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Home , Accipitridae, Buteo, Buteogallus, Common black hawk, Cuban black hawk, Great black hawk

THE JOURNAL OF RAPTOR RESEARCH A QUARTERLY PUBLICATION OF THE RAPTOR RESEARCH FOUNDATION, INC.

VOL. 39 DECEM}•E}• 2005 NO. 4

J. RaptorRes. 39(4):351-364 ¸ 2005 The Raptor ResearchFoundation, Inc.

TAXONOMIC STATUS AND BIOLOGY OF THE CUBAN BLACK- , ANTHIM CINUS GUNDLA CHII (AVES: )

JAMESW. WILEY1 USGSMaryland CooperativeFish and WildlifeResearch Unit, Universityof Maryland EasternShore, 1120 TriggHall, PrincessAnne, MD 21853 U.S.A.

ORLANDO H. GARRIDO 1706 Calle60 entre17 y 19, Marianao13 (Playa),La Habana,

ABSTRACT.--Wereevaluate the taxonomicstatus of the Cuban population of the Common Black-Hawk (Buteogallusanthracinus) based on our examinationof additionalspecimens, nests, eggs, and voicedata. Buteogallusa. gundlachiiis smaller than mainland populationsof anthracinusand differs from mainland in coloration and pattern. The common (alarm) call of gundlachiiis a seriesof three or four notes, differing from that of mainland anthracinus,whose call consistsof 9-24 notes. In the Isla de Pinos,Cuba, we observedgundlachii eating two speciesof land (71.4%), centipedes(7.1%), (10.7%), (7.1%), and a (3.6%). We considerButeogallus gundlachii Cabanis 1854 (1855), the Cuban Black-Hawk,to be a full ,endemic to Cuba, Isla de Pinos, and many of the caysof the Cuban Archipelago. KEYWOP, DS: CommonBlack-Hawk; Buteogallus anthracinus; Cuban Black-Hawk; Buteogallus gundlachii; Buteogallussubtilis; ; .

ESTADOTAXON(•MICO Y BIOLOGiA DE BUTEOGALLUSANTHRACINUS GUNDLACHII (AVES: ACCIPITRIDAE) RESUMEN.--Eneste estudio re-evaluamosel estatustaxon6mico de la poblaci6n cubana de Buteogallus anthracinus(subespecie gundlachii) con base en ex•tmenesde especimenesadicionales, nidos, huevosy datosde la voz.Los individuosde B. a. gundlachiison m•ts pequefios que los individuosde laspoblaciones continentalesde B. anthracinus,y difieren de las aves del continente en la coloraci6n y patr6n del plumaje. E1 llamado comfin de alarma de gundlachiies una serie de tres o cuatro notas, mientras que el llamado de anthracinusen el continente consistede entre 9 y 24 notas. En la Isla de Pinos, Cuba, observamosa gundlachiialimenfftndose de dos especiesde cangrejosterrestres (71.4%), ciempifis (7.1%), lagartijas(10.7%), mamiferos(7.1%) y un ave (3.6%). ConsideramosButeogallus gundlachii Cabanis,1854 (1855) debe ser tratado como una especiedistinta, endfimica de Cuba, la Isla de Pinos y muchosde los cayosdel archipifilagocubano. [Traducci6n del autores]

The New World ButeogallusLesson, 1830 bitinga)of the lowlandsof to northern Ar- includes five species,mostly restricted to tropical gentina, (B. meriodionalis)inhabit- areas,including Great Black-Hawk(Buteogallus uru- ing savannasand marshes of western to northern , Rufous -Hawk (B. aeqm- • Email address:[email protected] noctialis)occurring in of northeastern

