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j. RaptorRes. 38(3):263-269 ¸ 2004 The Raptor ResearchFoundation, Inc.

BREEDING BIOLOGY OF THE GREY-FACED ( INDICUS) IN NORTHEASTERN

WEN-HONG DENG 1 MOE KeyLaboratory for BiodiversityScience and Ecological En•neering, College of Life Sciences, BeijingNormal University, Beijing, 100875 China

WEI GAO Collegeof Life Sciences,Northeast Normal University, Changchun, 130024 China

JI•NG ZHAO Collegeof Life Sciences,illin NormalUniversity, Siping, 136000 China

ABSTRACT.--Westudied the breeding biologyof the Grey-facedBuzzard (Butasturindicus) in Zuojia Nature Reserve,Jinlin province,China from 1996-98. Grey-facedBuzzards are summerresidents in northeasternChina. Nesting sites were occupied in Marchand annualreoccupancy was 60%. Grey-faced Buzzardsbuilt new or repairedold nestsin late March and laid eggsin earlyApril. Layingpeaked in late April and spanned32 d (N = 15 clutches).Clutches consisted of 3-4 eggs,incubated for 33 -+ 1 d predominantlyby the female,to whomthe malebrought prey. After young hatched, the femalealso beganhunting. The mean brood-rearingperiod was 38 -+ 2 d and nestlingfemales attained larger asymptoticmass than males,but the lattergrew fasten Males fledged at a meanage of 35 d and females at 39 d. Youngwere slightlyheavier than adultsat fiedging,but the wing chordand tail lengthswere shorterthan thoseof adults.A total of 50 eggswas laid in 15 nests(i clutchsize = 3.3), of which80% hatchedand 90% of the nestlingsfledged. A mean of 2.4 youngfledged per breedingattempt. Overall nest successwas 80%. Causesof nest failure were addled eggsand predation on eggsor nestlingsby small (e.g., Siberian [Mustelasibe•ica] ). KEYWORDS: Grey-facedBuzzard; Butastur indicus; breeding biology; clutch size,, nestlings; fledglings; develop- m•t;, reproductivesuccess.

BIOLOG•A REPRODUCTIVA DE BUTASTUR INDICUS EN EL NORESTE DE CHINA REsUMEN.--Estudiamosla biologla reproductiva de Butasturindicus en la reservaNatural de la Provi- denciade Jinlin en Chinadesde 1996-98. B. indicuses un residentede veranoen el norestede China. Los sitiosde anidacionfueron ocupadosen Marzoy la reocupaci6nanual de los nidosfue el 60%. B. indicusconstruyo o repararolos nidosviejos a finalesde Marzoy pusohuevos a principiosde Abril. E1 pico de la posturaocurri6 en Abril y abarco32 dias (N = 15 nidadas).Las nidadasfueron de huevosincubados 33 +- 1 dias, los cualesfueron incubadospredominantemente pot la hembra, a la cual el machotraia presas.La media del periodo de crecimientofue de 38 _+2 dias,las hembras obtuvieronuna mayormasa corporal que los machos,pero estoscrecieron mas rSpidamente. Los ma- chosemplumaron en un promediode 35 diasy lashembras a los 39 dias.Los juveniles al emplumar fueron levementemas pesadosque los adultos.Una media de 50 huevosfue obtenidaen 15 nidos (tamafiode la nidada = 3.3), de loscuales un 80% eclosionarony un 90% de lospichones emplumaron una mediade 2.4 pichonesemplumados pot intento reproductivo.E1 6xito generalde anidacionfue de 80%. Las causasdel fracasode anidacionfueron atribuiblesa huevospodridos y ala depredacionde pichonespot pequefiosmamlferos (Mustela sibe•ica). [Traducci6n de C6sar Mfirquez]

Among subtropicalbirds, raptorsare one of the about their breeding biology,particularly in China. least-studiedgroups, and relativelylittle is known Since 1995, several surveyshave been conducted to document the distribution and population status E-mail address:[email protected] of Grey-facedBuzzards (Butasturindicus) during

