Monitoring of the Steppe Eagle Breeding Group in the Aktobe Region (Kazakhstan) in 2018–2023
Authors:   NGO Naurzum, Bragin A.E. , Katzner T. ,   Forest & Rangeland Ecosystem Science Center U.S. Geological Survey, Bragin E.A. ,   Naurzum State Nature Reserve
Published: October 2023

Steppe Eagle (Aquila nipalensis) is classified as Endangered (EN) species according to IUCN criteria and is included in the Red Books of the Republic of Kazakhstan and the Russian Federation. Since the 1950s, Steppe Eagle population have been rapidly declining throughout its habitat. It is a key species for Steppe biotopes and can be used as an indicator for the state of steppe ecosystems. In 2018 we examined an area of the Aktobe region with the aim of tracking Steppe Eagles with satellite transmitters. Surveyed area is located at watershed of the Or and Irgiz rivers and is limited by the Or floodplain in the west, Lake Belkopa in the east, the M-32 highway in the north, and the Mugodzhar foothills in the south. It is a hilly plain, cut throughout by a small number of seasonal rivers, outcrops of quartzite, granite, and, less commonly, hematite, located on the hilltops. Surveyed area was about 600 km2. The steppe is represented by black wormwood communities here, giving way to grassy forbs in depressions. Two villages on the outskirts of the area and several farms, the number of which is growing every year, apply anthropogenic pressure in the area. In addition, temporary shelters and cabins are installed here, cattle grazing and haymaking are carried out, there are several power lines. There are several kurgan burials, old Kazakh cemeteries, and detached mazars located on hills in the area. Surveys were carried out for five seasons in the area, in 2018–2019 and 2021–2023. In 2021, monitoring was carried out on June 20, in the remaining four years – in the first half of July, right before the start of fledglings’ departure. During the last visit to the area in 2018, 64 Steppe Eagle nests were identified, of which 23 (35.9%) were active; in two of them, clutches died for unknown reasons. 21 successful nests produced 41 nestlings. The number of nestlings in broods varied from one to three, averaging 1.95±0.13 nestlings per successful nest. In 2019, the number of detected nests increased to 75, of which 38 were not in use for two or more years. There were 11 active nests. Almost twofold increase in the number of active nests in comparison with 2018 we attribute to the state of a food supply, namely the epizootic in Little Ground Squirrel population. In one of active nests the clutch died. Ten successful nests produced 21 nestlings, one of which had a broken wing at the time of the visit, a result of fox or, more likely, a dog attack. The number of nestlings per nest was 1–3, the average number of nestlings per successful nest was 2.1±0.23. In 2021, the total number of nests have increased to 98. In 2021, the total number of nests has increased to 98, out of them 21 were active. In one active nest nestlings died at the age of 10–15 days, which was probably due to disturbance caused by activity on a new farm located 700 m from the nest. Successful nests produced 39 nestlings, 1–3 per nest, with an average of 1.95±0.15. In 2022, a total of 108 nests were located, of which 57 have not been used for two years or more. There were 17 active nests, in two of them the clutch died, in one – nestlings. Out of nests with failed breeding, two were located less than a kilometer away from the farms, and one (with abandoned clutch) was located 50 m away from a shelter. 14 successful nests produced 25 nestlings, 1–4 per nest, with an average of 1.79±0.24. In 2023, 127 nests were located, of which 73 had not been in use for two years or more. Four nests were new, yet without any signs of egg laying or incubation. 27 nests were active, in six of them breeding ended with a clutch death, and in one – with death of an adult bird. Four nests with failed clutches were located near farms. We attribute the greatly increased share of failed breeding in comparison with past years to a combination of two factors: an abnormally cold spring with strong winds and snowfalls and an increase in human presence. 20 successful nests produced 34 nestlings, 1–3 per nest, with an average of 1.7±0.16. In the surveyed area nests are concentrated in several clusters on elevations, clearly avoiding depressions with tall herbaceous plants. Within the cluster nests are distributed fairly evenly. Distances between neighboring active nests in clusters ranged from 400 m to 2.5 km, averaging 1.5 km. Nests were located on rock outcrops at small hilltops or slopes of larger hills. Only 1–2 nests were found on bushes and trees annually, and only once was an active nest located on an old mazar made of hematite blocks. During the observations, gaps appeared between the nests, with new farms as the centers, the number of which increased from one to four. Despite significant fluctuations attributed to the state of food supply, survey area has a tendency for a gradual decline in the number of Steppe Eagle. This is due to both general decline in global population of the species and the increase in local anthropogenic pressure. An increase of human presence in territories abandoned in the 1990s can be seen in Kazakhstan in all areas suitable for grazing. We consider it necessary to continue monitoring the state of Steppe Eagle breeding territories in Kazakhstan and to introduce molecular genetic analysis, which provides more accurate assessment of demographic processes.