Uj Q 'L I B R.ARY OF THL UNIVERSITY OF ILLINOIS 590-5 FI v.32 •num Return this book on or before the Latest Date stamped below. University of Illinois Library APR AUG 364 L161 — BIRDS OF THE ACARY MOUNTAINS SOUTHERN BRITISH GUIANA EMMET R. BLAKE FIELDIANA: ZOOLOGY VOLI/MM 32, Xr.MBKR 7 Published l>ij CHICAGO NATURAL HISToMV M DECEMBER 19, 1950 GUIANA 1 DUTCH JH GU.ANA • ^Collecting localities = Brozil-Bntish Guiana Boundary Markers MAP 1. Area covered by the report, with collecting localities of the expedition. BIRDS OF THE ACARY MOUNTAINS SOUTHERN BRITISH GUIANA EMMET R. BLAKE Associate Curator, Division of Birds FIELDIANA: ZOOLOGY VOLUME 32, NUMBER 7 Published by CHICAGO NATURAL HISTORY MUSEUM DECEMBER 19, 1950 PRINTED IN THE UNITED STATES OF AMERICA BY CHICAGO NATURAL HISTORY MUSEUM PRESS INTRODUCTION This report is based on a collection of 500 specimens that I made for Chicago Natural History Museum during the latter half of 1938, while undertaking a zoological reconnaissance of the Acary1 Mountains and adjacent lowlands of southern British Guiana. Four hundred eighty-seven additional bird skins and a considerable portion of the other collections unfortunately were destroyed when my boat was lost while descending King William Falls, a series of treacherous rapids in the Courantyne River some 300 miles from the coast. All but six of the 156 forms listed are represented by specimens that were salvaged after the river accident. The remainder are birds of such distinction as to be safely included as sight records. Altogether there are fewer than one-third of the species that might be expected to occur in an area flanked by the Guiana midlands and by the Amazon basin. Nevertheless, even so limited a sampling as this affords a welcome opportunity to investigate the faunal affinities of a biologically unexplored region about which naturalists have long speculated. The expedition, known as the Sewell Avery British Guiana Expedition in honor of its sponsor, a Trustee of the Museum, was planned to take advantage of unique opportunities that existed briefly in 1938. A survey of the British Guiana-Brazil boundary had just been completed, with the result that a previously unex- plored area became, for a period of months, relatively accessible. Experienced river men, surplus supplies and various facilities were made available to me by the Boundary Commission before it dis- banded. The Museum is therefore deeply indebted to Mr. Avery, without whose timely generosity the expedition could not have been undertaken. PHYSICAL CHARACTERISTICS OF THE ACARY MOUNTAINS The Acary Mountains form a distinct but rather unimposing sierra extending entirely across the southernmost portion of British 1 Sometimes spelled Acarai, Akarai, Acarahy or Arary. 419 420 FIELDIANA: ZOOLOGY, VOLUME 32 Guiana. Located approximately midway between the Amazon River and the Caribbean coast, they form a continuous watershed drained from the south by tributaries of the Rio Trombetas in Brazil, and from the north principally by the Courantyne and New Rivers, the latter an important tributary of the Courantyne. While this watershed was long accepted as the official British Guiana- Brazilian boundary, it was not until May, 1938, that the actual physical demarcation was completed by a joint survey commission after four years of labor. These mountains, both geologically and topographically, are quite unlike the famed "Guiana Highlands" of southeastern Vene- zuela and adjacent parts of British Guiana, the avifauna of which has been ably documented in recent years by Chapman, Phelps, Gilliard and others. Granite rather than sandstone is the dominant geological feature of the Acary range. Weathered plateaus and isolated tablelands are entirely lacking and there are no cliffs of importance. Outcroppings of matrix are both uncommon and of small extent, and nowhere in the area is there evidence of the formidable erosion that is so characteristic of the sandstone forma- tions of southern Venezuela. By contrast, the hard matrix of the Acary Mountains is generally covered with soil, although but thinly so on the summits and ridges. The crowns of individual mountains tend to be rounded, but from their sides radiate ridges that either drop away steeply to the ad- jacent lowlands or form saddlebacks with similar formations of other mountains. The ravines, sometimes decidedly precipitous at their points of origin, are generously strewn with boulders and support an abundance of the rank vegetation that flourishes in moist situations. The complex of heavily forested mountains, subsidiary ridges and associated ravines conforms to no orderly pattern, although the narrow sierra of which they are a part extends approximately one hundred miles along a generally southwestern-northeastern axis. None of the mountains are higher than 4,000 feet and few exceed 3,200 feet. The average elevation of the entire Acary range is somewhat less than 2,000 feet above sea level, the highest portion being toward the western end. Low passes near the headwaters of the Essequibo and Courantyne Rivers reflect this topographical cline from west to east very well, their altitudes being 1,130 feet and 794 feet, respectively. The flora of the highlands is virtually unknown. In all prob- ability it will be found to differ little, if at all, from the essentially BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 421 Amazonian flora of the adjacent lowlands. The magnificent humid- tropical, climax forest that blankets the entire area becomes some- what modified only on the upper slopes and summits of the higher mountains. There the ground-cover of herbs and shrubs usually is sparse, the trees generally smaller and the vegetation less diverse than in the lowlands. These conditions are local, however, and probably are due more to the dearth of moisture and of suitable soil than to any other factor. Although several birds characteristic of the Subtropical Zone elsewhere were collected on the higher mountains, I found no obvious botanical evidence of a true "cloud forest" in southern British Guiana. FAUNAL AFFINITIES As might be expected, the humid-tropical character of the mountain vegetation is abundantly reflected by the avifauna. All but 5 of the 125 species that were found above 1,500 feet altitude in the Acary Mountains are essentially lowland birds. Most are of widespread occurrence in all three of the Guianas and range southward to the north bank of the lower Amazon River. Many also occur south of the Amazon, or elsewhere in lowland areas not usually included in the Guianan sub-region, as the same or as closely related forms. The following table is an analysis of the distribution of the 125 species recorded in the Acary Mountains at elevations exceeding 1,500 feet. The faunal relationships suggested therein probably approximate, at least in a general way, the pattern to be expected in a much more inclusive survey of the Acary avifauna. Same Form Throughout British Guiana 113 (90.5%) Different Form Species Absent 5 (4%) 7 (5.6%) Dutch Guiana 103 (82.4%) 1 (0.8%) 21 (16.8%) French Guiana Ill (88.7%) 5 (4%) 9 (7.2%) Brazil: North of lower Amazon. . . 102 (81.5%) Brazil: South of lower Amazon. . . 40 (32%) Mt. Roraima 44 (35.2%) 8 (6.4%) 15 (12%) 56 (44.8%) 29 (23.2%) 16 (12.8%) 65 (52%) Mt. Auyan-tepui (above 5,000 ft.) 2 (1.6%) 123 (98.4%) Mt. Auyan-tepui (below 3,600 ft.) . 63 (50.4 %) Duida region 56 (44.8%) 12 (9.6%) 50 (40%) 35 (28%) 34 (27.2%) (Upper Orinoco River, Cassiquire Canal, upper Rio Negro) Middle and lower Orinoco River. . 63 (50.4%) 22 (17.6%) 40 (32%) It will at once be noted that the avifauna of the Guianas south to the north bank of the lower Amazon River is essentially homo- geneous, the continuity of distribution within the area being, how- 422 FIELDIANA: ZOOLOGY, VOLUME 32 ever, apparently considerably interrupted in Dutch Guiana. Actu- ally, it is probable that no very extensive or abrupt discontinuity of avian distribution occurs anywhere in the forested portions of the Guianas, or in the lower Amazon basin north of that river, indications to the contrary being those that are inherent in any tropical area so little explored. In support of this observation it may be pointed out that eleven of the twenty-one species of this collection that are as yet unknown in Dutch Guiana occur more or less extensively in the lowlands of both British and French Guiana, and may be presumed to inhabit Dutch Guiana as well. Nine of the twenty-one species are also unreported in French Guiana while one, Piculus chrysochloros capistratus, is represented there by another race (guianensis) of doubtful distinction. Such speciation as has taken place in the Guianas, and it is rela- tively minimal, appears to be associated with some of the larger rivers and, to a lesser extent, with the Acary Mountains. Even among the birds treated herein there are indications that the Es- sequibo, Courantyne and Maroni Rivers have inhibited the dis- tribution of some birds more or less effectively. However, the interiors of both French and Dutch Guiana, and of British Guiana east of the Essequibo River, must be explored much more thoroughly before the principal areas of genetic isolation can be delineated with certainty. Below are listed several birds of southern British Guiana that are replaced in French Guiana by another form. It is noteworthy that in only one instance (Phaethornis ruber) does the population in Dutch Guiana differ from that of British Guiana. British Guiana French Guiana Phaethornis ruber episcopus Phaethornis ruber ruber Topaza pella pella Topaza pella smaragdula Pteroglossus aracari roraimae Pteroglossus aracari atricollis Piculus chrysochloros capistratus Piculus chrysochloros guianensis Celeus elegans hellmayri Celeus elegans elegans Thamnophilus murinus murinus Thamnophilus murinus cayannensis Tachyphonus cristatus intercedens Tachyphonus cristatus cristatus I remarked above that certain Guiana rivers probably surpass the Acary Mountains as implements of isolation. While it is evident that this range is neither sufficiently high nor so isolated from similar elevations as to have been of much importance as a factor of evolu- tion, it nevertheless influences the local distribution of many birds very effectively. Obviously, species that are dependent upon a swampy or riverside habitat, to mention extreme examples, will not be BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 423 found in their absence. Unfortunately, the ecological requirements of all birds are not so clear-cut. Obscure factors or combinations thereof, often subtle or as yet unsuspected, probably influence the local distribution of tropical bird-life no less than do the obvious. Many species that are conspicuously abundant in lowland forests both north and south of the Acary Mountains were not found beyond their foothills, a circumstance only partly explained by the limita- tions of collecting. Other equally common lowland birds ranged to the tops of the mountains, but were much less abundant above 1,500-1,800 feet altitude, where, presumably, critical ecological factors become operative. Random examples of this category are Psophia c. crepitans, Momotus m. momota, Monasa atra, Xipho- rhynchus p. pardalotus, Lipaugus cineraceus, Perissocephalus tricolor, Pipra e. erythrocephala and Cyanocorax cayanus. On the other hand, a few characteristically lowland birds, as Sarcorhamphus papa, Leucolepis a. arada, Smaragdolanius 1. leucotis and Ostinops v. viridis, were unaccountably most abundant at higher altitudes. Only five essentially Subtropical birds were found in the Acary Mountains. The evident poverty of the Upper Zonal fauna in south- ern British Guiana is particularly striking when compared with that of Mounts Duida (52 species), Roraima (60 species) and Auyan- tepui (40 species), towering sandstone bastions of southern Vene- zuela, where far greater isolation obtains. Of interest, also, is the fact that two of the five Guiana species (Aulacorhynchus derbianus and Terenura callinota) are elsewhere restricted to the Subtropical Zone, while the other three (Piculus rubiginosus, Xiphocolaptes promeropirhynchus and Oxyruncus cristatus) sometimes also occur in the lowlands. It is significant that four of these essentially Upper Zonal representatives range eastward only as far as the Acary Mountains, and there most closely approach sea level. The fifth, Oxyruncus cristatus, is a disappearing relict species having a remarkably discontinuous range that extends from Costa Rica to Paraguay. Clearly, the highlands of southern British Guiana (and pre- sumably those to the eastward) have little evolutionary potential, although they now serve as a peripheral haven for an impoverished, and doubtless diminishing Subtropical fauna. Three of the five Upper Zonal birds are at present known only from the Acary Moun- tains, and are presumed to be endemic. Of these, Aulacorhynchus derbianus osgoodi and Piculus rubiginosus nigriceps are replaced in the "Guiana Highlands" (Mounts Roraima, Auyan-tepui and Duida) 424 FIELDIANA: ZOOLOGY, VOLUME 32 by one or more closely related forms. Terenura callinota guianensis, the third endemic Acary bird, is the slightly modified representative of a distinctive Andean species hitherto unrecorded east of Colombia (Aguadita) and western Ecuador (Pallatanga and Nanegal). Both Xiphocolaptes promeropirhynchus tenebrosus and Oxyruncus cristatus phelpsi occur locally in the eastern portion of the "Guiana High- lands." The former is known both from the western slopes of Mount Chimanta-tepui (2,300 feet) and from Arabupu (4,000 feet), near Mount Roraima, while the latter is found at 3,600 feet altitude on Mount Auyan-tepui. In the case of Oxyruncus this is a most surprising distributional pattern in view of the fact that Roraima, an intermediate locality, supports an endemic representative. From the foregoing it is seen that the impoverished Upper Zonal fauna of southern British Guiana stems principally from the sand- stone regions of southern Venezuela, the highland fauna of which shows a decided affinity