Spring 1994 Raptor Migration at Eilat, Israel
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J RaptorRes. 29(2):127-134 ¸ 1995 The Raptor ResearchFoundation, Inc. SPRING 1994 RAPTOR MIGRATION AT ElLAT, ISRAEL REUVEN YOSEF International Birding Center, P.O. Box 774, Eilat 88000, Israel ABSTRACT.--Inthe Old World, most raptors and other soaring birds breed north of 35øN latitude and winter between30øN and 30øS.An estimated3 000 000 raptors from Europe and Asia migrate through the Middle East. Israel is the only land bridge for birds migrating south between Europe and Asia to Africa in autumn, and north to their breedinggrounds in spring. In spring 1994 a total of 1 031 387 soaringbirds were countedin 92 d of observation.Of these 1 022 098 were raptors of 30 species,for an averageof 11 110 raptors per day. The most abundant specieswere the honey buzzard (Pernisapivorus) and the steppebuzzard (Buteobuteo vulpinus). Levant sparrowhawks(Accipiter brevipes), steppe eagles (Aquilanipalensis), and black kites (Milvus rnigrans)numbers were smallerby an order of magnitude.A total of 1999 raptorswere unidentifiedto species(0.19% of total). KEY WORDS: Eilat; Israel;migration; raptors; spring 1994;survey. Migraci6n de rapacesen la primaverade 1994 en Eilat, Israel RESUMEN.--Enel viejomundo, la mayorlade las rapacesy otrasaves planeadoras nidifican al norte de los 35øN,yen invierno se encuentranentre los 30øN y 30øS.Se ha estimadoen tres millonesde rapaces de Europa y Asia que migran a travis del Medio Este. Israel es solamenteel puentede tierra para aves que migran a Africa desdeEuropa y Asia durante el otofio, y al norte durante la primavera hacia sus fireasreproductivas. En la primaverade 1994 un total de 1 031 387 de avesfueron contadas en 92 dias de observaci6n.De elias,1 022 098 fueronrapaces de 30 especies,i.e., conun promediode 11 110 rapaces pot dla. Las especiesmils abundantesson Perhis apivorus y Buteobuteo vulpinus. Accipiter brevipes, Aquila nipalensisy Milvus rnigransresultaron set menosabundantes en un ordende magnitud.Un total de 1999 rapacesno ruetonidentificados a nivel de especies(0.19% del total). [Traducci6n de Ivan Lazo] Since Christensenet al. (1981) publishedtheir grate over this southernpoint of Israel including classicreport on the phenomenonof a bottleneckof waders,waterfowl, passerines,and pelagicspecies. raptors and other soaring birds over the northern These latter speciesare mostlynocturnal migrants tip of the easternarm of the Red Sea,several raptor (Bruderer 1994). migration(Thomson 1953) surveyshave been made Eilat is at the southernend of the Arava Valley in springand autumn (Shirihai 1987, 1988, Shirihai which forms part of the rift valley, a tectonicde- and Yekutiel 1991, Shirihai and Christie 1992). The pressionextending from Anatolia to central Africa most recentsurvey was in the spring of 1988. (Safriel1968). On the Israeliside of thevalley (west) In the Old World, most raptors breed north of the mountainsreach heights of 700 m abovesea level, 35øN latitude and winter between 30øN and 30øS and on the Jordanian side (east) about 1200 m. (Shirihai and Christie 1992). An estimated3 000 000 Eilat is on the northern fringe of the Saharo- raptorsfrom Europe and Asia migratethrough the Arabian desertbelt at the edge of almost 2000 km Middle East.The largestcount achieved in a survey of continuousdesert. Additionally, to the north- was in 1985 wherein 1 193 229 raptorsof 27 species northeastare 650 km of the Syrian Desert, and the (Shirihai and Christie 1992) were countedin 100 Arabian Desertlies to the east(Fig. 1). Hencemany days (for methodsee Thomson 1953). birds land in Eilat to rest before(in autumn) or after Eilat is at the hub of the only land bridgebetween (in spring) crossingthese deserts (Yom-Tov 1988). three continents,and is a junctionfor birdsmigrating The northwardjourney of thosethat have overwin- southbetween Europe and Asia to Africa in autumn tered in Africa is directed north or northeast in the and north to their breedinggrounds in spring(Safriel shortest route to their Palearctic or Holarctic breed- 1968, Yom-Tov 1988). Almost 300 bird speciesmi- ing grounds. 