Hunting Rabbits With Golden Eagles, Kazakhstan

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.
The intentional killing of Golden Eagles has been a huge conservation hurdle for the species. While illegal in most countries today, hunting, trapping and poisoning may still occur clandestinely across almost the entire range. During 1948, in Carter County, Montana, 286 Golden Eagles were shot and killed in the month of March alone. At the time $5 was offered by the Montana Fish and Game Commission for each eagle killed, a bounty initiated by pressure from sportsmen and ranchers who believed that eagles were killing large numbers of sheep and “antelopes”. Approximately 20,000 Golden Eagles were killed from light aircraft in the Southwestern United States in the 1940s, with the rate of such shooting in Texas having continued at over a thousand a year (5,000 from 1942 to 1947). In the United States, the Golden Eagle was given federally protected status in 1963. Allegedly, in 1972, over 800 Golden Eagles were shot from aircraft in Wyoming and Colorado. In Switzerland more than 100 Golden Eagles were reportedly shot each decade until the species was legally protected in 1953. In Scotland, many estate managers would pay gamekeepers to hunt down any and kill all eagle species in the 1800s and early 1900s. On one estate in Caithness, Scotland, allegedly 295 eagles (including both Golden and White-tailed Eagles) were shot and trapped from the years of 1820 to 1826. Occasionally, Golden Eagles may be caught in trap lines laid out to capture mammalian predators. Today, some authorities believe many game managers still try to deliberately destroy the contents of nests in spring or intentionally disturb the eagles during their nesting process. In a study conducted in Scotland, areas were broken down between low disturbance areas (with a low human presence and limited history of persecution), moderate areas (where minor disturbances occur, mainly unintentionally from hill-walkers or rarely intentionally by egg-collectors) or severe disturbance areas (where persecution, heavy disturbance and considerable egg-collecting is believed to still occur). In low disturbance areas, about 45% of nests failed, in moderate disturbance areas about 74% failed and in severe disturbance areas 93% of nesting attempts failed. 73 out of 147 inaccessible nesting sites in this study (50%) produced fledglings, whereas more accessible nests produced fledglings in only 21 out of 68 nests (31%). The Golden Eagle became legally protected in 1980 in Spain but the species is still regularly killed there today. In 266 Golden Eagle deaths from 1980 to 1990, 59% (157 specimens) had died from shooting or trapping and 8% (21 specimens) died from poisoning.
Poisoning, both intentional and unintentional, is perhaps the most insidious man-made threat to Golden Eagles. The usual targets of carrion-poisoning are species such as Coyotes, Red Fox and Gray Wolves, which are considered pest that threaten livestock (a charge usually vastly exaggerated by the human imagination). However, Golden Eagles are occasionally targeted as well for the same reasons. The main cause of mortality for Golden Eagles in Britain has been poisoning, with a number of 51 eagles verified to be killed by poisoning from 1980 to 2008 probably being far lower than the actual amount killed as such. A disproportionate amount of Golden Eagle poisonings in Scotland from 1981 to 2000 were linked to grouse moors (where grouse are kept for the pleasure of shooting) and were probably cases of gamekeepers deliberately poisoning eagles and foxes to keep their stock of grouse high. It is estimated that the adult survival rate is reduced by 3 to 5% in Scotland by intentional poisonings. In the 1980s, California Ground Squirrels, due to the perception among cattle rangers that they are agricultural pests, were poisoned by the anticoagulant rodenticide, Chlorophacinone. In turn, the poisonings caused Golden Eagles, as one of the major natural predator of California Ground Squirrels, to die in turn. At least 10 individuals died in 1971 from eating Thallium(I) sulfate – laced Pronghorn set out by sheep ranchers in Wyoming; despite public outcries, poisoning by sheep ranchers continued into the 1980s. In the 20th century, organochloride and heavy metal poisonings were also commonplace, but these have declined thanks to tighter regulations on pollution. In southern Idaho, 10 out of 17 Golden Eagles examined were found to have had exposure to lead. As a whole, the Golden Eagle is less susceptible than most raptors to organochlorine pesticides because of mammal-feeding habits, as opposed to predominantly bird-eating species like Peregrine Falcons and fish-eating species like Bald Eagles, both of which had huge population declines in the 20th century due to the use of pesticides like DDT . Eggs from Golden Eagle nests that were collected after 1946 in North America had shell thicknesses similar to (of less than a 10% difference) those collected in earlier years. However, in Scotland egg shell thickness did decrease by around 10% from 1951 to 1965. A dead Golden Eagle collected on the island of Lewis had the highest concentration of organochlorine known from a modern bird in Scotland. The higher effects of organochlorines in Scotland may be due to the fact that birds there consume a relatively high quantity of seabirds, as opposed to North America, where this practice is rare.