GIFT OF UNIVERSITY OF CALIFORNIA PUBLICATIONS BULLETIN OF THE DEPARTM ENT. OF GEOLOGY Vol. 7, No. 5, pp. 61-115 Issued October 12, 1912 CONTRIBUTIONS TO AVIAN PALAEON- TOLOGY FROM THE PACIFIC COAST OF NORTH AMERICA BY LOYE HOLMES MILLER UNIVERSITY OF CALIFORNIA PRESS BERKELEY UNIVERSITY OF CALIFORNIA PUBLICATIONS NOTE. — The University of California Publications are offered in exchange for the publi- cations of learned societies and institutions, universities and libraries. Complete lists of all the publications of the University will be sent upon request. For sample copies, lists of publications and other information, address the Manager of the University Press, Berkeley, California, U. S. A. All matter sent in exchange should be addressed to The Exchange Department, University Library, Berkeley, California, U. S. A. OTTO HARRASSOWITZ B. FRIEDLAENDER & SOHN LEIPZIG BERLIN Agent for the series in American Arch- Agent for the series in American Arch- aeology and Ethnology, Classical Philology, aeology and Ethnology, Botany, Geology, Education, Modern Philology, Philosophy, Mathematics, Pathology, Physiology, Psychology. Zoology, and Memoirs. Geology. — ANDREW C. LAWSON and JOHN C. MERRIAM, Editors. Price per volume, $3.50. Volumes 1 (pp. 435), II (pp. 450), III (pp. 475), IV (pp. 462), V (pp. 448), completed. Volume VI (in progress). Cited as Univ. Calif. Publ. Bull. Dept. Geol. Vol. 1, 1893-1896, 435 pp., with 18 plates, price $3.50. A list of the titles in this volume will be sent on request. VOLUME 2. 1. The Geology of Point Sal, by Harold W. Fairbanks ," 65c 2. On Some Pliocene Ostracoda from near Berkeley, by Frederick Chapman lOc 3. Note on Two Tertiary Faunas from the Rocks of the Southern Coast of Vancouver Island, by J. C. Merriam lOc 4. The Distribution of the Neocene Sea-urchins of Middle California, and Its Bearing on the Classification of the Neocene Formations, by John C. Merriam lOc 5. The Geology of Point Reyes Peninsula, by F. M. Anderson - 25c 6. Some Aspects of Erosion in Relation to the Theory of the Peneplain, by W. S. Tangier Smith 20c 7. A Topographic Study of the Islands of Southern California, by W. S. Tangier Smith 40c 8. The Geology of the Central Portion of the Isthmus of Panama, by Oscar H. Hershey 30c 9. A Contribution to the Geology of the John Day Basin, by John C. Merriam 35c 10. Mineralogical Notes, by Arthur S. Eakle lOc 11. Contributions to the Mineralogy of California, by Walter C. Blasdale 15c 1 2. The Berkeley Hills. A Detail of Coast Range Geology, by Andrew C. Lawson and Charles Palache 80c VOLUME 3. 1. The Quaternary of Southern California, by Oscar H. Hershey 20c 2. Colemanite from Southern California, by Arthur S. Eakle : 15c 3. The Eparchaean Interval. A Criticism pf.the use of the term Algonkian. by Andrew C. Lawson ./...".. -V .*.**. •..*.i?\.«...Jl lOc 4. Triassic Ichthyopterygia ifom ©aliforma? £»cl Nevada, by John C. Merriam 50c 6. The Igneous Rocks. n^aj- Pa^jarQ, Jjy .John .A.* -Reid 15c 7. Minerals from Leo£k Ke^gl^3,;A4arra5da:Girv California, by Waldemar T. Schaller 15c 3. Plumasite, an Oligo'cla'se-Cofuridum " phase of Polyborus tharus as represented by a single specimen from Argentina. As no appreciable difference could be noted, the fossil form is referred to the existing species, P. tharus. Anomalies in Distribution. — According to Ridgway32 the present distribution of Polyborus tharus is from Amazonia south- ward through South America. The bird thus reaches in the Argentine and the Patagonian climates a set of conditions as rigorous as any that it would be liable to experience in the northern hemisphere in the latitude of Los Angeles. The ex- tremes of climate due to the presence of the ice sheet is thought by Allen to have given rise to the periodical movements of birds which finally merged into the present seasonal migration.33 Would not a plausible explanation be that the polyborine under discussion was driven southward by the cold of the glacial epoch but failed to respond to the later amelioration of climate because of a nature less susceptible to the development of a migratory instinct and therefore remained in the lower latitudes or below the tropics? No record of the true Polyborinae is yet found in the deposits of the southern hemisphere to correspond with the Pliocene form, Palaeoborus umbrosus (Cope), from New Mexico or to extend the occurrence of the group even back to the Pleistocene, as the Bancho La Brea material does so abund- antly for the northern hemisphere. If, on this slender thread of negative evidence, we assume that the group arose in the North Temperate zone, the explanation suggested above seems a plausible one. Geranoaetus and Circus present cases similar to that of Poly- borus, while Morphnus differs in that the genus is at present limited to the tropics and probably never reaches a southward distribution which would correspond climatically with the region of Hawver Cave or of Los Angeles. These two cases of Polyborus and Morphnus mentioned above are typical of as many classes of change in distribution since the formation of the various Pleistocene deposits. Parallel with Polyborus there appear the following fossil forms whose nearest 32 Ridgway, R., U. S. Geol. & Geog. Surv. Terr., vol. 1, No. 6, p. 451, 1876. ss Allen, J. A., The geography and distribution of birds, Auk. vol. 10, No. 2, April, 1893. Miller: Pacific Coast Avian Palaeontology 97 relatives occur in the southern hemisphere at a latitude corres- ponding with the region of deposit in the northern hemisphere. Fossil Species Nearest Living Eelative Phoenicopterus copei Shufeldt Phoenicopterus ruber ? Linnaeus Cieonia maltha Miller Euxenura maguari (Temm.) Mycteria americana Linnaeus Mycteria americana Linnaeus Jabiru mycteria (Lichtenstein) Jabiru mycteria author Catharista occidentalis Miller Catharista urubu (Vieillot) Sarcorhamphus clarki Miller Sarcorhamphus gryphus Auct. Circus, sp Circus cenereus or C. maculosus Geranoaetus melanoleucus Auct Geranoaetus melanoleucus Auct. Geranoaetus fragilis Miller Polyborus tharus Auct Polyborus tharus Auct. Cases parallel with Morphnus in having their nearest related Recent phase limited to more tropical zones are as follows : Fossil Species Nearest Living Eelative Pavo californicus Miller Pavo cristatus or Meleagris ocellatus Morphnus woodward! Miller Morphnus guianensis Auct. Geranoaetus grinnelli Miller Morphnus guianensis Auct. Micropallas whitneyi (Cooper) Micropallas whitneyi (Cooper) Geococcyx (?),sp .Neomorpha geoffroyi (Temm.) One of the striking features in the study of so representative a series of deposits, all of so nearly the same age as are the bird-bearing deposits of the Pacific Coast, is the total absence of certain forms which one would expect to find