Eagle Studies

The World Working Group on Birds of Prey and Owls

Eagle studies


Dimitris E. Bakaloudis (Oral)

Aspects of the Ecology of the Short-toed Eagle Circaetus gallicus in Dadia Soufli Forest, NE Greece

The ecology of a population of Short-toed Eagle (Circaetus gallicus) was studied at the Dadia-Soufli forest complex in N.E. Greece, during 1996-1998. Short-toed Eagle nest sites were in mature pine forest associations, with a total tree density and total trunk basal area lower than for the surrounding forested areas. The eagles nested almost exclusively in Calabrian pine (Pinus brutia).

The average density of nesting pairs (18-21) from 1996 to 1998 ranged from 17.7 to 20.6 sq km per pair, and the distance separating neighbours varied from 2.9 to 3.4 km. From 1996 through 1998, 58 nests produced 52 eggs, 75% hatched and 92% of those that hatched resulted in fledged young, producing an average of 0.69 fledglings per breeding pair. Reptiles, especially the Grass snake (Natrix natrix) predominated both for nestlings and adult diet in terms of frequency of occurrence (44.8%) and biomass (29.0%).

Factors, which have had a profound effect on the population limitation of the Short-toed Eagle, and the recommended appropriate management that will conserve the eagle population in the Dadia-Soufli forest complex and surrounding areas is discussed.

Forestry Service, Dpt of Forest Management & Protection, Ermou 6, 68400, Soufli, Greece

Email: dimbak68@yahoo.co.uk

Evgeny A. Bragin1 and Todd Katzner2 (Oral)

Population Trends and Nesting Success of Imperial, Golden and White-tailed Sea Eagles in North-west Kazakhstan, 1990-2992

Eagle populations were studied over a 20-years period within the Naurzum Reserve in North-west Kazakhstan. Data from these long-term studies include spatial distribution, number and productivity, breeding phenology, survival, diet and others. The Imperial Eagle population was nearly stable; during 1990-2002, there were 40 regular breeding sites. The number of breeding pairs fluctuates. The White-tailed Sea Eagle had been slowly increasing during the 1980s, but a sharp increase was at the end of the 1990s-2002, coinciding with depression of lakes (1996-2001) in the region. Overall number of White-tailed Eagle breeding pairs increased from 8 in 1979 to 21 in 2002. Two breeding pairs of Golden Eagle first appeared in Naurzum in 1993. The number had been increasing before 1996, but declined again and stabilized at a level of 4 pairs in 1999-2002.

The expansion of White-tailed and Golden Eagles was not linked to prey resources, but possibly these data reflect positive population trends in general in Kazakhstan

1 Science Department, Naurzum National Nature Reserve, Kustanay, Tarana st., 165-12, 458003, Kazakhstan

 Email: naurzum@mail.kz

2 Wildlife Conservation Society, Central Asia Program, 2300 Southern Boulevard, Bronx, NY 10460, USA

 Email: tkatzner@asu.edu

Ta-Ching Chou1 , Huisheng Chen2, and Pei-Fen Lee3 (Poster)

Breeding Biology of the Crested Serpent Eagle Spilornis cheela in Kenting National Park, Taiwan

The Crested Serpent Eagle (Spilornis cheela) is widely distributed in the Oriental region. These snake-eating eagles generally soar above the hill ridges and cry noisily in the low hill country of Taiwan, which makes them conspicuous to birdwatchers but their nests were rarely found and described. We have located ten Serpent Eagle nests between 1995 and 2002 in Kenting National Park, Taiwan. All nest trees were standing in the creek valleys. Both evergreen broadleaf trees and hard-leaf trees were used as nest tree. All ten nests were built on top of vines, thus concealed from researchers and predators alike. Only females were observed to incubate the eggs. Only one egg was laid in all the nests and one eaglet fledged from each of these nests. The breeding success was 90% for all six pairs observed. Two forms of juvenile plumages were observed from these nests, dark and light. The plumage of the dark form juveniles was very similar to their parents, which was not described in any references.

