SUMMARY The large Magellanic Woodpecker (Campephilus magellanicus) inhabits the Nothofagus forests of southern South America, where only one small species of woodpecker (Dendrocopos lignarius) is a sympatric potential competitor. In the virtual absence of competition the Magellanic Woodpecker forages in diverse ways and at various sites. The sexes differ in bill length (almost no overlap between sexes), probably correlated with a difference in feeding habits. Nesting sites vary, as may the size of the clutch. The breeding season in southwestern Argentina commences in November. Drum-tapping is generally like that of other campephiline species for which data are available. Vocalizations resemble those of the Ivory-billed Woodpecker (Campephilus principalis) and other campephiline species (e.g., Phloeoceastes rubricollis). The Magellanic Woodpecker shows certain morphological similarities with the northern ivory-billed species (Campephilus principalis and C. imperialis), but also many differences which suggest that these two groups of woodpeckers independently evolved from ancestral species of Phloeoceastes. It is suggested that the Magellanic Woodpecker and the northern ivorybills comprise but two of five groups of campephiline woodpeckers, no group of which is sufficiently distinct to merit separate generic recognition. Accordingly, the 11 species of campephiline woodpeckers are considered congeneric (genus Campephilus).

HE Andes Mountains from central eastern Chile and central western Argentina south to Tierra del Fuego are cloaked with a south temperate forest dominated by various species of southern beech (genus Nothojagus) trees. Such forests are the home of a unique avifauna (Vuilleumier, 1967), including three species of woodpeckers. Only two of the latter actually gain their sustenance in true woodpecker fashion within the confines of the forest. The third species, the Chilean Flicker (Colaptes pitius), forages mainly on the ground about the edges of the forest, and around small isolated patches of forest in open country. The two forest woodpeckers are the small Striped Woodpecker (Dendrocopos lignarius) and the large Magellanic Woodpecker (Campephilus magellanicus). The latter was the subject of brief studies during late November 1967 in the region north of San Martin de los Andes, Neuqu6n, and at the Rio Villegas, 54 km south of San Carlos de Bariloche, Rio Negro. My particular interest in this species stemmed from its supposed close relationship (e.g., Peters, 1948) with the North American ivory-billed woodpeckers ( Campephilus principalis and C. imperialis). Vocalizations were recorded on tape, and movies were obtained, mainly of one nesting pair of birds at Rio Villegas on 28-29 November. ECOLOGY AND HABITS The general appearance of this large woodpecker is shown in Figures 1 to 3 (see also Fig. 7); a description is presented below. Magellanic Woodpeckers occurred mainly in mature, little disturbed southern beech forest and mixed southern beech-cypress (Cupressus) forest. They were observed less com- monly in cutover forest such as that shown in Figure 4. They were common at one and abundant at the other of the two localities where they were studied and they far outnumbered the uncommon Dendrocopos lignarius. Northeast of Lake Lolog, 18 km north of San Martin de los Andes, we located at least 13 pairs of these birds within a forest-edge strip about 100 m wide by about 2 km long (Figs. 5, 6). The sounds of their workings were not very loud; indeed, I could not distinguish with certainty the sounds made by feeding Magellanic Woodpeckers from those of feeding Striped Woodpeckers. The Magellanic Woodpeckers foraged in all parts of the trees. I saw them cling Dendrocoposdike to tiny twigs which seemed too small to support them and they fed as well on the. main trunks of large (to 1« m in diameter at breast height) trees. Two birds 115 116 THE WILSON BULLETIN u. 1970 Vol. 82, No. 2 I.,. ',  ,,.. ,, Fc. 1. Male Mage]]anic Woodpecker at nest cavit 5 1ometers south of San Carlos dc Ba]oche, Rio Negro, near the Rio Villeins. iFis. 14 kora 1- color movies.) Fig. 2. Figure 1. , , Female Magelladc Woodpecker at nest cavity; mate o[ male dpitd ia L ..... L. THE MAGELLANIC WOODPECKER 117 Short Fig. 3. Same