Loma Linda University TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works Loma Linda University Electronic Theses, Dissertations & Projects 8-1993 Status, Distribution and Biogeography of the Birds of Paraguay Floyd E. Hayes Follow this and additional works at: https://scholarsrepository.llu.edu/etd Part of the Biology Commons Recommended Citation Hayes, Floyd E., "Status, Distribution and Biogeography of the Birds of Paraguay" (1993). Loma Linda University Electronic Theses, Dissertations & Projects. 570. https://scholarsrepository.llu.edu/etd/570 This Dissertation is brought to you for free and open access by TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works. It has been accepted for inclusion in Loma Linda University Electronic Theses, Dissertations & Projects by an authorized administrator of TheScholarsRepository@LLU: Digital Archive of Research, Scholarship & Creative Works. For more information, please contact [email protected]. ABSTRACT STATUS, DISTRIBUTION AND BIOGEOGRAPHY OF THE BIRDS OF PARAGUAY by Floyd E. Hayes The Paraguay River divides the Republic of Paraguay into two distinct regions: the Chaco to the west and the Orient to the east. The relatively flat Chaco is characterized by thorn scrub forests in the west, subhumid forests in the northeast and palm savannas in the southeast. The topographically diverse Orient is characterized by campos cerrados in the northeast, savannas in the west and southwest, and humid forests elsewhere. Paraguay's climate is subtropical, with rainfall increasing roughly fourfold from west to east. Previous studies of the birds of Paraguay have focused primarily on the distribution and taxonomy of resident species. There have been no thorough reviews of the country's avifauna since 1940. This dissertation summarizes the status and distribution of the birds of Paraguay, documents patterns of bird distribution, and attempts to analyze the factors affecting bird distribution in Paraguay. It is based on a review of the literature, examination of ; 2 specimens in major American museums, and extensive field work in Paraguay during 1987-1989. The avifauna of Paraguay includes 641 species. An annotated checklist summarizes the status, habitats and relative abundance of each species in seven geographical regions. Distributional notes are provided for the more unusual bird records and taxonomic notes are provided for species represented by two or more forms in Paraguay that may represent distinct species. Species richness in Paraguay increases from west to east. Faunal similarity between regions is best explained by habitat similarity, with the avifauna of the Chaco-like southwestern Orient being more similar to that of Chaco regions than to other Orient regions. The avifauna of each region has high affinities with adjacent areas of South America. No species is endemic to Paraguay. The forest- savanna transition, which roughly coincides with the upper Paraguay River but shifts eastward in the southern Orient, appears to be the most effective barrier to bird dispersal in Paraguay. There is little evidence that the relatively broad Paraguay River is an effective dispersal barrier. The Pilcomayo River likely formed a forest bridge between Yungas and Paranense forests.during more humid interglacial periods, and subdivided the Chaco avifauna. Sin' LIBRA A LINDA. CALIFOR LOMA LINDA UNIVERSITY Graduate School STATUS, DISTRIBUTION AND BIOGEOGRAPHY OF THE BIRDS OF PARAGUAY by Floyd E. Hayes A Dissertation in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in Biology August 1993 Each person whose signature appears below certifies that this dissertation in their opinion is adequate, in scope and quality, as a dissertation for the degree Doctor of Philosophy. , Chairperson H. Thomas Goodwin, Assistant Professor of Paleontology Leonard R. Brand, Professor of Biology and Paleontology Ronald L. Carter, Professor of Biology David L. Cowles, Assistant Professor of Biology L. James Gibson, Assistant Research Scientist, Geoscience Research Institute ii ACKNOWLEDGMENTS Field work during 1987-1989 was funded by grants from the Pan American Section of the international Council for Bird Preservation, Sigma Xi, and the United States Fish and Wildlife Service, while I served as a United States Peace Corps Volunteer for the Museo Nacional de Historia Natural del Paraguay. Additional funds for field work were provided directly or indirectly by the Asociacion de Apoyo a las Comunidades Indigenas, Center for Human Potential, J. Escobar Argaila, Evany, German Technical Mission, itaipa Binacional, Japanese International. Cooperation Agency, New York Zoological Society, Ministerio de Agricultura y Ganaderia, R. Perrin, A. and