462 SHORT COMMUNICATIONS VOL. 39, NO. 4 j RaptorRes. 39(4):462-466 ¸ 2005 The Raptor ResearchFoundation, Inc. FAMILY BREAKUP, DEPARTURE,AND AUTUMN MIGRATION IN EUROPE OF A FAMILY OF GREATERSPOTTED EAGLES (AQUILA CIANGA) AS REPORTEDBY SATELLITETELEMETRY BERND-U. MEYBURG 1 WorldWorking Group on Birdsof Prey,Wangenheimstr. 32, D-14193 Berlin, Germany CHRISTIANE MEYBURG WorldWorking Group on Birdsof Prey,31 Avenuedu Maine, F-75015 Paris,France TADEUSZ MIZERA AND GRZEGORZ M•CIOROWSKI AgriculturalUniversity, Zoology Department, Wojska Polskiego 71C, 60-625Poznan, Poland JAN KOWALSKI Gugny2, 19-104 Trzcianne,Poland KEYWORDS: GreaterSpotted Eagle; Aquila clanga; depar- Terminals, PTTs) in the Biebrza river valleyof northeast- ture;family breakup; migration;satellite telemetry. ern Poland. The eagle nestwas located in a National Park protecting the largest peatlands in Central Europe, in- cluding 15547 ha of forests,18 182 ha of agricultural The transition of birds of prey to independenceis dif- land, and 25 494 ha of wetlands--the Biebrza marshes. ficult to study (Brown and Amadon 1968), as both old More than 70 natural and semi-naturalplant associations and young birds stray ever further from the nest site to- have been documented in the Biebrza valley.The most ward the end of the post-fledgingperiod. We know of no dominant forest associations include black alder (Alnus studyconcerning a raptor speciesin which the departure glutinosa),swampy birch (Betulapubescens), and peat co- on migration, the break up of the family,and subsequent niferousforests (Salici-Betuletum). Frequent anthropogen- migration have been investigated by satellite tracking. ic ecosystemsfound in the valley are pastures,cultivated Here, we report on a case concerning Greater Spotted groundsand urbanized areas.One of the greatestthreats Eagles (Aquila clanga).Available information on this spe- to the park is human modified drainagepatterns, which cies is limited, but Ivanov et al. (1951) and Dementiev causesthe invasionof marshesby shrubsand trees.Active conservationmeasures have been applied to stopfurther and Gladkov (1951) believed that Greater Spotted Eagle succession and maintain more natural intermediate suc- families departed as a unit on migration. cessionalstages. A broad public awarenesscampaign is In the closelyrelated LesserSpotted Eagle (Aquilapo- in place to encourage the adoption of organic farming, marina), both adults migrated separately,as determined as45% of the park is privatelyowned. The eaglenest was by satellite telemetry (Meyburg et al. 2006). The off- built in dense humid alder (Alnus glutinosa)and birch spring in this species,which were not tracked with satel- (Betulaspp.) forest. lite telemetry, normally leave before the parent birds. We used the dho gaza method (Hamerstrom 1963, However, in some cases, the females leave before the Clark 1981, Bloom 1987) with a Eurasian Eagle Owl young (Meyburg et al. 2006). Satellite telemetry has so (Bubobubo) to trap the adults. By this method, the eagles far been used to track one adult Greater Spotted Eagle "attacked" the live eagle owl, tethered to a perch and (Meyburg et al. 1995a). got entangled in the dho gaza net. We used transmitters As part of a long-term research program in northeast- supplied by Microwave Telemetry, Inc. (Columbia, MD U.S.A.) with a mass of 60 g. They were fitted as back- ern Poland (Mizera et al. 2001), we are endeavoring to packs,using Teflon ribbon (Bally Ribbon Mills, Bally,PA raise the level of knowledge, and thereby, the protection U.S.A.) to attach them to the bird. The young fledgling of the Greater SpottedEagle by making use of the avail- eagle was equipped with a battery-poweredtransmitter able technology (i.e., satellite telemetry) to investigate with a massof 60 g and a temperature sensor.To ensure the species'migration and wintering habits. as long a life as possible,this radio wasprogrammed to operate only at intervals of 4 d and then for only 10 hr. METHODS The adult birds were fitted with solar-poweredPTTs In 1996, an entire family of Greater SpottedEagles was These were programmed to be in continuousoperation, fitted with satellite transmitters (Platform Transmitter provided the level of light wassufficient to generatepow- er for the transmitter. All location data were analyzed individually and en- • Email address:[email protected] tered into databases.We used the computer program 2005 SHOI•T COMMUNiCaTiONS 463 Mapit (Allison 1997) to plot locations,which were pro- vided by ServiceArgos, Inc. (Toulouse,France), measure distances between locations, and trace the migration routes. This program is an integrated global mapping and digital displaysystem, which computesthe great-cir- cle distance between one point and another, while dy- namically displayingboth great-circleand constant-com- pass-bearing(rhumb) lines. Great-circle distancesare physicallythe shortestdistances on a globe. RESULTS Three eaglesin the family broke up when leaving the breedingterritory. The female was the first to depart (19 September1996), at least 2or 3 dbefore her young. The