female Magellanic Woodpker as in Figure 2, sho in silhouette with crest in typical posion. foraged on fallen, rotting logs, and one of these briefly descended to the ground while inspecting the fallen log. It struck me that this species seemed to occupy a broad "woodpecker niche," perhaps correlated with the virtual absence of competition. In its diversity of foraging sites it resembled species of Dryocopus (e.g., pileatus, lineatus) more than other campephiline species. The dimorphism in bill length between sexes of this species (Table 1) is in accord with the possibly broadened "niche" of Campephilus magel- lanicus in the absence of close competitors. Such sexual dimorphism was discussed by Selander and Giller (1963), who stressed its occurrence on islands inhabited by few or one species of woodpecker. It seems obvious that dimorphism in bill size, presumably correlated with differences in feeding habits between males and females (see, e.g., Kilham, 1965; Selander, 1965, 1966; Ashmole, 1967; and Ligon, 1968), can be expected wherever a species of woodpecker exists in the absence of other woodpeckers. In effect the &pauperate Fuegian Nothofagus forests are an "insular" situation for the Magellanic Woodpecker, as only the terrestrially feeding Colapres pitius and the diminutive Dendrocopos lignarius occur sympatrically. Unfortunately, I have too few observations of feeding Magellanic Woodpeckers to demonstrate a difference in feeding habits between males and females. However, it is June 1970 118 THE WILSON BULLETIN Vol. as, No. 2 TABLE 1 SEXUAL OVERLAP IN MILLIMETERS OF THE EXPOSED CULMEN OF TtIREE WOODPECKERS (CAMPEPHILUS). Sexual Per cent Per cent  c overlap range joht non- Species range range in range overlap overlap* N C. magellanicus 43.5-54.5 51.8-58.5 2.7 18 90 28 C. principalis 60.5-67.5 63.0-72.9 4.5 36 76 54 C. imperialis 72.5-84.7 78.5-85.5 6.2 48 70 34 * Determined from Coefficient of Difference (Mayr, Linsley and Usinger, 1953:146) obtained for both culmen length and bill length from nostril. C. D. values were below 0.70 in both measure- ments for the two larger species and were 1.29 (culmen) and 1.40 (bill length from nostril) for C. magellanicus. The differences exhibited are thought to be the miimal that can obtain, because adults from all areas and all tim,es of the year were utilized. On a local basis, allowing for possible temporal variation, the differences undoubtedly would be greater. noteworthy that the several individuals that were observed feeding at the tips of small branchlets were females. Magellanic Woodpeckers foraging on larger limbs and trunks move easily upward with the tail appressed to the surface of the tree and the legs spread outward. The head is often held quite far out from the surface of the tree (Fig. 3). Examination of movies I have taken clearly shows that all the toes of this woodpecker are normally directed forward and laterally, often well spread apart; the position of the toes varied within these limits from that illustrated in Figure 6 A to that in Figure 6 B by Bock and Miller (1959: 22). The action of the bill in feeding varies from light taps and probes to heavy blows. I never witnes.sed a sustained flurry of pecking; rather, pecking was deliberate, only one or few pecks being delivered at a time. A female feeding chickadee-like in the outermost branches of a Notho]agus tree, used her bill entirely for probing during 10 minutes of observation. Nevertheless, the bill can be used to deliver powerful blows, and ! was surprised at the ease with which one or two strong blows of a male cut a piece of bark from a live tree. Workings of these woodpeckers included areas on trees with several small to large (10 cm) pieces of bark removed, and deeply chiseled holes like those of a Pileated Woodpecker (Dryocopus pileatus). Foraging took place in both dead and live trees (species of Notho]agus and Cupresus), and in live and dead branches of living trees. Most trees had dead limbs or even fully dead tops; when viewed from a distance the mountain forest at 18 km northeast of San Martin de los Andes, where Magellanic Woodpeckers were abundant, appeared a peculiar gray-green color due to the dead gray tops of many of the trees (Fig. 5). Some feeding takes place on