pjms^eamif^m-' U.S. Department of the Interior National Biological Service l^!^^E.:«^^^?S:S;;;:: •■:.■=■. #■' Wif'i tli I esources A Report to the Nation on the Distribution, Abundance, and Health of U.S. Plants, Animals, and Ecosystems Cover photograph by Terry Donnellynbm Stack & Associates k^ Printed on recycled paper Our Living Resources — — ^ o ^^= CD ____ m For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington. DC 20402 Stock #024-010-00708-7 .^y H ij- ' U6c ■-^'■^ Our Living Resources A Report to the Nation on the Distribution, Abundance, and Health of U.S. Plants, Animals, and Ecosystems Senior Science Editor and Project Director Edward T. LaRoe Nationcd Biological Sen'ice Managing Editor Gaye S. Farris National Biological Sen'ice Senior Technical Editor Catherine E. Puckett Johnson Controls World Services, Inc., and Universit}- of Southwestern Louisiana Graphics Editor Peter D. Doran Bureau of Land Management Science Editor Michael J. Mac National Biological Sen'ice U.S. Department of the Interior — National Biological Service Washington, DC 1995 National Biological Service Cataloging-in-Publication Data Our living resources : a report to thie nation on the distribution, abundance, and healthi of U.S. plants, animals, and ecosystems / Edited by Edward T. LaRoe ...[et al.] Washington, D.C. : U.S. Dept. of the Interior, National Biological Service, 199.'i. .^130 p. ; ill. : 28 cm. Includes bibliograph- ical references and index. 1. Biotic communities — United States. 2. Ecology — United States. 3. Animal populations — United States. 4. Plant populations — United States. 5. Natural resources — United States. 1. LaRoe, Edward T. II. National Biological Service (U.S.) QH104 .098 1995 This report may be cited: LaRoe, E.T., G.S. Farris, C.E. Puckett, P.D. Doran, and M.J. Mac, eds. 1995. Our living resources: a report to the nation on the distribution, abundance, and health of U.S. plants, animals, and ecosystems. U.S. Department of the Interior. National Biological Service. Washington, DC. 530 pp. Our Liviiii; Resources The nation's biological resources are the basis of much of our current prosperity and an essential part of the wealth that we will pass on to future generations. Like other forms of wealth, biological diversity constitutes a resource that must be conserved and managed carefully. Proper management of any resource requires ( I ) inventorying and monitoring the resource. (2) understanding the factors deter- mining its supply and demand, and (3) analyz- ing options for cunent and future uses of the resource. Inventory and monitoring is the essen- tial first step in taking stock of the wealth rep- resented in our living resources and planning for their conservation and use. This report. Our Liviiii; Resoiirces. is the first product of the Status and Trends Program in the National Biological Service. The report compiles, tor scientists, managers, and the lay public, information on many species and the ecosystems on which they depend. As a first step toward a consistent, large-scale under- standing of the status and trends of these resources, this report brings together for the first time a host of information about our nation's biological wealth, highlighting causes for both comfort and concern. The report provides valuable information about causes for the decline of some species and habitats. It also gives insight into successful management strategies that have resulted in recovery of others. The report will also serve as a useful guide for identifying research needs by revealing information gaps that must be filled if we are to achieve a more comprehensive under- standing of both cunent conditions and the anticipated impact of change. The mission of the National Biological Service is to work with others to provide the information and technologies needed to manage and conserve the nation's biological resources. As the biological science arm of the Department of the Interior — with neither regulatory nor resource-management responsibilities — NBS has as its primary responsibility serving the bio- logical science needs of other Department of the Interior bureaus. NBS also has a broader role of working with other federal agencies, states, universities, museums, private organizations, and landown- ers in a "National Partnership" to ensure that a more comprehensive and consistent approach is taken to providing information about the nation's biological resources. All of the players in this new partnership have long and rich his- tories of collecting and interpreting biological information. The National Biological Service will work with its partners to supplement and integrate this scientific information and make it more accessible. Our Living Resources is a prime example of NBS's partnership approach. Authors are drawn from more than 15 federal agencies, 15 state agencies, 25 universities, and 13 private organi- zations. In some cases, individual papers are themselves products of interagency or intergov- ernmental partnerships. Statistically reliable information on the sta- tus and trends of biological resources is an essential step towards better stewardship of our nation's biological wealth. Equally important is an intensive research program aimed at under- standing what factors are responsible for bio- logical changes and the incorporation of that understanding into resource management and policy decisions. NBS works closely with resource managers and other decision makers to analyze how natural forces and human activities affect biological resources and to predict how alternative management and policy decisions might improve or degrade those resources. NBS is committed to providing better infor- mation and making that information easily accessible not only to those who manage and regulate how we use natural resources but also to every American who makes economic use or seeks recreation or simply cherishes the beauty of our living resources. More reliable informa- tion and better access to that information will result in better and fairer decisions and a more prosperous future for all Americans. Foreword H. Ronald Pulliam Director, National Biological Service Our Livtiii^ Rt'sount\s Preface This report is the first of a series of reports on the status and trends of the nation's plants, animals, and ecosystems. It represents an effort to bridge the gap between scientists and resource managers, policy makers, and the gen- eral public. Usually, scientists tend to write for scientific journals and communicate with other scientists: this report attempts to collect a great vainety of scientific data and inteipret it for the nonscientist while maintaining the full credibil- ity of the data. The articles included represent both invited and contributed papers; that is, where we could identify specific subject experts, we invited them to submit papers, and we also accepted papers contributed by other authors. Following scientific tradition, each article submitted was peer-reviewed, usually by three anonymous sci- entific reviewers. The articles are often abridged from a complete scientific treatise, but each article contains references and personal contacts if the reader is interested in pursuing the subject in greater depth. Finally, we recog- nize that this report is incomplete and that more status and trends data exist than we were able to uncover or incorporate into one volume. In Memoriam Edward Terhune LaRoe III Senior science editor Ted LaRoe died of can- cer October 19, 1994, having shepherded this report almost to its completion. Had he lived to see Our Living Resources published, he would not have lingered to bask in its accomplishment. He would have moved on to new projects, new plateaus, for Ted always had a vision, a sense of w here he was going. He also had a vision for the National Biological Service, which he was instrumental in helping to create. Ted was bright, creative, inquisitive, inspir- ing, and a man of many accomplishments. His scientific leadership was evident in his active role in issues relating to wetland science, glob- al climate change, coastal resources, ecosys- tem-based management, and, of course, NBS. Above all, he was a champion of scientific integrity, which, we trust, is evident in this report. We hope he would have been pleased. Our Living Hesoiirces Wc extend our sincere appreciation to all who helped produce this report. Especially important were the science editors — Austin K. Andrews, Raymond J. Boyd. Glenn R. Guntenspergen, Russell J. Hall, Michael D. Jennings, Hiram W. Li, Michael J. Mac, William T. Mason, Jr., O. Eugene Maughan, Roy W. McDiarmid, Carole C. Mclvor, J. Michael Scott, William K. Seitz. Thomas J. Stohlgren, Benjamin N. Tuggle, Wayne A. Willford, and Gary D. Willson. They served hy coordinating reviews, including the peer reviews of articles within their sections. In addi- tion, they each provided an overview to the material in their sections. Assisting with overviews were Gregor T. Auble and B.D. Keeland. Carl Anderson, Michalann Harthill, Deborah E. Peck, Helen V. Turner, and Sherri L. Hendren each provided tremendous technical