263 264 DENG ET A•. VOL. 38, NO. 3

study period. The vegetation within the study area was quite diverse,although the forest type wassecondary for- est. The seven tree speciesmainly present on the study area were Mongolian (Quercusmongolica), Dahurian birch (Betula davurica), Manchurian linden (T ilia mand- schurica),Japanese elm (Ulmusjap0nica),Scotch (Pi- nus sylvestris), Korean larch ( Pinus koraiensis), and Masson pine (Pinus massoniana;Deng et al. 1997). In the study area, Dahurian rose (Rosa dahurica), Korean rose (Rosa doreana),willowleaf spiraea (Spiraeasalicifolia), ural false- spiraea (Sorbariasorbifolia), and Sakhalin honeysuckle (Loniceramaximowiczii) dominated the shrub layer.

METHODS Breeding areas were surveyed by foot periodically Figure 1. The distribution of the Grey-faced Buzzard. throughout the breeding seasonto find mated pairs. We Dark shading indicates breeding range; grey shading in- defined nesting sitesas an area where aerial displaying, mating, nest-building, incubating, brooding, and repeat- dicates winter ranges. The white square indicates the ed prey-carryingoccurred. An area with a mated pair was study area. considered an occupied nesting site. Observations of Grey-facedBuzzards in their breeding areas were made from above canopylookouts and ground blinds with the their breeding season in Zuojia Nature Reserve, aid of 8-12x binocularsand a spottingscope. We distin- northeastern China. Because of these survey ef- guished mature males, females, and iramatures by their forts, the is known from more localities body sizeand plumage color (Deng 1998). The body size of maleswas smaller than that of females.Also, the plum- than ever before in China (Deng et al. 1997). Feng age color of adults was darker than that of iramatures. et al. (1991) estimated the population at a maxi- We classifieddisplay flight as territorial only if followed mum of 30 breeding pairs in Zuojia Nature Re- by an encounter between the resident and an intruder serve and 1000 breeding pairs in northeastern Chi- (Delannoy and Cruz 1988), otherwise interactions be- tween pair members were considered courtship. We es- na. The species occurs either in conifer forests, timated above-groundheights of flying in courtship broad-leaf forests, or mixed forests. Grey-faced relative to known above-groundheights of hills and other are summer residents in this area. A va- topographic features. Nest measurements were taken at rieW of reports suggestthat most Grey-facedBuz- accessiblenests. Nest height was measuredin plumb-line zards that breed in northeastern China migrate to distancefrom the nest to ground level. Shortestdiameter, longest nest diameter, nest depth exterior, and nest Okinawa, Taiwan, the Philippines, Indonesia, and depth interior were measured using a ruler. Malaysia for wintering (Ching et al. 1989, Severin- We measured egg dimensions (breadth and length to ghaus 1991, Deng et al. 2003). the nearest 0.1 mm) with vernier calipers, and deter- Until now only two casesof breeding by Grey- mined egg massand body massof nestlings(nearest 0.1 g) with a spring scale (Pesola, Barr, Swizerland). Individ- faced Buzzardshave been reported in China (Feng ual young were marked with colored leg bandssoon after et al. 1991, Zheng and Wang 1998), and these only hatching. Ricklefs' (1967) method of fitting equationsto included brief descriptions. The nests and eggs growth curveswas used to compare growth patterns of have been described(Cheng 1987, Xu 1995), and male and female nestlings.Nestlings were weighed, and breeding territory and roost characteristicshave the length of their wing chord, tail length, culmen, and tarsal length were measured at 3-d intervals. After fiedg- been reported (Kojima 1982, Deng et al. 1997, ing, mist nets were used to capture fledglings and adults, 2003). Here, we describebreeding biology of Grey- which were measured (tarsal length, wing chord, culmen, faced Buzzards based on 3 yr of observationsin and tail length) and weighed. Tarsal length wasmeasured Zuojia Nature Reserve in northeastern China. from the intertarsal joint to the bend of the foot. The tail length (mm) was measured from the base to the tip STU•)¾ APm^ of the center rectrix. Reproductiveoutput was the total number of fledglings produced over a nestling season. The studyarea, ca. 184 kme in size,was located in Zuo- Reproductive successwas a general term that included jia Nature Rcserveand included the Tumengling Moun- severalmeasures and components,expressed on per pair, tains and Zhujia Mountains ranging from the eastern per breeding attempt, or per egg basis.All statisticalpro- Changbai Mountains to the western plain (126o1'- cedures followed Zar (1999). 127ø2'N, 44ø6'-45ø5'E; Fig. 1). Elevation at the site ranged from 200-500 m above sea level. The climate is RESULTS east monsoon, characterized by hot, dry summers and cold, snowywinters. Mean monthly temperatures ranged Courtship and Territoriality. We observed the from -20.5øC in January to 23.6øc in August during movements and behavior of fledglings for 118 hr SEPTEMBER2004 GREY-FACEDBUZZARD BREEDING BIOLOGY 265