351 352 WILEY ANr• GAp,mtso VOL. 39, No. 4

Venezuela to eastern (Pararia), and Man- is also true for other forms of the genusButeogallus, grove Black-Hawk (B. subtilis),which is restricted e.g., anthracinusand subtilis,which are currently to the Pacific coasts and rivers of E1 Salvador south recognized as different species (Aldrich and Bole to northwestern . The Common Black-Hawk 1937,Areadon 1982, Mayr and Cottrell 1979,Stiles (Buteogallusanthracinus, Deppe 1830) ranges from and Skutch 1989, Sibleyand Monroe 1990, Amer- southwestern , south to extreme ican Ornithologists' Union 1998, Ridgely and northern (coastal Venezuela to Greenfield 2001), but with reservationby someau- northeastern Guiana), Colombia, to northern thors (Stiles and Skutch 1989, American Ornithol- Peru, including Trinidad, and some of the West ogists'Union 1998, Ridgely and Greenfield 2001). Indies (Bond 1950, American Ornithologists' Here, we reevaluate the taxonornic status of the Union 1998). One of the West Indian populations Cuban population of Buteogallusanthracinus gund- (B. a. cancrivorusClark 1905b) is restricted to St. lachii, based on our examination of more speci- Vincent, St. Lucia, Union Island (Grenadines), and mens, nests, eggs, and behavioral data, especially Grenada (accidental and doubtful in last two is- vocalizations, than were considered by previous lands; no specimenstaken; Clark 1905a, 1905b, workers. All published work on the Cuban form 1905c, Bond 1950, Evans 1990) in the Lesser An- has been based on information from the few spec- tilles, whereasthe only other Antillean population imens collected before 1960, all of which are de- (B. a. gundlachiiCabanis 1854 [1855]) occursin posited in foreign institutions.In this study,we in- Cuba and its satellites. The taxonomic status of the clude specimensin North American and Cuban Cuban population has been controversial,with collections, including those collected after 1960, some consideringthe form as a full species,- and not evaluated previously. gallusgundlachii (as originallydescribed by Cabanis Our main comparisonin this assessmentis with [1854, actually 1855]) instead of Buteogallusanth- anthracinus,the most often linked to gund- racinusgundlachii (American Ornithologists' Union lachii. In these comparisons,we refer to Cuban 1998). Among those authorities who have consid- populations as gundlachiiand other forms as anth- ered the Cuban form gundlachiiconspecific with racinus.It is not the purpose of this contribution the continental species (anthracinus)are Sharpe to speculateon the taxonomic statusof Buteogallus (1874, 1899), Cory (1887, 1892), Bangsand Zap- subtilis(including the three ),although pey (1905), Bond (1956a, 1956b), Areadon (1961), we make some comparisonsbetween subtilisand Brown and Amadon (1968), Mayr and Short gundlachii. (1970), Stresemannand Areadon in Mayr and Cot- trell (1979), Palmer (1988), Sibley and Monroe STUDY AREA (1990), Ferguson-Leesand Christie (2001), Dick- Many of the observationsreported here were made inson (2003), and others. Conversely,other au- during our 30 yr of field experience throughout Cuba. thorshave consideredgundlachii different from Bu- We made more intensive observationsof nesting black- from 1996 to 1998 at the Los Indios Ecological teogallusanthracinus at the specieslevel: Cabanis Reserve,Isla de Pinos (now Isla de la Juventud). Major (1855), Gundlach (1854, 1865-1866a, 1865-1866b, vegetationalcommunities at Los Indios include: (1) man- 1871, 1876), Ridgway(1876), Gurney (1876, 1934), grove forest formation, characterizedby black Bangs (1905), Swarm (1921-1922, 1930), Peters (Avicenniagerminans) and red mangrove(Rhizophora man- (1931), Bond (1936), Hellmayr and Conover gle); (2) semi-deciduousgallery forests,with prominent Cuban royal palm (Roystonearegia), beach hibiscus(H•- (1949), Friedmann (1950), Monroe (1963, 1968), biscustiliaceus), and pond apple (Annonaglabra); (3) the Wetmore (1965), and others. Some of these au- open forest (savanna)formation of an open pine (Pinus thors subsequentlychanged their opinions on the caribaeaand P tropicalis)and Cuban bottle palm (C01p0th- Cuban form's status,later consideringgundlachii rinax wrightii),with silversaw palm ( Acoelorraphewrightn) and a sparseundergrowth; and (4) the pine-barren for- conspecificwith anthracinus(e.g., Gundlach 1893, marion, with pines and palms, and an undergrowth pre- Bond 1950, 1956a, 1956b). With rare exception, dominantly of Pachyanthuscubcrisis, P poiretii,Kalmiella ag- however,previous evaluations did not considerthe gregata, Miconia delicatula, Polygala uncinata, Lyoma important characteristicsof breeding biology and myrtilloides,and Pinguiculafilifolia(Jennings 1917, Alain voice, mainly becauseof the limited knowledgeof 1946). Black-hawkobservations were made mainly in the mangroveand gallery forests.Additional intensiveobser- the Cuban form resulting from the difficulty in vations in red and black mangrove habitats were made reaching its breeding habitats.The lack of natural in Cifnaga de Zapata in December 1999. An elevated historyinformation is not unique to gundlachii,but road bed, lined with Casuarinaequisetifolia and scrubveg- DECEMBER 2005 CUBAN BLACK-HAWK STATUS AND BIOLOGY 353 etation, bisectsthe mangroveforest where we made our tion procedure within DFA revealed wing chord, observationsnear PlayaLarga. tail length, and exposedculmen were the most im- METHODS portant of the size variables measured. Plots con- trasting these variables within sex showed anthra- We examined specimensof Buteogallusa. anthracinus (N = 37), B. a. gundlachii(12), B. a. cancrivorus(4), B. cinusand gundlachiitended to occupygenerally subtilis(25), B. aequinoctialis(3), and B. urubitinga(24) distinctregions of the morphologicalspace (Fig. depositedin the Field Museumof Natural History (Chi- 1). cago), Museum of ComparativeZoology (Harvard Uni- To further examine size differences between the versity), American Museum of Natural History, United two populations, we used linear discriminant anal- StatesNational Museumof Natural History,Academy of Natural Sciencesof Philadelphia, Louisiana State Univer- ysisto classifyspecimens into two groups("race"), sity Museum of Natural History, Museo Nacional de His- mainland anthracinusand Cuban g'undlachii,using toria Natural de Cuba (La Habana), and Instituto de Eco- lengths of wing chord, tail, culmen, and tarsusas logia y Sistemgtica (Cuba) (Table 1). Conventional predictors.For male anthracinus,the analysispro- measurementsof wing chord (flattened againstthe rul- er), tail, tarsus,and exposedculmen were taken to the duced a true group classificationproportion of nearest0.1 mm with calipers.Egg masseswere measured 0.938 (15 of 16 correctly classified)and 0.857 (6 to the nearestgram usingspring scales. We presentsum- of 7 correctlyclassified) for gundlachiimales, for mary descriptivestatistics (mean, SD, and range) for the an overall proportion correct of 0.913 (21 of 23) specimens.We plotted body measurementsto assessthe (Wilks's lambda = 0.375; X2 = 17.646; df = 4, P • pattern of spatial segregationamong populationsand forms. The hypothesisof separation derived from the 0.001). For females,the analysisproduced a true plotsof bodymeasurements was tested using discriminate group classificationproportion of 0.857 (18 of 21) function analysis(DFA; Kleinbaum and Kupper 1978). for anthracinusand 0.800 (4 of 5) for g'undlachn SPSS (1999) for Windows was used to run DFA. individuals,for an overall proportion correct of