support. Contributing expertise in graphics were Nicholas R. Batik, Mary A. Helmerick, Dave Opp, Diane K. Baker, Janine J. Koselak, and M. Jennifer Kapus. Technical editors — Mary Catherine Hager, Beverly Kerr-Mattox, and Kristie A. Weeks — dedicated months to the editing of individual articles. Technical typists Deany M. Cheramie, Dana M. Girod, and Tiffany Alexander Hall assisted by keyboard- ing, correcting, and proofreading. Technical typist Judy Zabdyr helped in the final stages as did proofreaders Rhonda F. Davis and Lori E. Huckaby, under the direction of editor Beth A. Vairin, who also reviewed the report. Librarian Judy K. Buys performed numerous bibliograph- ic searches to verify citations, and Marilyn Rowland indexed the report. Robert E. Stewart, Director of the National Biological Service's Southern Science Center, graciously allowed the use of his staff, space, and equipment to pro- duce this report, as did Lawrence Bembry, Director of the Bureau of Land Management's Ser\ ice Center. We are also grateful to all those who gave permission to use their slides and graphics. Finally, we would like to thank the authors, the peer reviewers, and the state, federal, and private agencies who so willingly gave of their time and data. Without their hard work and cooperation, this report would not have been possible. Acknowledg- ments Our Livin,^ Resources Contents Foreword v Preface vi In Menioriam vi Acknowledgments vii Part 1 Introduction Overview 3 Biodiversity: A New Ciiailenge 6 Conservation Landmarks: Bureau of Biological Survey and National Biological Service .... 7 Activities of the Bureau of Biological Survey 8 Part 2 Distribution, Abundance, and Health Species ^^-^^^.^— — ^^^.^^^— — ^^^— — ^^^^^^^— — — ^— ^— — ^^^^^ Birds Overview 15 Breeding Bird Survey: Population Trends 1966-92 17 Winter Population Trends of Selected Songbirds 21 Breeding Productivity and Adult Survival in Nongame Birds 23 Canada Geese in North America 26 Canada Geese in the Atlantic Flyway 28 Arctic Nesting Geese: Alaskan Populations 30 North American Ducks 34 Decline of Northern Pintails 38 Canvasback Ducks 40 Breeding Seabirds in California, Oregon, and Washington 43 Seabirds in Alaska 49 Colonial Waterbirds 53 Shorebirds: East of the 105th Meridian 57 Western North American Shorebirds 60 Raptors 65 Causes of Eagle Deaths 68 Return of Wild Turkeys 70 Mourning Doves 71 Common Ravens in the Southwestern United States, 1968-92 73 Mississippi Sandhill Cranes 75 Piping Plovers 77 California Condors 80 Audubon's Crested Caracara in Florida 82 Puerto Rican Parrots 83 Red-cockaded Woodpeckers 86 Southwestern Willow Flycatchers in the Grand Canyon 89 Mammals Overview 93 Marine Mammals 94 Indiana Bats 97 Gray Wolves 98 Black Bears in North America 100 Giizzly Bears 103 Black-footed Ferrets 106 American Badgers in Illinois 108 California Sea Otters 110 White-tailed Deer in the Northeast 112 Deer Management at Parks and Refuges 113 North American Elk 115 Reptiles and Amphibians Overview 117 Turtles 118 Marine Turtles in the Southeast 121 Our Living RL'S(mrcc's Amphibians 124 A Success Story: The Barton Springs Salamander 125 American Alligators in Florida 127 Reptiles and Amphibians in the Endangered Longleaf Pine Ecosystem 129 Native Ranid Frogs in Calitornia 131 Desert Tortoises in the Mojave and Colorado Deserts 135 Coachella Valley Fringe-toed Lizards 137 Disappearance of the Tarahumara Frog 138 Fishes Overview 141 Imperiled Freshwater Fishes 142 Southeastern Freshwater Fishes 144 Loss of Genetic Diversity Among Managed Populations 147 Colorado River Basin Fishes 149 Cutthroat Trout in Glacier National Park. Montana 153 Columbia River Basin White Sturgeon 154 Invertebrates Overview 159 Diversity and Abundance of Insects 161 Grasshoppers 163 The Changing Insect Fauna of Albany's Pine Banens 166 Lepidoptera in North America 168 Fourth of July Buttertly Count 171 Species Richness and Trends of Western Butterflies and Moths 172 The Tall-grass Prairie Butterfly Community 174 The Biota of Illinois Caves and Springs 176 Freshwater Mussels: A Neglected and Declining Aquatic Resource 177 Freshwater Mussels in Lake Huron-Lake Erie Corridor 179 Aquatic Insects As Indicators of Environmental Quality 182 Biodiversity Degradation in Illinois Stonellies 184 Plants Overview 189 Microfungi: Molds, Mildews. Rusts, and Smuts 190 Macrofungi 192 Truffles. Trees, and Biodiversity 193 Lichens 194 Bryophytes 197 Floiistic Inventories of U.S. Bryophytes 198 Vascular Plants of the United States 200 Environmental Change and the Florida Torreya 205 Native Vascular Plants 205 Tracking the Mosses and Vascular Plants of New York (1836- 1994) 209 Ecosystems . Terrestrial Ecosystems Overview 213 U.S. Forest Resources 214 Southern Forested Wetlands 216 Rare Terrestrial Ecological Communities of the United States 218 Altered Fire Regimes Within Fire-adapted Ecosystems 222 Vegetation Change in National Parks 224 Air Pollution Effects on Forest Ecosystems in North America 227 Air Quality in the National Park System 228 Whitebark Pine: Ecosystem in Peril 228 Oak Savannas in Wisconsin 230 Aquatic Ecosystems Overview 233 Habitat Changes in the Upper Mississippi River Floodplain 234 Biota of the Upper Mississippi River Ecosystem 236 Our Liviiii; RcMiurccs Fish Populations in the Illinois River 239 Contaminant Trends in Great Lakes Fish 242 Lake Trout in the Great Lakes 244 Wetlands in Regulated Great Lakes 247 Decline in the Freshwater Gastropod Fauna in the Mobile Bay Basin 249 Protozoa 252 Marine and Freshwater Algae 255 Freshwater Diatoms; Indicators of Ecosystem Change 256 Coastal and Marine Ecosystems Overview 259 Nearshore Fish Assemblage of the Tidal Hudson River 260 Natural Resources in the Chesapeake Bay Watershed 263 Florida Manatees 267 Gulf of Mexico Coastal Wetlands: Case Studies of Loss Trends 269 Seagrass Distribution in the Northern Gulf of Mexico 273 Seagrass Meadows of the Laguna Madre of Texas 275 Coastal Barrier Erosion: Loss of Valuable Coastal Ecosystems 277 Reef Fishes of the Florida Keys 279 Coral Reef Ecosystems 280 Riparian Ecosystems Overview 285 Western Riparian Ecosystems 286 Surface Cover Changes in the Rio Grande Floodplain. 1935-89 290 Ecoregions ^^_-.^^^— i^^-^— ^— — ^.^-.^— ^^^^-^— ^-^— — ^-^-^^^— ^— — ^^ The Great Plains Overview 295 Declining Grassland Birds 296 Migratory Bird Population Changes in North Dakota 298 Duck Nest Success in the Prairie Potholes 300 Conservation Reserve Program and Migratory Birds in the Northern Great Plains 302 Decline of Native Prairie Fishes 303 The Coyote: An Indicator Species of Environmental Change on the Great Plains 305 Interior West Overview 309 Ecosystem Trends in the Colorado Rockies 310 The Greater Yellowstone Ecosystem 312 Subalpine Forests of Western North America 314 Southwestern Sky Island Ecosystems 318 Endangered Cui-ui of Pyramid Lake, Nevada 323 Bonytail and Razorback Sucker in the Colorado River Basin 324 Amphibian and Reptile Diversity on the Colorado Plateau 326 Wintering Bald Eagles Along the Colorado River Corridor 328 Mexican Spotted Owls in Canyonlands of the Colorado Plateau 330 Bighorn Sheep in the Rocky Mountain National Parks 332 Desert Bighorn Sheep 333 Alaska Overview 337 The Arctic Tundra Ecosystem in Northeast Alaska 338 Anadromous Fish of the Central Alaska Beaufort Sea 341 Pacific Salmon in Alaska 343 Wolves and Caribou in Denali National Park, Alaska 347 Kodiak Brown Bears 349 Polar Bears in Alaska 35 1 Sea Otters in the North Pacific Ocean 353 Pacific Walruses 356 Mentasta Caribou Herd 357 Tundra or Arctic Hares 359 Our Living Resources Hawaii Overview 361 Hawaii Biological Survey 362 Haleai^ala Silversword 363 Insects of Hawaii 365 Drosophila as Monitors of Change in Hawaiian Ecosystems 368 Birds of Hawaii 372 Hawaii's Endemic Birds 376 Part 3 Special Issues Global Climate Change Overview 385 Changes in Winter Ranges of Selected Birds, 1901-89 386 Changes in Nesting Behavior of Arctic Geese 388 Climate Change in the Northeast 390 Potential Impacts of Climate Change on North American Flora 392 Human Influences Overview 397 Significance of Federal Lands for Endangered Species 398 Status of U.S. Species: Setting Conservation Priorities 399 Increased Avian Diseases With Habitat Change 401 Captive Propagation. Introduction, and Translocation Programs for Wildlife Vertebrates . . . 