to that of the Andes. In accounting for the strong Andean element in the Duidan-Roraiman fauna, Chap- man (1931, pp. 46-48) dismisses as most improbable the theory of a successful eastward emigration resulting from fortuitous flight. Since there is no evidence of recent geologic connection between the two mountain masses, he postulates that the representatives of Andean forms now comprising the Duida-Roraima faunal complex are the survivors of birds that formerly occupied the intervening country. Such probably also is the case with the few Subtropical birds of southern British Guiana now isolated geographically and genet- ically from their nearest allies in the "Guiana Highlands." I can not so readily account for the presence in the Acary Mountains of at least two far-western species that are as yet unknown anywhere in the vast area between. One, Terenura callinota, has been men- tioned. A second, Contopus nigrescens, reappears in southern British Guiana as the identical form (canescens) of northeastern Peru, although the two populations apparently are separated by almost 1,500 miles. Since canescens presumably is non-migratory, and decidedly rare wherever found, there is reason to believe that it will yet be discovered in the sandstone highlands of southern Venezuela. ADDITIONS TO THE FAUNA OF BRITISH GUIANA Seventeen birds collected in the Acary Mountains were pre- viously unknown in British Guiana. Three of these (Aulacorhynchus BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 425 derbianus osgoodi, Piculus rubiginosus nigriceps, Terenura callinota guianensis) have been described elsewhere as new while the others represent greater or lesser extensions of range. Trogon collaris collaris Aulacorhynchus derbianus osgoodi Piculus rubiginosus nigriceps Xiphocolaptes promeropirhynchus tenebrosus Synallaxis rutilans dissors Philydor ruficaudatus ruficaudatus Herpsilochmus stictocephalus Terenura callinota guianensis Pipra serena serena Contopus nigrescens canescens Oxyruncus cristatus phelpsi Turdus albicollis poiteaui Coereba flaveola minima Parula pitiayumi elegans Tangara chilensis paradisea Hemithraupis guira nigrigula Hemithraupis flavicollis flavicollis COLLECTING STATIONS The map (frontispiece) indicates the route followed to the Acary Mountains and the approximate position of each collecting station. Several of the latter were occupied very briefly and most appear on no other published map. It will be noted that all of the collecting stations, with the single exception of my camp at King Frederick William IV Falls, are in British Guiana. Extensive collections were made only in the Acary Mountains, principally in the vicinity of Boundary Camp (1,800 feet altitude), where more than 600 birds were taken. All of the stations are listed below with dates of occupancy as represented by specimens still extant. King Frederick William IV Falls (August 16-20) Ashiru Falls (October 27) Oronoque Base Camp (August 27; October 26) Calf Bird Camp (August 30) Pairima Camp (August 31-September 1) Haimara Camp (October 24) Phantom Falls (October 22-23) New River Depot (September 3) Middle Base Camp (September 4-14; October 21) Navigation Head (October 20-21) Boundary Camp (September 20-October 15) I am indebted to Dr. Herbert Friedmann, Mr. Rodolphe Meyer de Schauensee, Mr. W. E. Clyde Todd and Mr. John T. Zimmer for the loan of many specimens in their charge. To Mr. Philip S. Peberdy, formerly Curator of the Natural History and Economic Science Museums of British Guiana, I wish to express appreciation for numerous personal courtesies in Georgetown, and for unfailing co-operation in assisting with the organization of the expedition before its departure from the coast. Much credit for the success of the enterprise is also due Mr. Richard Baldwin of Georgetown, 426 FIELDIANA: ZOOLOGY, VOLUME 32 my assistant and previously a member of the Boundary Survey Commission, whose knowledge of the rivers, efficiency and personal courage saved the expedition from disaster on many occasions. Finally, I am especially grateful to Abibul Rasool of Buxton Village, British Guiana, expedition taxidermist, whose presence of mind at the time of the boat accident was instrumental in saving hundreds of specimens that otherwise would have been lost. SYSTEMATIC LIST TINAMIDAE Tinamus major major Gmelin Tetrao major Gmelin, 1789, Syst. Nat., 1, (2), p. 767— Cayenne. Itabu Creek: Middle Base Camp; 1 female, September 10. This notoriously variable form often has characters that approxi- mate, or show a tendency toward, those of zuliensis or serratus. The Itabu Creek specimen is a case in point, being decidedly oliva- ceous above and heavily barred as in zuliensis, while the forehead differs from that of typical major in being concolorous with the crown. The sides of its head are dull rufous and seem to tend toward serratus. Crypturellus cinereus cinereus Gmelin Tetrao cinereus Gmelin, 1789, Syst. Nat., 1, (2), p. 768— Cayenne. Itabu Creek: Middle Base Camp; 1 female, September 10. As shown by Hellmayr and Conover (1942, pp. 30-31, footnote), the reddish brown bird previously known as macconnelli is, in fact, merely a color phase of cinereus. The latter designation usually has been reserved for birds of distinctly sooty appearance, but Chubb (1916, pp. 8, 9) reversed this concept, although clearly in contradiction of Buffon's original description. In any case, it is now known that both color phases and all manner of intermediate plumages are of fortuitous occurrence, although their relative abun- dance may vary locally. The sooty phase appears to predominate in British Guiana and the Itabu Creek specimen is of that plumage. Crypturellus variegatus variegatus Gmelin Tetrao variegatus Gmelin, 1789, Syst. Nat., 1, (2), p. 768 — Cayenne. Acary Mountains: Boundary Camp; 5 females, September 20- October 14. Itabu Creek: Middle Base Camp; 3 females, September 8-12. Three specimens collected October 1-3 are in subadult plumage characterized by white spotting of the breast and absence of bars on the dorsal parts, flanks and thighs. 427 428 FIELDIANA: ZOOLOGY, VOLUME 32 Crypturellus v. variegatus ranges throughout the forested areas of British Guiana and certainly is the most abundant tinamou in the Colony. It was common at all elevations in the Acary Moun- tains, but was most often found in fairly dry areas having little ground cover. ARDEIDAE Ardea cocoi Linnaeus Ardea cocoi Linnaeus, 1766, Syst. Nat., ed. 12, p. 237 — Cayenne. New River: Pairima Camp; 1 female, August 31. This magnificent heron occurs locally throughout the country. It is less numerous on the rivers of the coastal plain than in the interior, where we saw individuals almost daily while voyaging on the upper Courantyne and New Rivers. Cocoi herons are solitary in habit; in fact, I have never seen more than two birds together even directly after the breeding season. They were not found on Itabu Creek, a very constricted waterway, although fairly common on the near-by New River. Tigrisoma lineatum lineatum Boddaert Ardea lineata Boddaert, 1783, Tabl. PL Enl., p. 52— Cayenne. New River: New River Depot; 1 male, September 3. Tiger bitterns inhabit the riversides of the interior in considerable abundance but they frequent dense jungle growth and are not easily found. Unlike other large herons, this species is very furtive and never willingly takes flight over wide expanses of water. When suddenly disturbed it often seeks concealment by "freezing" in position, without, however, elevating the bill as with the American bittern (Botaurus). ANATIDAE Cairina nioschata Linnaeus Anas moschata Linnaeus, 1758, Syst. Nat., ed. 10, p. 124 — Brazil. Itabu Creek: Middle Base Camp; 1 male, October 21. Phantom Falls; 1 male, October 22. These specimens were collected from small flocks, probably family groups, of four and five birds respectively that were flushed from beneath overhanging waterside vegetation. The presence of this large duck on so small a forest stream is unusual, although muscovies are locally abundant on the larger rivers elsewhere in British Guiana. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 429 CATHARTIDAE Sarcorhamphus papa Linnaeus Vultur papa Linnaeus, 1758, Syst. Nat., ed. 10, p. 86 — Surinam. Acary Mountains: Boundary Camp; 2 males, September 25 (lost in river accident). This species is the dominant vulture in forest areas of extreme southern British Guiana. It was seen frequently as we ascended the Courantyne and New Rivers, and small flocks were attracted to each collecting site that was occupied several days or longer. The king vulture was especially numerous in the Acary Mountains, where it seems to replace all other members of the family. A refuse pile established in a densely forested ravine near Boundary Camp was, within twenty-four hours, constantly attended by a dozen or more of these birds. The peculiar relationship between this and other American vul- tures was often demonstrated at a refuse heap established near the camp at King Frederick William IV Falls. In this area, some distance from the mountains, turkey vultures far outnumbered Sarcorhamphus. Nevertheless, the arrival of a single king vulture invariably caused the immediate dispersal of an entire flock of Cathartes. No direct conflict was ever observed, but it was evident that a strong hierarchy of domination exists. Cathartes aura ruficollis Spix Cathartes ruficollis Spix, 1824, Av. Spec. Nov. Bras., 1, p. 2 — interior of Bahia and Piauhy, Brazil. No turkey vultures were collected, but individuals were seen in flight almost daily on the upper Courantyne and New Rivers. Unlike Coragyps atratiis, this vulture is generally distributed in forest areas of the interior. Small flocks quickly assembled about each of the river collecting camps, although none were found in the I tabu Creek drainage or Acary Mountains, where king vultures occurred in greatest abundance. ACCIPITRIDAE Harpagus bidentatus bidentatus Latham Falco bidentatus Latham, 1790, Ind. Orn., 1, p. 38 — Cayenne. Itabu Creek: Middle Base Camp; 1 female, September 13. 430 FIELDIANA: ZOOLOGY, VOLUME 32 Accipiter bicolor bicolor Vieillot Sparvius bicolor Vieillot, 1817, Nouv. Diet. Hist. Nat., nouv. 6d., 10, p. 325 — Cayenne. Itabu Creek: Middle Base Camp; 1 female, September 8. Acary Mountains: Boundary Camp; 2 females, October 1, 4. Leucopternis albicollis albicollis Latham Falco albicollis Latham, 1790, Ind. Orn., 1, p. 36 — Cayenne. Courantyne River: King Frederick William IV Falls; 1 female, August 20. Acary Mountains: Boundary Camp; 1 male, September 27. Urubitinga urubitinga urubitinga Gmelin Falco Urubitinga Gmelin, 1788, Syst. Nat., 1, pt. 1, p. 265 — Brazil. Itabu Creek: Middle Base Camp; 1 male, September 9. Harpia harpy j a Linnaeus Vultur harpyja Linnaeus, 1758, Syst. Nat., ed. 10, p. 86 — Mexico. Itabu Creek: Middle Base Camp; 1 male, October 21. Acary Mountains: Boundary Camp; 1 female, October. Both birds were shot by native hunters who remarked that in neither instance did they have difficulty in approaching within shot- gun range. The specimen from Boundary Camp first attracted attention by its call, which was said to resemble that of a cock-of- the-rock. The second bird was shot from the top of a very tall tree commanding a broad sweep of Itabu Creek. Its stomach contained the partially digested hind foot of a kinkajou (Potos flavus). Both skins were destroyed in the river accident. Harpy eagles occur throughout the forested areas of British Guiana but never in abundance. Although well known to the natives, I saw no living examples during the course of eight months of travel in the interior. FALCONIDAE Micrastur mirandollei Schlegel Astur mirandollei Schlegel, 1862, Mus. Pays-Bas, 2, Astures, p. 27 — Surinam. Itabu Creek: Middle Base Camp; 1 male, September 12. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 431 Micrastur ruficollis gilvicollis Vieillot Sparvius gilvicollis Vieillot, 1817, Nouv. Diet. Hist. Nat., nouv. 6d., 10, p. 323— Cayenne. Itabu Creek: Middle Base Camp; 1 female, September 5. Daptrius americanus americanus Boddaert Falco americanus Boddaert, 1783, Tabl. PI. Enl., p. 25— Cayenne. Itabu Creek: Middle Base Camp; 1 male, September 9. Acary Mountains: Boundary Camp; 1 female, September 30. This caracara is gregarious and very noisy. Small flocks were seen daily along the entire course of the upper Courantyne and on New River, but much less commonly in the Itabu Creek area. They were most often found in the vicinity of rapids. CRACIDAE Ortalis motmot motmot Linnaeus Phasianus motmot Linnaeus, 1766, Syst. Nat., ed. 12, p. 271 — Cayenne. Itabu Creek: Middle Base Camp; 1 female, September 8. Colonies of chachalacas were found at intervals all along the Courantyne and New Rivers, and on the lower portions of Itabu Creek. These arboreal birds habitually inhabit dense vegetation of moderate size that flourishes locally in marshy areas throughout the country. They probably seldom come to earth, and only occa- sionally ascend above twenty-five feet, the latter when disturbed or while acting as look-outs. The birds are relatively quiet during the autumn and winter months and I never heard the distinctive and far-reaching morning and evening call that is so characteristic of breeding chachalacas in spring. Pipile cumanensis cumanensis Jacquin Crax (cumanensis) Jacquin, 1784, Beytr. Gesch. Vogel, p. 25, pi. 10 — Orinoco River region near Cumana, Venezuela. New River: Pairima Camp; 1 female, September 1. Several skins collected at Boundary Camp were lost in the river accident. White-headed guans were abundant both in the Acary Mountains and in the adjacent lowland forests. Flocks numbering more than a dozen individuals were flushed on several occasions. 