RESULTS 0.846 (22 of 26) (Wilks's lambda = 0.4.95; X2 = 14.781.1; df = 4, P • 0.005). Morphometrics and Plumage. Adult . The four adult female St. Vincent (B. a. cancn- Our examinations of the two taxa of B. anthracinus vorus) specimens we examined were somewhat (anthracinusand g'undlachii)revealed differences in larger in wing chord (i = 389 --- 7.63, range = size and coloration. We found sexual size dimor- 385-401; t = -4.99, P = 0.002, df = 6) than g'und- phismin three of the measurementstaken of spec- lachii females, whereas we found no difference be- imens of mainland anthracinus (Table 1). There- tween the two island forms in tail (213.3 _+ 12.4; fore, size comparisonsbetween anthracinusand range = 200-230; t = -1.83, P > 0.05, df = 6), gundlachiiwere made within sex; i.e., male anthra- culmen (27.3 --- 0.8; range = 26.8-28.4; t = 0.60, cinuswith male g'undlachiiand female anthracinus P > 0.05, df = 5), or tarsus(85.5 + 6.4; range = with female g'undlachii.Tarsal length was not dif- 81.0-94.9; t -- -1.63, P > 0.05, df = 4) length. We ferent in either population,so for comparinganth- found no differences (P > 0.05) in measurements racinuswith g'undlachiitarsi we combined male and between anthracinus and cancrivorus. female measurementsfor that morphometricpa- In general coloration, gundlachiidiffers from B. rameter. Only measurementsof wing and exposed anthracinusand B. subtilisin being chocolate- culmen for gundlachiirevealed sexual size dimor- brown, not slate blackish or even black as in the phism (P • 0.01; Table 1), althoughthe smallsam- latter two forms. However,some specimens of anth- ple size of females (N = 5) precluded a reliable racinus, especially of the race cancrivorus,have a analysis. Measurements of gundlachiiyielded a tendencyto be lessblackish, almost dark brown. mean Dimorphic Index (Storer 1966) of 6.9, com- The underparts of gundlachiihave a pared with a mean index of 5.6 for anthracinus(Ta- light (brownish-gray)edge, more conspicuousto- ble 1). ward the abdominal region and more broadly Birds from Cuba (g'undlachii)are substantially edged on the alula covertsthan in anthracinus,with smaller than mainland (anthracinus) birds in some the edgingon the terminal alula covertsbecoming conventionalmeasurements, including wing chord white bands. The margins of the flank and thigh in both sexesand tail length in males (Table 2). feathers are heavily marked, forming a seriesof Also, tarsal lengths (combined male and female bands,although these bandstend to disappearin measurements) were significantly different be- older birds. The shoulder feathers are boldly tween the two forms (P = 0.001). A stepwiseselec- barred in white, contrastingwith the chocolate- 354 WILEY AND GAmUDO VOL. 39, No. 4

Table 1. Sexualsize dimorphismin four body measurementsfrom specimensof Buteogallusanthracinus (mainland Buteogallusa. anthracinus and CubanB. a. gundlachii),B. subtilis,B. aequinoctialis,and B. urubitinga,expressed as mean, standarddeviation, range, and samplesize (in parentheses).Statistical analyses are between-sexcomparisons (two- sample t-test;equal variancesnot assumed).

SPECIES SEX SIGNIF- STRUCTURE MALE FEMALE t df P 1CANCEa D.I.b

Buteogallusanthracinus Wing 371.69 + 11.95 (16) 385.19 + 11.21 (21) -3.50 31 0.001 * 3.6 341-393 360-421 Tail 195.50 _+7.40 (16) 213.81 __-10.61 (21) -6.18 34 0.0001 * 8.9 183-210 190-230 Exposedculmen 26.27 -+ 0.82 (16) 27.40 +_1.25 (20) 3.24 32 0.003 * 4.2 25.1-28.1 23.6-30.3 Tarsus 85.94 _+2.65 (16) 85.42 + 4.00 (21) 0.48 34 0.636 ns -0.6 80-90.0 80.3-92.7 Mean D.I. 4.0 Buteogallusgundlachii Wing 342.71_+ 12.16 (7) 363.00+ 8.43 (5) -3.41 9 0.008 * 5.8 323-370 350-372 Tail 179.29 _+9.12 (7) 191.60 +--22.16 (5) -1.15 4 0.313 ns 6.6 167-197 182-233 Exposedculmen 25.32 -+ 0.69 (7) 27.54 +--0.61 (5) -5.84 9 0.0001 * 8.3 24.5-28.5 26.7-28.1 Tarsus 81.33 _+3.57 (6) 79.67 + 3.56 (5) 0.77 8 0.464 ns -2.1 75.4-87 79.0-87.7 Mean D.I. 4.7 Buteogallussubtilis Wing 348.0 _+13.68 (12) 352.31 + 13.43 (13) -0.79 22 0.436 ns 1.2 330-370 328-373 Tail 189.92 -+ 14.58 (12) 191.69 + 8.65 (13) -0.37 17 0.719 ns 0.9 168-220 180-205 Exposedculmen 25.46+_ 2.06 (12) 26.56+ 1.56 (12) -1.47 20 0.157 ns 4.2 19.7-27.8 23.1-28.8 Tarsus 79.78 +_3.09 (11) 79.55 + 2.76 (13) 0.19 19 0.848 ns -0.3 73.3-84.1 75.0-84.0 Mean D.I. 1.5 Buteogallusaequinoctialis Wing 315.5 +_0.71 (2) 322 (1) 315-316 Tail 155.0 + 2.83 (2) 155 (1) 153-157 Exposedculmen 23.55 +- 0.92 (2) 16.8 (1) 22.9-24.2 Tarsus 74.5 + 3.54 (2) 72.8 (1) 72-77 Buteogallusurubitinga Wing 384.94+ 16.68 (16) 389.63_+ 18.36 (8) -0.61 12 0.555 ns 0.1 362-412 365-415 Tail 225.13 + 13.50 (16) 234.63 _+ 17.54 (8) -1.35 11 0.206 ns 4.1 190-250 210-260 Exposedculmen 29.72 +- 1.05 (16) 30.78 _+2.20 (8) -1.84 8 0.103 ns 3.5 26.7-30.9 27.2-34.2 Tarsus 112 + 8.25 (16) 113.16 -+ 7.76 (8) -0.11 14 0.910 ns 1.0 85.9-118.9 98.8-123.0 Mean D.I. 2.2

Significance,* = P < 0.05, ns = not significant. D.I. = Dimorphic Index (Storer 1966). DECEMBER 2005 CUBAN BLACK-HAWK STATUS AND BIOLOGY 355

Table 2. Mean, standarddeviation, and samplesize (parentheses)for wing chord, tail, culmen, and tarsuslength for mainland (Buteogallusa. anthracinus)and Cuban (Buteogallusa. gundlachii)populations of the Common Black- Hawk. Statisticalanalyses are within-sexcomparisons (two-sample t-test; equal variancesnot assumed)between mmn- land and Cuban specimens,except for tarsus,for which we found no sexualsize dimorphism.