1. Dept. of Zoology, National Taiwan University, Taipei, Taiwan

 Tel: 886-2-23623501  Fax: 886-2-23636837  Email: tcchou10@ms34.hinet.net

2. Dept. of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, USA.

 Tel: 1-479-5276330  Fax: 1-479-5276330  Email: hxc07@uark.edu

3. Dept. of Zoology, National Taiwan University, Taipei, Taiwan

 Tel: 886-2-23623501  Fax: 886-2-23636837  Email: leepf@ccms.ntu.edu.tw

Valery Dombrovsky (Oral)

Use of Breeding Area by Immature Spotted Eagles Aquila pomarina and A. clanga: Different Strategies

During a 1999-2002 RSPB-funded APB-BirdLife Belarus project, data on the occurrence of immature individuals of both Spotted Eagle species in the breeding season were collected.

25 im. GSE and 17 im. LSE were observed. Im. GSEs were sighted together with the first arriving adults (earliest date - March 9), spending the entire breeding season in the vicinity of occupied territories in the typical GSE's breeding biotopes (large forest-mire complex), never congregating in groups. In March-early April, solitary birds in juvenile plumage were often seen accompanying an adult in its breeding area (looking like a pair from a distance). But later on, im. birds left the territories occupied by adults. Im. LSE arrived later than im. GSE. The earliest date was April 15, but more than 70% of observations of im. LSE were made in June-July, when the birds congregated in small groups of 2-3 individuals. They feed on vast drained wetlands used for hay-making. Doubtless some several hundreds of im. LSEs stay in Belarus during summer. Low observation rate is explained only by absence of special counts of SE on open agricultural areas. Probably, most im. LSEs arrive in Belarus toward the hay-making season (late May-June).

On August 14, 2002 in Ivanovo Region (Russia), a LSE in second plumage was sighted near the north-easternmost recorded point of the species' breeding range (Melnikov et al., 2001). This case demonstrates that im. LSEs use the entire breeding area, not limited to Central Europe.

A 27 Academichnaia str, Institute of Zoologie, 220072 Minsk, Belarus

Tel: Private: +375-17-237 1704   Office: +375-17-2630130  Fax: + 375-17-263 0613  Email: valera@biobel.bas-net.by

M. Gavrilyuk (Poster)

Wintering of the White-tailed Eagle Haliaeetus albicilla in Ukraine

The White-tailed Eagle is included in the Red Book of Ukraine (1994). The current nesting population is estimated at 80-100 pairs. Up to now it is considered that at least 130-150 (Grishchenko, 1992) or 160-200 (Klestov,1994) White-tailed Eagles winter in Ukraine. The material collected permits us to specify these data.

The greatest number of birds winter in the south - on the coast of the Black Sea and Sea of Azov, at the mouths of the Dnieper, Danube and Dniester rivers. 140-160 eagles concentrate there. Non-freezing parts of the Dnieper River are the second significant place for wintering birds. In different years there are 80-130 White-tailed Eagles wintering on the Dnieper apart from those at the river's mouth. The total forecast number of individuals here is 100-150 birds. Some eagles winter in their own nesting territories, which are remote from non-freezing reservoirs, on steppe, near burial places of cattle.

There are from 9 to 12 (in some years even up to 30) eagles wintering on the Sivertsky Donets River. In the western pert of Ukraine wintering birds are not numerous because non-freezing reservoirs are absent. There are approximately only15 eagles wintering in this region.

So every year from 1996 to 2002 260-350 White-tailed Eagles have wintered in Ukraine. The number varies in different places in different years.