fallen logs, as mentioned above. The birds progress rather te,er L. THE MAGELLANIC WOODPECKER Short 119 FIC. 4. Cutover Notholagus forest (lower slopes) and mature forest (upper slopes) above Lake Meliquina, about 25 kilometers south of San Martin de los Andes, Neuqun. Magellanic Woodpeckers occupy mature forest, and, sporadically, patches of cutover forest. rapidly while feeding, moving often from tree to tree. The wings of these woodpeckers produce a flapping sound as the birds fly from tree to tree. The white in their wings (pattern described below) is also very obvious while they are in flight. Nesting (and, presumably, roosting) cavities are excavated in partly dead trees, and holes seen were 5-15 m above the ground. About 20 such holes were noted, and one is shown in Figure 6. The holes faced in all directions, and varied greatly in shape from almost circular to very oval or droplet-like. One nesting cavity examined closely (by R. S. Crossin) was 5% m up in a small, nearly dead Notho]agus tree about 32 cm in diameter at nest height. The hole was approximately 12 x 9 cm in dimensions. The cavity was about 40 cm deep and lined at the bottom with a small amount of sawdust and wood chips. Construction of the cavity was not observed. The cavity was occupied by a lone nestling about three days old. The fact that this nest contained only one young bird is interesting, since the only laying adult female that we collected had laid but one egg and contained no other large ova. Johnson (1967) noted a family of three young birds and a dutch of four eggs of Magellanic Woodpeckers in Chile. THE WILSON BULLETIN j .... 1970 Vol. 82, No. 2 120 FIG. 5. Edge of mature NothoJagus forest northeast of Lake Lolog, 18 kilometers north of San Martin de los Andes, Neuqu6n. Magellanic Woodpeckers were abundant in this forest (see text). Note the dead tops of many trees on the slopes. Cattle were pastured in the foreground (where scattered bamboo clumps are seen), but not in the forest itself. TAPPING AND DIIUMMING Sounds produced by the Magellanic Woodpecker's bill against wood are of two general types, tapping associated with feeding, and that serving a signal function. The latter may be the functional equivalent of "drumming" in other woodpeckers (e.g., species of Demlrocopo, Dryoco.pus, Colaptes, etc.), and is hence designated the "drum-tap." Tapping associated with feeding is variable in intensity, frequency and duration, depending upon the foraging site and the food being sought. There is no single means of feeding (see above). The sounds produced by a forag- ing Magellanic Woodpecker range from barely audible scraping noises (like those of a nuthatch, Sitta) to loud, repetitive taps. In the former case feeding is by probing; in the latter case, it is by the delivering of hard blows with the bill. I was unable to detect a difference in tapping between foraging individuals of Dendro,copos lignarius and those of Magellanic Woodpeckers feeding in smaller branches of trees. In those instances when large (about 10 cm in diameter) pieces of bark were chopped out of a Notho]agus tree ne,er . THE MAGELLANIC WOODPECKER Short 121 FIC. 6. The interior of the mature Notho]agus forest shown in Figure 5. Amid the large trees with draped mosses and a bamboo understoxy is the nest cavity (in pale- barked tree above bamboo, left center) of a pair of Magellanic Woodpeckers. the birds tapped loudly, and deliberately, usually at one to four blows in a series. The sounds of these blows are easily distinguished from drum-taps by their irregular pattern, lesser resonance, and (usually) lesser intensity. Drum-taps were heard most frequently from one pair near a nest. These loud, hollow-sounding taps were produced by double or (occasionally) single blows against a tree. They may have been directed at me as an intruder near the nest. The drum-tap may s4rve in the establishment and maintenance of territories, and perhaps also as a location note for members of a pair. The drum-taps of the Magellanic Woodpecker are like those of Phloeoceastes robustus (Fig. 9), which I heard in northeastern Argentina. Other species of Phloeoceustes ( P. melanoleucos, personal observation; P. guatemalensis, Slud, 1964; P. leucopogo, Wetmore, 1926), and Campephilus (C. princi- palis, Tanner, 1942; probably C. imperialis, see Nelson, 1898:221) have very similar drum-taps; indeed, these may characterize all campephiline species. VOCALIZATIONS Despite the brief time spent observing Magellanic Woodpeckers, several vocalizations were heard and recorded on tape. Other vocalizations prob- 122 THE WILSON BULLETIN June 1970 Vol. 82, No. 2 ably remain to be described, and further study of those which are discussed below is necessary to ascertain their functions. The vocalization uttered most often by the Magellanic Woodpeckers we observed is a variable, double-noted, harsh call, similar to that of Phlo.eoceastes rubricollis described by Snyder (1966:161) as an "explosive, nasal 'ngkah- ngkah.'" From two to five of these double-noted calls were given in each sequence. I noted variants of this call as follows: pi-cad; wieeeer; kee-adh (softer, less harsh); kee-drgh (harsher, more drawn out); and kee-yew (second note less emphatic). The call was emitted by lone individuals, apparently directed at me or elicited by my presence. It was employed also by males and females comprising groups of three or four birds observed 20-23 November at 18 km north of San Martin de los Andes. Here it appeared to be an agonistic vocalization utilized in encounters, but it may also function as an alarm call. The significance of the variation in this call is unknown, although it presumably is related to the various levels of motivation of birds uttering the call. Another call heard only from the pair of birds studied extensively can be designated the too.t call. This is somewhat similar to the kent call of Campephilus principalis (Tanner, 1942), but it lacks the' nasal quality of the latter (interestingly, the entire known vocal repertoire of C. principalis is comprised of nasal, trumpet-like notes). Single to'o.t notes were heard occasionally from members of the pair as they were feeding. These might function as location notes, but they were also emitted in series of two or three notes, often leading into a burst of pi.cad calls, by the adult birds near their nest. In one sequence of calls near the nest the male emitted a series of four too.t calls, followed by five or six pi-cad calls, and these in turn were followed by a drum-tap (see above). These notes may have been directed at me. I heard these woodpeckers utter only two other types of vocalizations. One of these is a low peep call heard only near a nest occupied by a single nestling. While I was not certain that the young bird produced this note, it seems likely. The pe.ep calls were interspersed with p.i-cad calls emitted by one or both adults. This situation may have been the result of my presence; the calling young bird may have been hungry, and the disturbed adults may not have been feeding it a sufficient amount of food. Another call, heard only once, was a loud, prolonged cray-cra-cra-cra-cra-cra, given by a lone male clinging to a tree about 70 m from me. The bird flew off shortly after it called. Prolonged calls of this nature function in other woodpeckers (e.g., species of Dendrocopos and Colaptes; personal observation) in the establish- ment and defense of territory, but the lone instance of this call in the Magellanic Woodpecker provides no basis for speculation regarding its function. Lester L. THE MAGELLANIC WOODPECKER 123 Short DATA FROM SPECIMENS Various data were obtained from 16 specimens that we collected, includ- ing one unfeathered nestling and 15 adults. Many of these were prepared as alcoholic specimens and skeletons for anatomical investigations. The adults examined generally had irides colored pale yellow near the pupil, progressively becoming gold, and finally orange, away from the pupil. One bird had irides uniformly yellow, but with flecks of orange scattered throughout. Most of the adult specimens, collected from 20-29 November, had not yet commenced breeding. One female (collected on 20 November) had laid an egg; its ovary measured 20 X 10 mm, and a brood patch was present. Six other females had ovary measurements of from 8 x 5 mm to 15 x 11 mm. One of the latter had slightly enlarged ova (to 2 mm) and an incipient brood patch, another had a defeathering brood patch, and a third female showed slight enlargement of