TAXON

STRUCTURE SEX B. A. ANTHRACINUS B. A. GUNDLACHII t df P SIGNIFICANCE a

Wing M 371.69 -+ 11.95 (16) 342.71 - 12.16 (7) 5.28 11 <0.001 * F 385.19 -+ 11.21 (21) 363.00 - 8.43 (5) 4.94 7 0.002 * Tail M 195.50 - 7.40 (16) 179.29 - 9.12 (7) 4.14 9 0.003 * F 213.81 - 10.61 (21) 191.60 _+ 22.16 (5) 2.14 4 0.099 ns Exposed M 26.27 - 0.82 (16) 25.32 -+ 0.69 (7) 2.86 13 0.013 * culmen F 27.40 -+ 1.25 (20) 27.54 +--0.61 (5) -0.36 13 0.728 ns Tarsus M and Fb 85.64 -+ 3.45 (37) 80.57 - 3.49 (11) 4.24 16 0.001 * Significance,* = P < 0.05, ns = not significant. Male and female tarsusdata combinedbecause specimens did not displaysexual size dimorphism. brown ground colon Remigesare dark brown, with marks are seldom present in fully-feathered im- wing covertsedged in grayish-cinnamon,especially mature birds. The sides of the face and throat are the secondaries.The undersidesof primaries and whitish, speckledwith brown. The pileum, nape, some secondarieshave an extensivewhite patch, and neck are heavily mottled or spotted with which constitutes the most distinctive character of brown on a light (white or beige) background. the Cuban form. In subtilis,and especiallyanthra- Flanks and thighs also displayconsiderable varia- cinus,this patch is mottled with grayish-brown.The tion, with youngerbirds showinga lighter (whitish tertiaries of gundlachiiare heavily mottled grayish. to brownish-beige) background, whereas older This mottling is similar to the coloration of the birds displaymore mottling or barring. The thighs primaries and secondariesof anthracinus,which are distinctly barred with light and dark bands in has only an inconspicuouswhitish patch on the un- subtilisand anthracinus,whereas gundlachii has mot- dersides of these feathers. On the other hand, tled or very lightly barred thighs. some specimensof subtilisdisplay more white in The white patch of the underside of primaries is this region than does anthracinus,but do not ap- even more expanded and conspicuousin subadult proach the amount shownin gundlachii. than in adult gundlachii.Also, the subadult's tail is The upperparts in gundlachiiare also brown, distinct from that of the adult's tail. When still not with brownish-grayor with a trace of cinnamon on in full adult plumage, the subadult's tail shows the margins.The head and pileum are uni- remnants of several(as many as nine) thin, brown- formly chocolatebrown. The rectricesare darker ish bands, instead of displaying a single broad brown, almost blackish, with a broad white band white band in the middle of the tail as in the adult. of variablewidth (averaging40 mm) in the middle Some bands are complete, whereas others are of the tail. The tip of the tail is edged in white (as somewhat broken. In Cuban birds, these bands are wide as 13 mm), which is a purer white than in straight and parallel, whereasin the other forms anthracinusand subtilis.The feet and cere are yel- they are oblique (chevron-like), as well as being low, the claws are black, and the iris is dark brown. much wider than in gundlachii.The bands become The bill is blackishat the tip, becomingmore yel- less delimited toward the tip; compared with the lowish toward the base on maxilla and mandible. adult, the white tip of the subadult'stail is lessde- Immaturemorphology. Immature gundlachiiindivid- marcated, more grayish than white, and becomes uals are not chocolate brown ventrally, but rather browner from the tip toward the base. whitish, and heavily mottled with brown, having Natural History. Habitat. Although we occasion- some feathers with considerablebeige suffusion. ally observed black-hawkswithin the white sand Many feathers are mottled with medallion-like palm savannaof Los Indios, Isla de Pinos, nearly marks,whereas others are marked with elongated all observationswere made in the coastalzone, pri- blotches, and some with streak-like dashes; these marily in mangrove forestsor at the edges of that 356 WILEY AND GARRIDO VOL. 39, NO. 4

Male Female 400 420 - 390 410 - 380 400 - 370 :

o 390 ß 360 380-- 350 ß o ß ß 370 -- 34O

360 -- ß 330 o

320 350 -- o i I i i i i i 170 1 0 1 0 200 210 160 170 180 190 200 210 220 230 Tail Tail

420 -- 420 -- 410 -- 410 -

400 -- ß 400 - ß ß ß 390- 390- ß ß ß 380- ß 380- ß ß ß ß 370 -- o 370 - o o

360- 360 - o

350 - 350 - o i i i i i i I I I • 23.5 24.5 25.5 26.5 27.5 28.5 29.5 30.5 23.5 24.5 25.5 26.5 27.5 28.5 29.5 30.5 Culmen Culmen

210 -- 230 -

ß ß oß ß ß 220 - ß ß ß 200 -- ß 210 - I I ß ß ß o ß ß ß ß ß ß'= 190 -- __ 200 -

190 -

180 - o o 180 -

170 - 170 - o 160 -

75 80 8 90 75 8 95 Tarsus Tarsus

Figure 1. Plotscontrasting body measurements of specimensof mainlandButeogallus anthracinus anthracinus (solid dots;N = 16 males,21 females)and Cuban B. a. gundlachii(open circles;N = 7 males,5 females). habitat. Hawks hunted in the sparsely-vegetated containedeggs, except the nest examinedon 27 mangrove pannes and flooded openings, where May 1996,which had one chick.During our obser- they foraged by perching in young or dead man- vations at Isla de Pinos, which were well into the groves.We also sawblack-hawks foraging or roost- breeding season,we observedno aerial courtship, ing in beachand coastalhabitats, frequently perch- although individual gundlachiiregularly soaredsi- ing in windbreaksof Casuarinaequisetifolia at the lently for short periodsabove their nestingareas. edge of mangrovesand dirt roads. Of the eight gundlachiinests we examinedat Los Nidification.We examined eight nestsat Los In- Indios, half were placed in black-mangrovesand dios within the period of 14-27 May 1996-98. All half in red-mangroves(Table 3). Each of the nests DECEMBER 2005 CUBAN BLACK-HAwK STATUS AND BIOLOGY 357