Cherkasy University, Department of Biology, Shevchenko Str. 81, 18031 Cherkasy, Ukraine

Email: Gavrilyuk@cdu.edu.ua

Vladimir Ivanovskiy (Poster)

The Short-toed Eagle Circaetus gallicus in Belarus

The material for this communication was collected in 1989-2002 mainly on six study areas of Vitebsk Region. 42 nesting cases are analysed, 11 clutches measured, 35 chicks ringed, 34 specimens of prey identified. All occupied nests without exception are found in sphagnum pine woods of the peat bogs with areas from 380 to 19984 ha. Overwhelming majority of nests (83.3%) are built in upper fork of pines with “flat” crown at a height from 5 to 17m, in average (n=29) 10,0+/-3,2 m. Short-toed Eagles willingly occupy artificial nests, occupancy was 25% (n=16). Egg-laying begins at the end of April – first days of May. average sizes of the single egg 73,8+/-2,1x57,5+/01,1 mm.

Chicks hatch in the first decades of June,and fledglings leave nests in the first decade of August. Breeding success for the study period was 87.8% Main reasons for unsuccessful breeding are disturbance from humans (40%), and also predatory activity of Raven (40%) and White-tailed Eagle (20%).

Feeding base in Northern Belarus consists mainly of snakes (Grass Snake and Adder) The North Belarus population can be characterized as stable with an insignificant trend towards increase. Fires on peat bogs and irrational forest management have the most negative impacts. Further fate of the North-Belarusian population looks hopeful provided that the optimal network of peat bogs is preserved.

NGO APB-BirdLife Belarus, Revolutsionnaya Str., 24-30,210001 Vitebsk, Belarus.

Tel: 21 94 87  Email: ivanovski@tut.by

Savvas Iezekiel1, Dimitris E. Bakaloudis2, and Christos G. Vlachos3 (Oral)

The Diet of Bonelli's Eagle Hieraaetus fasciatus in Cyprus

The feeding habits of 14 Bonelli's Eagle (Hieraaetus fasciatus ) pairs nesting in Calabrian pine (Pinus brutia) forest in Cyprus was studied during 1999-2001. In total, 1734 prey items were identified from 612 pellets and 528 prey remains, collected during the breeding period. Birds were found to form the main prey category, followed by mammals and reptiles. Birds always, formed >50% of the diet, throughout the years and breeding stages. However, the proportion of the prey species in the diet varied seasonally with Chukar (Alectoris chukar) predominating at all stages, while Columbidae species (Columba palumbus, C. livia and C. domestica) formed an increasing proportion during the pre-laying and incubation stage (from November to February). Mammals (mainly Black Rat Rattus rattus) formed a constant proportion (>30%) of the diet during the breeding period, whilst reptiles (mainly Sling-tailed Agama Agama stellio) increased in importance during the brooding period, both in pellets and prey remains analyses.

Bonell's Eagle seemed to be an opportunistic predator and this predation may be explained by the seasonal variation in food availability in the island of Cyprus. Its influence on game species also is discussed.

1. Forestry Dpt of Cyprus, Louki Akrita 1414str., Nicosia, Cyprus. Email: iezekiel@cytanet.com.cy

2. Forestry Service, Dpt of Forest Management & Protection, Ermou 6, 68400, Soufli, Greece.

3. Dpt of Forestry and Natural Environment, Lab of Wildlife & Freshwater Fisheries, Aristotle University of Thessaloniki,

 PO Box 241, 54006, Thessaloniki, Greece.

Jose E. Martinez, Ilu Pagan and Jose F. Calvo (Poster)

Diet of Booted Eagles (Hieraaetus pennatus) in Southeastern Spain

The diet of Booted Eagles in southeastern Spain was determined by analysis of prey remains and pellets collected from 23 nest sites between 1997 and 2000. We studied: (i) food habits; (ii) seasonal and interannual variations in diet composition; (iii) influence of diet on reproductive success; and (iv) diet overlap with Common Buzzard.

The Booted Eagle's diet was generalist and included at least 26 types of prey. Medium-sized birds and ocellated lizard formed the bulk of the diet, while rabbits and medium-sized birds were the main source of biomass. The proportion of medium-sized birds increased throughout the breeding season, while the proportion of small-sized prey decreased. Interannual variations were not related to the main prey, but to alternative prey. There was no significant relationship between diet and reproductive parameters (breeding success and productivity).

