The spotted eagle is a large bird of prey. Like all typical eagles, it belongs to the hawk family. Typical eagles are often grouped with buzzards, sea eagles, and other members of the family, but they seem to be less distinct from the more subtle hawks than thought. Spotted eagles live mainly in patchy forest areas, meadows, fields and natural pastures, often in humid environments.
Origin of the species and description
Based on a 1997-2001 analysis of the mitochondrial sequences of Greater Spotted Eagles in Estonia, the researchers found much greater genetic diversity in this species than in a larger sample of Lesser Spotted Eagles.
They suggested that colonization of northern Europe occurred earlier in this species than in the crested eagle, which lives east of the greater spotted eagle. It has also been suggested that it prefers nesting in birches and pines that extend further north, rather than in broad-leaved trees, as is the case with lesser spotted eagles.
Video: Spotted Eagle
Maximum lifespan for spotted eagles — from 20 to 25 years old. Threats include local habitat conditions, abundance of prey, deliberate poisoning, and hunting. Average annual mortality is 35% per year for juveniles, 20% for immature birds and 5% for adults. Because of these threats, their average lifespan is typically 8 to 10 years.
Spotted Eagles — top predators in their ecosystem. They help control populations of small mammals and other small vertebrates. Spotted eagles can be useful to farmers because they eat rabbits and other rodents, small birds, insects and reptiles that threaten crops.
Appearance and Features
There are these types of spotted eagles:
- greater spotted eagle;
- lesser spotted eagle.
Greater and lesser spotted eagles look the same. Their wingspan is 130-180 cm. The plumage of adults is completely brown, while young birds are more or less covered with light spots. Outwardly, spotted eagles resemble the common buzzard, and from afar, the species can only be distinguished by their silhouette while flying: while the spotted eagle usually lowers its wingtips when it glides, the common buzzard usually holds them.
Looking at the birds at closer distances, the common buzzard usually has a predominantly white plumage, while spotted eagles are usually uniformly brown and have only a few white patches on their feathers. On even closer inspection, the observer will find that the feet of the spotted eagle are feathered to the toes, while the feet of the common buzzard are devoid of feathers.
Based on plumage symbols, including the prohibition of wings, we can easily rule out the Steppe Eagle, which has few and sparsely spaced stripes on each feather compared to spotted eagles.
The Lesser Spotted Eagle has a lighter head and wings compared to the usually darker Greater Spotted Eagle. It has a uniform and dense stripe along the length of its primaries, while the Greater Spotted Eagle has a much thinner stripe that is mostly limited to the middle of its primaries, leaving the tips and base of the feathers unmarked. As with other large eagles, it is possible to determine the age of this bird based on plumage markings (for example, only juveniles have the characteristic white patches that give it its common name).
It is rather difficult to tell the difference between the two spotted eagle species. Usually the greater spotted eagle is darker, larger and stronger than the lesser spotted eagle. It is also difficult to distinguish between them, because they form mixed pairs that produce hybrids.
Where does the spotted eagle live?
The spotted eagle breeds in large moist deciduous forests bordering wet meadows, marshes and other wetlands up to 1000 m. In Asia, it is found in taiga forests, wetland forest-steppe, wetlands and agricultural lands. Forest areas are preferable for them in winter. Migrating and wintering birds are sometimes found in more open and often drier habitats.
At their wintering ground in Malaysia, these eagles live alone or in small groups. Although they forage individually, several individuals can peacefully wait in a loose group around the field on which the tractor is working. This species also frequents garbage dumps.
In Bangladesh, the birds are most commonly found along major rivers and estuaries, where they can be observed flying overhead or roosting on the ground on river banks or river islands. In Israel, during the winter in low Mediterranean climatic conditions, birds can be found in valleys and humid open areas, mainly in cultivated fields and fish ponds near tree patches, mainly eucalyptus.
In Russia, they are found in forests, forest steppes, river valleys, pine forests, small steppe forests in humid areas and forest swamps. In Kazakhstan — in coastal forests, lowland steppes and forest steppes.
What does the spotted eagle eat?