male wasthe last to leave (26 September 1996), I wk after thefemale. Whereas the adults headed straight for the Bosphorus(Fig. 1), the 1687 km coveredby the young bird terminatedin Albania,where this eagle apparently perishedatthe end of October. The young probably left on 21 or 22 September 1996, and the male was present on23 September, but only made minimal migration pro- gresstothe byprogramming midday on26of itsSeptember transmitter 1996(operation(Table 1). of4Due d) the progressof theyoung could not be determinedas accuratelyas that of thetwo adults. The date of departure of the young eagle wasassessed from the first locations awayfrom the nest, providing anaverage estimate of speed and distancefrom the breeding territory during the first stagesof its migration (Table 1, 2). On average, th•seagle flew only 57 kmper day. This young eagle may have coveredthe first 257 km up to the first locationaway from the nestin morethan 4 or 5 d, and thus,have left thebreeding area before 21 or 22 September. The young bird set off from the breeding territory in a southwesterlydirection (Fig. 1). The eagleremained in Polanduntil at least4 October,while the female and malewere located in the countryfor the lasttime on 19 and 26 September,respectively. The femalereached the Bosphoruson 14October and the male on 22 October. The youngbird apparentlymet its deathin southernAl- bania, ca. 70 km south of Tirana and 13 km north of Ballesh.All the datafrom its transmitter (temperature and no changeof location)after 26 Octoberindicate mortality.The transmitter wastransmitting signals until 13July 1997. However, it is alsopossible, but muchless likely,that the eaglelost or removedthe transmitter. DISCUSSION Inbirds ofprey, the transition toindependence isdif- ficultto study as toward the end of the post-fledging pe- riod, both old and young birds strayever further from the nest site. Direct observationdoes not accountade- quately for local movementsof raptors as they begin the departureprocess. Nevertheless, a number of studies concerning eaglesand other raptors (e.g., Alonso et al. 1987,Morvan and Dobchies1990, Bahat 1992, Busta- mante1995, Real et al. 1998,Rafanomezantsoa 2000) have been published during recent years. 464 SHORT COMMUNICATIONS VOL. 39, NO. 4 Poland '•,•,. ,3Oct. / 20 Sept. o ' ' 26Sept. $ $ Offspring ß ß ß 9 Oct. Oct. •4Oct. ,..-- Male Slovakia 5 Oct. Female•.•ß ' Hungary ß 13Oct. Romania ß=. $ ß 8Oct.' * 16 . 10 Oct. 44øS 19 Oct. Sea Bulgaria ' ' ' Male nia ß Female ----- Offspring 20øE 28øE Figure 1. The autumn migration of the three Greater Spotted Eaglesin Europe determined by satellite telemetry in 1996; datesof arrival at selectedpoints en route are indicated. DECEMBER 2005 SHORT COMMUNICATIONS 465 Table 2. The outwardmigration of the juvenile GreaterSpotted Eagle (seeFig. 1) 1996 wasdetermined by satelhte telemetry. BEGINNING AND LENGTH OF THE DURATION MEAN LENGTH END OF DIFFERENT STAGES OF EACH OF DAILY FLIGHT COUNTRIES EACHSTAGE a IN km STAGE(days) DISTANCES TP•NSWP,SED ca 21/22 Sept 257 km ? ? Poland 26 Sept: 0044 H 26 Sept: 0044 H Roosting 4.5 -- Poland 30 Sept: 1134 H 30 Sept: 1134 H 242 km 4.5 54 km/day Poland 4 Oct: 1534 H 4 Oct: 1720 H 76 km 4 19 km/day Polandand Slovakia 9 Oct: 0005 H 9 Oct: 0547H 329 km 4 82 km/day Slovakiaand Hungary 13 Oct: 0600 H 13 Oct: 0600 H 202 km 4.5 45 km/day Hungaryand Croatia 17 Oct: 1327 H 17 Oct: 1738 H 361 km 4 90 km/day Bosnia-Herzegovina 22 Oct: 0109 H 22 Oct: 0109 H 220 km 4 55 km/day Montenegroand Albania 26 Oct: 0619 H a Each migrationstage was 4 d, basedon the duty cycleof the satellitetransmitter. Location data providedby ArgosService, Inc (Toulouse, France). Dementiev and Gladkov (1951) and Ivanov et al. hasta Albania, donde aparentemente muri6 a fines de (1951) believed that Greater Spotted Eagle families de- octubre. parted together on migration. We know of no studyin [Traducci6n del autor] the literature on this species,or any other raptor, in which the datesof departure on migration, the break up ACKNOWLEDGMENTS of the family, and their combined or separatemigrations The authors wish to thank the Deutsche Forschungs- have been investigatedby satellite telemetry. The family gemeinschaft(DFG) in Bonn, Germany,for its unstinting of Greater SpottedEagles studied here clearlybroke up financialsupport of the SatelliteTelemetry Greater Spot- when leavingthe breeding territory. ted Eagle Project, the Polish Environment Ministry in We alsohave studied a pair of the closely-relatedLesser Warsaw, and the administration of the Biebrza National Spotted Eagle using this method over severalyears. The Park for kindly allowingus to studyand, in particular,to membersof this pair migratedseparately in 1997-98 and trap adult birds. We are also grateful to the Poznan Zoo 1998-99 and overwinteredca. 1000 km apart both years for providinga live eagle-owlto useas a decoyin trapping the eagles, to Joachim and Hinrich Matthes, as well as in southern Africa (Meyburg et al. 2006). However, in Mike McGrady,for help in the field, and to Robin Chan- this case,the offspring were not tracked.