405 Raccoon Rabies: Example of Translocation. Disease 406 Contaminants in Coastal Fish and Mollusks 408 Persistent Environmental Contaminants in Fish and Wildlife 413 Wildlife Mortality Attributed to Organophosphorus and Carbamate Pesticides 416 Acidic Deposition ("Acid Rain") 418 Atmospheric Deposition and Solute Transport in a Montane Mixed-Conifer Forest System 421 Agricultural Ecosystems 423 Non-Native Species Overview 427 Non-native Aquatic Species in the United States and Coastal Waters 428 Nonindigenous Fish 43 1 Non-native Reptiles and Amphibians 433 Non-native Birds 437 Non-native Animals on Public Lands 440 Exotic Species in the Great Lakes 442 Zebra Mussels in Southwestern Lake Michigan 445 Invasion of the Zebra Mussel in the United States 445 Africanized Bees in North America 448 Bullfrogs: Introduced Predators in Southwestern Wetlands 452 Invasions of the Brown Tree Snake 454 Wild Horses and Buitos on Public Lands 456 Purple Loosestrife 458 Habitat Assessments Overview 461 GAP Analysis: A Geographic Approach to Planning for Biological Diversity 462 Protection Status of Vegetation Cover Types in Utah 463 Biodiversity in the Southwestern California Region 465 Federal Data Bases of Land Characteristics 467 Monitoring Changes in Landscapes from Satellite Imagery 468 Landsat MSS Images 470 The Nation's Wetlands 473 Glossary 479 Index 483 Introduction Overview This report on the distri- bution, abundance, and health of our nation's biological resources is the first product of the National Biological Service's Status and Trends Program. This information has many potential uses: it can document successful management efforts so resource managers will know what has worked well; it can identify problems so managers can take early action to restore the resource in the most cost-efficient manner; and it can be used to highlight areas where additional research is needed, such as to determine why certain eco- logical changes are occurring. This report will also be useful to teachers, students, journalists, and citizens in general who are interested in national resource issues. Another purpose of this report is to help identify gaps in existing resource inventory and monitoring programs. It contains information collected by a variety of existing research and monitoring efforts by scientists in the National Biological Service, other federal and state agen- cies, academia. and the private sector. The pro- grams that produced the information in this doc- ument were not developed in a coordinated fashion to produce an integrated, comprehen- sive picture of the status and trends of our nation's resources; rather, each was developed for its own particular purpose, usually to help manage a specific resource. Thus, even though articles vary greatly in scope, design, and pur- pose, this report has identified and attempted to combine many of the existing information sources into a broad picture of the condition of our resources. In the future, these sources will be complemented by additional information from other sources — such as state agencies and other inventory and monitoring studies — to fill in the gaps of knowledge and to provide a more complete understanding of the status of our liv- ing resources. A second report, to be released by the National Biological Service in 1995. will use the information contained in this report and data from other sources to provide a synthesized account of the status and trends of the naUon's biodiversity. It will discuss from a historical perspective the factors influencing biodiversity, both natural and human-induced, and provide an integrated description of the status and trends of biological resources on a regional basis. Status and Trends The goal of inventory and monitoring pro- grams is to determine the status and trends of selected species or ecosystems. Status studies InUiidiiclion — Our Livinii Resources Figure. Northern pintail duck (Anas acuta) population data demonstrate the importance of long-temi data sets. Annual fluctu- ations (e.g., 1967-70 ) reflect year- ly fluctuations in breeding success that may have been caused, for example, by differences in rainfall and the abundance of temporary wetlands for nesting habitat. Short-term data sets can give erto- neous conclusions; for example, if only data from 1964 to 1972 were available, managers might con- clude that populations were increasing. The long-terai data, however, describe a statistically and biologically significant popu- lation decline. (Source: U.S. Fish andWildhfe Service, 1993. Status of Waterfowl and Fall Flight Forecast.) produce data on the condition of species or ecosystems for a single point in time; trend studies, in contrast, provide a chronological or geographic picture of change in the same resource. Either can measure a number of dif- ferent biological indicators, such as population size, distribution, health, or physiological fac- tors such as breeding productivity or seed pro- duction. Species composition, biodiversity, and age and physical structure are all important indicators of ecosystem status. Inventory and monitoiing programs can pro- vide measures of status and trends to determine levels of ecological success or stress; if such programs are appropriately designed, they can give early warnings of pending problems, allowing resource managers to take remedial action while there are more management options. These earlier options are less severe than if management response is delayed until problems are critical, such as when a species becomes endangered. One of the challenges resource managers face is to detect long-term trends because such trends are often masked by short-term, random, or undirectional variations (Figure). Plant and animal species often vary greatly in abundance, distribution, or fecundity as a result of forces that include annual or seasonal variations in cli- mate; chance events such as Hoods and hurri- canes; effects from predators or competing species; and even internal physiological processes. Some variations appear totally ran- dom; many are cyclic, recurring periodically; and others are long-term in one predominant direction. Scientists have many ways to deter- mine whether apparent changes are biologically and statistically significant, although it is often difficult to detect such trends in their early stages. The design of monitoring programs should address issues such as the number of samples needed, the sampling technique, and the frequency and duration of sampling. All are critical factors in determining the sensitivity of the monitoring program to detect directional 55 60 65 70 75 80 85 90 Year change. Data collected in a standard or consis- tent fashion over many years are especially crit- ical to identify and document trends. National Inventory and Monitoring Programs A number of inventory and monitoring pro- grams have been underway for several to many years in various agencies (Table). Historically, the federal government has been responsible for monitoring the status and trends of migratory species as well as those resident on federal lands. In addition, the federal government mon- itors habitat conditions on federal lands and, under some circumstances, private lands. Some of the monitoring programs also require international cooperation because many of the migratory species monitored cross international boundaries. States have monitored resident species and often cooperated in surveys of migratory species. A significant problem with these efforts has been that often the individual agencies or states have used different monitoring proce- dures and standards, and the results are not comparable from area to area or among differ- ent agencies. The private sector, including particularly The Nature Conservancy, has worked with states to establish Heritage Programs that mon- itor the distribution and abundance of selected species. This effort has resulted in standardized procedures. Most inventory and monitoring programs were established for a specific puipose. usually relating to management of natural resources. For example, the efforts to monitor duck popu- lations started 35 years ago to improve the basis for hunting regulations, and the National Wetland Inventory was started in 1979 to deter- mine the condition and rate of wetland loss. Until recently, few. if any. of these programs were intended or have been used to provide broad-based and predictive tools that could help resource managers identify future resource problems. The National Biological Service has the responsibility for developing information on the status and trends of our nation's plants and ani- mals and the habitats on which they depend. It will achieve this by building on the inventory and monitoring activities existing in the state, federal, and private sectors. The national status and trends effort will continue to depend upon the contributions of these existing programs, and NBS will avoid duplicating programs already under way. Its role will be to coordinate the activities of different agencies into a com- prehensive assessment of our living resources. Our Llvini^ Rt'sources — liitriiduiti(m coiilinuing its own contributions, and when nec- essary, supplementing the current array of activ- ities. Organization of This Report In addition to this overview, the report intro- duction includes articles on the importance ot biodiversity and a historical look at biological study in the federal government. The articles that follow, contributed by a variety of authors and agencies, represent the first effort to pull together information on the status and trends of different groups of biota, ecosystems, and ecoregions as well as related issues. Individual articles in each section are most often arranged from the most general or large scale, to the most specific or small scale. The organization is somewhat arbitrary in that many articles could appear with equally valid justifications in several