Table 1. Grey-faced Buzzard nest-sitecharacteristics in northeastern Ghina.

NEST-SITE CHARACTERISTICS MEAN SD RANGE N

Nest height (m) 13.3 3.5 8.8-16.6 15 Nest-tree height (m) 17.5 3.3 13.5-22.9 15 Nest tree DBH (cm) 30.8 9.3 22.1-44.2 15 Shortest nest diameter (cm) 30.3 6.2 25.5-38.6 13 Longest nest diameter (cm) 35.1 7.6 28.9-40.3 13 Nest depth exterior (cm) 42.6 11.5 33.7-55.6 13 Nest depth interior (cm) 17.3 8.1 9.8-29.5 13 Nest support branch diameter (cm) 8.6 3.7 5-18 10 at two nests. Grey-faced Buzzardsare summer res- the pair createda bowl by compactinga layer of identsthat establishnesting territories only during finer twigswith their talons and breast. The earliest the breeding seasonin northeastern Ghina. Reoc- nest-buildingactivity in a seasonwas observedon cupancyof nesting sitesoccurs in early March. An- 21 March 1998. The earliest copulation was ob- nual reoccupancywas 60% (N = 15). Six nests servedon 29 March 1997, ca. 4 wk before laying. were reoccupied at least twice. Most Grey-faced Copulation usuallyoccurred after a courtshipdis- Buzzardactivity during March and early April in- play. volved courtshipand territorial displayflights. A More than half (N = 8) of nests were located in typical courtship flight began when the male cir- Korean latches. Nests typicallywere placed in the cled above the nest site and the female followed upper half (• height = 13.3 m) of relativelytall shortly afterwards. Both male and female soared trees (x height = 17.5 m; Table 1). and activelyflew giving intermittent vocalizations. Egg Laying, Incubation, and Hatching. By late Malesused flapping more frequentlythan females April, females remained near the nest site and and circled in the skyhigher than the females.Buz- were mostly inactive. Males provided food at this zards reached estimatedabove-ground heights of stageand during the following months. Earliestre- 30-150 m (• = 80 m, N = 12). Displaybouts lasted corded laying dateswere 20 April 1996, 17 April 5-20 min (x = 14 min, N = 12). Most courtship 1997, and 19 April 1998. Laying of first clutches flights (75%, N = 12) ended with a steepdive into spanned 37 d (17 April-24 May). First clutches the forests. We observed 11 territorial display were on average completed on 12 April + 9 d flights in the study area in 1998. Resident males (mean + SD, N = 15 clutches) for 3 yr. Mean initiated territorial behaviorfrom a perch (N = 7) or while in flight (N = 4). When intruders entered clutch sizewas 2.9 --- 0.8 (N = 15). Mean egg di- mensions were 53.7 X 43.3 mm (N = 47). The air spacenear the nesting site, resident males flew straight at them and evicted intruders. Buzzards mean egg masswas 51.5 g (49.8-53.5 g, N = 47), only chasedraptors and relativelylarge birds such 9.9% of the female'sbody mass(x female body as corvids. mass = 490 g, N = 6) and 38.2% of her massfor Nest Building and Nest Characteristics.Grey- a clutch of four eggs. faced Buzzardsstarted nest building shortly after Females incubated while males provided food. occupyingtheir nestingareas in late March or early In 1997,we recordedincubation patterns of a fe- April. Both adults took part in nest construction. male during 12-hr periods (0600-1800 H) for 5 In 1997, during 80 hr of observationat three nests, consecutivedays. The female incubated 22% of the we observeddeliveries of 72 dry sticks;males con- first day (1 egg), 29% of the secondday (2 eggs), tributed 43 (60%) and females 29 (40%). Most 38% of the third day (3 eggs),39% of the fourth nest building activityoccurred between0600-0730 day (3 eggs),and 43% of the fifth day (4 eggs). H. Nests were built in trees on forked branches. Most hatching occurred during late May, except Buzzardsgathered dry sticksfrom the ground or when pairs renested.Hatching wasasynchronous, nearby trees within 50 m of the nest trees. Several spanning 1-3 d. Hatching for all yearspeaked on nests contained dried or green needles of Pinus 25 May + 4 d and spanned12 d (20 May-2 June, spp. in the nest platform. Near nest completion, N = 10). The incubation period from laying to 266 DENG ET AL. VOL. 38, NO. 3 hatching of the last egg averaged 33.5 + 1.6 d (N b 600 o Females = 9). oo • 100V oFemales o 500 ßMales o_o _o 8O , Males.•• •o • Nestling Period. Young emerged from eggswith 400 .o. 60 8 • eyesclosed. The eyesbegan to open after 0.5 d. By 300 the fourth day after hatching, the young could 2OO 40 • iO0 20 • stand up and showed improved coordination in 0 o pecking at food held above them by the female. 10 20 30 0 10 20 30 40 Nestlings could be sexed accurately in the nest af- Age (d) Age (d)