Typically, spotted eagles hunt their prey in unprotected pastures, as well as swamps, fields and other open landscapes, and often even forests. Their hunting grounds, as a rule, are located near nests located at a distance of up to 1-2 km from the nesting site.
The spotted eagle usually hunts its prey in flight or by chasing it in trees located near the edges of the forest and other higher places (lone trees, hayfields, electric poles). Sometimes a bird receives prey that walks on the ground. The spotted eagle actively hunts its prey by flying or walking in case of scarcity of food resources, but in case of rich resources, it chooses to pursue prey.
Their main diet consists of:
- small mammals hare-sized, such as voles;
- amphibians, such as frogs;
- birds (including waterfowl);
- reptiles, such as snakes, lizards;
- small fish;
- larger insects.
In many areas the main prey of spotted eagle — northern water vole (Arvicola terrestris). Birds wintering in Malaysia fed on carrion, mainly dead rats, which were poisoned in agricultural areas. This species participates in kleptoparasitism from each other and from other species of predators.
Character and lifestyle features
Spotted eagles are migratory birds. They winter in the Middle East, Southern Europe, Central and South Africa. Migration to and from Africa occurs mainly through the Bosphorus, the Middle East and the Nile Valley. Greater Spotted Eagle arrives back from wintering at the end of March, while Lesser Spotted Eagles may be seen somewhat later — in the beginning of April. Both species migrate in September, but single birds can still be seen in October.
Fun fact: Spotted eagles are usually found alone or in pairs, but they congregate near large food sources and migrate in flocks.
Spotted eagles live in a mosaic landscape where forests alternate with meadows, pastures, fields, river valleys and swamps. They are more adapted to life on agricultural land than their larger relatives. Birds usually build their own nests and populate them continuously in later years, especially if left undisturbed. Sometimes they use old nests of other birds of prey (common buzzard, northern hawk) or black stork. Sometimes a pair of spotted eagles has several nests, which are used alternately in different years.
Interesting fact: Spotted eagles are very territorial. They will fight other birds that get too close to their nests. Males are more aggressive than females and tend to only show territorial behavior towards other males. Females often visit the nests of other females during the breeding season.
Social Structure and Reproduction
Spotted eagles start building or repairing the nest as soon as they arrive. By the end of April or the beginning of May, one or two (very rarely three) eggs are in full clutch. The female begins to incubate them immediately after laying the first egg, which is why the chicks hatch at different times. The hatching process lasts 37-41 days. Chicks can fly at the age of 8-9 weeks, which usually coincides with the first half of August. Of the chicks, one, or very rarely two, learn to fly.
The breeding success of spotted eagles has a three-year cycle due to changes in the number of voles, the eagles’ preferred prey. In the best years, productivity can average over 0.8 young steamed birds, but during periods of low cycles this number can drop to below 0.3. Greater spotted eagles are sensitive to disturbance and have low breeding success. Although they lay two eggs, often only one chick fledges.
Fun Fact: Where spotted eagle populations struggle, their productivity can be increased artificially by ensuring that both chicks survive through fledging. Under natural conditions, one is almost always lost due to fratricide known as cainism.
Natural enemies of spotted eagles
Pupils and eggs of Greater Spotted Eagles can be preyed upon by the American mink and other predators. Chicks may be the target of other predators or owls. Otherwise Greater Spotted Eagles — top predators, and adults usually do not fall prey to other large predators.
Lesser Spotted Eagles have no natural predators and show no obvious adaptations against them. The main threat to them — these are people. They pose a threat to spotted eagles due to the use of chemicals such as azodrine, an organophosphate insecticide used to prevent small animals from feeding on crops. Predators, including lesser spotted eagles, often die from feeding on these poisoned animals. Another human influence on this species — hunting.
Another cause of mortality in lesser spotted eagles — fratricide. If there are two or three eggs in the nest, usually the offspring that hatch first kill the others first by knocking them out of the nest, attacking them, or eating food before their siblings have a chance to eat. As a result, most spotted eagles successfully raise only one or two offspring.
