parks in Alaska, USA, to examine their ability to accurately estimate nesting attempts and hypothesized that our ability to perfectly observe nesting activity was related to the timing of the survey relative to peak nest attendance by eagles. We therefore, developed 3 scenarios that evaluated our ability to correctly identify nesting status metrics: peak nesting remained unchanged (observed variation scenario), reduced ability to predict peak nest attendance (high heterogeneity scenario), and peak nest attendance occurred earlier than the survey window (low detection scenario). Eagle nest attendance was consistently underestimated using naive estimators, but productivity (predicted no. chicks/nesting attempt) was not affected by imperfect detection. All scenarios showed that using replicate observations to model imperfect detection corrected estimator bias for nest attendance and improved the estimator precision for both metrics. Our study demonstrates that imperfect observation of bald eagle nesting activity using standard methods results in estimator bias and reduced precision if not corrected. Further, our simulations show that changes in observation conditions can affect estimator bias and precision, which is an important consideration for long-term monitoring programs. Therefore, formally modeling imperfect detection should be completed for monitoring programs designed to use nesting status to inform management or conservation decisions. © 2017 The Wildlife Society.

Semi‐automated detection of eagle nests: an application of very high‐resolution image data and advanced image analyses to wildlife surveys

AbstractVery high‐resolution (VHR) image data, including from unmanned aerial vehicle (UAV) platforms, are increasingly acquired for wildlife surveys. Animals or structures they build (e.g. nests) can be photointerpreted from these images, however, automated detection is required for more efficient surveys. We developed semi‐automated analyses to map white‐bellied sea eagle (Haliaeetus leucogaster) nests in VHR aerial photographs of the Houtman Abrolhos Islands, Western Australia, an important breeding site for many seabird species. Nest detection is complicated by high environmental heterogeneity at the scale of nests (~1–2 m), the presence of many features that resemble nests and the variability of nest size, shape and context. Finally, the rarity of nests limits the availability of training data. These challenges are not unique to wildlife surveys and we show how they can be overcome by an innovative integration of object‐based image analyses (OBIA) and the powerful machine learning one‐class classifier Maxent. Maxent classifications using features characterizing object texture, geometry and neighborhood, along with limited object color information, successfully identified over 90% of high quality nests (most weathered and unusually shaped nests were also detected, but at a slightly lower rate) and labeled <2% of objects as candidate nests. Although this overestimates the occurrence of nests, the results can be visually screened to rule out all but the most likely nests in a process that is simpler and more efficient than manual photointerpretation of the full image. Our study shows that semi‐automated image analyses for wildlife surveys are achievable. Furthermore, the developed strategies have broad relevance to image processing applications that seek to detect rare features differing only subtly from a heterogeneous background, including remote sensing of archeological remains. We also highlight solutions to maximize the use of imperfect or uncalibrated image data, such as some UAV‐based imagery and the growing body of VHR imagery available in Google Earth and other virtual globes.

Common Raven (Corvus corax) kleptoparasitism at a Golden Eagle (Aquila chyrsaetos) nest in southern Nevada

ABSTRACT.— The Common Raven (Corvus corax) is a ubiquitous species in the Mojave Desert of southern Nevada and California. From 5 to 24 May 2014, using remote trail cameras, we observed ravens repeatedly kleptoparasitizing food resources from the nest of a pair of Golden Eagles (Aquila chyrsaetos) in the Spring Mountains of southern Nevada. The ravens fed on nine (30%) of the 30 prey items delivered to the nest during the chick rearing period. Kleptoparasitic behavior by the ravens decreased as the eagle nestling matured to seven weeks of age, suggesting a narrow temporal window in which ravens can successfully engage in kleptoparasitic behavior at eagle nests. The observation of kleptoparasitism by Common Ravens at the nest suggests potential risks to young Golden Eagles from Common Ravens.