d ter they were 8 d old by examining the feather tips c 300 _ o Females 200 (the primary feather tips of males emerged from o Females oa the sheaths at ca. 8 d, N = 14; females at 9-10 d, ß Males • ß ß Males N = 12) and extent of black in wing (males had o 100 more black than females). The first tail feathers 100 5O appeared at approximately 12.5 d in males (N = 2000 , , , 1500 _ ,e , , 14) and 12 d in females (N = 12). Young began to 20 40 replace the natal quill-coverts down 20 d after Age (d) Age (d) hatching. During the nestling period, males hunted more Figure 2. Changes of mass (a) tarsuslength (b) wing chord length (c) and tail length (d) of males (N = 9) frequently than females.However, only femalesdis- and females (N = 10) of Grey-facedBuzzard nestlingsin membered and fed prey to young. Late in the third northeastern China. week and early in the fourth week after hatching (19-26 d), females spent less time brooding. In one nest, the female brooded four 18-d-old young Fledgling and Post-fledglingPeriods. Fledging more than half of the time (N = 8 hr), but de- spannednearly 7 wk, from mid-June-lateJuly. After creased brooding to 8% (N = 8 hr) when the fiedging, young remained in the nest area and re- young were 26 d old. From 25-31 d after hatching, turned to the nest frequently. By 42-48 d after the young squabbled over prey and were able to hatching, the young had dispersed50-100 m from dismembermost soft parts. At 26-28 d, the young the nest. Adult females still fed young at this time. flapped their wings regularly and began to roost The young were capable of handling and carrying overnight in branches near the nests.The nestling prey to a perch away from the nest and their sib- period ended when the young flew short distances lings. Young constantlysolicited food and mobbed from the nest and roosted in trees 10-20 m away. adults when the adults entered the nest area. Nine males fledged at a mean of 35 d of age (range At two nest sites, we monitored movements of = 33-38, SD = 1.2), and 10 females at 39 d (range five young. One young did not spend time in the = 37-41, SD = 1.1), with a combinedmean fledg- nest area awayfrom the nest,but dispersedabrupt- ing age of 37 d (range = 31-41, SD = 2). ly. Four spent 2 d awaybefore their dispersal.The Growth Rate. Increase in tarsi length, mass,wing agesof young at one nest site averaged76 d (N = and tail length followed Gompertz or logistic 3) and in another 80 d (N = 2) when they dis- growth patterns (Fig. 2). Male and female nestlings persed. Adults and young did not staytogether af- showed differences in mass growth patterns. Fe- ter the latter dispersed. males attained a higher asymptotic mass than Reproductive Success.From 1996-98, 18 nests males (• female = 559 g, N = 10; 2 male = 462 g, were built and 15 nesting attemptswere observed N = 9). It took males 12.6 d to grow half their (eggs laid; Table 2). In 1.5 nesting attempts, two asymptoticmass, but 15.1 d for females. The time nest failures occurred during incubation and one •nterval of growth from 10-90% of the asymptote during the nestling stage.According to our obser- (tin-t90) was shorter in males than in females (• vations, the causes for nest failure (N = 5) were male = 25 d, N = 9; • female = 27 d, N = 10). predation on eggs or nestlingsby small mammals Males generally fledged earlier (36-38 d) than fe- (such as the Siberian weasel [Mustda siberica]). males (37-41 d). Both malesand femalesat fledg- ing were slightlyheavier than adults (adult mass:2 DISCUSSION male = 396 _ 11 g, N = 9; • female = 519 ___13 Our observation of Grey-faced Buzzard court- g,N = 10). ship and territorial behavior appearsto differ from SEPTEMBER2004 GREY-FACEDBUZZARD BREEDINGBIOLOGY 267

