Hunting Rabbits With Golden Eagles, Kazakhstan

In North America the situation is not as dramatic. It appears the greatest density of Golden Eagles anywhere in the world occurs in the Western United States and Western Canada. In total, the contiguous Western United States may hold up to 30,000 individual Golden Eagles, with a total of 70,000 to 100,000 individuals estimated across all of North America. One estimate of the number of breeding pairs in the contiguous Western United States that excluded California, South Dakota, Montana and Oregon was 9,387. The state with the largest known winter count of Golden Eagles is Montana with 13,138, followed by Wyoming with 10,072, Colorado with 7,081 and Utah with 5,993. Wyoming had the highest estimated set of breeding pairs 3,381-4,174, followed by 1,800 in Utah, 1,200 in Nevada and California and Idaho both with around 500 pairs (notably, Montana was not included in these particular studies, although the breeding population must include well over a thousand pair there). In 6 out of 8 Canadian providences where Golden Eagles breed, over 10,000 birds were observed in breeding bird surveys. In 1981, it was estimated that there were 63,242 wintering individual Golden Eagles in the 16 Western United States (excluding Alaska). However, there has still been a noticeable decline in some areas.
• Threats
In modern times, almost all threats to Golden Eagles are attributable, directly or indirectly, to human activities. In fact, all Aquila eagles in Eurasia face the same human-sourced threats as the Golden Eagle: habitat change, persecution, poisoning (often directed at other species) and collisions with man-made objects. Certainly the most widespread unintentional threat to Golden Eagles by humans is urbanization and human-population growth which have made areas historically used by eagles unsuitable both in terms of habitat and prey availability. Habitat destruction in North American had, by the late 19th century, already driven Golden Eagles from some regions they used to inhabit. In Southern California and the Colorado Front Range, this has been proved via long-term population and habitat surveys. In Western China, the main threats to Golden Eagles are land development, the use of pesticides and apparent regular captures for falconry. Fires since 1980 have caused large-scale losses of shrubs and jackrabbit habitat in areas used by eagles throughout the Intermountain West of North America. Wildfires that burned more 40,000 hectares of scrublands between 1981 and 1987 in the Morley Nelson Snake River Birds of Prey National Conservation Area affected nesting populations adversely. Nesting success at burned territories in Snake River Canyon declined after major fires. Abandoned burned territories have been subsumed by neighboring pairs, resulting in a decreased number of nesting pairs. In a few cases, mankind has accidentally benefited Golden Eagles by logging previously heavily wooded areas. This has been recorded in the 1800s and 1900s in the Appalachian Mountains of the Eastern United States, where reforestation has now made the habitat unsuitable for nesting eagles, and in Washington state, which still holds breeding eagles in desolate areas that have been logged. Afforestation, the commercial planting of non-native woodland, is a serious issue in Scotland, with the largest amount of it occurring in southwestern Scotland, especially in Argyll. During afforestation, the land is ploughed and in excess of 2,500 seedlings are planted per hectare, mainly with exotic conifers including Sitka spruce (Picea sitchensis) and lodgepole pine (Pinus contorta). The woodland canopy closes and ground vegetation dies, making these dark and gloomy places until harvesting in 40 to 50 years. More than 50% of land in Scotland at an elevation of 200–600 m (660–2,000 ft) has been planted as such. Afforestation requires removal of sheep and the fencing out or shooting deer, both important sources of carrion for Golden Eagles. Foraging areas of Golden Eagles have been confirmed to not include afforested areas.
Death by collisions with man-made structures and objects can be serious local issue. Electrocution or collision with power lines has become an increasingly significant cause of mortality since the early 20th century. Apparently, juveniles birds are more susceptible than adults, being generally less cautious and physically adept. Due to attempts to perch on or by flying into power lines, a total of 134 and 115 Golden Eagles were killed by power lines in the western United States in 1972 and ’73, with a peak of 66 in Utah in 1972. Today, Golden Eagles still regularly meet their demise due to power lines in the United States and the species was considered the bird-of-prey in North America most likely to killed by them. 266 examined Golden Eagle deaths from 1980 to 1990 in Spain showed that 14 of the deaths (5%) were from electrocution and 57 (21%) were from wire collision. Compared to the United States and Spain, in some other parts of the range such as Scotland and Scandinavia, electrocutions and wire-collisions are rare due to fewer high power-poles in the desolate areas that the Golden Eagles occupy. Controversially, the US Fish and Wildlife Service has permitted that a "wind-farmer" in central Oregon could legally cause the incidental killing of Golden Eagles by large wind turbines. Such turbines have set up as an alternative source of energy but are often fatal for high-flying birds such as raptors. Wind turbine blades appear to move slowly from a distance but at close range move so quickly as to appear a nearly invisible blur. It is estimated that up to 70 Golden Eagles may be killed locally by turbines each year in west-central California, almost all of them being juveniles as opposed to adults which tend to remain on their home ranges that largely occur outside of the wind farm area. There are mounting concerns of the effect of wind turbines in Europe as well, since construction of new ones are increasing in Scotland and Spain. Collisions with automobiles rarely claim Golden Eagle lives, though instances of this can increase in desolate areas during winter, when road-side prey or carrion may attract the eagles. In the Diablo Range, California, 5% of 61 radio-tagged birds died from vehicle collisions. Where disturbance is regular, breeding failure for Golden Eagles is significantly more frequent. This was certainly inferred in the 1982 Scottish breeding bird survey when disturbances were heavy in the Highlands. Sheep farmers and egg-collectors are the leading cause of disturbances at the nests. Recreation, forest management and development projects such as road construction, mining or power generation are other potential sources of disturbances. When disturbed by humans at the nest, the parents frequently leave their nest for a period of up to two hours, reduced provisioning rates, endangered eggs or young to predation, as well as overheating, chilling or desiccation. Human intrusion within 750–1,500 m (2,460–4,900 ft) of nests can cause disturbance. Nesting success was found to be reduced in Norway during years where the Easter holidays fell early, apparently due to the volume of vacationers in the countryside in these years during the pivotal early stages of nesting. During a study in Wrangell – St. Elias National Park and Preserve of Alaska, experimenters camped within 400 m (1,300 ft) of active nests, which led to reduced food delivery and nest attendance by the parents, then at 800 m (2,600 ft), at which distance the disturbance of nesting behavior seemed to decrease considerably. The topography of the landscape and location of the nest can affect how closely the nest can be approached without disturbance. Mining and various types of energy development occur in eagle nesting and wintering habitat. The practice of surface coal mining threatens the limited nesting sites in Wyoming. In the Italian Apennines, high levels of nesting failures have been contributed directly to disturbance, thanks to increased tourism in remote mountain areas, construction of new roads and mining. Aggressive behavior by Golden Eagles due to a human presence near the nest is considered exceptional and usually only result in minor injuries if any, as a particularly bold eagle may rarely attempt to dissuade a human trespasser. Golden Eagles are somewhat sensitive to human disturbance even while not nesting. Experimental studies showed that pedestrians, which caused flushing at 105–390 m (344–1,280 ft), were more likely to cause wintering Golden Eagles in Colorado to flush than vehicles, at 14–190 m (46–620 ft). This study showed that Golden Eagles were more sensitive to human disturbance during winter than several other raptor species, including Bald Eagles.