When comparing diets, it was found that Booted Eagles prey proportionally more on small and medium-sized birds, while Common Buzzards prey mainly on rabbits, reptiles and amphibians, resulting in a low percentage of diet overlap.

Jose E. Martinez, Departamento de Edologia & Hidrologia, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain

Tel: + 34 968 364986  Email: ecoliemt@um.es

Ilu Pagán, Departamento de Ecología e Hidrología. Universidad de Murcia. Campus de Espinardo, 30100 Murcia. Spain

Tel: + 34 968 364985  Email: ilupab@um.es

José F. Calvo, Departamento de Ecología e Hidrología. Universidad de Murcia. Campus de Espinardo, 30100 Murcia. Spain

Tel: + 34 968 364986  Email: jfcalvo@um.es

Vladimir B. Masterov1 and Keisuke Saito2 (Oral)

Problems of Conserving Steller's Sea Eagle Haliaeetus pelagicus in the southern part of its Home Range and on its Wintering Grounds

In 1997–2001, studies of the current status of the Steller’s Sea Eagle (SSE) population were carried out in the Lower Amur Region and Sakhalin Island. Total estimated number of nest sites was 940. The population numbers approximately 2000 birds (600-700 nesting pairs and about 600 immatures). Computer simulation model indicated negative trends; the size of the population tends to decrease by 0.5% annually.

Telemetry data showed that most of SSE wintered on the Southern Kuril Islands and Hokkaido. Up to 2500 (about 45 % of the total population) gather there annually. According to radio tracking data, SSE overwintering in Hokkaido use habitats in mountain areas, where they are threatened by lead poisoning from deer carcasses left by hunters. Up to 200 eagles may die for this reason annually.

Northern Sakhalin and adjacent areas are undergoing a dramatic increase in oil exploration activity. Disturbance and petroleum contamination pose the greatest threat. In the case of oil-spills, many key breeding habitats and wintering grounds would be polluted.

In the lower reaches of the Amur River, the population is significantly impacted by increasing water pollution. Phenol was detected in 70% of analysed fish specimens. This is probably linked to the frequent observations of dead chicks, which previously had not been recorded. The number of dead could reach 18% of the total number of nestlings. The total detrimental effect on the SSE population may be increased due to the concurrence of different threatening factors.

1. Dept of Vertebrate Zoology, Biological Faculty of the Moscow State University, Leninskie, Gory 1-12 119992 Moscow, Russia

 Tel.: +(095) 939-4424  Fax: +(095) 939-2718  Email: eagle@soil.msu.ru

2. Kushiro Shitsugen Wildlife Center, 2-2101 Hokuto Kushiro, Hokkido 084-0922, Japan;

 Tel.: +81-(0) 154-56-2051  Fax: +81-(0) 154-56-2052  Email: k_saito@marimo.or.jp

Vladimir B. Masterov (Poster)

Some Results of a Project to create a viable Captive Population of Steller's Sea Eagle Haliaeetus pelagicus in Zoos

The inevitable losses in Sea Eagle populations during the development of oil deposits in the Far East of Russia will require taking prompt preventive actions for their protection. In order to create the necessary prerequisites for the species’ long-term survival under the conditions of global modification of natural habitats. In 1994 it was decided to create viable captive populations in zoos and breeding centres. By 2001, the captive population included 96 individuals kept in 29 zoos and nurseries of the Former Soviet Union and Europe, where 39 birds were born and raised in captivity. Twenty-six eaglets were caught in the Lower Amur Region. The birds were distributed free of charge, on a breeding loan, to different zoos. At present time, the wild-born birds in the captive population of Steller's Sea Eagle have a unique genetic variety since almost all were taken from different parents. Six pairs of Steller’s Sea Eagles successfully breed within the framework of the project. Creation of an artificial population and stable breeding of birds in captivity is an effective measure of conservation of the species.