was in the subcanopy,shaded by foliage and was constructedcompletely of Avicenniaand Rhizophora twigs. The nests showed a large range of sizes, probably the result of additionsmade in successive years. Two of the nestswe monitored from 1996 through 1998 were reused by black-hawks,and in- creased in size with the addition of more nest ma- terials in subsequentyears. All nests examined at Los Indios contained fresh or older lining materi- als, consistingof green leavesand sprigsof Avicen- nia and Rhizophora,and some debris. Both adults were observed bringing green lining material to nests. Nests had notably deep bowls (Table 3) and when adultswere on nestsincubating or brooding, they remained low in the bowl and were difficult to detect. During our inspections of nests at Los Indios, adultsat three nestsregularly perched plac- idly within 2 m of us while we measured eggsand chicks. Adults at a fourth nest were somewhat more aggressive,but the pair only flew low above our heads, occasionallycalling, and vocalized from a nearby perch while we measured eggs. We measured 11 eggs at Los Indios (Table 3). Three eggs collected by O. H. Garrido in Cayo õ xx Cantiles (Archipi61agode los Canarreos;deposited at Instituto de Ecologia y Sistem•ttica)measured 55.16 x 44.1 mm, 55.8 x 42.6 mm, and 57.08 X 42.34 mm. The 14 gundlachiieggs we measuredav- eraged55.87 - 0.69 (range = 54.7-57.08) X 42.71 +--0.62 (range = 41.9-44.1) mm. Eggs of gundla- chii are typically short sub-elliptical to elliptical, with a finely granulated texture. Eggs have a dull grayish-white ground color, sometimes with a greenishor bluish castearly in incubation,and are marked with spotsand blotchesof dark or reddish- brown, particularly at the larger end. Glutch sizes at Los Indios averaged1.57 + 0.53 (N = 8; range = 1-2) eggs (Table 3). The egg of gundlachiiis usually more colored (bluish to greenish suffu- sion) than those of anthracinusor subtilis,which are typicallygrayish or whitish (Bent 1937, Wetmore 1965, O. Garrido pers. obs.). Diet and foraging behavior.Cuban birds were found to feed on a variety of prey (Table 4). No- table wasthe lack of prey, although fisheswere availablein tidal channelsin the studyarea. How- ever, twice, hawkswere observedwading in shallow tidal channelsand making foot thrustsat probable fish prey. During our observation periods (May- June) at Los Indios, land crab populations were particularly high, and crabs were active and con- 358 WILEY AND GARRIDO VOL. 39, NO. 4

Table 4. Prey of Buteogallusanthracinus gundlachii at Los Indios, Isla de Pinos, Cuba, 1996-1998, and Cifinagade Zapata, Cuba, 1999-2000.

NUMBER(%)

OBSERVEDBROUGHT TOTAL (%) ALL PREY TO NEST PREY REMAINS OBSERVED CAPTURES OBSERVATIONS

Invertebrates Crab Cardisomaguanhumi 4 12 2 18 (64.3) Ucidescordatus 1 I 2 (7.1) Centipedesp. 1 1 2 (7.1) Totals () 6 (21.4) 14 (50.0) 2 (7.1) 22 (78.6)

Vertebrates Lizards Anolisspp. 1 I 2 (7.1) Ameiva auberi I 1 (3.6) Totals (reptiles) 2 (7.1) 1 (3.6) 3 (10.7) Birds Sora Porzana carolina I 1 (3.6) Totals (birds) 1 (3.6) 1 (3.6)

Mammals Rattus rattus 2 2 (7.1) Totals (mammals) 2 (11) 2 (7.1) Total () 2 (7.1) 4 (14.3) 6 (21.4) Total (all observations) 8 (28.6) 18 (64.3) 2 (7.1) 28

spicuousin the early mornings and evenings,when hawksreturning to the cachesto feed on the stock- most of our observationsof prey delivery and cap- piled crabs. tures were made. In December 1999, we also ob- Although B. a. anthracinushas been observed served gundlachiicapturing severalcrabs (Cardiso- (0. Garrido pers. obs.) in Mexico hunting at the ma guanhumi) along the coast of Cifinaga de edge of a meadow in a fashion similar to that of Zapata, where the hawks hunted from a mixed the coursing behavior of the Northern mangrove-Casuarinaequisetifolia-coastal scrub zone. (Circus cyaneus),gundlachii was not observed for- During our observationsin the Los Indios man- aging aerially in an active manner. grove habitat, gundlachii displayed passive still Vocalbehavior. The common call of gundlachiiis hunting from low (i -- 1.3 ___0.94; range = 0.2-3 a seriesof three or, uncommonly,four notes,with m; N = 54) mangrove tree perches or from the emphasison the first two elements, suggestingits ground. Prey captureswere made in a low-angle Cuban common name, BA-TIS-ta (Gundlach 1893, flight, snatching the item (all observations of Garrido and Schwartz 1969, Garrido and Kirkcon- crabs) and continuing to a nearby perch, or the nell 2000; Fig. 2A). The call has a much shorter hawk landed near the crab and stalked it on foot. duration and fewer elements than in other popu- Once the hawk graspedthe crab, it controlled the lations of Buteogallusanthracinus (Table 5). The clawsand legs on either side of the prey with its common call of mainland anthracinus consists of 9- feet, then removed the carapacewith a quick tug 24 notes, with the middle to the final third of the at the head region using its bill. notes accentuated (Fig. 2C-F, Table 5). Stilesand We found apparent cachesof uneaten, though Skutch (1989) characterized the call of mainland dismembered,land crabsnear (range = 5-20 m) anthracinus as "klee klee klee KI.EE KI.EF. klee kle kle used gundlachiinests. However, we did not observe keki ki." The comparable call of cancrivorusconsists DECEMBER 2005 CUBAN BLACK-HAWK STATUS AND BIOLOGY 359

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Figure 2. Sonographsof common (alarm) calls of Buteogallusspecies. A. Buteogallusanthracinus gundlachii, showing typical three element "ba-tis-ta" phrase, Cuba (G.B. Reynard). B. Buteogallusa. cancrivorus,St. Vincent (J. Roche, courtesyBritish Library Sound Archive). C. Buteogallusa. anthracinus,Costa Rica (Cornell Library of Natural Sounds 27216). D. Buteogallusa. anthracinus,Venezuela (P. Schwartz).E. Buteogallusa. anthracinus,male, Arizona (courtesyJ. Schnell). E Buteogallusa. anthracinus,female, Arizona (courtesyJ. Schnell). G. Buteogallusurubitinga, Venezuela (P. Schwartz).H. Buteogallusaequinoctialis, Surinam (Paul Donahue, courtesyBritish Library Sound Archive). 360 W•.F.¾ AND GARRIDO VOL. 39, NO. 4

of a large number of elements (22-37), with em- phasison severalmiddle elements (Fig. 2B, Table 5). Similarly,the common call of B. subtillsis sub- stantially different from that of gundlachii,consist- ing of several,rapidly repeated elements, described by Ferguson-Leesand Christie (2001) as a seriesof shrill whistles, indistinguishable from anthracinus. The call of Buteogallusurubitinga consists of a single note, drawn out in a high shrill "heeeeeeeeh"(Fer- guson-Leesand Christie 2001; Fig. 2G), whereas that of Buteoaequinoctialis is a distinctseries of whis- tle-like notes (Ferguson-Leesand Christie 2001;

+1 +1 +1 +1 +1 +1 +1 Fig. 2H, Table 5).

