254 SHORTCOMMUNICATIONS VOL. 33, NO. 3 the Southern England Kite Group for helping to collect DEP,SSON, M. SYLVAN, A. SENOSIAIN AND EC. CARBO. kite chicksfor releasein the midlandsin 1997.The paper 1997. The re-establishment of Red Kite Milvus milvus benefitted greatly from the commentsof Dr. Ian Newton, breeding populationsin Scotlandand England. Br. Tom J. Cade and Harrison Tordoff. Birds 90:123-138. LOVEGROVE,R., G. ELLIOT AND K. SMITH. 1990. The Red LITERATURE CITED Kite in Britain. In CJ. Cadbury [ED.], RSPBConser- C&qTER, I.C., I.M. EV•NS •ND N. CROCKFORD.1995. The vation Review1990. Sandy,U.K. Red Kite re-introduction project in Britain--progress NEWTON,I. 1979. Populationecology of raptors.T. & A. so far and future plans. Br. Wildl. 7:18-25. D. Poyser,London, U.K. CR•vtP,S. 1985. Handbook of the birds of Europe, the , P.E. DAVISAND J.E. DAWS.1987. Age of first Middle East and North Africa: the birds of the West- breeding, dispersaland survivalof Red Kites Milvus ern Palearctic. Vol. 4. Oxford Univ. Press, Oxford, milvus in Wales. Ibis 131:16-21. U.K. , -- ANDD. Moss. 1994. Philopatryand pop- and K.E.L. SIMMONS. 1980. Handbook of the birds ulation growth of Red Kites Milvus milvusin Wales. Proc. R. Soc.Lond. B, 257:317-323. of Europe, the Middle East and North Africa: the INTERNATIONAL UNION FOR THE CONSERVATION OF NA- birds of the Western Palearctic. Vol. 2. Oxford Univ. TURE AND NATURAL RESOURCES. 1987. Translocation of Press, Oxford, U.K. living organisms:introductions, re-introductionsand EVANS, I.M., M.W. PIENKOWSKIAND R.H. DENNIS. 1991. re-stocking.IUCN, Gland, U.K. Experimental re-introduction of Red Kites:report to WATSON,J. 1997.The GoldenEagle. T. & A.D. Poyser, 1990. NCC CSD Res. Rep. No. 1224, Peterborough, London, U.K. U.K. , R.H. DENNIS, D.C. ORR-EWING,N. KJELLI•N,P. AN- Received29 August 1998; 11 April 1999

j. RaptorRes. 33(3):254-257 ¸ 1999 The Raptor ResearchFoundation, Inc.

FIRSTRECORDED POLYGYNOUS MATING IN THE RED KITE (MJLvusM[LVUS)

HEIN VAN KLEEF1 AND JAVIER BUSTAM_ANTE Departmentof AppliedBiology, Estaci•n Bioldgica de Do•ana, CSIC,Avda. Maria Luisas/n, 4101• Sevilla,Spain