K. Robinson, P. Scharf, G. Sequera, D. Snider, and The Nature Conservancy. Numerous persons assisted with the field work, most notably C. Aguilar, F. Areco de Medina, T. Granizo Tamayo,. J. Fox, M. Hayes, N. Lopez (de Kochalka), R. Perrin, J. Ramirez, P. Scharf, and D. Snider. Others included C. Acevedo Gomez, M. Angel, A. Colman, J. Contreras, K. Ericsson, J. Escobar Argaigia, B. Fostervold, J. Kochalka, D. Mandelburger, N. Neris, N. Perez, A. and K. Robinson, V. and B. Roth, C. Sorenson, W. Sosa, A. Taber, C. Yahnke, and numerous others who made life interesting. Museum work during 1992 was funded by collection study grants from the American Museum of Natural History (AMNH) iii and Field Museum of Natural History (FMNH), and by the Department of Natural Sciences of Loma Linda University. The following museum personnel provided assistance: A. Andors, M. LeCroy, L. Short and F. Vuilleumier (AMNH); A. Maurer, T. Schulenberg, and D. Willard (FMNH); P. Chu, D. Golden, J. Hinshaw, R. Payne, and R. Storer (University of Michigan Museum of Zoology); R. Browning, B. Farmer, M. Foster, and G. Graves (National Museum of Natural History). Pertinent data for additional museum specimens that I did not examine were provided by P. R. Colston (British Museum [Natural History), N. K. Johnson (Museum of Vertebrate Zoology, University of California at Berkeley), and J. Steinbacher (Natur-Museum Senckenberg). Unpublished observations of birds in Paraguay were kindly provided by R. Behrstock, D. Brooks, T. Brooks, R. Clay, D. Finch, J. Fox, S. Goodman, A. Taber, T. Granizo Tamayo, H. Loftin, A. Madrotio, R. Ridgely, A. Robinson, and P. Scharf. Assistance in obtaining literature was provided by T. Brooks, N. Collar, J. Contreras, M. Foster, K. Garrett, J. Gibson, S. Goodman, T. Goodwin, J. Hinshaw, N. Lopez (de Kochalka), A. Madrona, R. Paynter, T. Schulenberg, R. Storer, D. Stotz, F. Vuilleumier, and E. Willis. Interlibrary loans were paid for by the Graduate School of Loma Linda University, and patiently processed by F. Alemozaffer. iv I thank the Department of Natural Sciences and the Graduate School for financial support during my dissertation research. I especially thank my major professor, T. Goodwin, my former major professor, J. Galusha, and my committee members, L. Brand, R. Carter, D. Cowles, and J. Gibson, for their advice and encouragement during my disseration research. TABLE OF CONTENTS LIST OF FIGURES • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • LIST OF TABLES • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • I. INTRODUCTION • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 1 II. GEOGRAPHY, CLIMATE AND VEGETATION .. • • • . • • • • • • • .. 4 A. Introduction ........ • • • . • • • • • • • • • • • • • • • • • • • • 4 B. Geological History ........................... 17 1. Paleozoic Era ............................ 17 2. Mesozoic and Cenozoic Eras ............... 20 C. Geographical Regions ... .. • • ... • . • . • • • • • . • . 24 1. The Paraguay River . • • • • • • • • • • • • • ... • • . • 29 2. The Chaco ....... • • • • • • • • • • • • • • • • • • • • • • • . • 30 a. Alto Chaco .. • • . • • • • • • • . • . • • . • • • • • • • • . 36 b. Matogrosense .. • • . • • • • • • • • • • • • • • • • . • • . 38 c. Bajo Chaco .. • . • • • . • • e • • • • • • • • • • • • • • . 40 3. The Orient .......... • • • . • • • • • • • • • • . • • • . • . 42 a. Campos Cerrados . .• . •••••••••••••• . 45 b. Central Paraguay • • • • • .. • . • • • . • • • • . • • . 47 c. Neembuca ........ • • • . • • • • • • . ..... ... 49 d. Alto Parana .. • • • • • • • • • • • • • • • • • • . • • . 52 III. ORNITHOLOGICAL HISTORY .. • 6 • • • • • • • • • • • • • • • • • . 55 A. Introduction . ............. • ........... • 55 B. Pre-Columbian Period 57 C. Colonial Period, 1524-1811 .. .• . .. .. ..... 59 D. Early Independence Period, 1811-1870 .. ....... 62 E. Between Wars Period, 1870-1935 ... ....... 63 F. Post Chaco War Period, 1935-1975 ...... ..... 75 G. Modern Period, 1975-present ... ..... • ..... 82 IV. METHODS .. ... .. .. .. .. ..... • ........ .• ....... 93 A. Compilation of Data ... ................... .... 93 B. Evaluation of Records . ....... • • . • • • • • • • • • • • • • 97 vi C. Systematic Treatment ..... • ............. 104 D. Biogeographical Analyses . • • • . • • • • • • • • • .• •... 107 1. Regional Comparisons . • . • • • • • • • ........ ... 108 a. Species Richness . ................. ... 108 b. Faunal Similarity .. • • • • • • • • . • • • • • • . • c. Faunal Uniqueness ......... • • • • . • • . • •. 111109 d. Regional Affinities ..... ... • • • • • • • . • . 112 e. Body Size ..... • . • • . • . • • • • • • • • • • • • • • • . 113