Quadcopter applications for wildlife monitoring

Recently, Unmanned Aerial Vehicle (UAV) had been use as an instrument for wildlife research. Most of that, using an airplane type which need space for runaway. Copter is UAV type that can fly at canopy space and do not need runaway. The research aims are to examine quadcopter application for wildlife monitoring, measure the accuracy of data generated and determine effective, efficient and appropriate technical recommendation in accordance with the ethics of wildlife photography. Flight trials with a camera 12 - 24 MP at altitude ranges from 50-200 m above ground level (agl), producing aerial photographs with spatial resolution of 0.85 – 4.79 cm/pixel. Aerial photos quality depends on the type and setting of camera, vibration damper system, flight altitude and punctuality of the shooting. For wildlife monitoring the copter is recommended to take off at least 300 m from the target, and flies at 50 - 100 m agl with flight speed of 5 - 7 m/sec on fine weather. Quadcopter presence with a distance more than 30 m from White-bellied Sea Eagles (Haliaeetus leucogaster) nest and Proboscis Monkey (Nasalis larvatus) did not cause negative response. Quadcopter application should pay attention to the behaviour and characteristic of wildlife.

The Bald Eagle Nests: The United States Role in State-Building: Germany, Kosovo, and Iraq

The Bald Eagle Nests: The United States Role in State-Building: Germany, Kosovo, and Iraq

Nigerian football: a case of social media and sport insider information

The increasing use of information and communication technology, particularly social media, has extended the reach of football discourse beyond traditional boundaries determined by in-groups of administrators, other football stakeholders and legacy media gatekeepers. Privileged football information refers to football information that would otherwise be restricted to insiders and may include ongoing, real-time or proposed decisions or events by football administrators, players, and other key football stakeholders. The relative anonymity of social media provides football administrators, insider journalists, player agents and others who have access to privileged information, with a communication channel to clandestinely disseminate the information. The paper explores possible motivation of an insider, Muyiwalawal, who posted insider information on Eagles Nest, a discussion board for Nigerian football fans, before and during the 2014 World Cup. We also report on the impact of the information on members of Eagles Nest. We find that the insider in this case is motivated by identity as an insider, prestige and member appreciation. Additionally, we find that persuasive impact of the information narrative is dependent on recipient's interpretation of narrative fidelity.

Nonmotorized recreation and motorized recreation in shrub-steppe habitats affects behavior and reproduction of golden eagles (Aquila chrysaetos).

Different forms of outdoor recreation have different spatiotemporal activity patterns that may have interactive or cumulative effects on wildlife through human disturbance, physical habitat change, or both. In western North America, shrub‐steppe habitats near urban areas are popular sites for motorized recreation and nonmotorized recreation and can provide important habitat for protected species, including golden eagles. Our objective was to determine whether recreation use (i.e., number of recreationists) or recreation features (e.g., trails or campsites) predicted golden eagle territory occupancy, egg‐laying, or the probability a breeding attempt resulted in ≥1 offspring (nest survival). We monitored egg‐laying, hatching and fledging success, eagle behavior, and recreation activity within 23 eagle territories near Boise, Idaho, USA. Territories with more off‐road vehicle (ORV) use were less likely to be occupied than territories with less ORV use (β = −1.6, 85% CI: −2.8 to −0.8). At occupied territories, early season pedestrian use (β = −1.6, 85% CI: −3.8 to −0.2) and other nonmotorized use (β = −3.6, 85% CI: −10.7 to −0.3) reduced the probability of egg‐laying. At territories where eagles laid eggs, short, interval‐specific peaks in ORV use were associated with decreased nest survival (β = −0.5, 85% CI: −0.8 to −0.2). Pedestrians, who often arrived near eagle nests via motorized vehicles, were associated with reduced nest attendance (β = −11.9, 85% CI: −19.2 to −4.5), an important predictor of nest survival. Multiple forms of recreation may have cumulative effects on local populations by reducing occupancy at otherwise suitable territories, decreasing breeding attempts, and causing nesting failure. Seasonal no‐stopping zones for motorized vehicles may be an alternative to trail closures for managing disturbance. This study demonstrates the importance of considering human disturbance across different parts of the annual cycle, particularly where multiple forms of recreation have varying spatiotemporal use patterns that create human–wildlife interactions.