DISCUSSION As is normal among most birds of prey, female gundlachiiare somewhat larger than males, with culmen and wing length significantlydifferent be- tween genders.Sexual size dimorphismwas less ev- ident in anthracinus(• Dimorphic Index = 4.0) than gundlachii,where we found a mean Dimor- phic Index of 4.7 with males significantlylarger

+1 +1 +1 +1 +1 +1 +1 than femalesin wing and culmen length (Table 1). Snyderand Wiley (1976) reported a lower index (2.7) of sexualsize dimorphism for B. anthracinus. Whereas measurementsof selectedbody parts did not show complete distinction between anth- racinus and gundlachii (Table 2, Fig. 1), Cuban birds were consistentlysmaller or at the smallend of the range for anthracinusmeasurements. In con- trast to our measurements,Bangs (1905) partly based his determination of separatingg'undlach•z from anthracinuson the former being slightlylarg- er than the latter, and in havinga decidedlyheavi- er, broader bill. As a general pattern, Schnell (1994) noted that Common Black-Hawks of conti- nental (inland) North and are largest.Mainland anthracinuspopulations inhabit- ing mangrove habitat tend to be smaller and browner than others. The race B. subtilisrhizopho- rae, which inhabits mangrove habitat (Monroe +l • 1963, 1968,Blake 1977), showsa dark-brownplum- age. Our observations revealed that Cuban birds, also mangroveinhabitants, are consistentlybrown- er with substantialdifferences in plumage pattern compared with mainland birds. Thus, such color differences may be a result of ecologicalparallel- ism, rather than of phylogeneticrelationships. The speciesof Buteogallusare partial to wetlands, swampywoods, and seacoasts(Amadon 1982). In its mainland range, anthracinushas been charac- terized as inhabiting woodlands around coastal DECEMBER 2005 CUBAN BLACK-HAWK STATUS AND BIOLOGY 361 swamps,ponds, and streams,and especiallyman- aggressivetoward humans at their nests and al- grovesin the swampywoodlands adjacent to the lowed us to approach much closerthan other local poorly-drained inlands that are affected by tide- raptor speciestolerated, perhaps relying on their waters (Phillips et al. 1964, Wetmore 1965, Davis cryptic behavior to avoid detection at the nest. 1972, Schnell 1994). Wetmore (1965) noted that Others have also noted this tolerance in Cuban along large rivers they extend their range farther black-hawks (Todd 1916, Barbour 1923, Garrido inland. Thomas (1908) reported anthracinusin and Schwartz 1969). stretchesof sand dunes and savannaswith clumps Schnell (1994) reviewedavailable egg specimens of palmettos and pines. The Cuban population for Buteogallusanthracinus, summarizing mean showsa similar preference for lowland coastalar- measurements from Bent (1937) as 57.3 X 44.9 eas. Gundlach (1893) and Bangs (1905) noted mm (N = 60 eggs) and examplesin the Western gundlachiiwas found only in mangroveswamps and Foundationof VertebrateZoology as 57.30 X 45.50 on the banks of large rivers. In broad contrast,the mm (N = 12 clutches, 19 eggs; range = 52.61- other West Indian population, Buteogallusanthraci- 62.02 mm length, 42.69-47.35 mm breadth). Eggs nus cancrivorusof St. Vincent, mainly keepsto the of anthracinus we measured at the Delaware Mu- high wooded valleys,although it seldomoccurs far seum of Natural History averaged 57.46 (53.1- from water (Lister 1880, Clark 1905b, Bond 63.2) x 45.25 (41.7-49.1) mm (N = 13 clutches, 1956a). 21 eggs). Interestingly,an egg reported from St. Cuban populations of the black-hawk breed Vincent is at the high end for the species:61 x 47 from January through June (Garrido and Kirkcon- mm (Bond 1936) and exceedsthe range for gund- nell 2000), with egg-layingoccurring in late March lachii.Eggs of gundlachiiwe measuredat Los Indios or April. Bangs (1905) collecteda female contain- averaged only slightly smaller than those of main- ing a soft-shelledegg and found another tending land B. anthracinusanalyzed by Schnell (1994). a nest on 15 April. Bond (1950) reported a nest Gundlach(1876) reported that Cuban eggsmea- with a newly-hatchedchick on 4 April. Garrido and sured58 x 45 mm, whereasBangs (1905) reported Schwartz (1969) and Vald6s Mir6 (1984) com- 56 x 45.5 mm. Measurementspresented by Vald•s mented gundlachiibuilds its nest at a considerable Mir6 (1984) are obviouslyin error; i.e., • = 56.0 distance above the ground. Gundlach (1876) re- (range = 55.0-57.0) X 24.6 (23.0-26.5) mm. The ported a nest at 8 "varas" (6.8 m), whereasBond mean mass (61.0 + 1.8 g) of eggswe measured at (1936) noted one at 6.2 m. Los Indios was somewhatlighter compared with Nests of the Cuban form are typically rough Schnell's estimated mean massof 63.8 g for anth- structures of twigs, lined with green leaves and, racinus. sometimes, debris (Gundlach 1893, Bond 1936, Although we observed differences in egg color- Garrido and Schwartz 1969, Vald6s Mir6 1984). ation and pattern among anthracinus,subtills, and Bond (1936), describingnests found in St. Vincent gundlachii,these charactersshow considerablevar- (B. a. cancrivorus)and Cuba (gundlachii), noted, iation and do not appear to be a good character "The nest, a rough mat of sticks,is placed at vari- for determining relationships (L. Kiff pers. ous elevationsin trees." All nestslocated by us at comm.). Los Indios in 1996-98 were in mangroves (Avicen- Schnell (1994) noted that, in general, clutch size nia, Rhizophora).In contrast, Bond (1936) de- of Buteogallusanthracinus decreased from two eggs scribedblack-hawk nests in St. Vincent as "placed in the northern range to one in the southern on top of clumps of mistletoe and were rather range; several reported three-egg clutches were small." As Bond (1936) suggested,nests of the Cu- questionable.Clutch sizesat Los Indios fell within ban species are somewhat larger than those of that range, averaging1.57 eggsper clutch. birds in St. Vincent. Schnell (1994) gave the di- Buteogallusanthracinus feeds mainly on inver- mensionsof mainland anthracinusnests as ranging tebrates and lower vertebrates, with occasional from 38 cm diameter x 20 cm deep to 1.2 m di- small birds or mammals in the diet (Schnell 1994). ameter x 0.67-1.2 m deep. Bangs (1905) and For mainland populations,Thomas (1908) report- Bond (1936) also noted gundlachiire-used nests in ed anthracinuspreying on burrowing land crabs, more than one season, which we believe accounts, which form almost the sole diet of the hawks in in part, for the larger nest size of Cuban birds. British Honduras (Belize). The St. Vincent popu- Black-hawksat Los Indios were remarkably non- lation (B. a. cancrivorus)reportedly feeds on cray- 362 WILEY AND GAPd•DO VOL. 39, NO. 4 fish and freshwater crabs (Lister 1880). In Cuba, "eeeeee-eh"or "kree-ee-ee-er"(Ferguson-Lees and Gundlach (1893) reported remains of , Christie 2001). as well as , ,and fishesin the stomachs CONCLUSIONS of black-hawks.Barbour (1943) reported land crabs as its prey in Cuba. Garrido and Kirkconnell We considerButeogallus anthracinus (with its geo- (2000) reported its prey as mainly crabsand birds, graphical races, cancrivorusand anthracinus),B. whereas Ramsden (C. Ramsden, Museo de His- urubitinga,B. aequinoctialis,and B. gundlachiias sep- toria Natural, Universidadde Oriente, Santiagode arate species.This treatment of the Cuban popu- Cuba unpubl. data) noted the hawk fed on crabs lation agreeswith Wetmore (1965:234),who stated and . the other forms stand apart: "... from the bird of The hunting behaviorof Buteogallus,in general, the island of Cuba which it appears appropriate to has been characterized as sluggish. Schnell (in treat as a separate species,Buteogallus gundlachii." Palmer 1988, 1994) noted B. anthradnusnormally Thus, the Cuban Black-HawkButeogallus gundlachn hunts from a stationary perch, often near the Cabanis, 1854 (1855), becomesa speciesendemic ground, from branchesup to 15 m high, on boul- to Cuba, distributed in the main island, where it is ders, other low perches, and gravel beds along relativelyuncommon and quite localized, Isla de streams. For Cuban hawks, Barbour (1923) de- Pinos, and many of the keys of the Cuban Archi- scribed crab similar to our observations: pelago.