therein. While it is conceded that negative evidence in palaeontology is a frail peg upon which to hang an opinion, yet the negation may be so pronounced and so uniformly persistant that, in some cases at least, the only conclusion possible is that species did not occur in the region during the time of deposition. The particularly favorable conditions offered at Rancho La Brea for the trapping of vultures and eagles has been commented upon in a previous paper on the condors. There was exposed at that place during an indefinite period a more or less con- stantly baited trap which was unusually attractive to both vul- ture and eagle. It was automatic in its operation, effective in its hold upon the victim, and almost ideal in the preservation of its catch, the remains of which were sealed from the air in liquid asphalt while still in the flesh. The entire collection of raptorial remains includes, however, no specimen of the royal vulture (Gyparchus papa) or of the harpy eagle (Thrasaetus harpy a}, 98 University of California Publications in Geology [V°L- 7 both of which occur at present along the Mexican border within fifteen degrees of the latitude of Los Angeles. The collection of wading birds from the coast, while not rich in point of numbers, embraces a goodly variety. Jabiru, Myc- teria, Ciconia, Grus, Ardea, and Phoenicopterus are represented ; yet there is no record of the spoonbill (Ajaia) or of the ibis (Guard), both of which have been taken in the flesh well to the northward of Rancho La Brea. Grouse, quail, and meleagrines have been taken in various of the deposits under discussion; yet we find there none of the cracid birds such as Ortalis which occurs at present along the Rio Grande valley of Texas. The absence of the above-mentioned species, particularly the Raptores, from all the bird-bearing deposits thus far known to North America becomes very striking in view of the large num- ber of instances recorded of the southward retraction of species and genera since the Pleistocene period. It is possible that the forms mentioned above were more sensitive to the cold and were driven southward before the deposition of the Pleistocene strata thus far explored, or that they were, on the other hand, more tropical species that have only in Recent time diffused north- ward to their present range. Gyparchus is reported from the Pleistocene caves of Brazil by Winge (op. cit.) which fact would support the latter hypothesis. Polyborus ckeriway would fall in the same category with Gyparchus, being represented in the asphalt by its close relative Polyborus tharus. The same is per- haps true of the Recent species of Geococcyx found in the Son- oran zone of California at the present time but represented in the asphalt only by a longer-shanked form which can scarcely be considered as the direct ancestor of the living Geococcyx cali- fornianus. The species from the asphalt may be identical with one of the species of Neomorpha from South America, comparison between them having been thus far impossible. Approximately eighty species of true columbine birds inhabit the Americas today and many of the species are forms which feed on the ground and which congregate about water holes to drink; yet there is no specimen in all the material examined which is referable to this group. The commonest species in the 1912] Miller: Pacific Coast Avian Palaeontology 99 coast region today is the turtle-dove (Zanaidura macroura), a bird of wide distribution over the Austral region and even to the tropics. Its habits and its abundance are such that one can scarcely concede as possible that it could have been present during the deposition of the Pleistocene beds of Rancho La Brea and yet not be preserved as a fossil. Palamedea and Cariama have in their present home in South America a distribution and habits not unlike those of the stork, Euxenura. Both groups are, however, absent from the fossil collections. The peculiarly isolated positions which these birds occupy in the scheme of classification, as well as the measure of uncertainty as to their proper location systematically, makes any light that palaeontology might throw upon the subject especially desirable. Most careful search was made therefore to see if any part of the skeleton of these birds had been preserved, but nothing was found that resembled either species in the smallest degree. The parrot order, abundant a few degrees to the southward, is unrepresented in the deposits. This may be due to the fact that the only forest fauna which we have preserved to us (cavern deposits) is of Upper Sonoran and lower Transition zones, and thus local conditions may have been unfavorable for these birds. On the other hand, as suggested in the case of Ortalis, they may have been driven southward before the deposition of any of the beds thus far explored. All trace of true struthious birds is lacking in the collec- tions also. The northward diffusion of such forms as the eden- tates and Hydrockoerus among the mammals, the presence since early Pleistocene time of rheas in South America, the occurrence of tridactyl struthionids in the Pliocene of northern India, and" of Struthiolithus in the superficial deposits of northern China, increase the probability that some day the discovery of true struthious birds in North America will be announced. The most potent factors that would bring about such distribution are first, the possible northward diffusion of rheids along with eden- tate mammals and, second, the passage of Struthiolithus or its relatives along the line of proboscidean invasion from Asia by way of the land bridge to Alaska. 100 University of California Publications in Geology [VOL. 7 The earliest occurrence of rheids in South America is in strata now referred to the Pleistocene (the Pampean of Monte Hermosa). If the group had reached that continent by way of the Antarctic at an earlier time, their bones would probably be found with the primitive mammals supposed to have been derived from Australia and known to us from the Santa Cruz beds. The rheas with their true struthious characters could hardly have originated de novo in South America; hence the conclusion that they entered from the north, as did the true cats, deer, elephants and other mammals of northern or Old World origin. Cope's discovery of Diatryma94 in the Wahsatch Eocene of New Mexico was at first considered as fixing a very early date for the group of Struthiones in the New World. Lucas,35 how- ever, places this unique specimen in the group of Stereornithes with the great Phororkacos of South America (Miocene of Santa Cruz). A wide gulf exists between the ostriches and these South American phororhacids. The latter are more probably a local development brought out in response