Changes in Diurnal Cliff-Nesting Raptor Occurrence on the Ungalik River in Western Alaska: 1977, 1979, and 2008

Diurnal cliff-nesting raptors were inventoried on the Ungalik River, Alaska, in 1977 and 1979. In 2008 we resurveyed the drainage, replicating the techniques used in 1979. The density of nesting raptors during the late nesting season has doubled in the past three decades, from six occupied territories detected in 1977 and four in 1979 to 12 in 2008. A single Peregrine Falcon (Falco peregrinus) was sighted during aerial surveys in 1977, and a pair of Peregrine Falcons was detected during a boat survey in 1979; however, nesting by these birds was not confirmed. In contrast, we detected five occupied Peregrine Falcon territories along the Ungalik River in 2008. Other changes in cliff-nesting raptor occurrence included a decrease in occupied Gyrfalcon (Falco rusticolus) territories from four in 1977 to one in 1979 and two in 2008, a decrease in Rough-legged Hawk (Buteo lagopus) nests from one in 1979 (none in 1977) to none in 2008, and increases in Golden Eagle (Aquila chrysaetos) nests, from two in 1977 and 1979 to five in 2008. Changes in the number of nests of cliff-nesting raptors in this small population may have resulted, in part, from natural variation associated with changes in weather or prey abundance. However, it is likely that the increase in nesting Peregrine Falcons is related to global population recovery. Our data indicate that factors other than available nesting sites limit cliff-nesting raptor numbers along the Ungalik River. Spatial analysis indicated that cliff-nesting raptor nests were most often on hills or cliffs that face away from the coast, which is the source of most storms.

The Eagle's Nest in the Horn of Africa: US Military Strategic Deployment in Djibouti

Djibouti is the only country in the world in which US, French, German, Italian, Spanish, and Japanese military forces are stationed simultaneously; China will soon have a presence there as well. The US military deployment in Djibouti has shifted from a soft military presence to an arrangement of significant strategic import, and from a small outpost to a large garrison in the past two decades. The internal dynamics of the US deployment are geopolitical, as the US presence facilitates the carrying out of its strategies regarding antiterrorism, anti-proliferation, the protection of energy investments, and anti-piracy. The external dynamics of the US deployment are geo-economic: the government of Djibouti, as the host nation, reaps economic windfalls from the US presence in this strategically located country. Given that the United States has failed since 2008 to persuade any country on the continent to host AFRICOM, the base in Djibouti is likely to remain the only one in East Africa. Djibouti may be part of a pattern whereby some small African nations, such as São Tomé and Príncipe, collect revenue through the provision of military bases to big powers.

Use of Noninvasive Genetics to Assess Nest and Space Use by White-tailed Eagles

Abstract Movement and space use are important components of animal interactions with the environment. However, for hard-to-monitor raptor species, there are substantial gaps in our understanding of these key determinants. We used noninvasive genetic tools to evaluate the details of space use over a 3-yr period by White-tailed Eagles (Haliaeetus albicilla) at the Naurzum Zapovednik in northern Kazakhstan. We genotyped, at 10 microsatellite markers and one mitochondrial marker, 859 eagle feathers and assigned naturally shed feathers to individuals. We identified 124 White-tailed Eagles, including both members of 5–10 pairs per year, and were able to monitor birds across years. Distances between eagle nests and hunting perches were always greater than nearest neighbor distances, eagles never used the closest available hunting perch, and hunting perches were always shared with other eagles. When eagles switched nests between years, the nests they chose were almost always well outside the space that theory pre...