the oviduct. The single nestling was obtained on 29 November. Weights of seven adult males ranged from 312 to 363 g, with an average of 338.4 g. Six females weighed from 276 to 312 g, averaging 291.3 g. A female laying eggs weighed 326 g. A brood patch was evident in only three of seven males that were collected, including the mate of the female that had laid an egg. These brood patches were not completely formed. The testes of six of these males measured from 4 X 2mmto 10X 8min. The sole nestling was prepared as an alcoholic specimen, and few data are available for it. The essentially featherless, two or three day old bird was alone in a nest cavity (described above); its weight was 29.6 g. A COMPARISON OF THE EXTERNAL MORPHOLOGY OF THE MAGELLANIC WOODPECKER WITH OTHER CAMPEPHILINE WOODPECKERS The Magellanic Woodpecker is a large picid exceeded in size among the woodpeckers only by several species of the genera Campephilus, Dryocopus, and Mulleripicus. Like the other campephiline woodpeckers this species has a (moderately) broad bill, and the inner two pairs of its rectrices are especially hard and stiff. Among the campephiline woodpeckers the Magellanic Woodpecker is usually considered a close relative of the North American ivory-billed woodpeckers ( Campephilus principalis and C. imperialis, which probably comprise a superspecies; see Fig. 7). It approaches them in size, and in its white wing patches, which are visible when the bird is perched; the curled crest of the female is also like that of the female of C. imperialis. However, there are numerous differences between the Magellanic Woodpecker and the northern ivory-bills. 124 THE WILSON BULLETIN June 1970 Vol. 82, lXlo. 2 F;. 7. From left to right are adult pairs of Magellanic Woodpecker (Campephilus magellanicus), Imperial Woodpecker (C. imperialis) and Ivory-billed Woodpecker (C. principalis). The male of each species is at the left, and the femme at the right. The Magellanic Woodpecker has a large white wing patch restricted to the inner web of the secondaries and the basal portion of the inner vane of the primaries; the primaries are never tipped with white. In contrast, the northern ivory-bills have white over the entire distal portion of all secondaries, and white progressively restricted from the inner to the outer primaries toward their tips and not their bases. This renders the flight pattern of these birds entirely different. Like Ptdoeoceastes guatemalensis and P. melanoleucos (see Figs. 8, 9) and the Pileated Woodpecker (Dryocopus pileatus), the Magellanic Woodpecker exhibits a single, anterior, white underwing patch, because the white in its flight feathers is continuous with that of the under- wing coverts. The northern ivory-bills exhibit two white wing patches, an anterior patch formed by the white coverts, and a posterior white patch separated from it by the black bases of the flight feathers (see Tanner, 1942:2). The Magellanic Woodpecker has relatively narrow, tapered outer (tenth) primaries, but the northern ivory-bills have even narrower, strongly falcate outer primaries. The rectrices of the Magellanic Woodpecker are less sturdy than are those of its northern relatives, and the second rectrices often exhibit so much wear that the central rectrices stand apart from them; these two Lester L. THE MAGELLANIC WOODPECKER 125 Short Fie. 8. From left to right are a male Campephilus (Phloeoceastes--see text) guate- mslensis, a female of that species, a female Magellanic Woodpecker. and a male and female of Campephilus leucopogon. pairs of rectrices are equal in the northern ivory-bills. The bill of the Magellanic Woodpecker is black, never ivory in color like the bills of C. imperialis and C. principalis, which are also relatively sturdier, more massive and broader (more wedge-shaped from a dorsal view) than that of C. magellanicus. Indeed, the bill of the Magellanic Woodpecker is proportion- ally less massive than that of several species of Phloeoceastes (especially P. leucopogon, Fig. 8). This is particularly reflected in the weak ridge on the gonys of Campephilus magellanicus, as compared with C. imperialis, C. principalis, Phloeoceastes leucopogon, P. melanoleucos, and P. robutu& ]-he bill size difference between the sexes of