different locations. Animals and Plants Not all groups have received equal treat- ment, in large part because our current knowl- edge is not equal among all groups, and inven- tory and monitoring are focused on compara- tively few species. Scientific studies have been greatly assisted in some areas by the work of natural historians and public volunteers. Bird watchers, butterfly collectors, and shell collec- tors, for example, have provided invaluable sci- entific infonnation about the geographic ranges of groups in which they are interested. Some of the professional societies today owe their ori- gins to the efforts of amateurs to organize and improve their understanding of biota. Many of the less visible or charismatic taxa lack the scientific effort or information, much less the volunteer amateur support, to discuss trends in their abundance or distribution. The very title "Animals and Plants" could be viewed as biased by some biologists: although most of the public views mushrooms and other fungi as plants, specialists consider them a separate kingdom, equal both taxonomically as well as in ecological significance to both plants and animals. Despite their significance, plants are simply underrepresented in this report because the data are lacking. The report begins with birds, the single group for which we have the most data at national and large-scale levels. Because of the significance of birds as important migratory species, there has been a strong role for federal research scientists as well as scientists from state agencies and from Canada and Mexico. Some of the best long-term scientific informa- tion on status and trends comes from the Breeding Bird Survey and the Christmas Bird Count. Tahle, Selecled examples of existing ccolcigical inventory and monitoring programs. Subject Institution Migratory bird surveys Breeding birds Winlering birds Waterfowl surveys National Biological Service (NBS) The Audubon Society U.S. Fish and Wildlife Service (USI=WS), NBS, and states, with inter- national participation Rare and threatened species Listed endangered and threatened species Stale Heritage Programs Endangered manne species Slates. US, federal land managers (e.g., National Park Service. Bureau of Land Management (BLM). U.S. Forest Sen/ice (USPS)), USFWS. NBS State agencies and The Nature Consen/ancy National t^arine Fishenes Service (NMFS) Resident gaine species (eg, deer, turkey furbearers) State fish and wildlife conservation agencies Habitats and biological communities National Wetlands Inventory Gap Analysis Program Environmental Ivlonitoring and Assessment Program Resources Conservation Act, inventory of wildlife and habitat conditions of farmlands USFWS NBS in partnership with states and private sector U.S. Environmental Protection Agency U S Soil Conservation Sereice (now Natural Resources Conservation Sen/ice) Wildlife and habitat on public lands Resources Planning Act assessment of USPS USPS lands Federal Land Policy and Management Act BLIVI assessment ol BLIVI lands Contaminants Aquatic and terrestrial (Biomoniforing of Environmental Status & Trends National Water Quality Assessment) Marine and coastal NBS with USFWS; U.S. Geological Sun/ey National Oceanic and Atmospheric Administration and NMFS Ecosystems and Ecoregions We have also included information on ecosystems and ecoregions. Ecosystems are groups of plants and animals and their nonliving environment such as air and water. For example, one can speak of a coastal wetland ecosystem, whether in North Carolina or Florida, and understand that it includes several specific fea- tures or processes shared by all coastal wetland ecosystems. Ecoregions are geographically defined eco- logical units, often containing several types of ecosystems, that share common topographic, climatic, and biotic characteristics. Each ecore- gion, such as Alaska or Hawaii, can be defined as a single, individual unit on a map, while ecosystems, if mapped, would be scattered about as separate units. Special Issues After the status and trends of animals and plants, ecosystems, and ecoregions are present- ed, a section on related issues follows: global climate change, human influences, non-native species, and methods of habitat assessinent. The proliferation of introduced species, both plant and animal, has had a profound influence on the native biota of this country. Many human activ- ities, such as pollution and urbanization, both directly and indirectly affect the health of our living resources. The possibilities of global cli- mate change are examined, followed by a brief liifriuliulion — (^iir Ltviii!:; Rtwi'iirccs overview of national programs such as the Gap policy makers better protect our resources. Analysis Program, which scientists hope will pro\e useful in acquiring data to help resource Biodiversity: A New Challenge by Edward T. iMRoe National Biological Service Resource managers at many state and federal agencies are in the middle of a fundamental change in the practice and objectives of conser- vation. Traditional management has been directed toward maintaining, usually for harvest purposes, populations of individual species such as ducks, deer, or salmon. Increasingly, however, resource managers are recognizing the critical importance of conserving biological diversity, or biodiversity. In its simplest terms, biological diversity is the variety of life at all levels: it includes the array of plants and animals: the genetic differ- ences among individuals; the communities, ecosystems, and landscapes in which they occur: and the variety of processes on which they depend. Conserving biological diversity poses dramatic new problems for comprehen- sive inventory and monitoring: what should be measured or monitored? Biodiversity is important for many reasons. Its value is often reported in economic terms: for example, about half of all medicinal drugs (Keystone Center 1991; Wilson 1992) come from — or were first foinid in — natural plants and animals, and therefore these resources are critical for their existing and as yet undiscov- ered medicinal benefits. Additionally, most foods were domesticated from wild stocks, and interbreeding of different, wild genetic stocks is often used to increase crop yield. Today we use but a small fraction of the food crops used by Native cultures: many of these underused plants may become critical new food sources for the expanding human population or in times of changing environmental conditions. But biodiversity has an even greater impor- tance: it is the great variety of life that makes existence on eaith possible. As a simple exam- ple, plants convert carbon dioxide to oxygen during the photosynthctic process: animals breathe this fresh air. releasing energy and pro- viding the second level of the food chain. In turn, animals convert oxygen back to carbon dioxide, providing the building blocks for the formation of sugars during photosynthesis by plants. Microbes (fungi, bacteria, and proto- zoans) break down the carcasses of dead organ- isms, recycling the minerals to make them available for new life; along with some algae and lichens, they create soils and improve soil fertility. Biodiversity provides the reservoir for change in our life-support systems, allowing life to adapt to changing conditions. In a natur- al population, for example, some individuals will be more resistant to drought or disease or cold; as the environment changes, from season to season, year to year, or over longer periods, and as plagues come and go, these differences among individuals allow at least some members of the population or species to survive and reproduce. This diversity is the basis not only for short-term adaptation to changing condi- tions, but also for long-term evolution as well. Like air, water, and soils, biological diversi- ty is part of the capital upon which all life depends. The need for this diversity is greatest in times of environmental stress when plants, animals, and microbes must develop new char- acteristics or strategies for survival. As we look at the problems of the globe today — global cli- mate change, decreases in the ozone shield and increasing ultraviolet radiation, losses of natur- al habitats, and pervasive pollution in our streams and oceans — we must recognize that we. as a form of life on earth, need the ability to change in order to cope with new stresses. Humans cannot survive in the absence of nature. We depend on the diversity of life on earth for about 259f of our fuel (wood and manure in Africa. India, and much of Asia); more than 5(J% of our fiber (for clothes and construction); almost 50% of our medicines; and. of course, for all our food (Miller et al. 1985). As previously stated, biodiversity pro- duces other benefits: plants produce oxygen for our atmosphere; microbes break down wastes, recycle nutrients, and build the fertility of our soils. One reason our highways are not littered with the carcasses of dead dogs, cats, skunks, armadillos, and deer is biodiversity, in the form of the many scavengers and microbes that we don't often think about, but which play an essential role in the cycle of