Table 2. Annual reproductive successof Grey-facedBuzzards during breeding season(1996-98) at Zuojia Nature Reserve, northeastern China.

PRODUG- MEAN EGGS YOUNG SUCCESSFUL TIVITY NESTING EGGS CLUTCH HATCHED FLEDGED NESTS N PER NEST YEAR ATTEMPTSa LAID SIZE ( % ) ( % ) ( % ) ATTEMPT

1996 4 12 3.0 10 (83) 8 (80) 4 (100) 2.0 1997 6 22 3.7 15 (68) 14 (93) 4 (67) 2.3 1998 5 16 3.2 14 (87) 14 (100) 4 (80) 2.8 Total 15 50 3.3 40 (80) 36 (90) 12 (80) 2.4 Number of nestswith eggs. other Butasturbuzzards. White-eyed Buzzards (B. Buzzards and they had a relatively longer brood- teesa)and Rufous-wingedBuzzards (B. liventer)sel- rearing period (Cheng 1987, Xu 1995). dom circled above their nest site during the pre- It is possiblethat the breeding season,especially nestingperiod (Smythies1986, Cheng 1987, Xu the laying and nestling period of the Grey-faced 1995). GrasshopperBuzzards (B. rufipennis),which Buzzard, was restricted by food abundance. In occursin , performed soaringdisplays above northeastern China, the prey of the buzzards are the nest site (Rasa 1987, Thiollay and Clobert mainly , (snakesand ), , 1990). The behavior of Grey-faced Buzzards cir- and some small birds (Deng 1998). We suggestthat cling above the nest site during the pairing period the nestling and fiedging periods in Grey-faced might serveboth to attract potential matesand to Buzzardswere synchronizedwith the peak of prey give an assertivemessage to potential intruders. abundance. Grey-facedBuzzards showed strong territorial be- Grey-faced Buzzards preferred to build their haviorwhen birds of similar sizeand shapeentered nestsin large Korean larchesand Scotchpines with the territory. We frequently observedchasing be- high canopyclosure in wooded areas (Deng et al. haviorsof the buzzardsdirected toward congeners, 2003). This selection was different from that of other raptors,waterfowl, and corvids. White-eyedand Rufous-wingedbuzzards (Xu 1995, The nesting period was ca. 105 d from nest Deng et al. 2003). White-eyed Buzzards usually building to dispersalof young from their natal ar- built their nestsin broadleaf tree speciesin open eas.This is comparable to White-eyedand Rufous- countryor cultivatedareas (Cheng 1987). Howev- winged buzzards,which have relativelyshort nest- er, Rufous-winged Buzzards preferred to build ing periods(Smythies 1986, Cheng 1987,Xu 1995, their nestsin conifer or broadleaf tree speciesnear Gao 2003). Also, the breeding period in Grey-faced rivers and swamps in lowland plains (Smythies Buzzardsis shorter than that of their tropical coun- terpartsof comparablesize (Newton 1979, Mader 1986, Lekagul and Round 1991). 1981, Delannoy and Cruz 1988, Thorstrom and Most raptors select habitat typeswith relatively Quixch•tn 2000). The nesting cycle of songbirds open canopyfor easier accessto nests,and fewer alsois longer in tropical than in temperateregions. connectionsbetween neighboring trees,which lim- Differences between tropical and temperate avian its the movements of arboreal (e.g., Moore groupsare due to differencesin the length of time and Henny 1983, Cerasoli and Penteriani 1996, required to complete various stagesof breeding Malan and Robinson 2001, Malan and Shultz (Newton and Marquiss 1982, Delannoy and Cruz 2002). We did not find this selectionpattern in our 1988). The shorter breeding period of the Grey- study.On the contrary, Grey-facedBuzzards select- faced Buzzardscompared to that of the White-eyed ed their breeding habitat in dense conifer or and Rufous-winged buzzards (Smythies 1986, mixed forests. Thorstrom and Quixch•tn (2000) Cheng 1987, Xu 1995) resultedfrom shorter pe- suggestedthat denseforest habitat may limit raptor riods of nest building, courtship, egg laying, and hunting behaviors.According to our observations, brood rearing. White-eyedand Rufous-wingedbuz- Grey-facedBuzzards seldom hunt in the forest near zards built their nests earlier than the Grey-faced nest sites.Their foraging siteswere often in open 268 DENG ET AL. VOL. 38, NO. 3 areas such as pastures,peat bogs, and paddy fields and Bao-xue Zhang were very patient in helping with near the nest sites. data collection.Earlier draftsof this manuscriptwere im- proved by commentsfrom Zheng-wangZhang and Yan- Female nestlingsattained a higher asymptotic yun Zhang. The staff of Zuojia Natural Protection Area mass than males. However, males left the nests ear- provided logisticalsupport during the studyperiod. We her than females. Sexual differences in growth also thank the anonymousreviewers of The Journal of rates have been found in other raptors (e.g., Raptor Research.