432 FIELDIANA: ZOOLOGY, VOLUME 32 PHASIANIDAE Odontophorus gujanensis gujanensis Gmelin Tetrao gujanensis Gmelin, 1789, Syst. Nat., 1, (2), p. 769 — Cayenne. Itabu Creek: Middle Base Camp; 1 male, September 8. My assistant, Richard Baldwin, saw a specimen running through the forest near Navigation Head, Itabu Creek, and several minutes later shot a fox (Cerdocyon thous) that appeared to be following its trail. PSOPHIIDAE Psophia crepitans crepitans Linnaeus Psophia crepitans Linnaeus, 1758, Syst. Nat., ed. 10, p. 154 — French Guiana. Large flocks of trumpeters were encountered at intervals through- out the trip but they were much less common above 1,500 feet in the Acary Mountains than in lowland forests to the northward. The curiosity exhibited by this species approaches stupidity and it is not unusual to take several birds from a single flock. All of the specimens collected were lost in the river accident. HELIORNITHIDAE Heliornis fulica Boddaert Colymbus fulica Boddaert, 1783, Tabl. PI. Enl., p. 54— Cayenne. New River: New River Depot; 1 male, September 3. EURYPYGIDAE Eurypyga helias helias Pallas Ardea Helias Pallas, 1781, Neue Nord. Beytr., 2, p. 48, pi. 3— Brazil. We occasionally saw sun-bitterns along the shores of the Couran- tyne and New Rivers but no specimens were collected. COLUMBIDAE Columba plumbea wallacei Chubb Columba plumbea wallacei Chubb, 1917, Bull. Brit. Orn. Cl., 38, p. 32— Rio Capim, Para, Brazil. Itabu Creek: Middle Base Camp; 1 male, September 6. Acary Mountains: Boundary Camp; 1 female, 1 male, Sep- tember 24, October 15. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 433 Leptotila ruf axilla rufaxilla Richard and Bernard Columba (rufaxilla) Richard and Bernard, 1792, Act. Soc. d'Hist. Nat. Paris, 1, (1), p. 118— Cayenne. Itabu Creek: Middle Base Camp; 4 males, 3 females, September 6-14. Acary Mountains: Boundary Camp; 5 males, September 21- October 13. Gray-fronted doves are common throughout the forested areas of British Guiana, but they are most abundant in the interior, where they far outnumber any other member of the family. Oreopeleia montana montana Linnaeus Columba montana Linnaeus, 1758, Syst. Nat., ed. 10, p. 163 — Jamaica. Itabu Creek: Middle Base Camp; 1 female, September 12. This dove occupies the same habitat as the preceding, but it is largely terrestrial, and much more furtive in its habits. I am inclined to believe that it is far more abundant than has been supposed. Individuals were often flushed from the ground on the heavily wooded slopes of the Acary Mountains and I have found it to be generally distributed in the forested areas to the northward. PSITTACIDAE Pionopsitta caica Latham Psittacus Calca Latham, 1790, Ind. Orn., 1, p. 128, No. 137 — Cayenne. Itabu Creek: Middle Base Camp; 3 males, September 13. Two of these specimens are in subadult plumage, their heads being dull green shading to golden olive on the neck and forebreast, and only sparingly flecked with black. From adults they also differ in being less intensely colored throughout, and in having paler under parts and obscure nuchal collars. Pionus fuscus P. L. S. Muller Psittacus fuscus P. L. S. MUller, 1776, Natursyst., Suppl., p. 78 — Cayenne. Itabu Creek: Middle Base Camp; 2 males, September 13. Acary Mountains: Boundary Camp; 1 female, October 7. Deroptyus accipitrinus accipitrinus Linnaeus Psittacus accipitrinus Linnaeus, 1758, Syst. Nat., ed. 10, p. 102 — Cayenne. 434 FIELDIANA: ZOOLOGY, VOLUME 32 Courantyne River: King Frederick William IV Falls; 2 males, August 18. Itabu Creek: Middle Base Camp; 1 male, September 9. CUCULIDAE Piaya cayana cayana Linnaeus Cuculux cayamis Linnaeus, 1766, Syst. Nat., ed. 12, p. 170 — Cayenne. Courantyne River: King Frederick William IV Falls; 1 male, August 19. Itabu Creek: Middle Base Camp; 1 male, September 13. Acary Mountains: Boundary Camp; 1 male, October 10. Crotophaga major Gmelin Crotophaga major Gmelin, 1788, Syst. Nat., 1, pt. 1, p. 363 — Cayenne. This species evidently supplants ani on the Courantyne River above Wonotoba Falls. Although major is more partial to riverside vegetation than its smaller relative, it too is essentially a bird of forest-edge and clearing. The few individuals seen on the upper Courantyne and New Rivers were restricted to the small clearings made by the Boundary Survey Commission within three years of my visit. No specimens were collected, nor was the species found beyond New River Depot. CAPRIMULGIDAE Caprimulgus nigrescens nigrescens Cabanis Caprimulgus nigrescens Cabanis, 1848, in Schomburgk, Reisen Brit. Guiana, 3, p. 710 — Lower Essequibo River, British Guiana. Acary Mountains: Boundary Camp; 1 male, October 7. Itabu Creek: Navigation Head; 1 female, October 21. New River: Haimara Camp; 1 female, October 24. Courantyne River: King William Falls; 1 juvenile, November 8. The flightless juvenile collected November 8 on the exposed rocks of an island near King William Falls was unattended by an adult when found. 1 1 \ dropsul is climacocerca schomburgki Sclater Hydropsalis schomburgki "G. R. Gray" Sclater, 1866, Proc. Zool. Soc. London, 1866, p. 142— British Guiana. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 435 New River: Haimara Camp; 1 male, 1 female, October 24. Phantom Falls; 2 males, October 23. The gonads of all New River specimens were undeveloped and the rectrices are badly abraded, whereas two males collected at Rockstone (lower Essequibo River) on March 9 and 18 were in breeding condition. TROCHILIDAE Therenetes leucurus leucurus Linnaeus Trochilus leucurus Linnaeus, 1766, Syst. Nat., ed. 12, p. 190 — Surinam. Acary Mountains: Boundary Camp; 1 male, 1 female, September 28, October 2. Phaethornis superciliosus superciliosus Linnaeus Trochilus superciliosus Linnaeus, 1766, Syst. Nat., ed. 12, p. 189 — Cayenne. Acary Mountains: Boundary Camp; 6 males, 1 female, 2?, Sep- tember 22-October 14. Five specimens of both sexes differ from other Guianan skins in having the anterior under parts dull white to pale dusky gray. I judge this to be an indication of immaturity, since two skins from the same locality agree in all respects with typical examples of superciliosus. A skin of this species in Chicago Museum collected at Serra do Lua, on the upper Rio Branco, is virtually identical with adult specimens from Rockstone, British Guiana, and there is little doubt that saturatior, a weak race at best, will prove to be a synonym of the present form. Phaethornis ruber episcopus Gould Phaethornis episcopus Gould, 1857, Proc. Zool. Soc. London, pt. 25, 1857, p. 14 — British Guiana. Acary Mountains: Boundary Camp; 1 male, October 1. Phaethornis r. episcopus is readily distinguished from ruber by its rich bronzy dorsal parts, broader pectoral band, and particularly by the deep bronze tone of its tail. Both birds have short rounded wings but, contrary to previous published accounts, the wings of episcopus average slightly larger than those of ruber. Campylopterus largipennis largipennis Boddaert Trochilus largipennis Boddaert, 1783, Tabl. PI. Enl., p. 41 — Cayenne. Acary Mountains: Boundary Camp; 2 males, September 29, October 13. 436 FIELDIANA: ZOOLOGY, VOLUME 32 Florisuga mellivora mellivora Linnaeus Trochilus mellivorus Linnaeus, 1758, Syst. Nat., ed. 10, p. 121 — Surinam. Acary Mountains: Boundary Camp; 1 male, September 27. This bird was in breeding condition, although collected in September. Colibri delphinae Lesson Ornismya Delphinae Lesson, 1839, Rev. Zool., p. 44 — Santa F6 de Bogota, Colombia. Acary Mountains: Boundary Camp; 1 male, 1?, September 12, 14. The unsexed skin, evidently in mature plumage, has a distinctly bronze throat that is quite unlike the golden iridescence of most violet-ears. Immature birds of the series at hand have the rectrices broadly tipped with dull cinnamon similar to the edgings of the dorsal feathers. Thalurania fur car a furcata Gmelin Trochilus fur -catus Gmelin, 1788, Syst. Nat., 1, pt. 1, p. 486 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 2 females, 3?, September 20-October 10. A female collected October 10 was in breeding condition, and several other specimens are in subadult plumage. As to the latter, a stage apparently rare in collections, one male has a coppery rump and an iridescent golden throat bounded posteriorly by a small patch of metallic green followed by a breast-band of violet-blue. Topaza pella pella Linnaeus Trochiliis Pella Linnaeus, 1758, Syst. Nat., ed. 10, p. 119 — Surinam. New River: Phantom Falls; 1 female, October 23. Haimara Camp; 1 female, October 24. TROGONIDAE Trogon melanurus melanurus Swainson Trogon melanurus Swainson, 1837, Anim. Menag., 1838 (1837), p. 329 — Demerara. Itabu Creek: Middle Base Camp; 3 males, September 7-12. Acary Mountains: Boundary Camp; 1 female, 1 male, October 3, 5. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 437 Trogon strigilatus strigilatus Linnaeus Trogon strigilatus Linnaeus, 1766, Syst. Nat., ed. 12, p. 167, No. 1 — Cayenne. Itabu Creek: Middle Base Camp; 2 males, September 9. Acary Mountains: Boundary Camp; 1 male, October 11. Trogon collaris collaris Vieillot Trogon collaris Vieillot, 1817, Nouv. Diet. Hist. Nat., nouv. 6d., 8, p. 320 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 2 females, September 24-29. Although Beebe (Beebe, Hartley and Howells, 1917, p. 130) lists collaris among the 351 species observed at Bartica, Chubb does not include the species in his Birds of British Guiana and previous records in both British and Dutch Guiana are specifically denied by Peters (1945, p. 155). The male listed above has the wing coverts more boldly barred with black than in Tobago specimens and the tail bars are somewhat finer, but for the present it seems best to allocate this bird to the nominate race. Trogon rufus ruf us Gmelin Trogon rufus Gmelin, 1788, Syst. Nat., 1, pt. 1, p. 404 — Cayenne. Itabu Creek: Middle Base Camp; 1 male, 1 female, September 12, 13. Acary Mountains: Boundary Camp; 3 males, 1 female, September 21-October 15. These specimens are identical with birds from the coastal area. Two subadult males collected September 12 and 21 are in transition plumage and have a curious intermixture of adult characters. The tail, wings and ventral plumage of one specimen (September 12) are essentially like those of a female, but its crown, back and tail coverts are iridescent bronze-green as in adult males. The crown of the second bird is predominantly brown, although otherwise its plumage is that of an adult male. Trogon violaceus violaceus Gmelin Trogon violaceus Gmelin, 1788, Syst. Nat., 1, pt. 1, p. 404 — Surinam. Acary Mountains: Boundary Camp; 1 male, October 10. MOMOTIDAE Momotus momota momota Linnaeus Ramphastos momota Linnaeus, 1766, Syst. Nat., ed. 12, p. 152 — Cayenne. 438 FIELDIANA: ZOOLOGY, VOLUME 32 Itabu Creek: Middle Base Camp; 3 females, 1 male, September 6- 12. Acary Mountains: Boundary Camp; 1 male, 1 female, September 29, October 15. I found no motmots above 2,000 feet in the Acary Mountains but they occurred at lower elevations and were abundant in river forests to the northward. These solitary birds inhabit the deep forest and usually perch from six to fifteen feet above the ground, where they often remain motionless for long periods except for occasional twitching of the tail. GALBULIDAE Galbula albirostris albirostris Latham Galbula albirostris Latham, 1790, Index Orn., 1, p. 245 — Cayenne. Acary Mountains: Boundary Camp; 2 males, 1 female, September 28-October 3. Galbula dea dea Linnaeus Alcedo Dea Linnaeus, 1758, Syst. Nat., ed. 10, p. 116 — Surinam. Acary Mountains: Boundary Camp; 3 males, September 27- October 5. A specimen collected on October 5 is in adult plumage but has the abbreviated bill (33 mm.) and tail (85 mm.) of an immature bird. Jacamerops aurea aurea P. L. S. Miiller Alcedo aurea P. L. S. Miiller, 1776, Natursyst., Suppl., p. 94 — Berbice, British Guiana. Acary Mountains: Boundary Camp; 2 males, October 1, 15. BUCCONIDAE Notharcus macrorhynchos macrorhynchos Gmelin Bucco macrorhynchos Gmelin, 1788, Syst. Nat., 1, pt. 1, p. 406 — Cayenne. Acary Mountains: Boundary Camp; 1 male, October 8. Bucco capensis Linnaeus Bucco capensis Linnaeus, 1766, Syst. Nat., ed. 12, p. 168 — Guiana. Itabu Creek: Middle Base Camp; 1 female, September 11. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 439 Malacoptila fusca fusca Gmelin Buccofusca Gmelin, 1788, Syst. Nat., 1, pt. 1, p. 408 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 2 females, September 29-October 3. The only previous British Guiana record for this widespread puff- bird seems to be Bartica, on the lower Essequibo River. Monasa atra Boddaert Cuculus ater Boddaert, 1783, Tabl. PI. Enl., p. 30— Cayenne. Itabu Creek: Middle Base Camp; 1 male, 2 females, September 6-8. Navigation Head; 1 female, October 20. Acary Mountains: Boundary Camp; 1 male, 2 females, October 10, 14. This puff-bird is one of the most abundant non-colonial forest birds of the interior of British Guiana. It appears to be rare in the coastal area. CAPITONIDAE Capito niger niger P. L. S. Miiller Bucco niger P. L. S. Miiller, 1776, Natursyst., Suppl., p. 89 — Cayenne. .Acary Mountains: Boundary Camp; 2 males, 2 females, Sep- tember 30-October 10. RAMPHASTIDAE Aulacorh ynchus derbianus osgoodi Blake Aulacorhynchus derbianus osgoodi Blake, 1941, Field Mus. Nat. Hist., Zool. Ser., 24, p. 228 — Boundary Camp, head of Itabu Creek, Acary Mountains, British Guiana. Acary Mountains: Boundary Camp; 1 male, 1 female, October 1, 7. A strongly marked race characterized by the absence of chestnut tips on the rectrices and by the lack of a blue malar mark. As shown elsewhere (Blake, loc. cit.), osgoodi is nearest whitelyanus of the mountainous parts of western British Guiana and extreme eastern Venezuela. These races, while individually distinct, have in common with duidae several characters that differ in degree rather than in kind, a circumstance indicating a very close relationship 440 FIELDIANA: ZOOLOGY, VOLUME 32 that is not fully shared by the Andean form, derbianus. It is espe- cially noteworthy that the races of this species form, from west to east, a distinct cline involving both a reduction of size and a pro- gressive modification of the basic color pattern. In osgoodi, the easternmost or peripheral form that alone inhabits the Tropical Zone, this trend reaches its zenith with the final elimination of certain color elements that are present in the subtropical races to the westward. Pteroglossus aracari roraimae Brabourne and Chubb Pieroglossus roraimae Brabourne and Chubb, 1912, Ann. Mag. Nat. Hist., (8), 10, p. 261— British Guiana. Courantyne River: King Frederick William IV Falls; 1 female, August 16. Itabu Creek: Middle Base Camp; 1 male, September 11. The Courantyne River specimen tends only slightly towards atricollis of French Guiana in the color of its breast but there is definite evidence of intermediacy in the single bird from Itabu Creek. A series collected in the Acary Mountains unfortunately was lost in the river accident. Nevertheless, from the material now available, it may be predicted that the birds of southern Dutch Guiana south- ward and westward to the Rio Trombetas will prove to be either typical of atricollis, or strongly influenced by it. Pteroglossus viridis viridis Linnaeus Ramphastos viridis Linnaeus, 1766, Syst. Nat., ed. 12, p. 150 — Cayenne. Courantyne River: Oronoque Base Camp; 1 female, August 27. Selenidera culik Wagler Pteroglossus Culik Wagler, 1877, Syst. Av., Pteroglossus, sp. 10 — Cayenne. Itabu Creek: Middle Base Camp; 3 males, 1 female, September 7-10. Acary Mountains: Boundary Camp; 4 males, 5 females, Sep- tember 21-October 13. Ramphastos vitellinus vitellinus Lichtenstein Ramphastos vitellinus Lichtenstein, 1823, Verz. Doubl. Zool. Mus. Berlin, p. 7 — Cayenne. New River: Calf Bird Camp; 1 female, August 30. Itabu Creek: Middle Base Camp; 3 males, September 6-11. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 441 PICIDAE Piculus rubiginosus nigriceps Blake Piculus rubiginosus nigriceps Blake, 1941, Field Mus. Nat. Hist., Zool. Ser., 24, p. 230 — Boundary Camp, head of Itabu Creek, Acary Mountains, British Guiana. Acary Mountains: Boundary Camp; 3 males, 4 females, Sep- tember 21-October 15. This woodpecker differs from all other known races of rubiginosus in having the pileum blacker (less slaty-gray), the red of the nape reduced to an obscure, broken line in the male (lacking in the female) and the back and wing coverts clearer green, between Warbler Green and Pyrite Yellow of Ridgway. In size, pattern of throat and color of the under parts, nigriceps resembles guianae. However, an equally close relationship to the isolated subtropical form viridis- simus of Mount Auyan-tepui, Venezuela, is indicated by its intensely green dorsal parts and reduced nuchal band. Although presently known only from the type locality, nigriceps probably occurs gener- ally in the Acary Mountains and adjacent lowlands of both Brazil and British Guiana. Piculus flavigula flavigula Boddaert Picus flavigula Boddaert, 1783, Tabl. PI. Enl., p. 49— Cayenne. Acary Mountains: Boundary Camp; 2 females, September 26, 30. Piculus chrysochloros capistratus Malherbe Chloropicus capistratus Malherbe, 1862, Monog. Picid&s, 2, p. 140, pi. 83 — Rio Negro. Acary Mountains: Boundary Camp; 1 female, October 3. Previous British Guiana records are limited to the Rupununi River, approximately 150 miles northwest of the present locality. I have seen no examples of the French Guiana form guianensis, but Friedmann (1948, p. 440) has pointed out that the description of Todd's unique type practically fits the differences between two specimens of the present race collected at Cerro Yapacana, in the region of the upper Orinoco River. Geleus elegans hellmayri Berlepsch Celeus elegans hellmayri Berlepsch, 1908, Nov. Zool., 15, p. 272 — Cumacusa, Mazaruni River, British Guiana. Itabu Creek: Middle Base Camp; 1 female, September 9. 442 FIELDIANA: ZOOLOGY, VOLUME 32 This specimen is neither typical of hellmayri, nor clearly referable to approximans, a very distinct form of which there is one record from Quonga, in southwestern British Guiana (Hargitt, 1890, p. 428). It differs from all other British Guiana skins examined in having the rump and flanks almost immaculate lemon yellow, its crown paler and less ochraceous buff, and the chestnut plumage darker and less bright than in typical hellmayri. From representa- tive approximans it is readily distinguished by its larger size (wing 62 mm.), distinctly yellowish rump and flanks, and somewhat ochraceous crown. Although possibly an individual variant of hell- mayri, the Itabu Creek specimen probably is representative of an intermediate population tending towards approximans, but nearer the former. Celeus umlat us undatus Linnaeus Picus undatus Linnaeus, 1766, Syst. Nat., ed. 12, p. 175 — Surinam. Itabu Creek: Middle Base Camp; 1 female, September 12. Acary Mountains: Boundary Camp; 1 female, September 30. Celeus flavus flavus P. L. S. Miiller Picus flavus P. L. S. Miiller, 1776, Natursyst., Suppl., p. 91 — Cayenne. Itabu Creek: Middle Base Camp; 1 male, September 12. Celeus torquatus torquatus Boddaert Picus torquatus Boddaert, 1783, Tabl. PI. Enl., p. 52— Cayenne. Itabu Creek: Middle Base Camp; 1 male, September 12. Veniliornis cassini Malherbe Mesopicus cassini Malherbe, 1862, Monog. Picid6es, 2, p. 55; 3, pi. 58, figs. 2-4 — Cayenne. Acary Mountains: Boundary Camp; 1 male, October 15. Phloeoceastes rubricollis rubricollis Boddaert Picus rubricollis Boddaert, 1783, Tabl. PI. Enl., p. 37— Cayenne. Courantyne River: King Frederick William IV Falls; 1 male, August 20. Itabu Creek: Middle Base Camp; 1 female, September 5. Acary Mountains: Boundary Camp; 1 male, October 3. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 443 DENDROCOLAPTIDAE Dendrocolaptes certhia certhia Boddaert Picus certhia Boddaert, 1783, Tabl. PI. Enl., p. 38— Cayenne. Acary Mountains: Boundary Camp; 1 male, September 26. The intensified coloration and rather sharply defined ventral bars of this specimen probably can be attributed to the action of river water in which it was submerged for several days. I can not so readily account for its markedly robust bill. This specimen was in breeding condition, although collected in September. Xiphocolaptes promeropirhynchus tenebrosus Zimmer and Phelps Xiphocolaptes promeropirhynchus tenebrosus Zimmer and Phelps, 1948, Amer. Mus. Nov., No. 1373, p. 1 — Mount Chimanta-tepui, Gran Sabana, Bolivar, Venezuela. Acary Mountains: Boundary Camp; 1 female, September 26. Comparison of this specimen some years ago with the various races of promeropirhynchus known at that time raised serious doubt as to its taxonomic status. Although most nearly like orenocensis in several important features, the straighter culmen, somewhat striped and more buffy throat, and particularly the much darker crown and mantle of the Acary bird immediately distinguished it from all available examples of its geographically distant relative. In examining this bird with Mr. Zimmer at the time, consideration both of its subadult plumage (in partial molt) and its history of having been submerged in the river accident led to our conclusion that it might well be a variant of orenocensis or an immature ex- ample thereof. The subsequent separation of tenebrosus on the basis of several specimens from southeastern Venezuela having identical characters has revealed our error. This well-marked form appears to be the lowland representative of a species generally associated with the Subtropical or Temperate Zones. The present record extends its range approximately 300 miles from southeastern Venezuela, where the race was previously known only from the base of Mount Roraima (Arabupu) and from the western slope of Mount Chimanta-tepui at an altitude of 700 meters. By coincidence or otherwise, tenebrosus combines a geo- graphical position and zonal affinity in relation to other members of promeropirhynchus similar to those of another Acary bird, Aulaco- 444 FIELDIANA: ZOOLOGY, VOLUME 32 rhynchus derbianus osgoodi. Both are easternmost, lowland repre- sentatives of their respective species, which otherwise are confined entirely or very largely to the Subtropical Zone. Too little is known of these birds and of the areas they occupy to warrant any judgment as to the implication of this parallel, but it is evident that the Acary Mountains influence the distribution of certain species limited elsewhere to higher altitudes. Xiphorhynchus pardalotus pardalotus Vieillot Dendrocopus pardalotus Vieillot, 1818, Nouv. Diet. Hist. Nat., nouv. e"d., 26, p. 117 — Cayenne. Acary Mountains: Boundary Camp; 1 male, September 29. The nominate race differs from caurensis of southern Venezuela by its more olivaceous (less rufescent) upper parts and relatively prominent buffy streaks. The latter proves to be the more depend- able character, since, in pardalotus, the dorsal streaks are always more distinctly edged with black than in caurensis, whereas the general tone of the plumage varies considerably in both forms, although certainly of diagnostic value in series. Todd designated the range of caurensis as extending from the Caura River eastward only to the Guiana frontier. There is evi- dence, however, that it also ranges into western British Guiana, at least locally. A specimen in Chicago Museum taken on the Carimang River in northwestern British Guiana agrees In every respect with seven Venezuelan skins from the upper Caura, and it is evident that earlier locality records west of the Essequibo River require re-ex- amination. Some degree of intergradation east of the Essequibo is suggested by the striking rufescence of a Rockstone skin that other- wise is similar to typical examples of pardalotus from the same locality. This widespread woodhewer has been recorded at 1,100 meters above sea level, on Mount Auyan-tepui, Venezuela, but elsewhere it appears to be a bird of the lowland forests. A female collected at Rockstone on March 27 was in breeding condition, and specimens similarly developed have been taken in northern Brazil and extreme southern Venezuela from November to April (Friedmann, 1948, p. 449). Glyphorhynchus spirurus spirurus Vieillot Neops spirurus Vieillot, 1819, Nouv. Diet. Hist. Nat., nouv. 6d., 31, p. 338 — Cayenne. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 445 Acary Mountains: Boundary Camp; 1 male, 2 females, Septem- ber 20-29. FURNARIIDAE Synallaxis rutilans dissors Zimmer Synallaxis rutilans dissors Zimmer, 1935, Amer. Mus. Nov., No. 819, p. 4 — Campos Salles, Manaos, Brazil. Acary Mountains: Boundary Camp; 3 males, September 26- October 3. The range of this spine-tail occupies most of the area north of the Amazon westward to the left bank of the Rio Negro. Although the species was not previously known in British Guiana, it will most certainly be found to occur generally in the southern part of the Colony, since it is recorded both in the coast lands of Dutch and French Guiana and to the westward on the Caura and Orinoco Rivers in Venezuela. All three Acary specimens are subadults with somewhat short wings (55-58 mm.), but in other respects they agree with an adult female from the Rio Branco (Conceicao), Brazil. Philydor ruficaudatus ruficaudatus Lafresnaye and D'Orbigny Anabates ruficaudatus Lafresnaye and D'Orbigny, 1838, Syn. Av., 2, in Mag. Zool., 8, cl. 2, p. 15 — Yuracares, Bolivia. Acary Mountains: Boundary Camp; 1 male, 1 female, September 29-October 3. Birds from the southern extremity of British Guiana are identical with numerous specimens from French Guiana and Brazil (Obidos, Santare"m, Rio Purus, Maranhao, etc.). The species is unknown else- where in the Colony and, surprisingly, is not yet recorded from Dutch Guiana. A closely related form (flavipectus), characterized by more yellow- ish under parts, occupies a relatively limited area in Venezuela extending at least from the sources of the Caura and Ventuari Rivers eastward in the lowlands to Mount Auyan-tepui. Mount Duida birds are referable to the nominate race. Philydor erythrocercus erythrocercus Pelzeln Anabates erythrocercus Pelzeln, 1859, Sitzungsber. math.-naturw. Kl. Ak. Wiss. Wien, 34, pp. 105, 128— Barra do Rio Negro [=ManaosJ. 446 FIELDIANA: ZOOLOGY, VOLUME 32 Acary Mountains: Boundary Camp; 3 males, 2 females, Sep- tember 27-October 3. Previous British Guiana records of erythrocercus are limited to the region west of the Essequibo River, where the species occurs both in the coastal plain (Ituribisi River) and in the lowland forests of the interior (Ourumee, Kamakusa, Tumatumari). Although as yet unreported in Surinam, it is well known in French Guiana and southward to the north bank of the Amazon. FORMICARIIDAE Cymbilaimus lineatus lineatus Leach Lanius lineatus Leach, 1814, Zool. Misc., 1, p. 20, pi. 6 — Berbice, British Guiana. Acary Mountains: Boundary Camp; 1 male, 1 female, September 23,28. The chestnut crown of the female is much darker and richer in color than I have found elsewhere in this form, and its under parts are more extensively washed with buff. The male, however, is identical with other examples of the nominate race. Thamnophilus murinus murinus Sclater and Salvin Thamnophilus murinus (Natterer MS.) Sclater and Salvin, 1867, Proc. Zool. Soc. London, 1867, pp. 750, 756 — Xeberos, eastern Peru; Cayenne, etc. Acary Mountains: Boundary Camp; 4 males, 1 female, September 2&-October 3. Three of the four males listed above, as well as a specimen col- lected on the Mazaruni River, are in closest agreement with a representative series from Obidos. The fourth male approaches cayennensis and evidently is similar to certain British Guiana speci- mens discussed by Zimmer (1933, p. 8). Since the vicinity of Obidos is inhabited by a population found by Todd (1927, p. 153) to correspond with that of Manacapuru, it is not surprising that most British Guiana birds and those from Obidos are readily separable from the strikingly distinct French Guiana form, cayennensis. The latter was, in fact, described as a result of comparisons made with twenty-four males from Manacapuru and Obidos, a circumstance with implications that have been disregarded by all subsequent writers. Zimmer's conclusions (loc. cit., pp. 7, 8) as to the taxonomic status of birds from the north bank of the Amazon are at variance BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 447 with those of Todd, whose work I have corroborated in part during the course of the present investigation. While accepting the range of murinus as extending eastward into British and Dutch Guiana, Zimmer nevertheless allocates specimens from Faro, Rio Jamunda, to cayennensis. This viewpoint is, of course, untenable unless Obidos birds are similarly designated in contradiction of their evident agreement with numerous specimens (thirteen males) of murinus from Manacapuru. It is perhaps noteworthy that Zimmer had no Obidos specimens, and commented that those from Faro show "some approach toward" murinus, although closer to cayen- nensis. Later workers have followed Zimmer in this connection, evidently without having made a critical examination of Obidos specimens. Dysithamnus ardesiacus obidensis Snethlage Dysithamnus ardesiacus obidensis Snethlage, 1914, Orn. Monatsber., 22, p. 40— Obidos, Brazil. Acary Mountains: Boundary Camp; 2 males, 2 females, Sep- tember 23-30. Thamnomanes caesius glaucus Cabanis Thamnomanes glaucus Cabanis, 1847, Arch. Naturg., 13, (1), p. 230 — Cayenne. Acary Mountains: Boundary Camp; 4 males, 2 females, Sep- tember 24-October 3. Myrmotherula brachyura brachyura Hermann Muscicapa brachyura Hermann, 1783, Tab. Aff. Anim., p. 299 — Cayenne. Acary Mountains: Boundary Camp; 1 female (juv.), October 3. Myrmotherula gutturalis Sclater and Salvin Myrmotherula gutturalis Sclater and Salvin, 1881, Ibis, (4), 5, p. 269 — Bartica Grove, British Guiana. Acary Mountains: Boundary Camp; 1 male, 1 female, September 24, 29. Cory and Hellmayr's designation of Salvin and Godman as the describers of this species has been repeated by most later writers. Myrmotherula longipennis longipennis Pelzeln Myrmotherula longipennis Pelzeln, 1868, Orn. Bras., 2, Sept., pp. 82, 163 — Rio Negro, Marabitanas. 