to the peculiar con- ditions prevailing there in Tertiary time. There existed in South America no large carnivores among mammals until the northern incursion of machaerodonts and the true felines in relatively late geological time. Edentates were left free to develop to the tremendous extent noticeable in the South American Tertiary and Quaternary. In this region of low pressure among mam- mals there developed unrestrained the predatory bird Phoro- rhacos, to occupy a bionomic place like that of the mammalian carnivore. The reference by Lucas of the North American Dia- tryma to the Stereornithes is tentative. He states the case in these words in part: "Still there are sufficient resemblances be- tween the two to warrant the suggestion that if material comes to light it will be found that the affinities of Diatryma are with the Stereornithes and not with the Dromaeognathae. " In view of the indeterminate character of the single specimen of Diatryma where its relationship between two such distinct 34 Cope. E. D., U. S. Geol. Surv. Terr. W. of 100th Merid., vol. 4, pt. 2, p. 69, 1876. 35 Lucas, F. A., Proc. U. S. Nat. Mus., vol. 24, p. 545, 1903. 1912] Miller: Pacific Coast Avian Palaeontology 101 groups as the Struthiones and the Stereornithes are in question, it would seem that the chief value of Cope's discovery is to show us that a group of gigantic terrestrial birds can inhabit a region and leave almost no trace of their occupation of that part of the globe. The same fact is pointed out by Eastman30 in his discussion of Struthiolithus and the distribution of the Dromaeognathae. Before the discovery of this species in the superficial deposits in the mountainous regions of northern China no one would have surmised that this great area to the north of India was ever inhabited by struthious birds. Why not expect, then, with perfect propriety, that some day the path of immigration of Rhea into South America may be traced in yet undiscovered deposits of North America ? The other principle which encouraged the search for rheaids in the asphalt, that of a northward migration of southern forms in the Pleistocene, is applicable whether Rhea be considered a product of the southern continent or not. Among mammals we have the northward diffusion of the various edentates and Hydrochoerus, which may be considered products of southern soil, and we have also a re-entrance from the south of certain forms which are Neogaeic by adoption. For example, we may look upon Didelphys as having performed such migration. The objection might be raised that the tropical belt would act as a barrier preventing the plains-dwelling RJiea from retracing its steps, but such an objection is reduced to questionable validity by the presence of true rheids in the cavern deposits of Brazil. The following is a list of lipotypes which are considered by the author as of particular interest: LIST OF LIPOTYPES Gavia, sp. Palamedeidae — all species "Gyparchus papa Auct. Cariamidae — all forms Thrasaetus harpya Auct. Phororhacidae — all species Polyborus cheriway (Jaquin) Gaura, sp. Cracidae— all species Plegadis, sp. Columbae — all species Ajaia, sp1. Psittaci — all species Geococcyx calif ornianus (Lesson) 36 Eastman, C. R., Bull. Mus. Comp. Zool. Harvard Coll., vol. 32, p. 127-144, 1898. 102 University of California Publications in Geology [VOL. 7 Possible Influences Conditioning Present Distribution of Cer- tain Groups. — In considering the relation of past to present dis- tribution of American birds, at least two principles present them- selves in explanation of the apparent southward retraction of certain forms since Pleistocene time. The first is typified by the case of Polyborus tharus. May this species not have been driven southward across the equator after the time of formation of the asphalt deposits by the advance of a cold period such as sent the mammals of the Ovibos zone as far south as Big Bone Lick and Conard Fissure? Extremes of climate due to the presence of the ice sheet are thought by Allen37 to have given rise to the periodical move- ments of birds which finally merged into the present seasonal migration. The polyborine under discussion may thus have been driven southward, but lacked the incipient migratory instinct and furthermore failed to return northward upon the amelioration of the climate. This failure may have been due to the presence of more virile species blocking the return path, or it may have been due to the limiting tendency of the torrid zone which it would have had to recross in a return to the north. No record of the true Polyborinae has yet been found in the deposits of the southern hemisphere to correspond with the Pliocene Palaeo- borus of New Mexico or to extend the occurrence of the group even back to the Pleistocene, as the Eancho La Brea material does so abundantly for the northern hemisphere. If, on this slender thread of negative evidence, we assume that the group arose in the North Temperate Zone, the explanation suggested above seems a plausible one. The distribution of Circus, Geran- oaetus, Sarcorhamphus, and Euxenura would further uphold this view of the question. These birds are typically of the southern hemisphere in latitudes to the south of the tropics or at high elevations and the Tierra Caliente would act as a more or less effective barrier to their northward dissemination. The second hypothesis offered is that the returning annual isotherm has never yet reached the point at which it stood during the deposition of the fossil remains. Sinclair (Op. cit., p. 19) links the Potter Creek Cave deposits pretty closely with the 37 Allen, J. A., The Auk, vol. X, No. 2, Apr. 1893. 1912] Miller: Pacific Coast Avian Palaeontology 103 Upper San Pedro series of marine deposits and the San Pablo Bay oyster beds at Rodeo. These shell deposits are considered by western palaeontologists to represent a time of higher average annual temperatures than prevail in the region at present. The cases of Morphnus, Micropallas, Geococcyx (') and Pavo make a strong aggregate in favor of this theory. To harmonize the cases of Circus, Polyborus, Sarcorhamphus, Geranoaetus and Ciconia with those of the more tropical species, it would be neces- sary to assume nothing further than that these forms, since the partial amelioration of the climate, had developed powers of resistance to cold and had extended their ranges to the southward instead of remaining intertropical species. The extension of range took place from the tropics southward instead of to the northward again because of overcrowded conditions in the north. The advance of arctic cold toward the equator would drive north- ern animals into narrower and narrower quarters, while the forms of the southern hemisphere, under