Гнездование рыбного филина в гнезде белоплечего орлана, Магаданская область, Россия

In 2015 one Steller’s Sea Eagle nest was occupied by a Blakiston’s Fish Owl, the first record of which came from the Nature Reserve Inspector, E.A. Stepanov, who, on May 17, noted the pair of fish owls near a Steller’s Sea Eagle nest on the western bank of the Chelomdja River, 3 km downstream from the Moldot ranger’s station. On that date one of the owls was sitting in the nest, and another was sitting in a tree nearby the nest. On May 26, E. Stepanov observed the owls in the same position. We observed the nest on 20 and 21 June 2015, and saw one large Blakiston’s Fish Owl chick in the nest; no adults were noted. Inspector A. Stepanov saw the chick in the nest on June 23, and an adult in a nearby. Magadan State Reserve Inspector A. Akhanov reported that the nest was empty and no adults were seen on June 25.

Результаты мониторинга популяции степного орла в Забайкальском крае в 2015 г., Россия

Ornithological survey was carried out in July–August 2015 in steppe areas of Russian part of Dauria (Trans-Baikal Territory, or Zabaikalsky Krai) in the frames of monitoring the population of the Steppe Eagle ( Aquila nipalensis ). Research was conducted at 13 study sites in 10 administrative districts of the region, including 11 study sites which were surveyed repeatedly (after first survey in 2010). A total of 57 nesting territories with 95 nest structures were identified in 2010 and 2015 together. Additionally adult birds were recorded in 24 points but nests were not found. In 2015 we checked 35 of 40 nesting territories that were identified in 2010 while other 35 nesting territories (including 17 ones with nest structures) are localized for the first time. A total of 27 nestlings and fledglings (1.4±0.5 nestlings and fledglings produced per successful nest) in 19 nests were recorded during the 2015 survey. In 2010, the status of Steppe Eagle in Dauria was assessed as extremely unfavorable. The main population characteristics had not essentially changed to 2015. Actual average nesting density slightly increased but still is close to 1 pair per 100 km 2 . An average distance between neighbor active nests in Dauria is unexpectedly long as comparing with such figures in other regions of the Steppe Eagle nesting. More than a half of potentially available nesting territories remain unoccupied, and the share of unoccupied nesting territories almost did not change. The productivity of successful nests (average brood size) remains low – on average 1.4±0.5 fledglings and nestlings per successful nest in 2015. The negative factors such as power lines that are dangerous for birds and steppe wild fires are still acting. More than 40 % of all the nesting territories were affected by fires in 2015; the nest structures were completely burnt at 17% of the known nesting territories visited in 2015. Meanwhile the following positive trends can be noted: the population number increased more than by 30 % (estimating 219 vs. 152 breeding pairs); breeding efficiency increased by 24 %; the breeding efficiency was 0.93 fledglings per 1 breeding pair in 2015 vs. 0.55 in 2010, which represents a 60 % increase; the share of successful pairs of potential population size increased from 20 % to 32 %; the share of subadults (under the age of 4–5 years) in the breeding pairs was reduced almost twofold – from 76 % to 35 % what means the mortality of adults significantly reduced. The population trend of the Steppe Eagle in Dauria should be considered in the framework of significant land use and climate changes that had a place and continue in the region.

Nesting Pair Density and Abundance of Ferruginous Hawks (Buteo regalis) and Golden Eagles (Aquila chrysaetos) from Aerial Surveys in Wyoming

Abstract Raptors that inhabit sagebrush steppe and grassland ecosystems in the western United States may be threatened by continued loss and modification of their habitat due to energy development, conversion to agriculture, and human encroachment. Actions to protect these species are hampered by a lack of reliable data on such basic information as population size and density. We estimated density and abundance of nesting pairs of Ferruginous Hawks (Buteo regalis) and Golden Eagles (Aquila chrysaetos) in sagebrush steppe and grassland regions of Wyoming, based on aerial line transect surveys of randomly selected townships. In 2010 and 2011, we surveyed 99 townships and located 62 occupied Ferruginous Hawk nests and 36 occupied Golden Eagle nests. We used distance sampling to estimate a nesting pair density of 94.7 km2 per pair (95% CI: 69.9–139.8 km2) for Ferruginous Hawks, and 165.9 km2 per pair (95% CI: 126.8–230.8 km2) for Golden Eagles. Our estimates were similar to or lower than those from other stud...