127 128 REUVEN YOSEF VOL. 29, NO. 2 Until recentlyit was assumedthat the rift valley was a convenientflyway that funneledthe migrants headed north from eastern Africa (Yom-Tov 1988). However, detailed studies (e.g., $afriel 1968, Wimpfheimer et al. 1983, $hirihai and Christie 50 100Kin ß 1992), suggestthat the routes bypassthe Red Sea, cut acrossthe Sinai Peninsula, and convergeover the northern part of its eastern arm, at Eilat or MediterraneanSea slightly further north. A proportion of migrating birds also cuts acrossthe Straits of Jubal toward Ras Muhammad and Sharm-el-Sheikh (Christensen t Isr et el. 1981). These birds then continuenorth along the cliffs of the Gulf of Aqaba coastline.This ex- •, f Jordan plainswhy largeconcentrations of soaringbirds are seenmostly in the spring(February to May) at Eilat in the diurnal hours(Yom-Tov 1988), and why mi- Sinai grating waders, waterfowl, passerines (Bruderer Egypt Eilat 1994) and raptors (Stark and Liechti 1993) can be detectedby radar at night. METHODS Saudi Arabia Observationswere made at three points for approxi- mately 12 h a day from 15 February to 19 May 1994, except for 2 d of sandstorms;92 d of observationswere carried out. Each raptor observationincluded the exact time of observation,species, exact or estimatednumber seen,estimated height and directionof flight, and pre- Red Sea vailing weather conditions.Counting of small flocks(up to mid-hundreds)was fairly accurateby countingindi- vidual birdsor groupsof ten; and flocksof thousandswere countedto within an accuracyestimated as ñ 10% or better (similar to Shirihai and Christie 1992). Double counts Figure 1. Map of the regionshowing location of Eilat. were eliminated by comparingrecording sheets at the end Curvedline with dotsrepresents international boundaries of the day. All data were summarizedby 5-d periodsfor all species,and comparedto previoussurveys. Observationpoints were closeto those used by Chris- tensenet el. (1981) and were improvedby Hadoram Shi- RESULTS rihai (Shirihai and Christie 1992). The observationpoints A total of 1 022 098 raptors of 30 specieswere were suchthat soaringbirds frequentlyflew within 50 m of the observersin mornings and late evenings.During counted in 92 d of observation(Table 1); i.e., an midday the birds used thermals and could be discerned averageof 11 110 raptorsper day. The most abun- only with binocularsor telescopes.The use of telescopes dant speciesin my surveywere the honeybuzzard considerablyincreased the number of identified individ- (Pernisapivorus) and steppebuzzard (Buteo buteo uals. The extensiveinformation provided by previoussur- veysallowed us to concentrateon the best areas at the best vulpinus;Table 1). Levantsparrowhawks (Accipiter times of the day. However, observerswere at all stations brevipes),steppe eagles (Aquila nipalensis; see Clark at all times,even if no birdswere expectedin the vicinity. 1992) and blackkites (Milvus rnigrans) numbers were I classifiedthe speciesaccording to the schemesuggested smallerby an orderof magnitude.Egyptian vultures by Shirihai and Christie (1992), who separatedthe species into four classes based on their relative abundance in mi- ( Neophronpercnopterus), short-toed eagles ( Circaetus gration at Eilat. The most abundant specieswere further gallicus),booted eagles (Hieraaetuspennatus), osprey subdivided into two levels: level I were those seen in hun- (Pandionhaliaetus), marsh harriers (Circusaerugz- dreds of thousands and level 2 in tens of thousands. Com- nosus),and sparrowhawks(Accipiter nisus) were seen mon specieswere in their hundreds,uncommon species in in hundreds.Griffon vultures(Gypsfulvus), Bonel- tens, and rare were singles.This schemewas chosenfor consistencybecause Shirihai and Christie(1992) analyzed li's eagles (Hieraaetusfasciatus), long-legged buz- the migrationof six (nonconsecutive)springs, and my study zards (Buteorufinus), pallid harriers (Circusrna- representsonly spring 1994. crourus),lesser kestrels (Falco naurnanni), Eurasian JUNE1995 RAPTORMIGRATION IN ISRAlg[ 129 kestrels(Falco tinnunculus), hobbies (Falco subbuteo), on 19 March and the last on 5 May (Fig. 2). Peak and Eleonora'sfalcons (Falco eleonorae)were un- migrationoccurred over 2 d when compactflocks of common species. thousandswere observed.On 25 April 25 522 were A total of 1999 raptors were unidentified(0.19% seenand on 26 April an additional14472; i.e., 90% of total). Of thesethe majority (1685, 0.16%) were of the observationsoccurred within a spanof 48 hr. due to uncertaintyof identificationbetween species This concurswith earlier reports (Phillips 1915, with similar flight or silhouette,or were observed Hollom 1959, Safriel 1968, Shirihai and Christie from a distancethat did not allow a good view. In 1992) that peak migration of this speciesoccurs on this category,1557 (0.15%) remain unclassifiedas 25 or 26 April (Shirihai and Yekutiel 1991). steppe/honeybuzzards, 104 (0.01%) aslesser/Eur- Steppeeagles formed 3.0% of total raptors seen. asian kestrels,and 24 (0.002%) as sparrowhawks. My data concur with those of Safriel (1968) and In addition,others identified to genuswere 37 har- Shirihai and Christie (1992) that the steppeeagle riers (Circusspp.), 29 eagles(Aquila spp.), and 21 migrationbegins in late January with a major peak medium to large falcons (Falco spp.). Only 227 occurringbetween the third week of February and (0.02%) raptors could not be further classified. mid-March and a smaller secondarywave in mid- Abundant Species.Level