like encroachment of the antarctic, would experience the opposite effect. The conver- gence of all the Boreal species into the Austral on the continent of North America would be in effect like crowding the basal con- tents of a cone into its apex. The result would be an enormous intensification of the natural attrition of species upon species with a resultant stimulus to the surviving form. In the southern hemisphere conditions would be reversed and the advance of polar cold, whether synchronous with or alternating with the northern fluctuations, would have much less serious effect. As- suming the various faunal zones to be fully populated, the driv- ing of the Patagonian fauna into the wide expanse of Argentina and southern Brazil would serve to dilute greatly the Boreal fauna without materially disturbing the Austral. A form that had been obliged to flee the rigorous conditions resulting from an advance of the cold in North America might find, upon the return of milder conditions, that the path of least resistance to expanding range from the tropics led toward the south. Bird Remains as Indicators of Climatic Conditions. — Certain appearances in the deposits at Rancho La Brea might be inter- preted as evidence that the climate during deposition of the beds was warmer and more moist than it is at present in the region. 104 University of California Publications in Geology [VoL- 7 The fauna is certainly a rich one and embraces a considerable variety of ungulates of large size which were dependent on a goodly supply of grass and browse. Purely local conditions of dainage may, however, have brought about such a condition. In the fickle streams of the southwest such change of bed may occur in a single season and a deposit laid down under conditions of abundant moisture amounting almost to a peat formation may be left high and dry after a severe freshet to suffer a reversion to almost desert condition. Relatively few of the anserines are found in the collections from the asphalt. Geese of the Recent species become almost upland forms during the rainy season when grass is abundant. Euxenura is, according to Hudson's account in Naturalist in La Plata, a plains-dwelling form of the open pampa at some times of the year. The sand-hill crane, Grus canadensis, is notably a plains feeder in the winter and spring, while the great blue heron, Ardea herodias, has been seen by the author on the dry hillsides in midsummer seemingly in pursuit of grasshoppers. The presence of these birds in the asphalt in the limited numbers found is not then a positive indication of open water or of even marshy ground. The water- worn fragments of wood and the leaves in bedded deposit are such as occur in small steams of the region today when the streams may be more or less intermittant. A rich and varied mammalian fauna is taken by some writers as an indication of mild climatic conditions. Such conclusion seems scarcely war- ranted, however, in view of the present conditions in the desert parts of the world. The writer found deer abundant on the open and thorny desert of Lower California in the region of Cape San Lucas. On the mainland of Mexico, in the desert of Sonora, deer, peccary, and mountain sheep are abundant. The accounts by Roosevelt of game distribution in Africa indicate an abundance and a great variety of game in almost desert regions of that continent. On the Mohave, the Colorado, and the great Nevada deserts, the most ephemeral pools of water, even when highly impregnated with alkaline salts, are the resort of multitudes of waterfowl, while Cope and Shufeldt describe abundant life in the region near Fossil Lake on the Oregon Desert. 1912J Miller: Pacific Coast Avian Palaeontology 105 There is some very credible evidence that the mammals en- trapped in the asphalt pools were in part attracted to the locality by water. Over the top of the asphalt layer there may accumu- late after a shower a stratum of fairly pure rain water, so little does the viscid asphalt mix with the water. Such an accumula- tion remains in the impervious basins until evaporated by the heat of the sun, without loss by seepage through the oil-impreg- nated earth. Pools of water suitable for the use of cattle and horses thus remain impounded in natural reservoirs after adja- cent streams have vanished. Natural reservoirs are of such im- portance in the southwestern deserts as to have received the local Spanish name of "tinajas," and wild mammals of the desert come from long distances to drink at them. Such conditions would tend to concentrate the remains of mammals of a poorly watered region and furnish the asphalt trap with scores of victims which otherwise would have escaped.38 Summing up the evidence of a warm, moist climate during the Pleistocene, we have the following points, all of which are inconclusive : 1. The presence of species whose nearest relatives are at present more tropical in distribution. 2. The presence of an abundant fauna which is suggestive of favorable conditions of climate. 3. The presence of aquatic species and of waterworn chips laid down in places now dry but showing no great changes in topography. 4. The suggestion that the mammals of Rancho La Brea were in some measure led to the region by the presence of water. Time Relations as Suggested by a Study of Bird Remains. — Osborn divides the Pleistocene period into three great time subdivisions, namely, Pre-Glacial, Glacial- and Post-Glacial.39 The Glacial again shows evidence of division into five periods of fluctuation, during which the ice cap oscillated northward and southward with the changing isotherms. The period also represents a time of high elevation of the land surface in general ss See Darwin, C., Journal of Voyage of H.M.S. Beagle, 1845 (New ed. 1909), pp. 128-130. so Osborn, H. F., The Age of Mammals. New York, 1910. 106 University of California Publications in Geology [V°L- 7 as compared with the Pre-Glacial. The Post-glacial epoch was characterized by an ameliorated climate and a depression of the land surface. Great river floods and large lakes were the result of this amelioration, and extensive fluviatile and lacustrine de- posits appear, while the previously restricted species of verte- brates spread out over parts of the country that were formerly covered by the ice cap. The faunas of the time are divided by Osborn into three life- zones which are distributed through the Pleistocene, but do not coincide with the three time divisions as given above. They do not necessarily represent consecutive faunas, but rather faunas from different topographic divisions which, in some respects, overlap each other, though in the main consecutive. Charac- teristic mammals have given the names to these zones as follows : Equus Zone, a plains fauna partly earlier than and partly synchronous with the second, the Megalonyx Zone, which was a forest and meadow fauna mainly of mid-Pleistocene time. The third, or Ovibos Zone, is an impoverished fauna, perhaps cor- responding with the Arctic and Tundra period of Europe and synchronous with the last great glacial advance, the period of maximum glaciation, which is recorded in the great terminal moraine. RELATIONS OF SEVERAL PLEISTOCENE MAMMALIAN HORIZONS; ADAPTED FROM OSBORN Equus Zone Megalonyx Zone 6 — Kansas Pleistocene, several 9 — Big Bone Lick, Ken. localities. 