life. Even species often viewed as ""repulsive," such as vultures and maggots, play critical roles in our lives. Some people believe that because extinction is a natural process, we therefore should not worry about endangered species or the loss of biodiversity. Certainly extinction is natural; it usually occurs as newer forms of life evolve. But under the forces of population growth, tech- nology, and special interests, humans have dri- ven the rate of extinctions today to about 100 times — two orders of magnitude — the natural rate. Even worse, the rate of extinction is still increasing and will be 100 to 1,000 times faster yet in the next 55 years (Miller et al. 1985); sci- entists today predict that between now and 2030, half the expected lifetime of a child bom today, the Earth will lose between a quarter and a third of all existing species. And this is in the absence of new forms of life to replace them. Our Liviiif; Rt'souivex — Introdiirtinn The last lime Eurlh lost this large a share of its life was 65 million years ago when it may have collided with an asteroid; the impacts of humans on our planet today may have been last equaled hy the collision of two heavenly bodies (Wilson 1992). Scientists cannot honestly say that we need all species that exist today for humans to sur- vive; but as a general rule, the more diversity is diminished, the less stable ecosystems become and the greater the fluctuations that occur in plant and animal populations. The more diversi- ty we lose, the more our quality of life and eco- nomic potential are diminished, and the greater the risk that we will cause a critical pail of the cycle of life to fail. If humans were allowed to cause the extinc- tion of other species, who would determine which species ? If we had been asked 60 years ago what life we could let become extinct, who among us would have insisted that we preserve the lowly mold that was penicillin, the first of the series of antibiotics that have today so changed the quality of t)ur lives? And who. only 3 years ago. would have identified the need to preserve the Pacific yew. which today yields taxol. one of the greatest new hopes in our arse- nal against cancer? References Keystone Center. 1991. Biological diveisity on federal lands, report of a Key.slone policy dialogue. The Keystone Center, Keystone, CO. 96 pp. Miller, K.R., J. Fortado, C. De Klemm, J.A. McNeely. N. Myers, M.E. Soule, and M.C. Trexler. 1985. Is.sues on the preservation of biological diversity. Pages .^.17-362 //) Robert Repetto, ed. The global possible. Yale University Press, New Haven. Wilson, E.O. 1992. The diversity of life. Belknap Press of Harvard University Press. Cambridge, MA. 424 pp. A century separates the recent development of the National Biological Service (NBS) and an early predecessor, the Bureau of Biological Survey (BBS). Both organizations were established at critical crossroads for the conservation of the nation's living biological resources and are conservation landmarks of their times. The BBS of the 192()"s was described as "a government Bureau of the first rank, handling affairs of great scientific, educa- tional, social, and above all, economic impor- tance throughout the United States and its out- lying possessions'" (Cameron 1929:144-145). This stature was achieved at a time of great social, economic, and ecological change. BBS had the vision to pioneer new approaches that led to enhanced understanding of the relation between people, other living things, and the environment. The NBS faces similar challenges to address the issues of the 1990's and beyond. Diminished Natural Resources in a World of Plenty Early European colonists had an abundance of wildlife to serve subsistence needs. Seemingly endless flocks of ducks, geese, and swans; an abundance of wild turkeys, deer, and bison; green clouds of Carolina parakeets and millions of passenger pigeons; and a bounty of fish and shellfish. This abundance quickly established a viewpoint that the New World's wildlife resources were inexhaustible. Habitat changes that disrupted the balance of nature soon resulted in economic losses and other hardships because of in.sect and rodent eruptions. Negative effects of exotic species brought from the Old World further reduced the well-being of many colonists who had come to the New World for a better life. The nation's inexhaustible natural resources and returns from agriculture began to wane significantly. Decimation of previously vast wildlife resources greatly reduced opportunities for cul- tural and recreational uses of wildlife (Cameron 1929). Development of the BBS Roots of the BBS can be traced to the 1883 founding of the American OiTiithological Union (AOU) \n New York City. Initially, the AOU focused on three subject areas — distribution, biological information and economic impact, and migratory behaviors of birds — all of which became major activities of the BBS. Collaborations and partnerships were developed with numerous ornithologists, field collectors, sportsmen, and observers of nature who were asked to report specific information relative to bird migration. Cooperation also was obtained from the United States Lighthouse Board and the Department of Marine and Fisheries of Canada (Cameron 1929). Funds for government biological survey pro- grams related to economic ornithology were allocated in 1885 to the Division of Entomology of the U.S. Department of Agriculture. These funds were provided for "the promotion of eco- nomic ornithology, or the study of the interrela- tion of birds and agriculture, an investigation of the food habits, and migration of birds in rela- tion to both insects and plants." The following year additional funds were provided to include the study of mammals and expand the focus Conservation Landmarks: Bureau of Biological Survey and National Biological Service by Milton Friend National Biological Service InUndiictU' ■ Our Liviiii^ Rt'MiKixt'S Investigation and research Study of life habits of wild animals Classification of wild animals Studies in geographic distribution of wild animals and plants Life zone in\estigations of definite areas Biological surveys of definite areas Special big game investigations Investigations for improvement of reindeer in Alaska Investigations at reindeer experiment station Investigations of problems of fur fanners Studies in fur animal disease and parasites Investigations of problems of rabbit raisers Studies of rabbit diseases, etc. Investigations in animal poisons Studies in bird migration Bird censuses (general) Wild fowl censuses Bird banding Food habits studies by laboratory examma- tions of stomach contents of birds, mam- mals, reptiles, and amphibians Studies in game bird propagation Specific studies in covert restocking Surveys of food resources for waterfowl Investigations and experiments in predatory animal control Investigations and experiments in control of injurious rodents Investigations and experiments in control of other animal pests Investigations and experiments in control of bird pests Activities of the Bureau of Biological Survey (Cameron 1929) Encouragement of useful forms of wildlife Advice on game bird and animal propaga- tion methods Devising of methods for attracting birds about parks, homes, etc. Encouragement of conservation of wild fur bearers Advice on small annual production (for pets and laboratory use) Maintenance and protection of game pre- serves and birds refuges Restocking of reservations Disposal of surplus animals on reservations Issuance of permits for fur farming on cer- tain Alaskan islands Adininistration of Upper Mississippi Wild Life and Fish Refuge Act Administration of act protecting wildlife on reservations Repression of undesirable forms of wildlife Killing of predatory animals Leadership and demonstration in coopera- tive effort against predatory animals Leadership and demonstration in coopera- tive effort against injurious rodents Leadership and demonstration in coopera- tive effort against other animal pests and injurious birds Processing of poisons and food stuffs for use against predatory and noxious animals Protection of wildlife Administration of Migratory Bird Treaty and Lacey acts by warden service and in coop- eration with state law enforcement agen- cies Issuance of permits for game propagation Regulation of importation of wild birds and animals Preparation of regulations under Alaska game law Dissemination of information Preparation and editing of publications Preparation of exhibits and photographs Answering of inquiries Addresses by officers (conventions, univer- sities, etc.) Miscellaneous Regulation of grazing of domestic stock in certain Alaskan islands from agriculture and hoiticulture to the new subject of forestry. At the same time, the work was moved from the Division of Entomology to the new Division of Economic Ornithology and Mammalogy. Dr. C. Hail Meiriam became the first division chief in July 1886 (Cameron 1929). The new division continued to study wildlife food habits, migration, and species distribution. It placed considerable emphasis on educating farmers about birds and aniinals affecting