I•Y Worn)s: Red Kite,,Milvus milvus; bigamy;polygyny; be associatedwith relativelyproductive habitats with an Dohana, Spain. abundant food supply. The Red Kite (Milvusmilvus) is considereda monoga- Diurnal birds of prey are predominantlymonogamous mousraptor and to our knowledgeno instancesof polyg- (Newton1979). Alternative mating systems like polygyny, yny have been reported previously(Glutz von Blotzheim polyandry, or cooperative breeding are rare, but have et al. 1971,Newton 1979, Cramp and Simmons1980). Ac- been recorded in at least 16 speciesof raptors (Newton cordingto Glutzvon Blotzheimet al. (1971) and Cramp and Simmons (1980), both adults build nests. Incubation 1979, Faaborgand Bednarz 1990, Heredia and Donfizar is mainly done by femalesalthough malesmay incubate 1990, Tella 1993, Tella et al. 1996). Nonmonogamousre- for short periodsduring the day.Males bring prey to fe- lationshipsare easilyoverlooked when working with un- malesand defendnest sites during incubationand the first marked individualsand are almostcertainly more wide- twoweeks after hatchingwhile femalesbrood and feed the spread than published records show (Newton 1979). young. Later, both membersof pairs defend nest sitesand Polygynyin birds of prey has only been regularly ob- bring food to nests,where the youngfeed themselves.On servedin harriers (Circusspp.) although it has been oc- average,young fledge 55 d after hatching and are fed by casionally recorded in another nine species (Newton both parentsfor another 26 d in the vicinityof the nest 1979, Hiraldo et al. 1991, Tella et al. 1996) and seemsto (Bustamante1993). The entire hunting territoryis not de- fended,but Red Kitesdefend areassurrounding nest sites at leastuntil the youngbecome independent (Bustamante • Presentaddress: Burghardt van den Berghstraat163, and Hiraldo 1993). 6512 DK, Nijmegen, The Netherlands. In 1996 and 1997,we recordedthe presenceof a po- SEPTEMBER 1999 SHORT COMMUNICATIONS 255 lygynoustrio of Red Kites in the area around the "Palacio pine with prey and began incubating. The male "2AU" de Dofiana," Dofiana Biological Reserve, southwest was still incubating at 1415 H when observationswere Spain (37øN, 6ø30'W;Valverde 1958, Rogersand Myers stopped. 1980). The male could be identified by a white PVC band The nest tended by F2 could be checked from an ob- on the left leg with the code "2AU" that could be read servation tower nearby. F2 laid one egg that failed to with a telescopefrom approximately200 m. This bird was hatch for unknown reasons. We did not check the nest banded as a nestling by L. Garcia on 6 May 1977 in a used by F1 until 8 May 1996. We found it contained two pine forest named "Pinar de San Agustin," <1000 m young that hatched on 20 and 21 April based on the from the "Palacio de Dofiana." The bird was retrapped length of their 7th primary feathers (Bustamante1990) and observed several times during its life close to this Both young fledged. pine forest and was documented breeding in this area at OBSERV^TIONS IN 1997 least since 1984 (B. Heredia, L. Garcia, G. Vilchez, E Hiraldo, M. Pineda and R. Lafitte pers. comm.). One fe- We made opportunistic observationsof the polygynous male (F1) associated with this male was not banded and trio from 9 February-9 March. The male "2AU" wasseen could only be identified due to her proximity to one of copulating with both an unbanded female on three oc- the nests.The other female (F2) using the territory had casions (9, 10, and 11 February) and a female with a a metal band on the right leg, but we could not read this metal band on the right leg on three occasions(13 Feb- band. Due to the absence of differences in coloration or ruary, 9 and 13 March). We suspectthey were the same molting between the individuals,they could only be iden- females, F1 and F2, from 1996. F1 was seen copulating tified when they were perched in plain sight. and perched close to the male "2AU" in the same pine forest as in 1996 and F2 wasseen bringing nest mater•al OBSERVATIONS IN 1996 to a nest in a poplar (Populusalba) 100 m north of the Observations in March 1996 indicated that there was 1996 F2 nest. Only on one instance was the male seen a polygynous trio in the area around the "Palacio de bringing nestmaterial to the pine forestnest. The F1 nest Dofiana." On 8 March 1996, from 0757-1200 H, we were waslocated in a stone pine 50 m westfrom the 1996 nest simultaneouslyobserving what we thought were two dif- The distancebetween F1 and F2 nestswas approximately ferent pairs of breeding Red Kites.' One pair was ob- 750 m. servedbuilding a nestin a stonepine (Pinuspinea) inside Both nests were observed on a regular basis from 24 a small pine forest named "Pinar de San Agustin." One April-26 June, during which time the young of both nests kite was banded with a white PVC band on the left leg grew from a few daysold to fledging. Observationswere that was read with the telescope as "2AU." The other carried out from a blind and were restrictedto daysthat kite (F1) wasnot banded. During observations,both kites were mostlywithout cloudsand low wind speedsto min- were observedbringing material to the nest. On one oc- imize the effects of weather conditions on the hunting casion, they copulated indicating they were pair-bonded successand feeding frequency of the kites. During this and we deduced "2AU" was the male and F1 the female. period, F1 nest was observedfor a total of 33.4 hr on 11 A secondnest being observedwas in a tall eucalyptustree different days (i = 3.0 --- 2.0 hr, -SD). F2 nest was ob- (Eucalyptusglobulus) approximately 50 m east of the "Pa- served for a total of 41.9 hr on 11 different days (i = 3.8 lacio de Dofiana" and 800 m east of the first nest. Most + 1.6 hr, +SD). of the time only one kite (F2) was observedin the area, The F1 nest contained two young that were banded on flying and perching on the nest tree. This kite wasband- 30 April. We estimatedthat the young had hatched on 7 ed with a metal band on the right leg. At 0934 H, a sec- and 12 April. A total of 10 prey was observed delivered ond kite, banded with white PVC band on the left leg, to the nest during 33.4 hr of obserx•ation;five were wasseen perched 100 m from the nest.At 0959 and 1002 brought by the male "2AU," two by the female Fl. In H, the kites copulated twice in another eucalyptusclose three instances,it wasnot possibleto identify the individ- to the nest tree. The copulation positionsindicated that ual bringing the prey. F2 nest contained one young that F2 was a female but we were not able to read the PVC was banded on 17 May. We estimated hatching date to band code of the male with a telescope.At 1005 H, the have been 24 April. We recorded eight prey delivered to male with the white PVC