8— Samwel Cave, Calif. 5— Lake Lahontan, Nev. 7— Potter Creek Cave, Calif. 4— Fossil Lake, Ore. 6— Washtucna Lake, Wash. 3 — Eock Creek, Texas. 5 — Rancho La Brea, Calif. 2 — Hay Springs, Neb. 4 — Ashley Eiver, S. Carolina. 1 — Peace Creek, Fla., Late Plio- 3 — Frankstown Cave, Penn. cene or Early Pleistocene. 2 — Port Kennedy Cave, Penn. 1 — Afton Junction, Iowa. — 1st in- terglacial stage. Ovibos Zone 4 — -Alaska Ground Ice. 3 — Conard Fissure, Ark. 2 — Scattered middle west. 1 — Big Bone Lick, Ken. 1912] Miller: Pacific Coast Avian Palaeontology 107 The exact time-relations between the several faunas is not determinate, and the overlap of one column upon another is purposely indefinite. The Equus fauna is considered in part older than the Megalonyx fauna and this in turn than the Ovibos. It must be stated also that the study of mammalian remains from Rancho La Brea, from the caves of California, and from Fossil Lake, Oregon, is still being actively pursued and the list of species revised. Any statement of time-relations must be considered as purely tentative. Few investigators have had so wide and so comprehensive an acquaintance with the mammalian palaeontology of North America as has Professor Osborn; hence it is considered in this connection that his chronological arrange- ment of the various mammal-bearing horizons represent the truth as nearly as we have yet arrived at it. It will be noted that the Fossil Lake horizon is placed by him midway in the tabulation of the Equus Zone fauna while Rancho La Brea and the caves occupy the middle and upper parts of the Megalonyx Zone. Thus Fossil Lake is to be con- sidered as the earliest Pleistocene horizon on the coast produc- tive of avian remains. If we apply the criterion of percentage of extinct forms, the evidence furnished by the avian remains would indicate a different time-relation than that suggested by Professor Os- born. The various horizons here discussed show the following sequence when arranged according to the percentage of Recent species of birds recorded fossil: Eancho La Brea 60% still living Fossil Lake 66% still living Potter Creek Cave 68% still living Samwcl Cave 72% still living Hawver Cave 79% still living The application of this principle in the case of fossil birds seems, however, less accurate than in the case of mammals when we consider the migratory nature of many bird species. The Fossil Lake fauna according to this basis of estimate would appear to be younger than that of Rancho La Brea. A glance at the list of species from Fossil Lake shows, however, the large 108 University of California Publications in Geology [VOL. 7 percentage of migratory forms such as the anserines and the pygopodes. These birds by their migratory habits are rendered largely immnne to the effects of climatic change that might have brought about extinction in such forms as the raptors and the scratchers. Ten of the fifteen extinct species recorded from Fossil Lake belong to genera which are at present non-migratory in the region. Whether or not these genera were migratory during Pleisto- cene time is, of course, a matter of pure conjecture. Allen40 suggests that it was during the Glacial Epoch that the migratory instinct was indelibly impressed upon birds by the pronounced seasonal contrast prevailing at that time. Whether the instinct was at that time incipient or real, it seems proper to conclude that those genera which now display it are the ones which would have profited by its initial operation and have escaped extinction. There presents itself, then, the very potent suggestion that the relatively small proportion of extinct forms represented in the Fossil Lake horizon is due to the fact that many of the genera there represented possessed or else developed the migra- tory instinct and were preserved except as influenced by other factors. The remaining four horizons may more properly be com- pared as to age upon the basis of percentage of surviving species, and such comparison bears out the conclusions reached by Os- born in his study of the mammals. Causes of Extinction of Birds. — After a consideration of the varied and in many respects remarkable avifauna of Pleistocene times, it is natural that the causes of extinction of these forms should hold an important place in our attention. Why should we now have but two eagles in southern California where five once flourished? Why does but one condor remain of the five species found fossil ? The large phase of the variable Pleistocene Haliaetus has withdrawn toward the north into British Col- umbia and Alaska, while Phoenicopterus, the ciconids, Polyborus and the morphnine eagles have withdrawn to the southward. The gigantic Teratornis disappeared, leaving no near relative 40 Allen, J. A., The geography and distribution of birds, Auk, vol. 10, No. 2, Apr. 1893. 1912] Miller: Pacific Coast Avian Palaeontology 109 to represent the family among the Catharti formes. How late did this great bird persist, and did that important factor, man, have anything to do with his disappearance? According to Dr. C. Hart Merriam,41 the Me-wah Indians of California have a legend concerning a gigantic vulture, Yel-lo-kin, so large that he was able to capture the condor and carry him up through a hole in the sky. The bird myths of these Indians indicate a close acquaintance with the California species. It may be that Tera- tornis persisted until the arrival of man upon the scene, and thus gave rise to the Mew-wah Indian myth of Yel-lo-kin. Granting the possible truth of such an assumption as the con- temporaneity of man and Teratornis, the primitive human animal could have had but little cause to direct his efforts against the large raptorial birds. His meagre offensive armament would probably have availed him but little in any event. Thus the only influence he would have been likely to exert would be but the indirect effect through the extermination of large mammals. The possibility of man's having exerted any such influence on the lives of avian species seems remote, in view of the negative evidence afforded by the absence thus far of human remains from western horizons of undoubted Pleistocene age. Direct extermination, or the sharpening of competition, by incursions of Old World forms, is a theory without the support of any tangible evidence in the case of birds. The procyonids and Didelphys are of long standing in America. Felines would greatly influence the larger birds by direct attack either upon the bird or its nest. It seems highly improbable, then, that birds could have been directly influenced by man or the other mammals, but that the chief relation of mammals to the large birds was in the dependence of the latter upon the former for food-supply. As has been pointed out in an earlier paper,42 the large rap- torial birds depended in a dual respect upon the large mammals. First, these birds fed upon the bodies of either carnivores or herbivores dying of whatever cause ; second, the vulture fed upon the rejected portion of the carnivore's kill. Thus, any factor 41 Merriam, C. H., The Dawn of the World, p. 163, 1910. 