448 FIELDIANA: ZOOLOGY, VOLUME 32 Acary Mountains: Boundary Camp; 4 males, 6 females, 2 juveniles, September 20-October 3. Myrmotherula menetriesii cinereiventris Sclater and Salvin Myrmotherula cinereiventris Sclater and Salvin, "1867," pub. 1868, Proc. Zool. Soc. London, 1867, p. 756 — Cayenne. Acary Mountains: Boundary Camp; 6 males, 3 females, Sep- tember 21-October 13. Herpsilochmus stictocephalus Todd Herpsilochmus stictocephalus Todd, 1927, Proc. Biol. Soc. Wash., 40, p. 159 — Tamanoir, French Guiana. Acary Mountains: Boundary Camp; 1 male, September 24. Although morphologically very close to sticturus Salvin, sticto- cephalus occupies much the same range and hence must be accorded specific rank. In several respects the relationship between these forms is strikingly similar to that of Myrmotherula brachyura and M. obscura as brought out by Zimmer (1932a, pp. 2-4). Measurements of the present specimen (wing 50; tail 41) are at the upper limits recorded for stictocephalus and exceed by several millimeters the extremes known for sticturus. It differs from the latter also in having the forehead minutely streaked with white, although this character is less pronounced than in several Cayenne skins examined. The range of stictocephalus is known at present to extend only from French Guiana westward to the Rio Yuruan in extreme eastern Venezuela, and southward (in British Guiana) to the Acary Moun- tains. Its distribution within this area is less certain since records prior to 1932 may refer either to sticturus or to stictocephalus. Never- theless, a male from Ourumee, British Guiana, in the American Museum (no. 490556) proves to be the latter, whereas certain specimens from Tumatumari, Bartica and Kamakusa are referable to sticturus. The present species is not yet recorded in Dutch Guiana. Terenura callinota guianensis Blake Terenura callinota guianensis Blake, 1949, Fieldiana, Zool., 31, p. 267 — Boundary Camp, head of Itabu Creek, Acary Mountains, British Guiana. Acary Mountains: Boundary Camp; 1 male, September 30. This surprising addition to the Guianan fauna constitutes the first record of the species east of the Andes and represents a minimum BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 449 range extension of about 1,200 miles. Terenura c. guianensis differs from the nominate race of Ecuador, Colombia, and Panama prin- cipally in having the rump and lower back notably darker and richer, these parts being Claret Brown of Ridgway rather than Sanford's Brown or Orange Rufous. The discovery of a race of cattinota in the Acary Mountains, east of the Essequibo River drainage, represents a considerable exten- sion of the Andean influence, a circumstance of some significance, in view of the discovery in the same area of a typical example of Contopus nigrescens canescens, previously known only from Peru. Terenura spodioptila spodioptila Sclater and Salvin Terenura spodioptila Sclater and Salvin, 1881, Ibis, p. 270, pi. 9 — Bartica Grove, British Guiana. Acary Mountains: Boundary Camp; 2 males, September 30. Adult British Guiana specimens agree in every respect with ex- amples of spodioptila of comparable maturity from both Venezuela and French Guiana. Thirty-seven specimens from these areas show only minor individual variation in the color of their under parts. Similarly, the edgings of their remiges, whether olive-green or slate- gray, are entirely lacking in geographical significance. Hitherto the presence of olive-green margins on the remiges has been considered diagnostic of elaopteryx, a questionable form de- scribed from French Guiana and believed to range southward to the north bank of the lower Amazon. Although recognized without comment by Griscom and Greenway (1941, p. 242) and by Pinto (1938, p. 490), the validity of an eastern representative of spodioptila has been seriously questioned by other authors. In commenting on four birds from Faro, Rio Jamunda, Brazil, Zimmer (1932c, p. 7) states that two adults have the margins of the remiges gray, whereas one immature specimen has these parts olive-green and a second young bird is molting from olive to gray. A male from Mount Auyan-tepui, Venezuela, was reported by Gilliard (1941, p. 481) as having the outer edges of the primaries and secondaries washed with green, being in this respect similar to a specimen from Tumatumari, British Guiana, and hence unlike representative examples of the nominate race. Similarly, I find a specimen from the Rio Yuruan, in eastern Venezuela, bearing the distinctive character of elaopteryx, whereas the majority of a series of thirteen birds from Cayenne have remiges with gray margins. 450 FIELDIANA: ZOOLOGY, VOLUME 32 In brief, it is clear that elaopteryx was based upon a variable factor that is, in fact, merely an expression of immaturity. I can find no alternate character of significance that would establish its claim to recognition. Hypocnemis cantator cantator Boddaert Formicarius cantator Boddaert, 1783, Tabl. PL Enl., p. 44 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 2 females, September 26-October 10. The British Guiana race, notea, is described as differing (males) from the widespread nominate race of adjacent areas by the promi- nence of its concealed dorsal white patch, by the presence of streaks rather than spots on the mantle and by the deeper, more intense rufous tone of the flanks, crissum and rump. The notable varia- bility of these characters as found in 47 British Guiana specimens and 23 examples of cantator was discussed by Zimmer (1932a, p. 19) who, nevertheless, recognized notea on the basis of its average ap- pearance. Nine British Guiana males now before me emphasize still further the unreliability of each of the characters that have been used to distinguish notea from cantator. The concealed white patch is prominent in only three of the British Guiana series whereas it is considerably reduced in five skins and absent in another. The mantles of five specimens are more nearly spotted than streaked, and in the series as a whole the rufous tone of the flanks, crissum and rump varies from pale to rich. The positive characters of notea are, in fact, combined in only three specimens, whereas six skins have one or more of the characters that are attributed to cantator. The Acary specimen is a good example of diverse subspecific characters in fortuitous combination. In this bird the concealed white patch of notea is lacking, although the mantle is distinctly streaked and the posterior parts are more intensely rufous than in the average of that form. If notea can be distinguished at all, this speci- men would properly be considered an intermediate. However, similar combinations of characters occur at random elsewhere in British Guiana and the four French Guiana males (cantator) available to me are so diverse as to undermine still further the concept of an endemic subspecies in British Guiana. Percnostola rufifrons rufifrons Gmelin Turdus rufifrons Gmelin, 1789, Syst. Nat., 1, (2), p. 825— Cayenne. Acary Mountains: Boundary Camp; 1 male, September 27. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 451 The Acary Mountains evidently separate the ranges of rufifrons and subcristata, since the latter is known to occupy the area west of the Rio Trombetas and southward to the Amazon. The single Acary specimen is identical with two Rockstone males and measures as follows: wing 75; tail 63. Myrmeciza fermginea ferruginea P. L. S. Miiller Turdus ferrugineus P. L. S. Miiller, 1776, Natursyst., Suppl., p. 141 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 2 females, September 24, 26. Formicarius colnia colma Boddaert Formicarius Colma Boddaert, 1783, Tabl. PI. Enl., p. 44 — Cayenne. Acary Mountains: Boundary Camp; 1 female, October 10. In an immature British Guiana female in Chicago Museum the forehead is rather pale rufous, the lores are white and the throat is immaculate except for minute black feather tips that form a fringe posteriorly. The Acary specimen is in fully adult plumage except that the throat, surprisingly, is boldly stippled with black as in birds less mature than the preceding. The immature plumage of males has been discussed by Zimmer (1932c, p. 10). Formicarius analis crissalis Cabanis Myrmornis crissalis Cabanis, 1861, Journ. Orn., 9, p. 96 — Roraima, British Guiana [= Venezuela]. Acary Mountains: Boundary Camp; 1 male, September 23. Pithys albifrons albifrons Linnaeus Pipra albifrons Linnaeus, 1766, Syst. Nat., ed. 12, p. 339— "Guiana" [= Cayenne]. Acary Mountains: Boundary Camp; 1 male, 2 females, October 1-11. Gymnopithys rufigula rufigula Boddaert Turdus rufigula Boddaert, 1783, Tabl. PI. Enl., p. 39— Cayenne. Acary Mountains: Boundary Camp; 1 female, October 1. Hylophylax naevia naevia Gmelin Pipra naevia Gmelin, 1789, Syst. Nat., 1, (2), p. 1003— Cayenne. Acary Mountains: Boundary Camp; 4 males, 2 females, Sep- tember 21-29. 452 FIELDIANA: ZOOLOGY, VOLUME 32 Two specimens of the present series agree in part with consobrina of southern Venezuela and Brazil north of the Rio Negro. Of these, the female has a pure white throat untinged with buff and the male is somewhat more heavily streaked below than average examples of naevia. Carriker (1932, pp. 3-4) has reviewed the races of this species in detail, but more material is needed from critical areas in southeastern Venezuela and from the southern extremity of British Guiana to establish the boundaries of intergradation in these forms. For the present, birds from the southern extremity of British Guiana are best assigned to the nominate race. Hylophylax poecilinota poecilinota Cabanis Hypocnemis poecilinota Cabanis, 1847, Arch. Naturg., 13, (1), p. 213, pi. 4 — British Guiana. Acary Mountains: Boundary Camp; 5 males, 3 females, Sep- tember 22-October 1. Myrmornis torquata Boddaert Formicarius torquatus Boddaert, 1783, Tabl. PL Enl., p. 43 — Cayenne. Itabu Creek: Middle Base Camp; 1 female, September 11. Acary Mountains: Boundary Camp; 4 males, 7 females, Sep- tember 22-October 15. A very abundant and conspicuous species throughout the forest areas of the interior. It appears to be unrecorded in Dutch Guiana, although widely distributed in adjacent countries. Myrmothera companisona companisona Hermann Myrmornis companisona Hermann, 1783, Tab. Aff. Anim., p. 189 — Cayenne. Itabu Creek: Middle Base Camp; 1 male, 1 female, September 12, 14. Acary Mountains: Boundary Camp; 1 female, October 14. Grallaria varia varia Boddaert Formicarius varius Boddaert, 1783, Tabl. PL Enl., p. 44 — Cayenne. Itabu Creek: Middle Base Camp; 1 male, September 8. Acary Mountains: Boundary Camp; 3 females, 1? This magnificent antpitta is limited to the Guianas. A single Brazilian record (Calama, Rio Madeira) is erroneous, pertaining instead to distincta (Griscom and Greenway, 1941, p. 252). BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 453 Grallaria macularia macularia Temminck Pitta macularia Temminck, 1823, Nouv. R6c. PI. Color., livr. 85, Genre Breve, esp. 11, p. 4 of text — "le Br6sil." Acary Mountains: Boundary Camp; 1 female, September 28. CONOPOPHAGIDAE Corythopis torquata anthoides Pucheran Muscicapa anthotdes (Cuvier MS.) Pucheran, 1855, Arch. Mus. d'Hist. Nat. Paris, 7, p. 334 — Cayenne. Acary Mountains: Boundary Camp; 2 males, September 22, 30. One of these specimens differs from anthoides, as usually described, in having its pileum and back concolorous as in sarayacuensis. Investigation of this apparent anomaly in the light of ample compara- tive material has led to the discovery of well-marked sexual dimor- phism in anthoides and also a secondary racial character serving to distinguish these subspecies. C. t. anthoides has been characterized as having a slate-gray pileum sharply contrasted with the rufescent-brown of its back. This description is misleading, since by no stretch of the imagina- tion can the pileum be considered "slate-gray." In males only, a variable degree of contrast between pileum and back is created by the gray or blackish tips and borders of individual feathers of the crowns that otherwise are similar in color to those of the back. No such contrast is found in the females of anthoides, which resembles sarayacuensis (both sexes) superficially in being concolorous above. Judging from the material at hand it is probable that the Acary specimen discussed above actually is a female, although sexed as a male. This supposition gains weight when the distinctive color tones of these races are taken into consideration. In anthoides the dorsal plumage is appreciably less rufescent (more olivaceous) than in sarayacuensis. This character is perceptible in the Acary male (female?) and I find no exceptions in a series of 22 specimens of both forms. Four female sarayacuensis of my series are decidedly more rufescent than six males, but I am not certain that the difference is significant. COTINGIDAE Phoenicercus carnifex Linnaeus Lanius carnifex Linnaeus, 1758, Syst. Nat., ed. 10, p. 94 — Surinam. 