Golden eagles usually mate for life. A breeding pair is formed in a courtship display. This courtship includes undulating displays by both in the pair, with the male bird picking up a piece of rock and dropping it only to enter into a steep dive and catch it in mid-air, repeating the maneuver 3 or more times. The female takes a clump of earth and drops and catches it in the same fashion. Small sticks may also be used in this display. Compared to the bald eagle, golden eagles do not repeat courtship displays annually (which is believed to strengthen pair bonds) and rarely engage in talon-locking downward spirals.Cornell University. Bna.birds.cornell.edu. Retrieved on 2012–08–22.
Golden eagles typically build several eyries within their territory and use them alternately for several years. Their nesting areas are characterized by the extreme regularity of the nest spacing. In 9 studies of annual nest spacing, the average minimum distance between nests range from apart in Norway to apart in Switzerland.Bergo, G. 1984. Population size, spacing and age structure of Golden Eagles Aquila chrysaetos (L.) in Handaland, West Norway. Fauna Norvegica, Series C, Cindus: 7: 106–108. Nests in Scotland may found at anywhere from 10 to 65 pairs per , with an average of over 20 pairs found per area.
In much of continental Europe, densities of less than 10 pairs per are typical. In the United States different areas had from 10 to more than 20 pairs on average per . Wyoming had the greatest densities of breeding golden eagles of any complied study, though numbers were comparable to western Scotland as there were an average of just over 20 pairs per , with greatest estimated densities of possibly 125 per area. In Wyoming, the distance between nests ranged from , averaging . In the wooded peatlands of Sweden and Belarus, a maximum of 5 pairs appear to occur per . In Quebec, the distance between nests ranged from . In the Snake River canyon in Idaho, nests are apart, while two other nearby studies in Idaho found the average distance were and , respectively. The nesting density for a breeding population near Livermore, California, and the Altamont Pass Wind Farm is among the highest in the world for golden eagles, with at least 44 pairs in 1997, a density of one pair per . Due to the consistency of use by golden eagle pairs, population densities change generally happens only quite gradually.
Nest requirements
Golden eagles seem to prefer to build their nests on cliffs where they are available. Nests are generally located at around half of the maximum elevation of the surrounding land. This height preference may be related to having the ability to transport heavy prey downhill rather than uphill. A massive benefit to cliff nests is that they tend to be largely or entirely inaccessible to mammalian predators on foot (including humans). In Spain, studies revealed the preferred sites of golden eagle nests were on inaccessible cliffs at a great distance from tracks, roads and villages. 95.6% of 410 nests built in Scotland were on cliffs. Similarly, in Bulgaria, Italy, Switzerland, France and Yugoslavia, more than 90% of golden eagles nests were located on cliffs.Mathieu, R. & Choisy, J.P. (1982). "L'Aigle Royal Aquila chrysaetos dans les Alpes Meridonales Francaises de 1964 a 1980". Essai sur la distribution, les effectifs, le regime alimentaire et la reproduction. Bievre, 4: 1–32.Fasce, P. & Fasce, L. (1984). L’Aquila Reale in Talia: Ecologia e Conservazione. Lega Italian Porotezione Uccelli, Serie Scientifica, Parma. Greek nests are mostly on cliff ledges, but in the Evros District, nearly 30% of the population nests on trees, mostly pines.Handrinos, G., & Akriotis, T. (1997). The birds of Greece. Christopher Helm Ltd., A & C Black, London. Rural, arid areas of Europe such as the Iberian peninsula, Provence in France and the Apennines in Italy, fire combined with pastoral activity has maintained suitable nesting sites at relatively low elevations. In the Spanish Pyrenees, however, nest were found at up to in elevation. 80% of nests in Spain are on rocky cliffs, the remaining 20% being in trees. Rocky, low mountainous areas are used for nesting in Israel. All known nests in Iraq have been on cliffs. In Norway, the mean elevation of nests was . Throughout the Baltic States and eastern Fennoscandia, golden eagles inhabit relatively flat wooded peatlands and, here, the local golden eagles generally nest in trees. Tree nests are known to be used exclusively in Estonia and Belarus. On the island of Gotland in Sweden, the trees holding nests had an average trunk diameter of more than and an average height of with the nest being located at an average of above the ground. Cliff nests are preferred as nesting sites in most of North America.Baglien, J. W. 1975. Biology and habitat requirements of the nesting Golden Eagle in southwestern Montana. Master's Thesis. Montana State University, Bozeman. In Northern California, tree nests were apparently mainly used.Hunt, W. G., Jackman, R.E. Brown, T. L., Gilardi, J. G., Driscoll, D. E. & Culp, L. 1995. A pilot Golden Eagle population study in the Altamont Pass Wind Resource Area, California. Predatory Bird Research Group, University of California, Santa Cruz. In the forested landscape of western Washington, where large clear cut areas having provided suitable hunting habitat, golden eagles almost exclusively nest in Douglas firs (Pseudotsuga