42 Miller, L. H., Univ. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 2, 1910. 110 University of California Publications in Geology [ VoL- 7 which tended to reduce the numbers of either group of mam- mals must have reacted also upon the large birds of prey. It is not at all improbable that the things which brought about the extinction of Pleistocene mammals were also directly operative in bringing about the extinction of many species of birds. Non-raptorial birds, except where migratory, would re- spond to climatic changes very much as did mammals. Osborn makes suggestions regarding the mammals as follows: ' ' the Glacial period in North America originated certain new con- ditions of life which directly or indirectly resulted in extinction. "These conditions include diminished herds, enforced migrations, the possible overcrowding of certain southerly areas, changed conditions of feeding, disturbance in the period of mating and reproduction, new rela- tions with various enemies, aridity, deforestation; in short, a host of indirect causes. ' '43 Disease, in all probability a factor in the extinction of some mammals, may likewise have been the determining influence in the case of certain birds. During the winter of 1908-9 in south- ern California, the bodies of thousands of sea-birds were cast up on the beach within a comparatively short time. Many of these specimens were examined by Dr. F. C. Clark of Los An- geles and by the author. The intestines were found filled with tape-worms. Mildness of the weather coupled with the profound emaciation of the birds indicated that death was not due to violence or sudden cause. While the presence of parasites may not have been the only influence leading to death, it was, in all probability, an important and possibly the determining factor. If, as is so variously suggested, the rainfall is now much less than it was during the Pleistocene, the influence upon bird life may have been effective over wide areas through the several factors of food, shelter and nesting sites. Pavo and Meleagris, although not always confined to wooded country, are both forms which might have been strongly influenced by deforestation. The morphnine eagles, with the possible exception of Geranoae- tus, are forest-dwelling birds. The local extinction of these birds in California may have resulted from a thinning-out of the forests. 43 Qsborn, H. F., The Age of Mammals (New York, Macmillan, 1910). 1912] Miller: Pacific Coast Avian Palaeontology 111 Development of gigantic size in the cathartids is in effect a case of over-specialization in that it works frequently to the detriment of the species. The condors of today are of such unwieldy size that, after a full meal, they experience much diffi- culty in taking wing from low ground. This fact is reported to have caused the destruction of many individuals which had been led to alight in places from which they could not rise again into the air. Teratornis must have attained a bulk almost thrice that of the condor if we may judge from coracoid and furcula. The suggestion conveyed by the sternum is that the pectoral muscles were not so heavy in proportion, yet the weight of the bird must have been far greater than that of the condors. The nature of its food was such that it must have come to the ground to feed. The effort to rise again, gorged with food, must have been a severe tax upon its strength, and slowness in taking wing may have subjected it to frequent danger. The high, compressed beak of Teratornis resembling the eagle's in form, though struc- turally cathartine, indicated the extreme of specialization. The large body size, likewise a phase of specialization, may have mili- tated in the end against the life of the species. The principle of specific decay or senility of species as a cause of extinction may have suffered somewhat through the too frequent application of it by the palaeontologist, yet there often appear cases in which no other factor seems adequate to explain the loss of a species. Certainly the intersterility of species would lead to inbreeding with its attendant ill effects. Incipient strains of intersterility within a species might, where geographically restricted, lead to the more rapid deterioration of the stock; generation upon generation of individuals, like the succeeding generations of somatic cells, become less and less virile until the species would decline in a manner comparable to the senile decay of the individual. The rapid decline of certain of the less con- spicuous species of Hawaiian birds, such as Palmeria and Chae- toptila, seems almost of necessity the result of such depleting influence. How effective this factor was in robbing us of many Pleistocene birds it is of course impossible to estimate; it would seem proper, however, to look upon it as possibly a contributing cause. 112 University of California Publications in Geology [VOL. 7 TABULAR ARRANGEMENT OF WEST-AMERICAN PLEISTOCENE AVIFAUNAS ^Echmophorus lucasi Miller ............................................ * ^chmorphorus occidentalis (Lawrence ........................ Colymbus holboelli (Eeinhardt) ........................................ * Colymbus auritus Linnaeus .............................................. * Colybus nigricollis californicus (Heermann) .............. * Podilymbus podiceps (Linnaeus) .................................. * Larus argentatus Pontoppidan ...................................... * Larus robustus Shufeldt .................................................. * Larus californicus Lawrence ............................................ * Larus oregonus Shufeldt ................................................ * Larus Philadelphia (Ord) ................................................ * Xema sabini (J. Sabine) ................................................ * Sterna elegans Gambel .................................................... * Sterna forsteri Nuttall .................................................... * Hydrochelidon nigra surinamensis (Gmelin) ................ * Phalacrocorax macropus (Cope) ........................ ............ Pelecanus erythrorhynchos Gmelin ................................ * Lophodytes cucullatus (Linnaeus) .................................. * Anas platyrhynchos Linnaeus ............... . .......................... Chaulelasmus streperus (Linnaeus) .............. -. ................. * Mareca americana (Gmelin) ............................................ Nettion carolinense (Gmelin) .......................................... * Querquedula discors (Linnaeus) .................................... * Querquedula cyanoptera (Vieillot) ................................ Spatula clypeata (Linnaeus) .......................................... * Dafila acuta (Linnaeus) .................................................. Aix sponsa (Linnaeus) ...................................................... Marila valisineria (Wilson) ............................................ * Clangula islandica (Gmelin) .......................................... Harelda hyemalis (Linnaeus) ............................. •. ............ * Erismatura jamaicensis (Gmelin) .................................. Anser condoni Shufeldt .................................................. * Anser albifrons gambeli Hartlaub .................................. ? Branta hypsibata (Cope) ................................................ Branta canadensis (Linnaeus) ...................................... Branta propinqua Shufeldt ............................................ * Chen hyperboreus (Pallas) ............................................ Olor paloregonus (Cope) .................................................. * Indeterminate anserine .................................................... Indeterminate anserine .. 1912] Miller: Pacific Coast Avian Palaeontology 113 »• fS -M fc C .73 o o> ? r ca c £ S IJ2 1 jS Pi H M. OR fM Indeterminate anserine Phoenicopterus copei Shufeldt * Ciconia maltha Miller Jabiru mycteria (Lichtenstein) Mycteria americana Linnaeus Ardea herodias Linnaeus Ardea paloccidentalis Shufeldt * Grus minor Miller Grus canadensis (Linnaeus) Fulica americana Gmelin Fulica minor Shufeldt * Lobipes lobatus (Linnaeus) * Oreortyx picta (Douglas) Lophortyx californica (Shaw) Lophortyx, sp Dendragapus obscurus (Say) Bonasa umbellus (Linnaeus) .'. Tympanuchus pallidicinctus (Eidgway) * Pedioecetes phasianellus columbianus (Ord) * Pedioecetes lucasi Shufeldt * Pedioecetes nanus Shufeldt Palaeotetrix gilli Shufeldt * Indeterminate odontophorid Meleagris, sp Pavo californicus Miller Gymnogyps californianus (Shaw) 7 ... Gymnogyps amplus Miller Sarcorhamphus clarki Miller Cathartornis gracilis Miller Pleistogyps rex Miller Cathartes aura (Linnaeus) Catharista occidentalis Miller Catharista shastensis Miller Teratornis merriami Miller Elanus leucurus (Vieillot) Circus hudsonius (Linnaeus) Circus, sp Accipiter velox (Wilson) Buteo borealis (Gmelin) Buteo swainsoni Bonaparte (?) Buteo, sp - Archibuteo ferrugineus (Lichtenstein) Aquila chrysaetos (Linnaeus) -~. 114 University of California Publications in Geology [VOL. 7 3 J I 5 £ I * 1 fill fa Pi P-i 02 Aquila pliogryps Shufeldt * Aquila sodalis Shufeldt * Haliaetus leucocephalus (Linnaeus) Morphnus woodwardi Miller * Geranoaetus melanoleucus Auct. (?) Geranoaetus grinnelli Miller * Geranoaetus fragilis Miller * Falco peregrinus Tunstall Falco, sp * Falco sparverius Linnaeus Polyborus tharus Auct * Aluco pratincola (Bonaparte) Asio wilsonianus (Lesson) Asio flammeus (Pontoppidan) Otus asio (Linnaeus) Bubo virginianus (Gmelin) Bubo sinclairi Miller * * Speotyto cunicularia hypogaea (Bonaparte) Glaucidium gnoma Wagler Micropallas whitneyi (J. G. Cooper) Neomorpha ?, sp Colaptes cafer (Gmelin) Otocoris alpestris (Linnaeus) Cyanocitta stelleri (Gmelin) Corvus corax Linnaeus Corvus brachyrhynchos Brehm Corvus annectens Shufeldt * Corvus, sp Xanthocephalus xanthocephalus (Bonaparte) Agelaius gubernator (Wagler) Sturnella neglecta Audubon Euphagus cyanocephalus (Wagler) Euphagus affinis Shufeldt * Pipilo, sp Lanius ludovicianus Linnaeus ... * 1912] Miller: Pacific Coast Avian Palaeontology 115 BIBLIOGRAPHY OF PACIFIC COAST FOSSIL/ AVIFAUNAS 1878. Cope, E. D., Bull. U. S. Geol. Surv. Terr, iv no. 2, May 3, 1878. Describes three species of birds from Fossil Lake, Ore. 1892. Shufeldt, E. W., A Study of the Fossil Avifauna of the Equus Beds of the Oregon Desert, Journ. Acad. Nat. Sci. Phila. no. 9, p. 389. 1894. Cope, E. D., On Cyphornis, an Extinct Genus of Birds, Journ. Acad. Nat. Sci. Phila. no. 9, p. 449. 1901. Lucas, F. A., A. Flightless Auk, Mancalla californiensis, from the Miocene of California, Proc. U. S. -Nat. Musv vol. 24; p. 133. 1909. Miller, L. H., Pavo californicus, a Fossil Peacock from the Quater- nary Asphalt Beds of Eancho La Bre£^ Univ. Calif. Publ., Bull. Dept. Geol., vol. 5, p. 285. 1909. Miller, L. H., Teratornis, a New Avian Genus from Eancho La Brea, Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 305. 1910. Miller, L. H., Wading Birds from the Quaternary Asphalt of Eancho La Brea, Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 437. 1910. Miller, L. H., The Condor-like Vultures of Eancho La Brea, Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, p. 1. 1911. Miller, L. H., Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, p. 79. 1911. Miller, L. H., A Series of Eagle Tarsi from the Pleistocene of Eancho La Brea, Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, p. 305. 1911. Miller, L. H., Avifauna of the Pleistocene Cave Deposits of Cali- fornia, Univ. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 385. NOTE. — Since the text of this paper went to press, bird remains have been found in the Upper San Pedro Pleistocene at San Pedro, Cal., by Dr. F. C. Clark of Los Angeles. These remains were very generously presented to the present writer by Dr. Clark, and by permission of the latter, were deposited in the Vertebrate Palaeontology Collections at the University of California. Three of the specimens are almost perfect, the several others are too fragmentary for determination. One specimen repre- sents an undescribed species of grebe of the genus ^chmophorus but in view of the fact that the active exploration of these beds now going on will possibly bring to light other remains of like nature, a description of the species is thought unwise at present. Eemains of Bison, Equus, a camelid, rodents, seals, small turtles, and sting rays have also been taken from these beds by Dr. Clark and the writer. * LIST OF SPECIES FROM UPPER SAN PEDRO Mammals Birds Equus ^chmophorus, n. sp. Bison Nettion carolinense (Gmelin) Camelid Sturnella neglecta Audubon VOLUME 4. PBICK 1. The Geology of the Upper Region of the Main Walker River. Nevada, by Dwight Smith I..; .".... aoc Primitive Ichthyosaurian Limb from the Middle Triassic of Nevada, by John Merriam ." lOc 3. Geological Section of the Coast Ranges North of the Bay of San Francisco, by V. C. Osmont „ 40c 4. Areas of the California Neocene, by Vance C. Osmont. .r loc ntribution to the Palaeontology of the Martinez Group, by Charles E. Weaver ; w or Imperfectly Known Rodents and Ungulates from the John Day Series, by William J. Sinclair .'