Schnell 1958, Moss 1979, Delannoy and Cruz LITERATURE CITED 1988). In this study, during the late nestling period, BORTOLOTTI,G.R. 1986. of growth rates in ea- young were slightly heavier than adults, and the gles: sibling competition vs. energy considerations. mass decreased slightly at least for females when Ecology67:182-194. CERASOLI, M. AND V. PENTERIANI. 1996. Nest-site and ae- the fledgling period began (Fig. 2). This pattern rial point selectionby Common Buzzards( buteo) also was found in the (B. l•teo; in central . J. RaptorRes. 30:130-135. Xu 1995) and the (Buteohemilas- CHENC,T. 1987. A synopsisof the avifaunaof China. Sci- zus;Gao 2003). Grey-facedBuzzard young fledged ence Press,Beijing, China. (took their first flight from the nest tree) 31-41 d CHINe, H.C., S.T. Yu, ) C.H. CHIANC,.1989. A survey after hatching. This is comparableto the Rufous- of Grey-faced Buzzard hunting in ManChou winged Buzzard'srelatively short brood-rearingpe- Area. KenTing National , Taipei, China. riod (Gao 2003). DELANNOY,C.A. ANDA. CRUZ.1988. Breeding biologyof Productivity seemed high during the study,with the Puerto Rican Sharp-shinnedHawk (Accipiterstria- 2.4 young fledged per breeding attempt. High pro- tus venator). Auk 105:649-662. ductivitywas the result of a low nest predation rate DEN(;, W.H. 1998. Breeding ecology and habitat charac- and high nestingsuccess (80%). In our study,caus- teristicsof Grey-faced Buzzard. M.S. thesis,Northeast Normal Univ., Changchun, China. es of nest failure were addled eggs (N = 9) and --, W. (•AO, AND G.M. ZHENG. 2003. Nest and roost predation on eggs or nestlings (N = 8) by mam- habitat characteristicsof the Grey-faced Buzzard in mals such as the Siberian weasel. The richness and northeasternChina. J. RaptorRes. 37:228-235. density of animals that prey on Grey-faced Buz- --, X. WANe, ANDW. G,•o. 1997. Breeding habitat zards was low in the study area (Deng 1998). Few selection of the Grey-facedBuzzard Eagle.J. Northeast mortalities were observed in either adults or Norm. Univ. 9:57-61. young. For example, two adult females banded in FENG,H.L, G.Q. X•ANc,,AND K.Q. ZH•'4G. 1991. Obser- 1996 were still on their