their interests so that destruction of useful species might be prevented. Dr. Merriam pursued the development of an extensive biological survey, advancing the argument that mapping of fauna] and floral areas would benefit farmers by iden- tifying the boundaries of areas tit for the growth of ceilain crops and those hospitable for certain breeds of livestock, in 1 890, the appropriation language for the Department of Agriculture pro- vided for the investigation of "the geographic distribution of animals and plants." causing Dr. Meniam to note that "the division is now in effect a biological survey" (Cameron 1929:27). The major part of the division's 1891 activi- ties involved an extensive biological survey and biogeographic mapping of the Death Valley region of southern California and southern Nevada. This was followed by additional bio- logical surveys of various areas of the West. Biological surveys also were conducted beyond the continental borders of the United States into Alaska, Canada, and Mexico. In 1896 the Division of Ornithology and Mammalogy became the Division of Biological Survey (Cameron 1929). Food habit studies, which were continued along with the survey work, emphasized trans- mitting information to those who could benefit from it. Popular bulletins were prepared on bird migration, the economic impacts of specific wildlife species on agriculture, and the intro- duction of exotic species. In 1889. the division initiated the more scientific Norrli American Fauna series, which included that year a gener- al paper discussing Dr. Merriam's concept of the life zones of North America (Cameron 1929). The division was elevated to bureau status on July 1, 1905. During the next 34 years, activ- ities expanded to serve the growing U.S. con- servation movement. Diverse investigations and Oui Lniiifi Kc.'.inircc.s — Imiodmtion research were canied out as well as technical assistance to the public and to game managers; animal damage control: regulatory functions including conservation law enforcement; administration of refuge lands; and public edu- cation through publications and exhibits (sec box). Conservation problems included habitat loss, declining wildlife populations, species extinction, control of exotic species, control ot predatory and injurious wildlife, pollution and disease control, and competition between wildlife, agriculture, and forestry. The BBS was transfened to the Department of Interior on July 1. 1939. and was made part of the U.S. Fish and Wildlife Service (USFWS). In November 1993, the biological research components within the Department of Interior, including those from the USFWS, the National Park Service, the Bureau of Land Manage- ment, the Bureau of Reclamation, and the Minerals Management Service were reorga- nized to form the National Biological Survey. The name was changed to the National Biological Service on January 5, 1993, lo more accurately rellect the agency's mission. Then and Now Dr. Merriam noted that the chief work of the BBS was to obtain facts, for without a knowl- edge of facts there can be neither efficient administration nor intelligent regulation of wildlife to meet the needs of the nation (Cameron 1929). That same philosophy is inherent in Secretary of the Interior Bruce Babbitt's remarks about the NBS; The National Biological Survey will pro- duce the map we need to avoid the eco- nomic and environmental "train wrecks" we see .scattered across the country. NBS will provide the scientific knowledge America needs to balance the compatible goals of ecosystem protection and eco- nomic progress. . . . |The| National Biological Survey will unlock information about how we protect ecosystems and plan for the future. (National Research Council 1993:181-182). Land management, regulatory, and law enforcement activities of the BBS remained with the LISFWS and other parent bureaus with- in the Department of Interior when the NBS was formed. Only the biological research com- ponents of the department have become part of the NBS. This nonadvocacy biological science program will help the nation to resolve increas- ingly contentious and challenging issues in managing its biological resources. References Cameron. J. 1929. The Bureau of Biological Survey: its tiis- tory. activities, and organization. John Hopkins Press. New York. .1.^9 pp. National Research Council (Committee on the Formation ot the National Biological Survey). 199.^. A biological sur- vey lor the nation. National Academy Press, Washington. DC. 2(l.'i pp. For further information: Milton Friend National Biological Service National Wildhle Health Center 6006 Schroeder Rd. Madison. Wl 53711 ■:W&&i^ Distribution, Abundance, and Health Distribution, Abundance, and Health of Birds 15 Mammals ^ 93 Reptiles and Amphibians 117 Fishes 141 Invertebrates 159 Plants 189 Jfl 1 ' I -k' j^ - ■>- ^^ r K A- ^^llj 1 / ^v' ^ .^k. If 4- tf ! ! >. ^. <\ Birds Overview Migratory bird popula- tions are an international resource tor which there is special federal responsibility. Moreover, birds are valued and highly visible components of natural ecosys- tems that may be indicators of environmental quality. Consequently, many efforts have been directed toward measuring and monitoring the condition of North America's migratory bird fauna. The task is not an easy one because the more than 700 U.S. species of migratory birds are highly mobile and may occur in the United States during only part of their annual cycle. Some species annually make round-trip migra- tions spanning thousands of kilometers or miles, others engage in short or irregular migra- tions of tens or hundreds of kilometers, and even resident species are capable of moving great distances over short intervals. One often cannot tell whether a bird observed at a given moment is a resident, a migrant, a visitor from another locality, or the same individual seen 10 minutes earlier. Determining status and trends is further complicated by the fact that each of these species has its own patterns of distribution and abundance, and each species has populations that respond to different combinations of envi- ronmental factors. Finally, the sheer abundance of birds estimated at 20 billion individuals in North America at its annual late-summer peak (Robbins et al. 1966) may make it difficult to obtain accurate counts of common species, and the absolute abundance of some may mask important changes in their status. Biologists have developed many different approaches to determining abundance and trends in abundance, and nearly all of the recog- nized census methods applicable to birds are represented by the articles in this section. Not suiprisingly, trends among the large number of populations treated are mixed. Results from the nationwide Breeding Bird Survey (Peterjohn et al., this section) and a por- tion of the large-scale Christmas Bird Count (Root and McDaniel, this section) show that some populations are declining, others increas- ing, and many show what appears to be normal fluctuations around a more or less stable aver- age. Overall, approximately equal numbers of species appear to be increasing and decreasing over the past two to three decades. Groups of species with the most consistent declines are those characteristic of grassland habitats, appar- ently reflecting conversion of these habitats to other types of vegetative cover. Waterfowl populations are monitored close- ly as a basis for regulating annual harvests at levels consistent with maintenance of popula- tions. Goose populations (Rusch et al.. by Science Editor RussellJ.Hall National Biological Service Division of Research Washington, DC 20240 16 Birds — Our Liviiii^ Rtwoiirctw Hestbeck's "Canada Geese," Hupp et al., all this section) have shown some impressive gains over the past decades, but most gains have been registered by large-bodied geese, with several smaller species and smaller subspecies of the highly variable Canada goose {Branta caiuulcii- sis) having depressed populations. Censusing and determining the status of nat- ural Canada goose populations are made more difficult by the widespread introduction and establishment of resident goose populations, which breed outside the traditional Arctic nest- ing areas and mix with migratory populations on the wintering grounds. Duck surveys address more than 30 species that might be legally hunted. Even though some species are stable or even increasing, many duck populations have declined in the past decade (Caithamer and Smith, this section). Biologists attribute these declines to losses of breeding and wintering habitats and a long peri- od of drought in breeding areas. Among species receiving special emphasis, canvasbacks (,4\t/Mfl valisineria: Hohman et al., this section) showed a complex pattern with regional changes in distribution and abundance, and pin- tails [Anns acuta: Hestbeck"s "Decline of Northern Pintails," this section) showed a wide- spread and nearly consistent pattern of decline. Results are preliminary, but two new census programs, the MAPS and BBIRD programs (Martin et al., this section), promise to provide much higher quality information on