band flew away.On 20 March the nest during 41.9 hr of observation and all were 1996, F2 was observed copulating with the male with a brought by the female F2. The male "2AU" was never white PVC band and both kites brought sticksto the nest seen at F2 nest. We approached both nests on several in the eucalyptustree. On 22 March 1996 at 1026 H, the occasions.F1 nest was defended by two adults (kites hov- nest was observed while F2 incubated. The male with the ering abovethe nest) while F2 nestwas defended by only white PVC band flew to the nest and copulated with F2. one kite. On this occasion, the PVC band of the male was identi- DISCUSSION fied as "2AU." At 1234 H on the same day, a blind was set close to the nest occupied by F1 in the pine forest. Observationsin 1996 clearly showed that the same At 1353 H, the male "2AU" entered the nest in the stone male "2AU" copulated with two females that used differ- 256 SHORT COMMUNICATIONS VOL. 33, NO. 3 ent nests, helped both females with nest building and was 16 (maximum 19 nests). Red Kites layed eggsin 13 helped one of them (F1) with incubation. Both females nestsin 1996 and in 14 nestsin 1997 (F. Hiraldo unpubl. lard eggsand only one bred successfully.We cannot com- data). Nesting sitesdid not seem to be limited in any of pletely exclude from the 1996 observationsthat copula- the two years.We do not know if there could be an un- uons with F2 were extra-pair copulationsby "2AU" and balanced sex ratio or a lack of bachelor males. The ter- that F2 may have had an undetectedpartner. Observa- ritory of the male "2AU" could be of a higher quality uons in 1997 were detailed enough to showthat "2AU" than other territories in the area. The fact that F2 was was the only male seen with both females during nest able to raisea youngin 1997 without the help of the male building, incubation and brood rearing. The male suggeststhat food was abundant in the proximity of the "2AU" copulated seeminglyequally with both females nest. The F2 nest wasvery close to a group of inhabited and helped both during nest building. During brood houses,the "Palacio de Dofiana," that constitutesa pre- rearing, the male's attention was directed exclusivelyto dictable source of food for the kites. Also, we cannot ex- the F1 female and F2 raised its single nestling alone. clude the possibilitythat the male "2AU" wasof higher Polygynyhad not been previouslydocumented in Red quality than other males. Male "2AU" was 19 years old Kites, but as individuals tend to be very similar in color- in 1997, the oldest known-ageRed Kite in our marked ation this behavior could be very easilyoverlooked unless population (F. Hiraldo unpubl. data). The longevity of kites are marked. This polygynoustrio was similar to po- "2AU" may suggestthis bird carried "good genes"and lygynousbondings observed in Northern Harriers ( Circus he may have been a high-qualitymale. cyaneus)(Simmons et al. 1986) in that there was a hier- archybetween females. In the caseof the Red Kites,the RESUMEN.•Sedescriben las observacionesde un trio po- secondfemale to lay eggsreceived no attentionfrom the liglnico de milanos reales (Milvus milvus) en la Reserva male once its younghatched. Nearest-neighbor distance Bio16gicade Doftana, durante dos aftos consecutivos: betweenRed Kite nests (i = 893.1 m, range = 690-2250, 1996 y 1997. Un macho marcado, de edad conocida,se N = 21, Bustamante and Hiraldo 1990) was much shorter apare6 con dos hembras,posiblemente las mismas ambos than elsewhere in Europe (4-5 kin, Davies and Davis aftos, que utilizaron para poner nidos distintos.En 1996 1973, Valet 1975), probably indicating that there was la primera hembra cri6 dos pollos y la segundafracas6. abundant food for breeding Red Kites in Dofiana. The En 1997 la primera hembra en realizarla puestacri6 dos Dofiana area includes a highly productive marsh. The pollos y la segundauno. Se comprob6 este afto que el short distancebetween nesting territories in Dofiana may macho cebabay defendia exclusivamenteel nido de la have been a proximate causefacilitating this polygynous primera hembra y que la segundafue capaz de criar con mating. •xito su pollo sin la ayuda del macho. Four main hypotheseshave been proposedto explain [Traducci6n de Autores] how polygyny may be advantageous.The "polygyny threshold" hypothesis(Verner and Wilson 1966, Orians ACKNOWLEDGMENTS 1969) suggeststhat a female should chooseto mate po- We thank M. de la Riva, A. Fern/tndez, N. Lawson, D. lygynouslyin a high-qualityterritory when her fitness Lawson, and G. Vilchez for contributing with their ob- would be equal or greater than if she mated monoga- servations,and F. Hiraldo for accessto unpublisheddata. mouslyin a lower-qualityterritory. The "sexy son" hy- J.J.Negro, J.A. Don/tzar,R. Rodrlguez-Estrella,J. Bednarz and K. Bildsteinprovided helpful commentson the man- pothesis (Weatherheadand Robertson1979) suggests uscript.Funding was provided by projectPB96-0855 from that the female choiceof polygynycould be basedon the the Direcci6n General de Ensefianza Superior e Investi- quality of the male rather than his territory. A third pos- gaci6n Cfica, Ministerio de Educaci6n y Cultura, Spain, sibility is that if suitable breeding sites are limited and and by the Agencia de Medio Ambiente, Junta de An- monopolized by a few males, females may be forced to dalucia, Spain. mate polygynouslyrather than forgo breeding (Orians LITERATURE CITED 1961). A skewedsex ratio (shortageof males) could be equivalent to limited breeding sites.Finally, the "decep- ALATALO, R.V., A. CARI.SON, A. LUNDBERGAND S. ULF- uon" hypothesis(Alatalo et al. 1981) suggeststhat the STP,AND. 1981. The conflict between male polygyny male may be able to concealits mated statusto the fe- and female monogamy:the caseof the Pied Flycatch- males holding two separateterritories. er P•cedulahypoleuca. Am. Nat. 117:738-753. It is difficult to believe that the male was able to de- BUST^MANTE,J. 1990. Condicionanteseco16gicos del pe- ceive the second female and hide its mated status consid- riodo de emancipaci6n en Falconiformes.Ph.D. dis- ering the polygynoustrio wasstable for twoyears and that sertation, Univ. Aut6noma de Madrid, Madrid, Spain. the two nestswere very close.In 1996 and 1997, we sur- 1993. Post-fledgingdependence period and de- veyed32 nestingterritories inside the Dofiana Biological velopmentof flight and hunting behaviourin the Red Reserve(10 000 ha) that had been occupiedby Red Kites Kite Milvus milvus.Bird Study40:181-188. at least once since 1981. For the period 1981-97, the -- ANDF. HIRALDO.1990. Adoptionsof fledglingsby averagenumber of nestsin which Red Kites layed eggs Black and Red Kites. Anim. Behar. 39:804-806. SEPTEMBER1999 SHORT COMMUNICATIONS 257