.. 2oe ". Xew Mammalia from the Quaternary Caves of California, by William J. Sinclair 25c 8. Preptoceras. a New Ungulate from the Samwel Cave. California, by Eustace L. Furlong lOc 9. A New Sabre-tooth from California, by John C. Merriam . 5c 10. The Structure and Genesis of the Comstoek Lode, by John A. Reid 15c 11. The Differential Thermal Conductivities of Certain Schists, by Paul Thelen.. etch of the Geology of Mineral King. California, by A. Knopf and P. Thelen 35c 13. Cold Water Belt Along the West Coast of the United States, by Ruliff S. Holway 14. The Copper Deposits of the Robinson Mining I Nevada, by Andrew C. Lawson 50c 15. I. Contribution to the Classification of the Amphiboles. II. On Some Glaucophane Schists, Syen. by G. Murgoo. 35c 16. The Geomorphic Features of the Middle Kern, by Andrew C. Lawson.... . loc res on the Foothill Copper Belt of the Sierra Nevada, by A. Knopf. 18. An Alteration of Coast Range Serpentine, by A. Knopf. 17 and 18 in one cover loc 19. The Geomorphogeny of the Tehachapi Valley System, by Andrew C. Law- 35c VOLUME 1. Carnivora from the Tertiary Formations of the John Day Region, by John C. Merriam 60c me Edentate-like Remains from the Maseall Beds of Oregon, by William J. Sinclair. Mollusca from the John Day and Maseall Beds of Oregon, by Robert E. C. Stearns. "2 and 3 in one cov loc rstraciont Teeth from the West American Tria- Ina M. Wemple lOc 5. Preliminary Note on a New Marine Reptile from the Middle Triassie of Nevada, by John C. Merriam 10c .tes on Lawsonite, X^olumbite, Beryl, Barite. and Calcite. by Arthur S. Ea'.de lOc California, with Supplemer :s on Other Species of David Starr Jordan 5^c 8. Fish Remains from the Marine Lower Triassic of Aspen Ridge. Idaho, by Malcoln. Goddard — 5c 9. Benito!- difornia Gem Mineral, by George Davis Louderback. with Chemical Analysis by Walter C. Blasdale oc .tes on Quaternary Felidae from California, by John F. Bovard 11. Tertiary Faunas of the John Day Region, by John C. Merriam and William J. iopods and Insects of California, by Fordyce Grinnell, Jr lOc 13. Notes on the 0 >f the Thalattosaurian Genus Xectosaurus. by John C. Merriam _ >tes on Some California Mineral- hur S. Eakle loc tes on a Collection of Fossil Mammals from Virgin Valley, Nevada, by James Williams Gidley 16. Stratigraphy and Palaeontology of the San Pablo Formation in Middle California. by Charles E. Weaver -w Echinoids from the Tertiary of California, by Charles E. Weaver oc on Echinoids from the Tertiary of California, by R. W. Pack 19. Pavo californicus. a Fossil Peacock from the Quaternary Asphalt Beds of Rancho La Brea. by Lcye Holmes Miller VOLUME 5 — (Continued}. PRICE 20. The Skull and Dentition of an Extinct Cat closely allied to Felis atrox Leidy, by John C. Merriam 15C 21. Teratornis, a New Avian Genus, from Raneho La Brea, by Loye Holmes Miller lOc 22. The Occurrence of Strepsicerine Antelopes in the Tertiary of Northwestern Nevada, by John C. Merriam k 10c 23. .Benitoite, Its Paragenesis and Mode of Occurrence, by George Davis Louderbaek, with chemical analyses by Walter C. Blasdale 75c 24. The Skull and Dentition of a Primitive Ichthyosaurian from the Middle Triassic, by John C. Merriam 10c 25. New Mammalia from Raneho La Brea, by John C. Merriam 5c 26. An Aplodont Rodent from the Tertiary of Nevada, by Eustace L. Furlong lOc 27. Evesthes jordani, a Primitive Flounder from the Miocene of California, by James Zacchaeus Gilbert 15c 28. The Probable Tertiary Land Connection between Asia and North America, by Adolph Knopf lOc 20. Rodent Fauna of the Late Tertiary Beds at Virgin Valley and Thousand Creek, Nevada, by Louise Kellogg 15c 30. Wading Birds from the Quaternary Asphalt Beds of Raneho La Brea, by Loye Holmes Miller , lOc VOLUME 6. 1. The Condor-like Vultures of Raneho La Brea, by Loye Holmes Miller 15o 2. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern Nevada, by John C. Merriam. Part I. — Geologic History 50c 3. The Geology of the Sargent Oil Field, by William F. Jones 25c 4. Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, by Loye Holmes Miller lOc 5. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by John A. Reid 60c 6. Note on a Gigantic Bear from the Pleistocene of Raneho La Brea, by John C. Merriam. 7. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Desert, by John C. Merriam. Nos. 6 and 7 in one cover lOc 8. The Stratigraphic and Faunal Relations of the Martinez Formation to the Chico and Tejon North of Mount Diablo, by Roy E. Dickerson 5c 9. Neocolemanite, a Variety of Colemanite, and Howlite from Lang, Los Angeles County, California, by Arthur S. Eakle lOc 10. A New Antelop" from the Pleistocene of Raneho La Brea, by Walter P. Taylor 5c 11. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern Nevada, by John C. Merriam. Part IL— Vertebrate Faunas $1.00 12. A Series of Eagle Tarsi from the Pleistocene of Raneho La Brea, by Loye Holmes Miller lOc 13. Notes .on the Relationships of the Marine Saurian Fauna Described from the Triassic of Spitzbergen by Wiman, by John C. Merriam. 14. Notes on the Dentition of Omphalosaurus, by John C. Merriam and Harold C. Bryant. Nos. 13 and 14 in one cover - — 15c 15. Notes on the Later Cenozoic History of the Mohave Desert Region in Southeastern California, by Charles Laurence Baker 50c 16. Avifauna t)f the Pleistocene Cave Deposits of California, by Loye Holmes Miller 15c 17. A Fossil Beaver from the Kettleman Hills, California, by Louise Kellogg 5c 18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam lOc 19. The Elastic-Rebound Theory of Earthquakes, by Harry Fielding Reid 25c VOLUME 7. 1. The Minerals of Tonopah, Nevada, by Arthur S. Eakle 25c 2. Pseudostratification in Santa Barbara County, California, by George Davis Louder- back 20c 3. Recent Discoveries of Carnivora in the Pleistocene of Raneho La Brea, by John C. Merriam 5° 4. The Neocene Section at Kirker Pass on the North Side of Mount Diablo, by Bruce L. Clark 15c 5. Contributions to Avian Palaeontology from the Pacific Coast of North America, by Loye Holmes Miller 60c NON-CIRCULATING BOOK 244558 UNIVERS 10m-l,'28 ftARY