"The hawk pounceson the crab, gathers the legs ACKNOWLEDGMENTS and claws of each side in one of its feet, and reach- A grant from the American Museum of Natural History ing down removesthe carapaceby hooking the bill allowed Garrido to undertake studies of West Indian under its front edge." Kirkconnell and Garrido birds in its and other United StatesMuseums. We grate- (1991) reported gundlachiidrowning its avian prey fully acknowledgehelp and supportfrom the RARECen- (Common Moorhen [ Gallinula chloro•us]),which ter for Tropical Conservation,through John Guarnaccia and Victor L. Gonzalez, enabling visitsto collectionsin they suggestedwas unusual and perhapsrelated to several museums. We also thank the curators of the the abundant rain that caused the raising of the American Museum of Natural History, the Smithsonian water level in the swamp,rendering crabsdifficult Institution, the Museum of ComparativeZoology, Loui- to find. siana State University Museum of Natural History, Acad- We observed Cuban Black-Hawkscaching crab emy of Natural Science, Delaware Museum of Natural History, Instituto de Ecologia y Sistemgtica,and Museo prey near their nest, a habit that has also been re- Nacional de Historia Natural de Cuba for their cooper- ported for B. anthracinusin mainland sites (Thom- ation. Wiley's researchin Isla de Pinoswas supported by as 1908, Schnell 1991, 1994). grants from Wildlife Preservation Trust International, As noted by Schnell (1994), descriptionsof the World Parrot Fund, International Crane Foundation, and the U.S. Department of the Interior. We are particularly vocal behavior of Buteogallusanthracinus have been grateful to Lic. Xiomara Gglvez,Empresa Nacional para confusingand conflicting.Schnell (1994) charac- la Conservaci6nde la Flora y Fauna, for logisticalsupport terized the common call (= alarm call) as of a and field assistanceat Los Indios. For use of tape record- complex, un-raptor-like quality. The common call ings of Buteogallusvocalizations, we thank GeorgeB. Rey- of mainland Buteogallusanthracinus is distinct from nard, Paul Schwartz, L. Irby Davis, R. Grimshaw,J Schnell, Richard Ranft, and the British Library Sound the three-note call of gundlachii,consisting of 9-24 Archive. We thank Lloyd F. Kiff, Jay H. Schnell, and an notes (Reynard and Garrido 1988, Schnell 1994) anonymousreviewer for their helpful suggestions,which (Figs. 2A, 2C-F, Table 5). Similarly, the common greatlyimproved the manuscript. call of B. subtilisis distinct from that of gundlachii, LITERATURE CITED consistingof several, rapidly-repeatedelements, describedby Ferguson-Leesand Christie (2001) as Ai•iN, H. 1946. Notas taxon6micasy eco16gicassobre la a series of shrill whistles, indistinguishablefrom flora de Isla de Pinos. Contr. Ocas. Museo Hist. Nat. that of anthracinus.The call of Buteogallusaequinoc- Coleg.La Salle7:11-115. ALDRICH,J.W. ANDB.P. BOLE,JR. 1937. The birds and t•alis is a series of six or seven whistle-like notes, mammals of the western slope of the Azuero Penin- the first three rapid, followed by slower and de- sula, Republic of Panama. Sci. Publ. ClevelandMus scending elements (Fig. 2H; Ferguson-Leesand Nat. Hist. 7:1-196. Christie 2001). Finally, B. meriodionalishas a call AMADON,D. 1961. Remarkson the genusButeogallus. Nov consisting of a prolonged whistle, described as Colombianas 1:358-360. DECEMBER 2005 CUBAN BI•ACK-HAWK STATUS AND BIOLOGY 363