C. magellanicu was discussed above; this difference is gTeater than that occurring between the sexes of C. principalis and C. imperialis. The male Magellanic Woodpecker has an all-red head and a rather short crest, matched among campephiline woodpeckers by Phloeoceastes guate- malensis. The female typically has a long, curled crest resembling that of the female of C. imperialis. Some species of Phloeoceastes such as P. leucopogon, P. mdanoleucos and P. guatemalensis, have males with essentially all-red 126 THE WILSON BULLETIN ju.e 970 Vol. 82, No. 2 Fig. 9. From left to right are a female and a male of Campephilus melanoleucus, a female Magellanic Woodpecker, and a male and female of Campephilus robustus. heads, including the crest, and females with a crest that is black anteriorly and red posteriorly. The black crest feathers of these females are usually more elongate than the red feathers (sometimes red feathers are longer, but, if so, they have black tips). These black crest feathers occasionally curl somewhat forward (specimens of P. leucopogon and P. melanoleucos). I suggest that differential wear of black and red feathers may have been a factor in the evolution of the crests of these species, for melanin-containing feathers appear to be more durable and resistant to wear than are red feathers. The evolution of the three large species of Campephilus has been marked by reduction or elimination of red in the female's crest and head pattern. In the northern ivory-bills the females have entirely lost their red coloration of the head, and their long crests are black. The males of these two species have a reduced amount of red in the crest; essentially they have assumed the ]emale head pattern of Phloeoceastes melanoleucos and P. guatemalensis. However, males of the northern ivory-bills have the red feathers of the crest longer than the black ones. The head pattern of the Magellanic Woodpecker has developed differently. The female of this species has a reduced amount of red, which occurs around the bill (the only other campephiline species the Lester L. THE MAGELLANIC WOODPECKER 127 Short females of which have red in this region is Phloeoce'astes guatemalensis), and a curled black crest. However, reduction of red coloration has not occurred in the male. Instead, the latter has an all-red head like that of Phloeoceastes guatemalensis and P. leucopogon (the latter has a longer crest, however). The Magellanic Woodpecker resembles Phloeoceastes rubrico. Ills and differs from all other campephiline species in the absence of white on its back and neck. Ventrally, most specimens show some evidence of white at the tips of the abdominal feathers. A few individuals have most abdominal feathers with white tips. This condition gives a somewhat barred appearance to the abdomen, perhaps reflecting such a pattern in the ancestors of C. magellanicus. No other campephiline species with black underparts (C. imperialis, C. prin- cipalis, Phloeoceastes le'ucopogon) exhibits this white barring. COMMENTS ON {ELATIONSHIPS OF CAMPEPHILINE WOODPECKERS The Magellanic Woodpecker has been considered to comprise a monotypic genus (Ipocranto.r Cabanis and Heine), or to be congeneric (in Campephilus Gray) with the northern Imperial and Ivory-billed Woodpeckers. I believe that the Magellanic Woodpecker is not related directly to the northern ivory- bills, but rather is related to them indirectly by virtue of the independent evolution of both groups from species of Phloeoceastes Cabanis. The simi- larities between the Magellanic Woodpecker and the northern ivory-bills (e.g., tendency toward a falcate outer primary, longer gonys, plumage patterns; see above) seem to be the result of parallel evolution of large woodpeckers from the same basic ancestral stock of Phloeoceastes. Other similarities among the three large "ivory-bills" (e.g., vocalizations, color pattern, tail structure; see above) are shared with various species of Phloeoceastes. On the other hand the differences (see above) between the Magellanic Woodpecker and the northern ivory-billed group appear to reflect their recent independent evo- lutionary history. The "generic" characters setting Campephilus and Ipocrantor apart from Phloeoceastes (chiefly their more falcate primaries