Dept of Vertebrate Zoology, Biological Faculty of the Moscow State University, Leninskie Gory 1-12, 119992 Moscow, Russia

Tel: +(095) 939-4424  Fax: +(095) 939-2718  Email: eagle@soil.msu.ru

Bernd-U. Meyburg1, Tomas Belka2, Oldrich Sreibr3, (Poster)

Josef Vrana and Christiane Meyburg

Migration and Breeding of a Lesser Spotted Eagle Aquila pomarina from Slovakia

In northern Slovakia an adult male Lesser Spotted Eagle occupied the same nest site for 11 years running (1992-2002), where it was ringed and fitted with a satellite transmitter. In six of these years it successfully reared a young. In 1994 and 2000-2002 its behaviour during migration could be followed in detail by means of satellite telemetry. The eagle took the known route for this species to South Africa. In 2001 it spent 43% of the year at its breeding site, 33% in its winter quarters, the remainder (1/4) being spent on migration. In three cases the autumn migration took 40, 48 and 61 days respectively. In both cases the spring migration took 49 days each. All five recorded autumn and spring migrations averaged a daily distance of 178 km. In spring the daily distance flown was in general slightly greater than in autumn. The longest was recorded from 30.3-2.4.2001, between Uganda and the Red Sea, during which the bird covered a total of 1650 km, thus averaging 412.5 km per day. In 2001 the spring migration from the wintering grounds was 2-2.5 weeks later than in 2002.

1. Wangenheimstr. 32, D-14193 Berlin, Germany. Email: WWGBP@aol.com  Fax: +49-30-892 80 67

2. Druzstevni 918, 51721 Tyniste n. Orl. Czech Republic. Email: tomas.belka@worldonline.cz

3. Email: oldrich.sreibr@esab.cz

Bernd-U. Meyburg1, Kai Graszynski2 , Torsten Langgemach3 (Poster)

and Wolfgang Scheller4

Action Plan for the Lesser Spotted Eagle Aquila pomarina in Germany

The western limit of the Lesser Spotted Eagle's range runs through Germany.

Over the last two centuries this has progressively shrunk and the surviving remnants of the population are today still in constant decline. Apart from a small completely isolated group of 3-4 pairs in the Hakel forest in the federal state of Sachsen-Anhalt, the species now occupies only a very small area of ca. 10,000 sqkm in the extreme north-east. Out of the 115 pairs recorded in 2001, about 80% live in the eastern part of Mecklenburg-Vorpommern, the remainder in the north-eastern part of Brandenburg.

While its former breeding range covered at least 83,000 sqkm in 1850, this has today shrunk by around 90% and the species is now in grave danger of extinction in the longer term in Germany. At the invitation of WWGBP (World Working Group on Birds of Prey) on 17 November 2002 ca. 45 specialists met, to discuss and initiate an Action Plan at national level, to be carried out in conformity with the EU's international Action Plans. The four authors were appointed to draft this and it is now being actively prepared. In it will be depicted the threats posed by major developments, e.g. in forestry, agriculture and water supply and on the migration routes and the conservation measures that need to be developed.

1. Bernd-U. Meyburg, Wangenheimstr. 32, 14193 Berlin, Germany. Email: WWGBP@aol.com  Fax: +49-30-892 80 67

2. Kai Graszynski, Schreberstr. 8 A, 14167 Berlin, Germany

3. Torsten Langgemach, Akazienweg 1, 14715 Stechow, Germany

4. Danschowstr. 16, 17166 Teterow, Germany

Rozen Morvan (Poster)

Bonelli's Eagle in France: Conservation Measures

1. Treatment against trichomonosis

Trichomonosis is caused by Trichomonas gallinae, a microorganism transmitted during feeding. From 6% to 17% of eaglets born in France between 1990 and 1997 died of this disease, the main carrier being the domestic pigeon Columba livia. In 1998, a preventive therapeutic programme was launched using pigeons treated with imidazole. In 1998, carnidazole was used, followed in 1999 by ronidazole. Between 1998 and 2001, all pairs subjected to the preventive treatment raised their young to fledging, without any apparent clinical problem.