454 FIELDIANA: ZOOLOGY, VOLUME 32 Acary Mountains: Boundary Camp; 1 male, 2 females, September 26-October 7. Cotinga cayana Linnaeus Ampelis cayana Linnaeus, 1766, Syst. Nat., ed. 12, p. 298 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 1 female, September 21-October 8. Xipholena punicea Pallas Turdus puniceus Pallas, 1764, in Vroeg's Catalogue, Adumbrat., p. 2 — Surinam. Itabu Creek: Middle Base Camp; 1 male, 1 female, September 11- 13. Acary Mountains: Boundary Camp; 1 male, 2 females, Sep- tember 22-October 10. Xipholena punicea has lately been recorded (Friedmann, 1948, p. 485) as far west as the Brazo Casiquiare, Venezuela, a notable extension beyond Mount Auyan-tepui, where the species evidently is abundant at an altitude of 1,100 meters above sea level. Rhytipterna simplex frederici Bangs and Penard Lipaugus simplex frederici Bangs and Penard, 1918, Bull. Mus. Comp. Zool., 62, p. 71 — vicinity of Paramaribo, Surinam. Acary Mountains: Boundary Camp; 1 female, October 10. Material in Chicago Museum fails entirely to support the separa- bility of a southern race, intermedia. Eleven birds collected both north and south of the Amazon, as well as westward in Bolivia, Peru (Rio Ucayali) and Colombia, vary considerably as individuals, but I can find no character of geographical significance. Evidence tending to substantiate the homogeneous nature of these birds has been published by Griscom and Greenway (1941, p. 258). Gylden- stolpe (1945, p. 209) professes to find some merit in the southern form, but his statement that it "does not appear to be a well-marked race, although it is distinguishable in a series," lacks assurance. Lipaugus cineraceus Vieillot Ampelis cineracea Vieillot, 1822, Tabl. Enc. Meth., Orn., livr. 91, p. 761 — Cayenne. Acary Mountains: Boundary Camp; 3 males, September 24- October 15. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 455 Although very abundant in lowland forests elsewhere in British Guiana, cineraceus was only occasionally found in the Acary Moun- tains. The ventriloquial and piercing, but not unmusical, quality of its call has been described frequently and cannot fail to delight the newcomer to northern South America. Screaming pihas ordi- narily associate in small colonies that might easily escape detection in view of their obscure coloration and retiring habits were it not for the explosive calls that immediately greet an intruder. My experience with this species over much of its extensive range differs from that of Schomburgk in that it appears habitually to prefer low elevations (10-30 feet) rather than tree-tops, and its social organization is in the nature of a loose association of individuals rather than as a flock in the usual sense. Platypsaris minor Lesson Querula minor Lesson, 1830, Trait6 d'Orn., livr. 5, p. 363 — Cayenne. Acary Mountains: Boundary Camp; 1 male, September 26. The appearance of this specimen corroborates the opinion that certain cotingas require two years to attain fully adult plumage. Although it was collected in advanced breeding condition, its upper parts are more nearly brownish-black than glossy black and the remiges, in partial molt, are dull blackish-brown. The gular patch is more restricted and paler (less rich) than in fully adult birds, and the gray under parts, particularly the throat, are washed with brown. Traylor (in MS.) has commented on the variability of bill-size in minor, a characteristic demonstrated by the present specimen, which has a bill strikingly narrower than that of any other specimen of either sex examined. Querula purpurata P. L. S. Miiller Muscicapa purpurata P. L. S. Miiller, 1776, Natursyst., Suppl., p. 169 — Cayenne. Acary Mountains: Boundary Camp; 2 males, September 23. One specimen is in immature plumage, the characteristic throat patch being represented by only a few crimson feathers. Perissocephalus tricolor P. L. S. Miiller Corpus tricolor P. L. S. Muller, 1776, Natursyst., Suppl., p. 85 — Cayenne. Itabu Creek: Middle Base Camp; 2 females, September 10, 12. Acary Mountains: Boundary Camp; 1 female, September 22. 456 FIELDIANA: ZOOLOGY, VOLUME 32 Capuchin birds occur throughout the forested areas of British Guiana but were particularly abundant in the extreme south, along New River and Itabu Creek. Individuals were heard daily in that region, whereas the species appears to be uncommon on the lower Essequibo (Rockstone) and in the Oko Mountains to the northward, and decidedly rare in the coastal belt. The vernacular name of this bird ("calf bird") is derived from its characteristic call and was applied to an overnight camp (August 30-31) on the lower New River where the species was notably abundant. Rupicola rupicola Linnaeus Pipra rupicola Linnaeus, 1766, Syst. Nat., ed. 12, p. 338 — French Guiana. Acary Mountains: Boundary Camp; 6 males, 3 females. The cock-of-the-rock occupies an extensive range in northern South America, but fundamental ecological requirements sharply control its local distribution. Although limited to the Tropical Zone, the species is further restricted to areas of precipitous terrain that support more or less dense primeval forest. Locally it is most abundant in the vicinity of humid, shady ravines having rock out- croppings or large boulders, and swiftly flowing water. In British Guiana cocks-of-the-rock occur, in varying abundance, throughout the forested hills and mountains of low altitude in the west and extreme south. They were decidedly abundant in the Acary Mountains and were heard daily in the vicinity of the expedi- tion's Boundary Camp, at an altitude of 1,800 feet. Individuals were also seen, but not collected, on a small isolated hill (900 feet) on the right bank of Itabu Creek opposite Middle Base Camp, a locality not less than ten miles distant from the Acary foothills. The longevity of uncaged cocks-of-the-rock is not known, but Crandall (1949, p. 31) has reported a captive specimen in the New York Zoological Park that attained an age of "more than 15 years." PIPRIDAE Pipra serena serena Linnaeus Pipra serena Linnaeus, 1766, Syst. Nat., ed. 12, p. 340 — Cayenne and Surinam. Acary Mountains: Boundary Camp; 5 males, 1 female. Sep- tember 22-October 10. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 457 A prominent orange pectoral spot immediately distinguishes the nominate race from suavissima of western British Guiana and southern Venezuela. Hitherto serena has been recorded only in French Guiana (numerous localities) and from upper Rocana, in northern Para, Brazil. Pipra erythrocephala erythrocephala Linnaeus Parus erythrocephalus Linnaeus, 1758, Syst. Nat., ed. 10, p. 191 — Surinam. Acary Mountains: Boundary Camp; 2 males, 1 female, September 25. Few golden-headed manakins were seen in the Acary Mountains. They are generally distributed and locally abundant in lowland forests elsewhere in British Guiana. Pipra pipra pipra Linnaeus Parus pipra Linnaeus, 1758, Syst. Nat., ed. 10, p. 190 — Surinam. Acary Mountains: Boundary Camp; 4 males, 4 females, Sep- tember 21-October 3. This manakin occupies much the same range as the preceding, but in British Guiana it appears everywhere to be the more abundant of the two; pipra largely replaces erythrocephala in the extreme south, but to the northward (Rockstone, Oko Mountains, etc.) I would judge their proportions to be approximately 2 to 1. Corapipo gutturalis Linnaeus Pipra gutturalis Linnaeus, 1766, Syst. Nat., ed. 12, p. 340 — Cayenne. Acary Mountains: Boundary Camp; 2 males, 3 females, Sep- tember 23-29. TYRANNIDAE Ochthornis littoralis Pelzeln Elainea littoralis Pelzeln, 1868, Orn. Bras., 2, pp. 108, 180— Cachoeira Guajara- guacu, Rio Mamore, Amazonas. New River: Phantom Falls; 1 female, October 23. Haimara Camp; 2 males, 2 females, October 24. The worn plumage of these specimens is browner and much darker than that of a series from Brazil and Peru. The remiges and wing coverts also lack the buffy or light-colored margins found in the latter. This species is uncommon in British Guiana, and its dis- 458 FIELD IANA: ZOOLOGY, VOLUME 32 tribution appears to be discontinuous. A few individuals were seen along New River and on the lower portion of Itabu Creek, but I found none at Rockstone or elsewhere to the northward. Ourumee evidently is the only previous record for British Guiana. Contopus nigrescens canescens Chapman Contopus nigrescens canescens Chapman, 1926, Amer. Mus. Nov., No. 231, p. 7 — Rio Negro, Dept. San Martin, Peru. Acary Mountains: Boundary Camp; 1 male, September 26. This specimen agrees in minute detail with four examples of canescens from the Rio Negro, some thirty-five miles west of Moyo- bamba, Peru. The presence of this rare and presumably sedentary Peruvian flycatcher in British Guiana, more than 1,400 miles north- east of its known range, can hardly be regarded as a fortuitous circumstance. If, as is most likely, a resident population is found to occupy the virtually unexplored Brazilian-Guiana frontier there can be no further question of the integrity of nigrescens as a species. In any event, there is no reason to regard the birds of this group as conspecific with cinereus, a well-marked form represented in the Guianas by surinamensis. Myiobius barbatus barbatus Gmelin Muscicapa barbata Gmelin, 1789, Syst. Nat., 1, (2), p. 933 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 1?, September 23, 29. Platyrinchus saturatus Salvin and Godman Platyrhynchus saturatus Salvin and Godman, 1882, Ibis, (4), 6, p. 78 — Merum6 Mountains, British Guiana. Acary Mountains: Boundary Camp; 1 male, September 24. There is a considerable range of individual variation in saturatus, especially as to the richness of brown dorsally, and in the intensity of the chestnut coronal patch. The latter is exceptionally dark in the Acary bird, but I find the tone duplicated fairly well in several Venezuelan and Brazilian skins. Platyrinchus coronatus gumia Bangs and Penard Placostomus coronatus gumia Bangs and Penard, 1918, Bull. Mus. Comp. Zool., 62, p. 74 — vicinity of Paramaribo, Dutch Guiana. Acary Mountains: Boundary Camp; 2 males, 2 females, Sep- tember 21-October 4. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 459 Tolmomyias flavotectus examinatus Chubb Rhynchocydus sulphurescens examinatus Chubb, 1920, Bull. B. O. C., 40, p. 108 — Bartica Grove, British Guiana. Acary Mountains: Boundary Camp; 3 males, October 3. Uncertainty as to the relationship between two superficially similar, but actually quite distinct species has confused the taxonomic status of examinatus for a number of years. Although originally referred to the sulphurescens group and considered endemic to British Guiana (numerous localities), it was reduced subsequently to a synonym of cherriei (Hartert and Goodson), a widespread form previously described from Cayenne. Zimmer's revision of Tolmomyias (1939, pp. 1-17) re-established examinatus and proved it to be actually an eastern representative of flavotectus. This species is distinguished from sulphurescens by the presence of a more or less prominent, but sometimes obscure, whitish or pale yellowish speculum on the outer webs of the primaries (usually limited to the seventh, sixth, and fifth feathers) just beyond the tips of the primary coverts, and by the greater length of the tenth (outermost) primary as compared with the fourth. The wing speculum is lacking, and the fourth primary exceeds the outermost in length in all races of sulphurescens. Both sulphurescens and flavotectus are represented in all three Guianas, a circumstance that confuses the proper allocation of early locality records, with consequent uncertainty as to the local dis- tribution of each. Nevertheless, in so far as British Guiana is concerned, I find that certain specimens from Potaro Landing, Tumatumari, Minnehaha Creek and the Mazaruni River, as well as all Acary specimens, are unquestionably referable to examinatus. Present data indicate that this form exceeds cherriei by approximately 3 to 1 in British Guiana, whereas the proportion is reversed in French Guiana. Myiopagis gaimardii guianensis Berlepsch Elaenia gaimardi guianensis Berlepsch, 1907, Ornis, 14, p. 421 — Camacusa, British Guiana. Acary Mountains: Boundary Camp; 1 male, 1 female, September 30. Tyranniscus gracilipes acer Salvin and Godman Tyranniscus acer Salvin and Godman, 1883, Ibis, (5), 1, p. 206 — Bartica Grove and Camacusa, British Guiana. Acary Mountains: Boundary Camp; 2 males, 1? 460 PIELDIANA: ZOOLOGY, VOLUME 32 Leptopogon amaurocephalus obscuritergum Zimmer and Phelps Leptopogon amaurocephalus obscuritergum Zimmer and Phelps, 1946, Amer. Mus. Nov., No. 1312, p. 16 — Mount Auyan-tepui, Bolivar, Venezuela. Acary Mountains: Boundary Camp; 1 male, 1 female, September 24, October 3. Birds from the Merume" Mountains presumably also belong to this recently described form, which ranges westward to Mount Duida in Venezuela. Pipromorpha macconnelli macconnelli Chubb Pipromorpha oleaginea macconnelli Chubb, 1919, Ann. Mag. Nat. Hist., (9), 4, p. 303 — Camacabra Creek, British Guiana. Acary Mountains: Boundary Camp; 1 male, September 27. The slightly brighter abdomen and under wing coverts and possibly lighter upper parts of this specimen suggest some degree of intergradation with roraimae of southern Venezuela (Roraima, Auyan-tepui, Duida, etc.), but this trend needs to be evaluated in the light of additional material from the western and southern parts of the colony. Pipromorpha m. macconnelli occurs both on the coast and in forest areas over much of the interior, whereas roraimae evidently has very limited distribution in British Guiana. Other than an early record for the Merume' Mountains, it has been taken only at Paruima Mission and on the Adaroo River (Phelps Collection, Caracas), in the vicinity of Mount Roraima. OXYRUNCIDAE Oxyruncus cristatus phelpsi Chapman Oxyruncus cristatus phelpsi Chapman, 1939, Amer. Mus. Nov., No. 1047, p. 1 — Mount Auyan-tepui, Venezuela. Acary Mountains: Boundary Camp; 1 male, 3 females, Sep- tember 29-October 12. The curious distribution of this species, in which the geograph- ically distant peripheral forms frater (Costa Rica) and cristatus (southern Brazil and Paraguay) are morphologically closer than is either to its nearest geographical relative, was regarded by Chapman (1939, pp. 2-4) as having resulted from evolutionary pressure ex- pressed at or near a common center of dispersal. While there is theoretical basis for this viewpoint, supporting evidence is needed to eliminate the factor of parallelism as an alternative explanation. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 461 Fortunately, there is less uncertainty as to the probable center of dispersal. The presence of phelpsi in extreme southern British Guiana, as well as on Mount Auyan-tepui, considerably enhances Chapman's designation of the Roraima tablelands as the probable ancestral home of cristatus. In appearance phelpsi is intermediate between hypoglawus of Roraima and the Memine* Mountains, and brooksi of eastern Panama. A race from the Tocantins is very close to hypoglaucus, although smaller, whereas the peripheral forms previously mentioned differ from all others in having greenish under parts. HIRUNDINIDAE Atticora melanoleuca Wied Hirundo melanoleuca Wied, 1820, Reise Bras., 1, p. 345 — Rio Belmonte, Bahfa, Brazil. New River: Haimara Camp; 1 male, October 24. Black-collared swallows were common along the full length of the Courantyne River, but they occurred in greatest abundance above King Frederick William IV Falls, and on New River. None were seen above Middle Base Camp on Itabu Creek, nor did I find them at Rockstone on the Essequibo River, in March, 1937. Chubb also comments upon the discontinuous distribution of melanoleuca. Iridoprocne albiventer Boddaert Hirundo albiventer Boddaert, 1783, Tabl. PI. Enl., p. 32— Cayenne. New River: Haimara Camp; 1 female, October 24. This swallow is perhaps the most characteristic bird of the inland waters of British Guiana. Although present in some abundance along the greater extent of Itabu Creek, white-winged swallows prefer the shore lines and broad expanses of larger streams, from which they seem never to be absent. CORVIDAE Cyanocorax cayanus Linnaeus Cortws cayanus Linnaeus, 1766, Syst. Nat., ed. 12, p. 157 — Cayenne. Courantyne River: King Frederick William IV Falls; 2 males, August 17, 19. Itabu Creek: Middle Base Camp; 1 male, September (?). 462 FIELDIANA: ZOOLOGY, VOLUME 32 Cayenne jays were occasionally heard in the Acary Mountains but the species is far more numerous in lowland forests nearer the coast. Small, vociferous flocks were encountered at Wismar and Rockstone in March, 1937, and available records indicate very general distribution in all wooded areas of the Colony. Adult plumage is not acquired before the second year. Two Guiana specimens collected August 19 and March 4, respectively, have mature measurements, but represent successive stages of sub- adult plumage. While the first is clearly a bird of the year, the plumage of the second bird is much more advanced, although still lacking well-defined mystacial marks. TROGLODYTIDAE Microcerculus batnbla bambla Boddaert Formicaritis bambla Boddaert, 1783, Tabl. PI. Enl., p. 44 — Cayenne. Acary Mountains: Boundary Camp; 1 male, September 27. Recent investigations of Gilliard and of Griscom and Greenway have extended the range of this Guianan form to eastern Venezuela (Mount Auyan-tepui), and southward to the north bank of the Amazon (Obidos). The Acary Mountains are, therefore, very nearly the center of its distribution as now known. Leucolepis arada arada Hermann Myrm[ornis] arada Hermann, 1783, Tabl. Aff. Anim., p. 211 — Cayenne. Acary Mountains: Boundary Camp; 2 females, September 28, 29. Like many of its relatives, this obscurely colored and furtive wren is more often heard than seen. Numerous individuals were heard daily in the Acary Mountains and my field notes referred to the "organ bird" long before I realized that the designation has often been applied to this incomparable songster. TURDIDAE Turdus albicollis poiteaui Bonaparte Turdus poiteaui Bonaparte, 1854, Compt. Rend. Acad. Sci. Paris, 38, p. 4 — Cayenne. Itabu Creek: Middle Base Camp; 2 males, September 12, 13. Acary Mountains: Boundary Camp; 2 males, 2 females, Sep- tember 26-October 13. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 463 As pointed out by Hellmayr (1934, p. 372, footnote), poiteaui was applied to French Guiana birds long before Todd's designation cayennensis. This is a well-defined race differing from phaeopygus princi- pally by its deeper (richer) dorsal parts and smaller size. Although both forms range into the Guianas, uncertainty as to the status of Dutch Guiana birds beclouds the geographical boundaries of each. Some inferences, however, may be drawn from the present series. British Guiana specimens collected west of the Essequibo River (numerous localities) are quite properly assigned to phaeopygus, but the discovery of poiteaui in the Acary Mountains and adjacent low- lands not only suggests the probable identity of Surinam birds but also directs suspicion towards the status of eastern British Guiana birds, which hitherto have been referred arbitrarily to phaeopygus. My series from the southern extremity of the Colony includes intermediate specimens as well as typical examples of poiteaui. Four skins (1 male, Itabu Creek; 1 male, 2 females, Acary Mountains) are indistinguishable from French Guiana birds, whereas two males show some tendency toward phaeopygus. Intermediacy of birds in this area is indicated also by measurements of the four males: wing 102-110 (105); tail 82-90 (84). VIREOLANIIDAE Smaragdolanius leucotis leucot is Swainson Malaccmotus leucotis Swainson, 1837, Anim. Menag., p. 341 — "Africa," in error. Acary Mountains: Boundary Camp; 1 male, September 26. VIREONIDAE Hylophilus muscicapinus muscicapinus Sclater and Salvin Hylophilus muscicapinus Sclater and Salvin, 1873, Nomencl. Av. Neotrop., p. 156 — St. Louis d'Oyapock, French Guiana. Acary Mountains: Boundary Camp; 1 female, September 26. This bird was, surprisingly, in advanced breeding condition. Hylophilus ochraceiceps luteifrons Sclater Hylophilus luteifrons Sclater, 1881, Ibis, (4), 5, p. 308— Bartica Grove, British Guiana. Acary Mountains: Boundary Camp; 3 males, 2 females, Sep- tember 24-October 3. 464 FIELDIANA: ZOOLOGY, VOLUME 32 The range of ferrugineifrons has recently been extended eastward to Paruima Mission, at the confluence of the Paruima and Kamarang Rivers in west-central British Guiana (Blake, 1948, p. 317). Else- where in the Colony ochraceiceps is represented by the present form. COEREBIDAE Chlorophanes spiza spiza Linnaeus Motacilla spiza Linnaeus, 1758, Syst. Nat., ed. 10, p. 188 — Surinam. Acary Mountains: Boundary Camp; 7 males, 2 females, Sep- tember 22-October 12. Progressive fading of the blue-green shades in museum speci- mens has been mentioned by Friedmann (1948, p. 537). I find little or no evidence of this in males dating back into the last century, but the green plumage of females becomes distinctly yellowish with age. Cyanerpes caeruleus caeruleus Linnaeus Certhia caerulea Linnaeus, 1758, Syst. Nat., ed. 10, p. 118 — Surinam. Acary Mountains: Boundary Camp; 3 males, 3 females, Sep- tember 30-October 12. In describing a new race, hellmayri, from the "Potaro Highlands" of British Guiana, Gyldenstolpe evidently failed to take sufficiently into account both the extent of variability shown by caeruleus and the extreme improbability of an endemic subspecies in so small and fundamentally undistinguished an area within the range of another form. I have seen no topotypical specimens of hellmayri, but a com- parison of skins from numerous other British Guiana localities with birds taken in northern Brazil, Dutch Guiana and French Guiana fully establishes the intrinsic continuity of this population. It is illuminating to find that a male from Kalakoon, on the lower Mazaruni River, answers the description of hellmayri very well both in size (wing 60; tail 30; culmen 22) and color, whereas a second specimen, also from the lower Mazaruni, differs in no way from typical examples of the nominate race. Similarly, a female from Potaro Landing has the cinnamon-buff throat and robust bill credited to hellmayri, but these characters also occur in a French Guiana series. The limited area available to hellmayri is clearly isolated within the range of caeruleus and lacks both topographical and ecological BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 465 features of significance. In the absence of topotypical material its status is necessarily uncertain but for the present there seems to be no reason to recognize so nebulous a form. A male with enlarged gonads was collected in the Acary Moun- tains on October 11. Dacnis cayana cayana Linnaeus Motacilla cayana Linnaeus, 1766, Syst. Nat., ed. 12, p. 336 — Cayenne. Acary Mountains: Boundary Camp; 5 males, 1 female, Sep- tember 23-October 12. A breeding male collected at Rockstone on March 30 resembles a female except for a few black feathers on the throat and back. One of the Acary males collected September 23 is also in subadult plumage, but less advanced, its throat alone being partly black. Coereba flaveola minima Bonaparte Certhiola minima Bonaparte, 1854, Compt. Rend. Acad. Sci. Paris, 38, p. 259 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 2 females, October 10, 12. Earlier British Guiana records of flaveola (numerous localities) are referable to guianensis. Birds of the present series are easily distinguished by their more sooty upper parts and less bright rumps. Specimens of minima average slightly larger than the series of guianensis at hand, but the measurements of all Acary birds (male: wing 52; tail 30; females: wing 50, 55; tail 28, 28) are unaccountably small for either form. PARULIDAE Parula pitiayumi elegans Todd Compsothlypis pitiayumi elegans Todd, 1912, Ann. Carnegie Mus., 8, p. 204 — Anzoategui, Lara, Venezuela. Acary Mountains: Boundary Camp; 2 males, October 1. This very interesting record extends the known range of elegans eastward from Forte do Sao Joaquim, on the Rio Branco, by more than 200 miles. A closely related olive-backed warbler is found in the Subtropical Zone of both Duida and Roraima, but has not yet been reported in British Guiana. One of the Acary birds is in immature plumage, with dull brown upper parts, the wing coverts barely tipped with white, and yellow 466 FIELDIANA: ZOOLOGY, VOLUME 32 limited to the throat and a patch in the center of the abdomen. The second specimen is adult, but in worn plumage. ICTERIDAE Ostinops decunianus decumanus Pallas Xanthornus decumanus Pallas, 1769, Spic. Zool., fasc. 6, p. 1, pi. 1 — Surinam. Upper Courantyne River: King Frederick William IV Falls; 2 females, August 16, 17. Crested oropendolas are a prominent element of the Guianan lowland fauna and occur in abundance over most of the Colony. Although generally distributed throughout the forested areas, they are most partial to the vicinity of clearings and large waterways. The species was not found in the Acary Mountains and only occa- sionally on New River. Ostinops viridis viridis P. L. S. Mtiller Oriolus viridis P. L. S. Miiller, 1776, Natursyst., Suppl., p. 87 — Cayenne. Acary Mountains: Boundary Camp; 2 males, 2 females, Septem- ber 30-October 10. Green oropendolas largely supplant the previous species in the southern extremity of British Guiana and were abundant both on the New River and at all elevations in the Acary Mountains. They were very common in the Oko Mountains in 1937, but much less so at Rockstone. They appear to be considerably outnumbered by decumanus throughout the coastal area. Cacicus cela cela Linnaeus Pants Cela Linnaeus, 1758, Syst. Nat., ed. 10, p. 191 — Surinam. Itabu Creek: Middle Base Camp; 1 male, September 4. Oronoque River: Oronoque Base Camp; 1 male, October 26. This cacique was not found in the Acary Mountains beyond the foothills, although generously represented elsewhere in British Guiana. THRAUPIDAE Tanagra violacea violacea Linnaeus Fringilla violacea Linnaeus, 1758, Syst. Nat., ed. 10, p. 182 — Surinam. New River: Ashiru Falls; 1 male, October 27. BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 467 Tangara chilensis paradisea Swainson Aglaia paradisea Swainson, 1837, Nat. Hist. Classif. Bds., 2, p. 286 — Brazil. Acary Mountains: Boundary Camp; 1 male, September 30. Thjs specimen is very clearly a typical example of the eastern race that occupies an extensive range north of the Amazon, extend- ing westward at least to the Rio Manacapuru (lower Solimoes), a locality represented by birds tending slightly towards coelicolor, but much nearer paradisea. Its occurrence in southern British Guiana is, therefore, not unexpected. Previous British Guiana records of this species (Merume' Moun- tains) have been referred to coelicolor, a questionable designation since Zimmer (1943, p. 2) finds Roraima and Caura birds to be intermediates. Four British Guiana specimens from Paruima Mission and Membaro Creek in the Phelps Collection have, never- theless, been determined as coelicolor! Tangara punctata punctata Linnaeus Tanagra punctata Linnaeus, 1766, Syst. Nat., ed. 12, p. 316 — Surinam. Acary Mountains: Boundary Camp; 1 male, 3 females, Sep- tember 22-October 11. Cyanicterus cyanicterus Vieillot Pyranga cyanicterus Vieillot, 1819, Nouv. Diet. Hist. Nat., nouv. 6d., 28, p. 290— Cayenne. Acary Mountains: Boundary Camp; 1 female, September 26. A rare and little-known bird. Previous British Guiana records are limited to the western parts. Lanio fulvus Boddaert Tanagra sulva Boddaert, 1783, Tabl. PI. Enl., p. 50— Cayenne. Acary Mountains: Boundary Camp; 11 males, 2 females, Sep- tember 24-October 13. The western race, peruvianus, described by Carriker from Peru, requires substantiation. "Bogota" skins in Chicago Museum are minutely similar to Guiana birds, and Zimmer's study of 64 speci- mens of this species demonstrates further the instability of characters that might distinguish subspecies. Tachyphonus cristatus intercedens Berlepsch Tachyphonus intercedens Berlepsch, 1880, Ibis, (4), 4, p. 113 — "Orinoco dis- trict or Trinidad." 