and longer gonys, Ipo- crantor being intermediate in the latter respect between Campephilus and Phloeoceastes; see Ridgway, 1914:9-10) are trivial and possibly correlated with the larger size of these birds. In any event, species groups within Phloe'- oceastes (these groups are: the P. leucopogon-guatemalensis-melanoleucos- guayaquile'nsis group; the P. robustus group, probably including P. rubri- collis; and the P. haematogaster-pollens group.) seem at least equally as distinct as Campephilus and Ipocrantor. The recognition of the latter two genera seems to necessitate the splitting apart from Phlo.eoceaste of at least two genera ("Cniparchus," "Scapaneus"; for their characters see Ridgway, 1914) for taxonomic consistency. June 1970 128 THE WILSON BULLETIN Vol. 82, No. 2 The various groups of campephiline species, including the Magellanic Woodpecker group and the northern ivory-bill group, can be accommodated within a single genus (Campephilus) comprised of 11 species. These species are so fundamentally similar in coloration, structure and habits that their inclusion in one genus far better expresses their relationships than does splitting them into two genera (Campephilus and Phloeoceastes; this would be incorrect, as the species of Ca'mpephilus are not strictly monophyletic), three genera (Campephilus, lpocrantor, and Phloeoceastes), five genera (the three last mentioned, Cniparchus and Scapaneus) or even more genera (e.g., including Megapicos Malherbe). Hence, I follow Bock (1963) in consider- ing the campephiline woodpeckers to comprise the single genus Campephilus. ACKNOWLEDGMENTS I thank Richard S. Crossin and Francisco Espinola for assistance rendered in the field, and authorities of the National Science Foundation for support of my field studies in Argentina (N.S.F. grant G.B.-5891). Martin Morton and Roxie C. Laybourne kindly provided data from specimens at the Moore Laboratory of Zoology of Occidental College, and the United States National Museum, respectively. Mrs. Ilse Atkinson was helpful in facilitating our field work around San Martin de los Andes, Argentina. LITERATURE CITED AsaaoLE, N. P. 1967. Sexual dimorphism and colonial breeding in the woodpecker Centurus striatus. Amer. Naturalist, 101:353-356. Bocs:, W. 1963. Evolution and phylogeny in morphologically uniform groups. Amer. Naturalist, 97:265-285. BOCK, W. AiD W. DE W. MILLER. 1959. The scansorial foot of the woodpeckers, with comments on the evolution of perching and climbing feet in birds. Amer. Mus. Novitates, no. 1931. Lester L. THE MAGELLANIC WOODPECKER 129 Short JOHNSON, A. W. 1967. The birds of Chile and adjacent regions of Argentina, Bolivia and Peru. Vol. II. Platt Establ. Graficos, Buenos Aires. KILaM, L. 1965. Differences in feeding behavior of male and female Hairy Wood- peckers. Wilson Bull., 77:134-145. LIGON, J.D. 1968. Sexual differences in foraging behavior in two species of Dendrocopos woodpeckers. Auk, 85:203-215. MAYR, E., E.G. LI3;SLEY, AND R. L. USINGER. 1953. Methods and principles of system- atic zoology. Mcgraw-Hill Co., New York. NELSON, E. W. 1898. The Imperial Ivory-billed Woodpecker, Campephilus imperialis (Gould). Auk, 15:217-223. PETERS, J.L. 1948. Check-list of birds of the world. Volume VI. Harvard Univ. Press, Cambridge. RIDGWAY, R. 1914. The birds of North and Middle America. Part VI. U.S. Natl. Mus. Bull., 50. SELANDER, R.K. 1965. Sexual dimorphism in relation to foraging behavior in the Hairy Woodpecker. Wilson Bull., 77:416. SELADER, R.K. 1966. Sexual dimorphism and differential niche utilization in birds. Condor, 68:113-151. SELADER, a. K. AND D. a. GILLER. 1963. Species limits in the woodpecker genus Centurus (Aves). Bull. Amer. Mus. Nat. Hist., 124:213-274. SLED, P. 1964. The birds of Costa Rica. Bull. Amer. Mus. Nat. Hist., 128. SNYDER, D.E. 1966. The birds of Guyana. Peabody Mus., Salem, Mass. TArriER, J. T. 1942. The Ivory-billed Woodpecker. National Audubon Soc., Res. Report 1, New York. VUILLEUMIER, F. 1967. Phyletic evolution in modern birds of the Patagonian forests. Nature, 215:247-248. 'WETMORE, a. 1926. Observations on the birds of Argentina, Paraguay, Uruguay, and Chile. U.S. Natl. Mus. Bull., 133. THE AMERICAN MUSEUM OF NATURAL HISTORY, NEW YORK, NEW YORK 10024, 27 MAY 19'68.