2. Tagging and modification of power lines

95% of eaglets (n=287) were tagged in France from 1990 to 2002. During 2001, 27 birds were recaptured. On average, they were one year old (0.5 to 3yrs) and had travelled 147 km (0.5 to 620 km). From 1990 to 1998, of 20 tags returned, of known origin, 16 (80%) were attributable to electrocution. The Crau region was identified as the most dangerous in France for Bonelli Eagle. The power lines at fault have been adequately modified. Since then, GRIVE, electrocution has dropped to 20% (1/5) of the known causes of death.

GRIVE, Espace Republique de l'Hotel de Region, 20 rue de la Republique, 34000 Montpellier, France.

Tel: Private + 33-6-10-09- 65-71  Office + 33-4-67-22-80-70

Fax: + 33-4-67-22-68-27  Email: rozen.morvan@wanadoo.fr

Ilu Pagan, Jose E. Martinez and Jose F. Calvo (Poster)

Nest Occupancy Patterns of Booted Eagles (Hieraaetus pennatus) in South-eastern Spain

Between 1998 and 2002 we analyzed the spatial and temporal patterns of nest occupancy of a Booted Eagle population in a forested area in Murcia Region (SE Spain). We used the G statistic and computer simulations to test for randomness in territorial spacing, and compared the observed frequencies of temporal occupancy of each territory (number of years occupied) with the expected frequencies of a Poisson distribution. Logistic regression was used to model the probability of occupancy with respect to the nearest neighbour distance to conspecific pairs.

Mean density of breeding Booted Eagles in the study area was 1 pair / 3.5 km2. The spatial pattern of nest occupancy was random for three years, and uniform for the other two. Mean nearest neighbour distance was 1.121 ± 0.116 km. Probability of occupancy significantly increased with nearest neighbour distances. Temporal occupancy frequencies differ from a random pattern, indicating that some preferred nests are frequently occupied, as opposed to many others scarcely used.

Ilu Pagan, Departamento de Ecologia & Hidrologia, Universidad de Murcia, Campus de Espinardo, 30100 Murcia, Spain.

Tel: + 34 968 364 985  Email: ilupab@um.es.

José E. Martínez, Departamento de Ecología e Hidrología. Universidad de Murcia. Campus de Espinardo, 30100 Murcia,. Spain.

Tel: + 34 968 364 986  Email: ecoljemt@um.es

José F. Calvo, Departamento de Ecología e Hidrología. Universidad de Murcia. Campus de Espinardo, 30100 Murcia. Spain.

Tel: + 34 968 364 986  Email: jfcalvo@um.es

Wolfgang Scheller1 , Ugis Bergmanis2 and Bernd-U. Meyburg3 (Poster)

Home Range Size, Habitat Utilisation and Time Budgets of Lesser Spotted Eagles Aquila pomarina

The home range size, habitat utilisation and time budgets of Lesser Spotted Eagles (LSE) were investigated with particular regard to disturbances and fragmentation of the landscape. To this end a total of 9 LSEs were studied by using conventional radio-telemetry in different natural landscapes in Northern Germany and 6 LSEs in Latvia.

With regard to size of home range of successfully breeding males it was evident that the home ranges exploited throughout the whole breeding season in Germany were significantly larger than those in Latvia. Thus in Germany the home range size amounted to a mean of 2,711.2 ha, whereas in Latvia the mean was only 1,142.7 ha. Despite the considerable difference in overall size of home ranges between German and Latvian territories, those in daily use by the eagles studied showed no such marked difference between Germany and Latvia.

The agricultural policy of the EU should be adapted to cater for ecological requirements. Thus, vast expanses of rape or hemp entail a loss of feeding places for the LSE, whilst fallow land or cereal crops provide a continuous source of prey.

1. Danschowstr. 16, D-17166 Teterow, Germany,

2. Toces - 3, LV - 4862 Laudona, Madonas raj., LATVIA

3. Wangenheimstr. 32, D-14193 Berlin, Germany. Email: WWGBP@aol.com  Fax: +49-30-892 80 67



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