Date of the interview: 12 July 2010
In this interview Emil Todorov talks about the current situation and the biology of the White-tailed Eagle in Bulgaria.
White-tailed Eagle nestling
White-tailed Eagle nest on Danube island
First color ringing of White-tailed Eagle in Bulgaria
Working with local people
Monitoring of White-tailed Eagles
White-tailed Eagle breeding areas along Danube River
© Emil Todorov
Markus Jais: What is the current situation of the White-tailed Eagle in Bulgaria (number of pairs, young fledged in 2009?)
Emil Todorov: In 2010 the breeding population of the White-tailed Sea Eagle in Bulgaria reached its highest number of 15-20 pairs in the period after the 1970s. The backbone of the breeding population is located along the Danube River with about 10 pairs, but in recent years eagles successfully bred inside the country.
BSPB/BirdLife Bulgaria implements monitoring of the known breeding pairs along the Danube, Black Sea and inland wetlands. Along the Danube this year we know five islands with successful breeding eagles.
This year BSPB joins the International color ringing program for White-tailed eagle in Europe and in May 2010 we ringed 3 nestlings from 2 nests on the Danube Islands.
Markus Jais: How has the population developed during the last 20 years?
Emil Todorov: In the begging of the 20th century, the species was often nesting on the Danube River Black Sea and along some other large rivers. After 1930 began a decline (HARRISON, 1933). The population dropped sharply and continued to do so until 1985 when only one breeding pair was known in the country (Ivanov, 1985).
In the 90s it began to increase gradually with fluctuating rates, with roughly one pair each year. Most of the new pairs appear in the areas where the species used to breed in the past. Currently, the trend of the population can be evaluated as increasing.
Markus Jais: Which habitat do the eagles use? How far from human settlement are most nests?
Emil Todorov: They bred between 0m and 140m above sea level. They prefer mostly tall white and black poplar trees in very wet forests of the Danube Islands. In the other part of the country and around large lakes close to the Black Sea , nests are located in deciduous forests, mainly on oaks and poplars.
There are pairs breeding in old native riparian forest along inland rivers. Several pairs occur near large artificial reservoirs. Usually the hunting area is close to the nest. For feeding the eagles prefer mostly big rivers, wetlands, lakes, dams and fishponds.
Markus Jais: In some European countries, at least some White-tailed Eagles seem to get more used to people. There are more and more nests in open agricultural areas or close to busy streets, villages or cities. Do you notice a similar trend in Bulgaria?
Emil Todorov: In Bulgaria we don’t have such close proximity to civilization. Nests are relatively distant from urban areas and difficult to access, especially on the Danube islands. However there are at least two nests that are close to agricultural fields and not far from local dirt roads. So with a growing population the White-tailed Eagles may soon become our closer neighbors.
Markus Jais: Is there suitable habitat not yet used by the eagles?
Emil Todorov: Yes, especially along the Danube River are still areas suitable for breeding. Although most islands have been turned into poplar plantations, there are still part of them where there are small patches of natural forests. An example is the couple established as nesting in recent years on the island, which is almost 90% of its territory is a hybrid poplar plantation for timber industry. Given the growing population we could soon expect the appearance of eagles in each Danube Island between Bulgaria and Romania.
Markus Jais: What tree species are used mostly for the nests and is there a difference in the breeding success between the different tree species?
Emil Todorov: About 70% of nests are in forest on islands along the Danube. Most nests are known for the classic size, about 2m in height and with a diameter of 1 to 1.5 meters built high in the crown of more than 20m black and white poplar (Populus nigra and P. alba). Nests in the Black Sea region and inland are often on oaks (Quercus sp.) in forests near large lakes and reservoirs.
Markus Jais: What is the main food of White-tailed Eagles in Bulgaria?
Emil Todorov: We don’t have detailed studies about food spectrum of the eagles in Bulgaria, but our observations often shows that eagles feed mostly on fish during the breeding season and during winter on waterfowl. Food collected from two nests in May 2010 indicate two major fish species – Danube Herring (Alosa pontica) and Gibel carp (Carassius gibelio), but there were also remnants of Coots and other species, which we will analyze in the future.
Markus Jais: How many White-tailed Eagles do spend the winter in Bulgaria?
Emil Todorov: The results of Mid-winter count of waterfowl in the country reported almost regularly numbers between 7 and 34 wintering eagles often around wetlands near their nesting areas.
Markus Jais: How many birds die from illegal poisoning and electrocution?
Emil Todorov: Up to now we haven’t reports of eagles found dead, due to poisoning or collisions with power transmission network, but it might exist. There is one case of illegal shooting. However the eagle has successfully recovered.
Markus Jais: How many birds die from lead poisoning? Are there efforts to make lead ammunition illegal or are hunters encouraged to use non lead ammunition?
Emil Todorov: We haven’t recorded yet this kind of mortality resulting from the impact of lead shot, but it probably occurs. The lead shots are still used although in Bulgaria it is officially prohibited in the wetlands and around 200 meters around.
Markus Jais: What other threats to White-tailed Eagles do exist in Bulgaria?
Emil Todorov: The main threats for the White-tailed Sea Eagle are the destruction of its breeding (forestry activities) and feeding habitats (drainage of wetlands), disturbance and probably illegal killing. In many cases these threats are consequences of poor knowledge about the eagles and of low conservation awareness of the local people.
Markus Jais: Which areas currently occupied by White-tailed Eagles are threatened by development like the construction of dams or highways?
Emil Todorov: The most significant threat for the future for our breeding areas along the Danube will be the realization of a big European project about Danube navigation. Many technical constructions will affect many of the islands with eagle pairs.
Markus Jais: How much of the habitat currently used by the breeding pairs is protected? Are the areas around the nests protected from forestry work during the breeding season?
Emil Todorov: More than 70 % of the nests are within protected areas. Some of the nests are in strict nature reserves where all human activities are prohibited, while others have less stringent management regimes. In these areas there is a threat of disturbance as a result of forestry activities, despite the prohibition of any activities during the breeding season. There are also several nests of new pairs who are not yet placed under legal protection.
Markus Jais: What needs to be done so that the population can continue to increase?
Emil Todorov: All breeding areas must be placed under legal protection and management regimes to be respected unconditionally, especially during the breeding season. Wherever possible efforts should be undertaken to restore the natural Danube floodplain forests and marshes in order to ensure adequate habitat.
Markus Jais: How do you see the future of the White-tailed Eagle in Bulgaria?
Emil Todorov: I think that the future of white-tailed eagle in Bulgaria will become brighter and brighter if the increase of the Northern populations continue and in the same time, here in Bulgaria we maintain the habitats and reduce mortality. BSPB/BirdLife Bulgaria will continue to monitor the status of the species and where is necessary to carry out conservation activities to protect the eagles. By this way I believe that very soon this magnificent eagle will be soaring again in the sky over its former breeding grounds.
Markus Jais: What was your most amazing experience with White-tailed Eagles?
Emil Todorov: I remember my first observation of the White-tailed eagle. I was so inspired by the flight of this magnificent bird that I said I would do anything to keep this eagle in the area where I live and now I spend part of my professional time on activities for the conservation of this species. Each observation of this majestic eagle for me is very exciting and filled with many emotions. Certainly the most memorable was the first color ringing of the Sea eagle in Bulgaria, we have made in May 2010. I had a chance to see the “Lord of the Islands” at one hand distance. Climbing of 30 meters high poplar is extremely difficult and risky task, but thanks to experienced climbers, we were able to reach the nests. The nestlings were dropped on the ground, where we put colored aluminum rings on them.
Markus Jais: Emil, thank you very much for the interview.