--AND --'. 1993. The function of aggressive ORIANS,G.H. 1961. The ecology of blackbird (Agelaius) chasesby breeding Black and Red Kites Milvus mi- socialsystem. Ecol. Monog• 31:285-312. gransand M. milvusduring the post-fledgingdepen- --. 1969. On the evolutionof mating systemsin birds denceperiod. Ibis 135:139-147. and mammals. Am. Nat. 103:589-603. CRAMP, S. AND K.E.L. SIMMONS. 1980. Handbook of the ROGERS, P.M. AND K. MYERS. 1980. Animal distribution, birds of Europe, the Middle East and North Africa. lanscapeclassification and wildlife management,Coto Vol. II. Oxford Univ. Press, Oxford, U.K. de Dofiana, Spain.J. Appl.Ecol. 17:545-565. DAVIES,P.W. •ND P.E. DAVIS.1973. The ecologyand con- SIMMONS, R.E., R.E. SMITH AND R.B. MACWHIRTER. 1986. servation of the Red Kite in Wales. Br. Birds 66:183- Hierachies among Northern Harriers (Circuscyaneus) 224. haremsand the costof polygyny.J. Anim.Ecol. 55:755- 771. FAABORG,J. ANDJ.C. BEDNARZ.1990. Gal/tpagosand Har- ris' Hawks:divergent causesof socialityin two raptors. TELL%J.L. 1993. Polyandroustrios in a population of Pages357-383 in P. Staceyand W.D. Koenig [EDS.], EgyptianVultures. J. RaptorRes. 27:119-120. Cooperative breeding in birds. Cambridge Univ. --, JJ. NEGRO,M. VILLARROEL,U. KUHNLEIN,F. HI- Press,Cambridge, NY U.S.A. RALDO,F. DON•ZARAND D. BIRD. 1996. DNA finger- GLUTZ VON BLOTZHEIM, U.N., K.M. BAUERAND E. BEZZEL. printing revealspolygyny in the LesserKestrel (Falco naumanni). Auk 113:262-265. 1971. Handbuch der VGgel Mitteleuropas.Vol. 4. Fal- VALET,G. 1975.La sedentarisationdu Milan RoyalMilvus coniformis. Vol. 4. AcademischeVerlagsgesellschaft milvus en Auxois. Alauda 43:263-269. AULA-verlag,Wiesbaden, Germany. VALVERDE,J.A. 1958. An ecological sketch of the Coto HEREDIA,B. ANDJ.A. DON•ZAR.1990. High frequencyof Dofiana. Br. Birds 51:1-23. polyandroustrios in an endangeredpopulation of VERNER,J. ANDM.E WILSON.1966. The influence of hab- Lammergeiers ( Gypaetusbarbatus). Biol. Conserv.53: itat on mating systemof North American passerlne 163-171. birds. Ecology47:143-147. HIRALDO,F.,jj. NEGROANDJ.A. DON•ZAR. 1991. Aborted WEATHERHEAD,PJ. ANDRJ. ROBERTSON.1979. Offspring polygynyin the LesserKestrel Falco naumanni (Aves, qualityand the polygynythreshold: "the sexyson hy- Falconidae). Ethology 89:253-257. pothesis". Am. Nat. 113:201-208. NEWTON,I. 1979.Population ecology ofraptors. T. & A.D. Poyser,Berkhamsted, U.K. Received 5 December 1998; accepted 20 April 1999