It has been suggested that lesser spotted eagle eggs may be eaten by other animals, particularly snakes. However, this has not been clearly documented. Greater spotted eagle eggs are eaten by American minks. Therefore, it is possible that minks may also hunt lesser spotted eagle eggs.
The main threats to — loss of habitats (in particular, the draining of wet forests and grasslands and continued deforestation) and hunting. The latter threat is particularly prevalent during migration, with thousands of birds being killed annually in Syria and Lebanon. Forest management activities are reported to have a negative impact on species. It is also very vulnerable to the impacts of potential wind power development. The accident at the Chernobyl nuclear power plant may have negatively affected this species.
Population and species status
The Greater Spotted Eagle is listed as an endangered species worldwide. Its global population is estimated to be between 1,000 and 10,000 individuals, but there are suggestions that a higher figure seems unlikely. BirdLife International (2009) estimates that the number of adult birds is between 5,000 and 13,200 individuals. BirdLife International/European Bird Census Council (2000) estimated the European population at 890-1100 breeding pairs and later revised to 810-1100 breeding pairs.
The Lesser Spotted Eagle is considered the most numerous species of eagle in Europe. Previously, the species was not as common as it is today, and its numbers were further reduced in the first half of the 20th century as a result of “hawk warfare”. After that, the population gradually recovered. In the 1960s and 1970s, there was a change in ecological niche, with eagles starting to nest near the cultural landscape. Thereafter, during the 1980s, the number of lesser spotted eagles probably increased rapidly. Now the largest habitats of the Lesser Spotted Eagle are located in Belarus, Latvia and Poland.
The Lesser Spotted Eagle has an extremely large range and therefore does not approach the thresholds for vulnerable in terms of range size (rate of occurrence <20,000 km² combined with declining or fluctuating range size, degree/quality of habitat or population size and small number of locations or severe fragmentation). The population of spotted eagles is about 40,000-60,000 individuals. The population trend of lesser spotted eagles is unknown, but it is believed that it is not declining fast enough to approach the demographic threshold (>30% decline over ten years or three generations).
Population size can be moderately small to large, but is not considered to be close to thresholds for vulnerable in terms of population size (<10,000 mature individuals with continued decline estimated to be >10% over ten years or three generations ). For these reasons, the species is rated as the least threatened.
Spotted Eagle Conservation
Although the greater spotted eagle has a much wider distribution than the lesser spotted eagle, it has a smaller global population and is declining in the western parts of its range. Reasons for this condition — habitat changes caused by forest and wetlands, afforestation of former crop areas, nest disturbance, shooting, intentional and accidental poisoning, especially with zinc phosphide.
The consequences of hybridization with lesser spotted eagles are not yet clear, but the spectrum of the latter species is moving eastward at the expense of the greater spotted eagle. An action plan for this species has been developed for Europe. The Greater Spotted Eagle is classified worldwide as vulnerable. But it is still quite common in the Western Siberian Lowland from the Urals to the Middle Ob and further to Eastern Siberia, and it is possible that its population exceeds 10,000 individuals, which is the threshold for inclusion in the list of vulnerable.
Measures for the protection of spotted eagles have been taken by many countries of Eastern Europe, and especially Belarus. The Greater Spotted Eagle is protected by the Belarusian law on nature conservation, but this law is considered too complex to implement. For example, national legislation states that only those sites that have sheltered birds, properly inspected and sufficiently documented before approval by all relevant Belarusian state bodies and institutions can be converted from “management areas” to “specially protected areas”. It can take up to nine months to complete this procedure.
In Germany, the Deutsche Wildtier Stiftung program attempts to increase breeding success by removing the second born eagle (usually killed by the firstborn) from the nest shortly after hatching and raising it by hand. A few weeks later, the bird is put back in the nest. At this time, the first-born is no longer aggressive, and two eagles can live together. In the long term, maintaining suitable habitat is critical to the survival of the Spotted Eagle in Germany.
The Spotted Eagle is a medium-sized eagle that breeds in wooded areas, usually on plains and near wetlands, including wetlands. meadows, peatlands and swamps. During the breeding season, it extends from Eastern Europe to China, with most of the European population being very sparse (less than 1000 pairs), common in Russia and Belarus.