468 FIELDIANA: ZOOLOGY, VOLUME 32 Acary Mountains: Boundary Camp; 6 males, 2 females, Sep- tember 24-October 15. Unlike the great majority of Guianan birds, intercedens occupies a very restricted range centering in British Guiana (numerous localities) and extending beyond with certainty only to Surinam (Paramaribo and Altonaweg) and eastern Venezuela (Orinoco Delta and Mount Auyan-tepui). All specimens from the Acary Mountains are perfectly typical, but some intergradation with the nominate race is evident in Mount Auyan-tepui birds. Tachyphonus surinamus surinamus Linnaeus Turdus surinamus Linnaeus, 1766, Syst. Nat., ed. 12, p. 297 — Surinam. Acary Mountains: Boundary Camp; 2 males, September 27- October 15. Tachyphonus luctuosus luctuosus Lafresnaye and D'Orbigny Tachyphonus luctuosus Lafresnaye and D'Orbigny, 1837, Syn. Av., 1, in Mag. Zool., 7, cl. 2, p. 29 — Guarayos, Bolivia. Acary Mountains: Boundary Camp; 1 male, September 29. Hemithraupis guira nigrigula Boddaert Tanagra nigrigula Boddaert, 1783, Tabl. PI. Enl., p. 45 — Cayenne. Acary Mountains: Boundary Camp; 2 males, September 26, October 1. Measurements of these specimens (wing 64, 66; tail 51, 53; bill 11, 11) agree with those of a fine series from French Guiana and Brazil north of the Amazon. The subspecies roraimae, a highland bird distinguished by its greater size, occurs in the Merume" Moun- tains and has been reported on the Abary River (Chubb, 1921, p. 544). The latter record obviously refers to the present form, although hitherto unrecognized in British Guiana. Hemithraupis flavicollis flavicollis Vieillot Nemosia flavicollis Vieillot, 1818, Nouv. Diet. Hist. Nat., nouv. &L, 22, p. 491 — Cayenne. Acary Mountains: Boundary Camp; 1 male, 2 females, October 3. Comparison of these specimens with other British Guiana material, and a large series from French Guiana and Brazil north of the Amazon, seriously weakens the previous concept of a separable race endemic to western British Guiana. Hemithraupis f. hellmayri BLAKE: BIRDS OF ACARY MOUNTAINS, BRITISH GUIANA 469 of the Merume" Mountains and adjacent areas is described as similar to the nominate race, but markedly larger. Comparative measure- ments of males provided by Hellmayr (1936, p. 382, footnote) clearly support this distinction: wing 74-79 (against 70-72); tail 55-60 (against 52-54); bill 13-13.5 (against 11-12). The superior measurements of hellmayri listed above presumably are based upon the four topotypical specimens examined by Dr. Hellmayr himself (loc. cit.). Although additional material from the Merum£ Mountains is not now available, the dimensions of a series taken at several localities within the range of hellmayri agree, instead, with those of flavicollis. Six males from the Caramang River, Potaro Landing and Tumatumari measure as follows: wing 65-74 (69); tail 51-56 (54). Of this series, only one specimen (Caramang River) equals the minimum size of hellmayri, whereas the wings and tail of a second bird from the same locality measure 68 and 61 millimeters respectively. A single Rockstone male (wing 70; tail 50) agrees with the nominate race, and birds from the Acary Mountains are similarly indistinguishable. A series from Obidos in the Carnegie Museum has been identified by Griscom and Green way (1941, p. 331) as flavicollis, although otherwise it seems to be unknown beyond the Guianas. Pinto does not list it in his Brazilian catalogue. From the foregoing it is evident that the range of hellmayri is limited to the Merume" Mountains alone, if, in fact, it can be main- tained at all. Lamprospiza melanoleuca Vieillot Saltator melanoleucus Vieillot, 1817, Nouv. Diet. Hist. Nat., nouv. 6d., 14, p. 105 — Cayenne. Acary Mountains: Boundary Camp; 2 females, September 23. The distribution of this little-known tanager is surprisingly extensive, although evidently discontinuous or "spotty." Beebe (1917, p. 137) lists it at Bartica without comment, but I find no other record of its occurrence in British Guiana. Saltator maximus maximus P. L. S. Mtiller Tanagra maxima P. L. S. Muller, 1776, Natursyst., Suppl., p. 159 — Cayenne. Acary Mountains: Boundary Camp; 1 male, September 24. Caryot hraust es canadensis canadensis Linnaeus Loxia canadensis Linnaeus, 1766, Syst. Nat., ed. 12, p. 304 — Cayenne. Acary Mountains: Boundary Camp; 4 males, 2 females, Sep- tember 23-October 1. 470 FIELDIANA: ZOOLOGY, VOLUME 32 Pitylus grossus grossus Linnaeus Loxia grossa Linnaeus, 1766, Syst. Nat., ed. 12, p. 307 — Cayenne. Acary Mountains: Boundary Camp; 2 males, September 22. These grosbeaks, as well as the two previous species, occur in more or less abundance throughout British Guiana. Although they are more easily observed in the villages and plantations of the coastal area, I have found them to be no less numerous in the forests of the interior. Both maximus and grossus prefer shrubs or trees of low elevation, and are relatively solitary in habit, whereas canadensis ordinarily ranges the tree-tops in noisy flocks. Arremon taciturnus taciturnus Hermann Tanagra tadturna Hermann, 1783, Tab. Aff. Anim., p. 214 — Cayenne. Acary Mountains: Boundary Camp; 2 males, 1 female, Sep- tember 23-27. Three specimens collected at Rockstone, March 12-30, were in breeding condition. REFERENCES BEEBE, WILLIAM, HARTLEY, I. G., and HOWELLS, P. G. 1917. Tropical wild life. N. Y. Zool. Soc., New York. BLAKE, EMMET R. 1948. Three new records for British Guiana. Auk, 65, pp. 316-317. CARRIKER, M. A. 1932. Additional new birds from Peru with a synopsis of the races of Hylophylax Naevia. Proc. Acad. Nat. Sci. Phila., 84, pp. 1-7. CHAPMAN, FRANK M. 1931. The Upper Zonal bird-life of Mts. Roraima and Duida. Bull. Amer. Mus. Nat. Hist., 63, pp. 1-135. 1939. The riddle of Oxyruncus. Amer. Mus. Nov., No. 1047, pp. 1-4. CHUBB, CHARLES 1916. The birds of British Guiana, 1, xlvi+528 pp. 1921. The birds of British Guiana, 2, lxxviii+615 pp. CRANDALL, L. S. 1949. A longevity record. Bull. N. Y. Zool. Soc., 52, p. 31. FRIEDMANN, HERBERT 1948. Birds collected by the National Geographic Society's expeditions to northern Brazil and southern Venezuela. Proc. U. S. Nat. Mus., 97, pp. 376-569, pis. 16-27. GILLIARD, THOMAS E. 1941. The birds of Mt. Auyan-tepui, Venezuela. Bull. Amer. Mus. Nat. Hist., 77, pp. 439-508. GRISCOM, LUDLOW and GREENWAY, JAMES C. 1941. Birds of Lower Amazonia. Bull. Mus. Comp. Zool., 88, No. 3, pp. 83- 344. GYLDENSTOLPE, NILS 1945. The bird fauna of Rio Jurud in western Brazil. K. Sv. Vet. Akad. Handl., 22, No. 3, pp. 1-338. HARGITT, EDWARD 1890. Catalogue of the birds of the British Museum, 18, xv+597 pp. HELLMAYR, CHARLES E. 1934. Catalogue of birds of the Americas. Field Mus. Nat. Hist., Zool. Ser., 13, pt. 7, pp. 1-531. 1936. Catalogue of birds of the Americas. Field Mus. Nat. Hist., Zool. Ser., 13, pt. 9, pp. 1-458. 471 472 FIELDIANA: ZOOLOGY, VOLUME 32 HELLMAYR, CHARLES E. and CONOVER, BOARDMAN 1942. Catalogue of birds of the Americas. Field Mus. Nat. Hist., Zool. Ser., 13, pt. 1, No. 1, pp. 1-636. PETERS, JAMES L. 1945. Check-list of birds of the world, 5, xi+306 pp. PINTO, OLIVEIRO 1938. Catalogo das Aves do Brasil, pt. I, pp. 1-566. TODD, W. E. CLYDE 1927. New gnatcatchers and antbirds from tropical America, with a revision of the Genus Myrmeciza and its allies. Proc. Biol. Soc. Wash., 40, pp. 149-178. ZIMMER, JOHN TODD 1932a. Studies of Peruvian birds III. The Genus Myrmotherula in Peru, with notes on extralimital forms. Pt. 1. Amer. Mus. Nov., No. 523, pp. 1-19. 1932b. Studies of Peruvian birds V. The Genera Herpsilochmus, Microrhopias, Formicivora, Hypocnemis, Hypocnemoides and Myrmochanes. Amer. Mus. Nov., No. 538, pp. 1-27. 1932c. Studies of Peruvian birds VIII. The formicarian Genera Cymbilaimus, Thamnistes, Terenura, Percnostola, Formicarius, Chamaeza, and Rhegmatorhina. Amer. Mus. Nov., No. 584, pp. 1-20. 1933. Studies of Peruvian birds X. The formicarian Genus Thamnophilus. Pt. 2. Amer. Mus. Nov., No. 647, pp. 1-27. 1939. Studies of Peruvian birds XXXIII. The Genera Tolmomyias and Rhyn- chocyclus with further notes on Ramphotrigon. Amer. Mus. Nov., No. 1045, pp. 1-23. 1943. Studies of Peruvian birds XLVI. The Genus Tangara. Pt. 1. Amer. Mus. Nov., No. 1245, pp. 1-14. INDEX Principal page references in bold-faced type ACCIPITRIDAE, 429 accipitrinus, Deroptyus, 433 acer, Tyranniscus, 459 albicollis, Leucopternis, 430 albifrons, Pithys, 451 albirostris, Galbula, 438 albiventer, Iridoprpcne, 461 americanus, Daptrius, 431 ANATIDAE, 428 anthoides, Corythopis, 453 arada, Leucolepis, 423, 462 ARDEIDAE, 428 atra, Monasa, 423, 439 atricollis, Pteroglossus, 422 aurea, Jacamerops, 438 bambla, Microcerculus, 462 barbatus, Myiobius, 458 bicolor, Accipiter, 430 bidentatus, Harpagus, 429 brachyura, Myrmotherula, 447 BUCCONIDAE, 438 caeruleus, Cyanerpes, 464 cai'ca, Pionopsitta, 433 callinota, Terenura, 423, 424 canadensis, Caryothraustes, 469 canescens, Contopus, 424, 425, 458 cantator, Hypocnemis, 450 capensis, Bucco, 438 capistratus, Piculus, 422, 441 CAPITONIDAE, 439 CAPRIMULGIDAE, 434 carnifex, Phoenicercus, 453 cassini, Veniliornis, 442 CATHARTIDAE, 429 cayana, Cotinga, 454 cayana, Dacnis, 465 cayana, Piaya, 434 cayannensis, Thamnophilus, 422 cayanus, Cyanocorax, 423, 461 cela, Cacicus, 466 certhia, Dendrocolaptes, 443 cineraceus, Lipaugus, 423, 454 cinereiventris, Myrmotherula, 448 cinereus, Crypturellus, 427 cocoi, Ardea, 428 COEREBIDAE, 464 collaris, Trogon, 425, 437 colma, Formicarius, 451 COLUMBIDAE, 432 companisona, Mymothera, 452 CONOPOPHAGIDAE, 453 CORVIDAE, 461 COTINGIDAE, 453 CRACIDAE, 431 crepitans, Psophia, 423, 432 crissalis, Formicarius, 451 cristatus, Oxyruncus, 423 cristatus, Tachyphonus, 422 CUCULIDAE, 434 culik, Selenidera, 440 cumanensis, Pipile, 431 cyanicterus, Cyanicterus, 467 dea, Galbula, 438 decumanus, Ostinops, 466 delphinae, Colibri, 436 DENDROCOLAPTIDAE, 443 derbianus, Aulacprhynchus, 423 dissors, Synallaxis, 425, 445 elegans, Celeus, 422 elegans, Parula, 425, 465 episcopus, Phaethprnis, 422, 435 erythrocephala, Pipra, 423, 457 erythrocercus, Philydor, 445 examinatus, Tolmomyias, 459 EURYPYGIDAE, 432 FALCONIDAE, 430 ferruginea, Myrmeciza, 451 flavicollis, Hemithraupis, 425, 468 flavigula, Piculus, 441 flavus, Celeus, 442 FORMICARIIDAE, 446 frederici, Rhytipterna, 454 fulica, Heliornis, 432 fulvus, Lanio, 467 furcata, Thalurania, 436 FURNARIIDAE, 445 fusca, Malacoptila, 439 fuscus, Pionus, 433 GALBULIDAE, 438 gilvicollis, Micrastur, 431 glaucus, Thamnomanes, 447 grossus, Pitylus, 470 guianensis, Myiopagis, 459 guianensis, Piculus, 422 guianensis, Terenura, 424, 425, 448 gujanensis, Odontophorus, 432 gumia, Platyrinchus, 458 473 474 FIELDIANA: ZOOLOGY, VOLUME 32 gutturalis, Corapipo, 457 gutturalis, Myrmotherula, 447 harpyja, Harpia, 430 helias, Eurypyga, 432 HELIORNITHIDAE, 432 hellmayri, Celeus, 422, 441 HIRUNDINIDAE, 461 ICTERIDAE, 466 intercedens, Tachyphonus, 422, 467 largipennis, Campylopterus, 435 leucotis, Smaragdolanius, 423, 463 leucurus, Therenetes, 435 lineatum, Tigrisoma, 428 lineatus, Cymbilaimus, 446 littoralis, Ochthornis, 457 longipennis, Myrmotherula, 447 luctuosus, Tachyphonus, 468 luteifrons, Hylophilus, 463 macconnelli, Pipromorpha, 460 macrorhynchos, Notharcus, 438 macularia, Grallaria, 453 major, Crotophaga, 434 major, Tinamus, 427 maximus, Saltator, 469 melanoleuca, Atticora, 461 melanoleuca, Lamprospiza, 469 melanurus, Trogon, 436 mellivora, Florisuga, 436 minima, Coereba, 425, 465 minor, Platypsaris, 455 mirandollei, Micrastiir, 430 momota, Momotus, 423, 437 MOMOTIDAE, 437 montana, Oreppeleia, 433 moschata, Cairina, 428 motmot, Ortalis, 431 murinus, Thamnophilus, 422, 446 muscicapinus, Hylophilus, 463 naevia, Hylophylax, 451 niger, Capito, 439 nigrescens, Caprimulgus, 434 nigrescens, Contopus, 424 nigriceps, Piculus, 423, 425, 441 nigrigula, Hemithraupis, 425, 468 obidensis, Dysithamnus, 447 obscuritergum, Leptopogon, 460 osgoodi, Aulacorhynchus, 423, 425, 439 OXYRUNCIDAE, 460 papa, Sarcorhamphus, 423, 429 paradisea, Tangara, 425, 467 pardalotus, Xiphorhynchus, 423, 444 PARULIDAE, 465 pella, Topaza, 422, 436 PHASIANIDAE, 432 phelpsi, Oxyruncus, 424, 425, 460 PICIDAE, 441 pipra, Pipra, 457 PIPRIDAE, 456 poecilinota, Hylophylax, 452 poiteaui, Turdus, 425, 462 promeropirhynchus, Xiphocolaptes, 423 PSITTACIDAE, 433 PSOPHIIDAE, 432 punctata, Tangara, 467 punicea, Xipholena, 454 purpurata, Querula, 455 RAMPHASTIDAE, 439 roraimae, Pteroglossus, 422, 440 ruber, Phaethornis, 422 rubiginosus, Piculus, 423 rubricollis, Phloeoceastes, 442 rufaxilla, Leptotila, 433 ruficaudatus, Philydor, 425, 445 ruficollis, Cathartes, 429 rufifrons, Percnostola, 450 rufigula, Gymnopithys, 451 rufus, Trogon, 437 rupicola, Rupicola, 456 saturatus, Platyrinchus, 458 schomburgki, Hydropsalis, 434 serena, Pipra, 425, 456 smaragdula, Topaza, 422 spirurus, Glyphorhynchus, 444 spiza, Chlorophanes, 464 spodioptila, Terenura, 449 stictocephalus, Herpsilochmus, 425, 448 strigilatus, Trogon, 437 superciliosus, Phaethornis, 435 surinamus, Tachyphonus, 468 taciturnus, Arremon, 470 tenebrosus, Xiphocolaptes, 424, 425, 443 THRAUPIDAE, 466 TINAMIDAE, 427 torquata, Myrmornis, 452 torquatus, Celeus, 442 tricolor, Perissocephalus, 423, 455 TROCHILIDAE, 435 TROGLODYTIDAE, 462 TROGONIDAE, 436 TURDIDAE, 462 TYRANNIDAE, 457 undatus, Celeus, 442 urubitinga, Urubitinga, 430 varia, Grallaria, 452 variegatus, Crypturellus, 427 violacea, Tanagra, 466 violaceus, Trogon, 437 VIREOLANIIDAE, 463 VIREONIDAE, 463 viridis, Ostinops, 423, 466 viridis, Pteroglossus, 440 vitellinus, Ramphastos, 440 wallacei, Columba, 432 UNIVERSITY OF ILLINOIS-URBANA