j. RaptorRes. 33 (3) :257-260 ¸ 1999 The Raptor ResearchFoundation, Inc.

MITES IN GREATER SPOTrED EAGLE NESTS

DAPaUSZJ. GWIAZDOWICZ,TADEUSZ MIZERA AND MACIEJSKORUPSKI AkademiaRolnicza, Katedra Ochrony Lasu, and Zoologii •rodowiska Przyrodniczego, ul. Wojska Polskiego 71c, PL 60-625 Poznmi, Poland

KEYWoRDs: SpottedEagle;, Aquila clanga;mites; Acari; Me- (Querqusspp.) and willows (Salix spp.). While the mite sostigmata;Biebrza National Park Poland. fauna in the nests of severalpredatory birds has been studied in Europe (Nordberg 1936, Philips 1981, Wi•- niewski and Hirschmann 1985, 1990, Mizera 1990, Maian The Greater Spotted Eagle (Aquila clanga)is among 1993), the acarofaunaof Greater SpottedEagle nestshas the rarest predatory birds in the world, nestingfrom the never been described.In this paper, we identify mites of eastern areas of Poland, through Belarus and Russiato the order Mesostigmatawhich inhabit the nestsof Greater the Pacific coast (Meyburg 1994). In Poland, it is legally Spotted Eagles in Poland. These mites are small (adult protected and classifiedin the Red Data Book as Endan- length 0.4-1.6 mm), free4iving arachnids which have gered (Kr61 1992). It nestsin impenetrable boggywoods phoretic or other relationshipswith birds. and, in Poland, only about 12 pairs remain in Biebrza National Park (Maciorowskiet al. 1996). Greater Spotted METHODS Eagles build their nests only in birches (Betula spp.), Samples were obtained at two Greater Spotted Eagle black beech (Alnusglutinosa) and, lessfrequently, in oaks nests in Biebrza National Park in northeastern Poland.