status and trends by measuring not only the presence of bird populations in breeding areas, but also their success. When fully operational, this approach may offer important clues regarding the causes of observed population changes. Shorebirds are highly migratory, and status and trends of their populations are largely deter- mined from observations made during periods in their life cycles in which birds congregate in limited breeding, staging, or migratory stopover areas. Populations of eastern (Harrington, this section) and western (Gill et al., this section) species show general patterns of decline, although soine species, including those using inland areas, are too poorly studied to detect trends. Apparent dependence on critical breed- ing and staging areas suggests that populations of many species are vulnerable to habitat loss and disturbance, Seabirds in the Pacific region (Carter et al.. Hatch and Piatt, both this section) include many diverse species that respond differently to fac- tors such as human proximity to nesting areas, oil spills, introduction of predators, depletion of fishery stocks, and availability of human refuse as food. Some species, including certain gulls, brown pelicans {Pelecanus occidciiuilis), and double-crested cormorants {Phalacrocurax aiiritus), have responded positively to recent changes in some areas, whereas others, includ- ing munelets and munes (Family Alcidae) and kittiwakes (Genus Ri.ssa). have shown declining trends. Populations of other species appear to fluctuate widely, and information for many species is insufficient to determine long-term trends. Colonial waterbirds of the continental and east coast regions of the United States (Erwin, this section) show trends related to many of the same factors operating in the Pacific region, with some species recovering from past losses from pesticides while some other species that exploit human refuse are increasing dramatical- ly. Populations of other species, especially cer- tain terns, are declining, probably as a result of habitat loss and degradation or other kinds of human disturbance. Special efforts have been made to determine status and trends of the pip- ing plover (Chanuhius inclodiis: Haig and Plissner. this section), a species listed as endan- gered in certain parts of its range and as threat- ened in others. Populations of raptors (Fuller et al., this sec- tion) are difficult to census, but ospreys (Puiuliou haliaeliis). bald eagles {Haliaeetiis leucocephalits). and peregrine falcons (Falco pcregrimis) have increased in numbers as they recover from past effects of pesticides. Populations of most vultures, hawks, and owls are either poorly known or believed to be stable. Notable exceptions are California condors (Gymnogyps califaniiamis: Pattee and Mesta, this section), the crested caracara {Caracara plancus: Layne. this section), and spotted owls (Stri.x occidentalis), all of which enjoy or have been considered for additional protection. Mortality factors of eagles (Franson et al., this section) have been monitored and, although these data do not directly measure population status, they do indicate trends in the kinds of factors that tend to depress population growth. The wild turkey (Meleagris gallopavo; Dickson, this section) has shown dramatic increases in distribution and abundance in recent decades because of translocations, habi- tat restoration, and harvest control. Mourning doves {Zenaida macroiira: Dolton. this section) have shown generally stable populations, although recent population declines in the west- em states are disturbing. Regional increases of ravens (Corviis corax) in the southwest (Boarman and Berry, this section) are primarily of concern because of their potential effects as predators on eggs and young of the desert tor- toise (Gophenis agassizu)- Populations of severely endangered species, like the California condor (Pattee and Mesta, this section), the Mississippi sandhill crane (Gnis canadensis piilla: Gee and Hereford, this Our Lrvini^ Rfsoinvcs — Hinls 17 section), and the Puerto Rican parrot {AnuKxnui vittaur, Meyers, this section), are reasonably well known. Through censusing these species, biologists have tracked declines, often to a few indi\ iduals. and slow recoveries resulting from intensi\e management activities. Other rare species have populations that are depleted or vulnerable because of recent trends, but which can be censused with far less certainty. For example, willow tlycatchers (Fjupidomix tniil- lii: Sogge. this section) breed sparsely m parts of the Grand Canyon where exotic species have displaced natural riparian vegetation; likewise, the status of the red-cockaded woodpecker {Picoidcs hoivalis) appears closely tied to the decline of the longleaf pine {Pinus paliistrls) ecosystem (Costa and Walker, this section). Broad-scale programs such as the Breeding Bird Survey, annual waterfinvl surveys, and wintering surveys such as the Christmas Bird Count may provide information on status and trends for as many as 75% of U.S. bird species, at least to the extent that they would provide evidence of catastrophic declines. Remaining species may be censused only with difficulty and often with imprecision because they are secretive, rare, highly mobile, or occupy poorly accessible areas. Specialized surveys provide information on some of these groups but. as indicated by the articles in this section, they do so with varying degrees of success. Much work remains to be done on obtaining better informa- tion and developing better ways of inteipreting a\ailable information on difficult-to-census species. If any overall conclusion is possible on the wide array of information now available on sta- tus and trends of bird populations it is this: apparent stability for many species; increases in some species, many of which are generalists adaptable to altered habitats; and decreases in other species, many of which are specialists most vulnerable to habitat loss and degradation. Reference Robbins. C.S . B. Bruun. and HS. Zim. 1966. Birds of North .'\nierica. Golden Press. .New \'ork. .^40 pp. The North American Breeding Bird Survey (BBS) was begun in 1966 to collect stan- dardized data on bird populations along more than 3.400 survey routes across the continental United States and southern Canada. The BBS has been used to document distributions and establish continental, regional, and local popu- lation trends for more than 250 species. We summarize here survey-wide patterns in the 1966-92 population trend estimates for 245 species of birds observed on a minimum of 40 routes with a mean relative abundance of 1 .0 bird per route. Survey-wide trend estimates are also summarized for six groupings of birds, pro- viding insight into broad geographical patterns of population trends of North American birds. Methods The BBS routes are located along secondary roads and surveyed each year during the peak of the breeding season by observers competent in bird identification. Each route is 39.4 km (24.5 mi) long, with 50 stops placed at 0.8-km (0.5- mi) intervals (Robbins et al. 1986). To estimate population change, we used a procedure called route regression, described in greater detail by Geissler\indSauer(1990). We examined population change in several ways. First, we estimated overall population change for individual species over the entire survey area. Second, we looked for temporal and geographic patterns in individual bird species (e.g.. Sauer and Droege 1990). Additionally, we analyzed overall patterns of population change for several species of partic- ular management interest. Groups of birds were defined by migration status (nonmigratory. short-distance, and Neotropical migrants) or by breeding habitat (grassland, shrubland. or woodland: see also Peterjohn and Sauer 1993). For each group, we determined the percentage of species with positive (> 0) trends. If popula- tion change is not consistent within the group, about half (50%) of the species should show positive trends. Clearly, some species will show very significant declines (or increases) over the interval, and these species can be identified in the Appendix. However, the percentage of species with positive population trends is a con- venient summary of information from all species within the group to demonstrate overall trend patterns. Finally, to display regional patterns of popu- lation change, we calculated the mean trend for the species in each group for each survey route. We used an Arc/Info geographic infomiation system to summarize and display geographic patterns of population change (Isaaks and Srivastava 1989: ESRI 1992). Trends Of the 245 species considered. 