territories in 1998. Thus, if vation on breeding Grey-facedBuzzard Eagle. Chi- a pair of Grey-fhcedBuzzards was successfulin lay- nese SciencePublishing House, Beijing, China. ing eggs, they had a good chance of producing G^o, W. 2003. Ecologyof order in China. Chinese offspring successfully. SciencePress, Beijing, China. There are no data for productivityof other Bu- KOJIMA,Y. 1982. Territory and territorial behavior of the Grey-fhced Buzzard Eagle Butasturindicus. Tori Bull tastur species.However, productivity and nesting Ornithol.Soc. Jpn. 30:117-147. successwas higher for the Grey-facedBuzzard than LEg•CUL,B. ANt) P.D. ROUND.1991. A guide to the birds for the Puerto Rican Sharp-shinnedHawk ( of Thailand. Saha Barn Bhaet, Bangkok, Thailand. striatus;Delannoy and Cruz 1988), and the Bicol- MArmR,WJ. 1981. Notes on nestingraptors in the llanos ored (Accipiterbicolor; Thorstrom and Quix- of Venezuela. Condor 83:48-51. ch•n 2000). Sharp-shinnedHawks suffered a high- MALAN, G. AND E.R. ROBINSON. 2001. Nest-site selection er degree of nest failures fi:om nestling mortality by Black SparrowhawksAccipiter melanoleucus: imph- attributed to parasiteinfkstation and clutch deser- cationsfor managingexotic pulpwoodand sawlogfo•: tion. Bicolored laid addled eggs and suf- estsin South Atkica. Environ.Manage. 28:195-205. fered predation on eggs or nestlings.These pat- --•Nt) S. SnULTZ. 2002. Nest-site sclection of the terns were consistentwith the general trend that Crowned Hawk-Eagle in the forestsof Kwazulu-natal, tropical birds have lower fecundity and reproduc- , and TaL Ivory .J. RaptorRes. 36. 300-308. tive successthan their counterpartsin temperate MOORE,K.R. AND CJ. HENNY.1983. Nest site character- latitudes (Ricklefs 1969, Newton 1979). isticsof three coexistingaccipiter hawksin northeast ACKNOWLEDGMENTS Oregon. Raptorlies. 17:65-76. We thank Liu Yang, Yan-hui Li, Ren-kai Song, Lu-ye Moss, D. 1979. Growth of nestling Eurasian Spar- Tang, and Ya-meiYu for help in the field. Wei-dongLuo rowhawks,Accipiter nisus. J. Zool.197:297-314. SEPTEMBER 2004 GREY-FACED BuzzAm) BREEDING BIOLOGY 269

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