menziesii) at forest edge. There, the nest-hosting tree were with the nest being located at a height of . In a study of 170 eyries in the state of Wyoming, 111 were on deciduous trees, 36 in ponderosa pines (Pinus ponderosa) and 23 on sides of buttes or bluffs along river. Cottonwood and willow trees dominated the trees selected, averaging in diameter and in height. In Wyoming, the tree nests are often the tallest tree in a stand and are in a small or isolated woodlot less than away from large clearcuts or fields. Ground nest are rare in Scotland but not uncommon in the United States, especially in arid areas of states such as Nevada, North Dakota and Wyoming. Ground nests typically occur on lofty hills which have little ground vegetation and require adults to have a good protective all-around view.Seibert, D. J., R. J. Oakleaf, J. M. Laughlin, and J. L. Page. (1976). Nesting ecology of Golden Eagles in Elko County, Nevada. Technical Note 281. U.S. Department of the Interior, Bureau of Land Management, Denver, CO.Ward, J. P., L. R. Hanebury, and R. L. Phillips. (1983). Raptor inventory of coal areas in western North Dakota. Report prepared for U.S. Fish & Wildlife Service, Bismarck Field Office, Bismarck, ND. Other exceptional nest sites known in North America have included river banks,Phillips, R. L., A. H. Wheeler, J. M. Lockhart, T. P. McEneaney, and N. C. Forrester. (1990). Nesting ecology of Golden Eagles and other raptors in southeastern Montana and northern Wyoming. Technical Report 26. U.S. Department of the Interior, Fish & Wildlife Service, Washington, D.C. abandoned gold dredges and electrical transmission towers.
Both heavy rain and excessive heat can potentially kill nestlings, so golden eagles often place their nests to suit the local climate. In northern areas, such as Alaska, sun exposure (southern orientation) may help nesting success, while those nesting in hot, lowland Utah and arid regions of Israel were mainly northerly facing to keep the nest out of the hot glare of the sun.Bahat, O. (1989). Aspects in the ecology and biodynamics of the Golden Eagle (Aquila chrysaetos homeyeri) in the arid regions of Israel. Master's Thesis. Tel Aviv Univ. Tel Aviv, Israel. Almost all established breeding golden eagles build more than one nest. A typical range of nests per pair is between 2 and 5. In Sweden, pairs on average built 2.4 of them. There is an average of about 4.5 nests per pair in Scotland. In Idaho, there was an average of 6 nests per pair. In more exceptional cases, up to 13 nests have built by a single pair in Scotland and up to 12 by a single pair in Idaho. Some pairs utilize alternate nest sites every year, others apparently rarely use alternate nests. Some golden eagle pairs may not use a nest for up to six years after its construction. Golden eagle nests usually consist of heavy tree branches, upholstered with grass when in use. As is typical of a large accipitrid, the nests of golden eagles are very large. However, they are smaller on average than bald eagle nests. In Kazakhstan, golden eagle nests were similar in size to white-tailed eagle nests. In the Isle of Mull in Scotland, however, white-tailed eagle nests were slightly larger as they used thicker, larger sticks lined with grass that make a more massive nest than the isle's golden eagle nests, which used thinner sticks or heather and lined their nest with woodrush. In Arizona, golden eagle nests averaged in length (ranging from ), in width (range of ), and in height (range of ). The sticks used in the Arizona nests ranged up to a length of , a diameter of and a weight of . Nests in Scotland average in length, in width and in depth. In Washington state, tree nests averaged in depth and in diameter. Nests in Sweden averaged in length, in width and in depth. Nests in Kazakhstan averaged in length, in diameter and in depth. The nest of the golden eagle may weigh well over .Kulves, H. Havornens Haliaeetus albicilla albicilla L ekogi pa Aland. Skrifer utgiuna av Alands Kultus tense Lnr 9. As the eagles use a nest repeatedly, they repair their nests whenever necessary and enlarge them during each use. If the eyrie is situated on a tree, supporting tree branches may break because of the weight of the nest. The largest known golden eagle nest, located on a steep river butte along Sun River in Montana, was deep and in width. Certain other animals—too small to be of interest to the huge raptor—sometimes use the nest as shelter or even as a nest for themselves, for the incidental protection offered. This has mainly been associated with Eurasian wren (Troglodytes troglodytes) in Europe, though has also been recorded remarkably with ring ouzels (Turdus torquatus) and pine martens, both of which have been recorded as prey for golden eagles elsewhere in Europe. In a similar situation, little curlews in northeastern Siberia apparently gain some protection from predators by nesting close to golden eagle eyries. In each case, the natural predators of these animals are just the right size for golden eagle prey, and therefore avoid active eyries. Related species such as eastern imperial and Bonelli’s eagles have been observed to nest in abandoned golden eagle nests, as well as distantly related or unrelated raptors including white-tailed eagles, lammergeiers, gyrfalcons and peregrine falcons.Ratcliffe, D.A. (1990). Bird life of mountains and upland. University Press, Cambridge.
Mating and egg-laying