ß 1982. A revision of the sub-Buteonine hawks (Ac- EvANs, P.G.H. 1990. Birds of the eastern Caribbean. Mac- cipitridae,Aves). Am. Mus. Nov.No. 2741:1-20. Millan PressLtd., London, Englandß AMERICAN ORNITHOLOGISTS' UNIONß 1998. Check-list of FERGUSON-LEES,J. AND D.A. CHRISTIE.2001. Raptors of North American birds, 7th Ed. American Ornitholo- the worldß Houghton Mifflin Co., New York, NY gists'Union, Washington,DC U.S.A. UßS.Aß BANGS,O. 1905. The Cuban Crab Hawk, Urubitingagund- FRIEDMANN,H. 1950. Birds of North and Middle America, lachii (Cabanis). Auk 22:307-309. . U.S. Nat. Mus. Bull. 50, pt. 11. -- AND W.R. ZAP?EY. 1905. Birds of the Isle of Pines. GAaPaDO,O.H. ANDA. KmKCONNELL.2000. Field guide to Am. Nat. 39:179-215. the birds of Cuba. Cornell UniversityPress, Ithaca, NY BAP,BOUR, T. 1923. The birds of Cuba. Mem. Nuttall Or- UßSßAß nithol. Club 6. --AND A. SCHWARTZ.1969. Antibios, reptiles y aves ß 1943. Cuban .Mem. Nuttall Ornithol. de Cayo Cantiles.Poeyana 67:44. Club 9. GUNDLACH,J. 1854. Beitrage zur Ornithologie Cuba'sß BENT, A.C. 1937. Life histories of North American birds Nach Mittheilungen des Reisenden an Hr. Bez.-Dm of prey.Part I. U.S.Nat. Mus. Bull. 167. Sezekornin Cassel;von Letzterem zusammengestellt. BLAIr, E.R. 1977. Manual of NeDtropicalbirds. Vol. I. Mit Zustzen und Anmerkungen geordnet vom He- UniversityChicago Press,Chicago, IL U.S.A. rausgeber.J. Ornithol.2 (extra-heft):77-87. BOND,J. 1936. Birds of the West Indies. Acad. Nat. Sci. 1865-1866a. Revista y cat•logo de las aves Cu- Philadelphia, PA U.S.A. banas. Pages 165-180 in Repertorio F•sico Natural de --. 1950. Check- of the West Indies. Acad. la Isla de Cuba. Vol. 1 (E Poey, lED.I). Imprenta del Nat. Sci. Philadelphia, PA U.S.A. Gobierno y Capitania General, La Habana. --. 1956a. Check-list of birds of the West Indies, 4th 1865-1866b. Revistay catfdogo de las aves Cu- banas. Pages221-224 in Repertorio Fisico Natural de Ed. Acad. Nat. Sci. Philadelphia,PA U.S.A. la Isla de Cuba. Vol. 1 (E Poey, lED.I). Imprenta del --. 1956b. First supplementto the Check-listof birds Gobierno y Capitan•a General, La Habana. of the West Indies (1956). Acad. Nat. Sci. Philadel- 1871. Neue Beitrage zur Ornithologie Cubas. phia, PA U.S.A. Nach eigenen 30 jahrigen Beobachtungen zusam- BROWN,L. ANDD. AMADON.1968ß , hawks and fal- mengestellt.J. Ornithol.19:353-378ß cons of the world. Vol. 2. McGraw-Hill Book Co., New ß 1876. ContribuciGna la ornitologiaCubana. La York, NY U.S.A. Habana: "La Antilia." CABANIS,J.L. 1855. Dr. J. Gundlach'sBeltrage zur Ornit- 1893. Ornitolog•a Cubana. La Habana: La Mo- hologie Cuba's.J. Ornithol.2 (extra-heft 1854 [pub- derna. lished 1855] ):77-87. GURNEY,J.H. 1876. Notes on a "Catalogue of the Acc•- CLARK,A.H. 1905a. The Crab Hawk (Urubitinga) in the pitres in the British Museum," by R. Bowdler Sharpe island of St. Lucia, West Indies. Auk 22:210. (1874). Ibis, series 3, 6:467-493. 1905b. Preliminary descriptionsof three new 1934. A list of the diurnal birds of prey, with birds from St. Vincent, West Indies. Proc. Biol. Soc. references and annotations. John Van Voorst, Lon- Wash. 18:61-63. don, Englandß --. 1905c. Birds of the southern . Proc. HELLMAYR,C., ANDH. CONOVER.1949. Catalogue of birds Boston Soc. Nat. Hist. 32:203-312. of the AmericasßField Mus. Nat. Hist. Zool.Sex., 13, part CORY,C.B. 1887. The birds of the WestIndies, including 1(4). the Bahama Islands, the Greater and the Lesser An- JENNINGS,O.E. 1917. A contribution to the botany of the rilles, excepting the islandsof Tobago and Trinidad. Isle of Pines, Cuba, based upon the specimensof Auk 4:37-51. plantsfrom that island contained in the herbarium of ß1892. Catalogueof WestIndian birds, containing the Carnegie Museum under date of October, 1916. a list of all speciesknown to occur in the Bahama Ann. CarnegieMus. 11:19-290. Islands, the Greater Antilles, the Caymans,and the KIRKCONNELL,A. AND O. GARRIDO. 1991. Aberrante com- LesserAntilles, excepting the islandsof Tobago and portamiento de caza del Gavil/tn Batista Buteogallus Trinidad, Privatelypublished by the author, Boston, anthracinusgundlachii (Aves: Accipitridae) en Cuba MA U.S.A. Vol.Migrat. No. 16:27-28. D^vIs,L.I. 1972. A field guide to the birdsof Mexico and KLEINB^UM,D.G. ANDL.L. KUPPER.1978. Applied regres- Central America. University Texas Press,Austin, TX sion analysisand other multivariable methods. Dux- U.S.A. bury Press,North Scituate,MA U.S.A. DICKINSON, E.C. [ED.]. 2003. The Howard and Moore LISTER, C.E. 1880. Field-notes on the birds of St. Vincent, complete checklist of the birds of the world, rev. and West Indies. Ibis, ser. 4, 4:38-44ß enlarged 3rd Ed. Princeton UniversityPress, Prince- MAYR, E. AND G.W. COTTRI•LL [EDS.]. 1979. Check-list of ton, NJ U.S.A. birds of the world. Vol. 1, 2nd Ed. (rev. of the work 364 WILEY AND GAm•IDO VOL. 39, NO. 4

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