130 have negative trend estimates, 57 of which exhibit significant declines. Species with negative trend estimates are found in all families, but they are especially prevalent among the mimids (mock- ingbirds and thrashers) and sparrows. A total of 115 species exhibits positive trends, 44 of Breeding Bird Survey: Population Trends 1966-92 by Bruce J. Peterjohn John R. Sauer Sandra Orsillo National Biological Service IS Birds — Our Living Resouncs Fig. 1. Geographic patterns in the mean trends tor grassland bird species during 1466-^2. Table. Percentage of species with increasing populations for six groups of birds having shared life- history traits. The P value indi- cates the probability that the per- centage differs from 50%. which are significant incieases. Flycatcheis and warblers have the largest proportions of species with increasing populations. The percentage of increasing species within each group of species having shared life-history traits is sumniarized in the Table. The most con- sistent declines are by grassland birds; only 1 8% have increasing population tiends. These declines are most widespread in eastern Noilh America, where few grassland species breed (Fig. 1). Declining populations are also preva- lent across the Great Plains, which includes the breeding ranges of most grassland birds. The pattern within western North America is mixed, except for regions of declines along the Pacific coast. A significant proportion of shrubland and old-field bird species also exhibits population declines (Table). As with grassland birds. regions with declines are most prevalent in east- Group No. of species in each group Increasing (%) P Breeding habitats Grassland 17 18 0.01 Shrubland 58 34 002 Woodland 80 59 0.15 Migration Short distance 69 42 0.23 Nonmigratory 41 41 0.35 Neotropical 98 50 0.92 All species 237 47 0-36 Negative trends Positive trends Fig. 2. Geographic patterns in the mean trends for shnibland and old- field bird species during 1966-92. em North America as well as in the southern Great Plains from Kansas and Missouri south to Texas (Fig. 2). Shrubland species appear to be generally increasing in western North America. A majority of woodland bird populations is increasing across most of the continent (Fig. 3). Decreasing populations prevail in a few regions, such as along the Appalachians from West Virginia to northern Alabama, from Arkansas across central Texas, and along the Pacific coast from Oregon to central California. Woodland birds, however, are increasing in more areas than either grassland or early successional species. Negative trends Positive trends Fig. 3. Geographic patterns in the mean trends for wood- land bird species during 1966-92. Neotropical migrants have received consid- erable attention in recent years, yet as many species have increased as have decreased during 1966-92 (Table). A region with apparently declining populations extends from the southern Great Plains across the southeastern states and along the Appalachian Mountains to southern New England (Fig. 4). Increasing mean popula- tions prevail across the northern Great Plains and throughout much of western North America. The pattern of population decline in the eastern United States noted by Robbins et al. (1989) occuiTed after 1978 and is not reflect- ed in these long-term trends. Short-distance migrants and permanent resi- dents have slightly greater percentages of decreasing species (Table). Both groups have negative mean trends in the southeastern states and from the lower Great Lakes into the Appalachian Mountains, but the patterns else- where are mixed (Figs. 5. 6). These results indicate that grassland and shrubland birds are experiencing the most con- sistent and widespread declines of any group of species. Whenever possible, appropriate conser- vation measures should be undertaken to enhance the population trends of these species. While the BBS data indicate the population Our Living Resources — Birds 19 Negative trends Positive trends Fig. 4. Geographic patterns in the mean trends for Neotropical migrant bird species during 1966-92. trends for breeding birds, these data are not designed to identify the factors responsible for these trends. To understand how bird popula- tions are responding to the changing habitat conditions in North America, additional studies are needed that would combine the BBS results with regional data on land-use changes, weath- er conditions, and other variables. References ESRI. 1992. Understanding CIS; the Arc/Info method. Environmental Systems Research Institute, Inc.. Redlands.CA. 416 pp. Geissler, P.H., and J.R. Sauer. 1990. Topics in route-regres- sion analysis. Pages 53-56 in J.R. Sauer and S. Droege, eds. Survey designs and statistical methods for the esti- mation of avian population trends. U.S. Fish and Wildlife Service Biological Rep. 90( 1 ). Isaaks, E.H., and R.M. Srivastava. 1989. An introduction to applied geostatistics. O.xford University Press, New York. 561 pp. Peterjohn. B.G., and JR. Sauer. 1993. North American Breeding Bird Survey annual summary 1990-1991. Bird Populations 1:52-67. Species Scientific name Trend '■, No. of Qutes American while pelican Pelecanus er/throrhynchos 3,60 0,00 152 Great egret Casmerodius albus 1.5 ns 513 Little blue heron Egretta caerulea ■1,45 ns 429 Cattle egret Bubulcus ibis 2.09 ns 475 While Ibis Eudocimus albus 3.17 ns 173 While-laced ibis Plegadis chihi 32.27 0,01 61 Canada goose Brania canadensis 7,05 0,00 1,090 Mottled duck Anas lulvigula •5.27 0,03 64 Mallard A. plalyrtiynclios 098 ns 1.890 Nonhern pintail A. acuta -5.65 0,00 502 Blue-winged leal A- discors -0.92 ns 814 Northern shoveler A. clypeala 0.18 ns 379 Gadwall A. sirepera 3,76 0,00 389 Lesser scaup Aythya affinis 2.08 ns 263 Red-breasted merganser Mergus serralor -9,57 0,02 53 Black vulture Coragyps atratus 1.72 ns 540 Turkey vulture Calhartes aura 0.37 ns 1,691 Ring-necked pheasant Phasianus colchicus -1.24 0.10 1,263 Northern bobwhite Colinus wginianus •2 43 0,00 1,338 Scaled quail Callipepla squamata •3.31 0.00 104 Gambel's quail C. gambelii 0,90 ns 82 California quail C. californica •0.04 ns 264 Mountain quail Oreortyx piclus 1,37 ns 112 American coot Fulica amehcana -0.51 ns 620 Negative trends Positive trends Rohbins. C.S., D. Bystrak, and PH. Geissler. 1986. The Breeding Bird Survey: its first fifteen years, 1965-1979. U.S. Fish and Wildlife Service Resour.Publ. 157, 196 pp. Robbins, C.S., JR. Sauer, R.S. Greenberg, and S. Droege. 1989. Population declines in North American birds that migrate to the Neotropics. Proceedings of the National Academy of Science USA 86:7658-7662. Sauer, JR., and S. Droege. 1990. Recent population trends of the eastern bluebird. Wilson Bull. 102:239-252. Species Scientific name Ttend p. No. of routes Sandhill crane Gfus canadensis 430 0 00 259 Killdeer Charadrius \iocilems •0.38 ns 2,692 Black^necked stilt Himanlopus mexicanus 0.63 ns 119 Willel Catoplrophorus semipalmatus -0.72 ns 295 Upland sandpiper Bariramia longicauda 3,28 0.00 687 Long^billed curlew Numenius americanus •1,61 ns 234 Marbled godwit Limosa ledoa 071 ns 188 Common snipe Gallinago gallinago 0,14 ns 1,011 Laughing gull Laws atncilla 601 0.00 125 Franklin's gull L pipixcan •5.95 ns 231 Ring^billed gull L delawarensis 7.43 0,02 684 California gull L californicus •1.27 ns 230 Herring gull L argentalus -2,06 009 474 Glaucous^winged gull L glaucescens 3,85 0.09 40 Great black-backed gull L marinus -147 ns 125 Black tern Chlidonias niger •4,51 0.00 368 Rock dove Columba livia 1,04 0,06 2,255 Band-lailed pigeon C. lasciata •3.69 0.00 189 While-winged dove Zenaida asiatica 003 ns 78 Mourning dove Z. macroura 0.02 ns 2,726 Common ground dove Columbina passenna ■3,13 001 194 Yellow^billed cuckoo Coccyzus americanus •1.30 0.00 1,637 Lesser nighthawk Chordeiles aculipennis 5.08 003 118 Common nighthawk C. minor -0.34 ns 1,609 Fig. S. Geographic patterns in the mean trends for short-distance migrant bird species during 1966- 92. Fig. 6. Geographic patterns in the mean trends for permanent resi- dent bird species during 1966-92. Appendix. Population trends of birds from the North American Breeding Bird Survey. To appear in tJiis list, the species must have been seen on > 40 routes at an average count of > 1 bird/route. We present trends (%/year), proba- bility (P). and the number of routes on which the species was seen. See Peteijohn and Sauer 1 993 for group classification. Binh - Our /.niiii^ Rtwnurccs Species Chuck-will's-widow Scientific name Capnmulgus carolmensis Cypseloides niger Chaetura pelagica Aeronautes saxatalis Selasphorus platycercus S. rufus Melanerpes erythrocephalus M. lormiavorus erM auntrons M. carolinus Sphyrapicus varus Picoides nuttallii P pubescens Colaptes auralus C caler Contopus borealis C sordidulus C. virens Empidonax llaviventris £ virescens E alnorum £ traillii E minimus £ hammondii £ oberholsen £ ditlicilis Sayomis phoebe Myiarchus cinerascens M crinitus M. tyrannulus Tyrannus vociterans T. verticalis T tyrannus T foriicatus Eremophila alpestns Progne subis Tachycinela bicolor T thalassina Slelgidopleryx sempennis Riparia riparia Hirundo pyrrhonota Trend -0 78 1.61 -0.84 ■3.38 0.42 -3.38 -184 0.98 -186 0.59 -0 85 1 44 0 14 -2.75 -087 -2.52 -0 39 -164 3 58 0,50 1.30 -0.62 -0 55 150 0 72 1.47 0.64 2.38 0 03 6.15 -174 1.51 -010 -0.08 -065 0.71 127 0.76 0 95 -0.48 0.98 P- ns ns 0 08 ns ns 0.00 0,00 ns ns ns ns ns ns 0.00 ns 0.00 ns 0.00 0 01 ns 0 04 ns ns ns ns ns ns 0.01 ns 000 ns 0.01 ns ns ns ns 004 ns No. of outes 522 79 1,789 189 115 188 1.236 138 56 1,246 605 95 2.214 2.062 689 736 637 1.719 263 854 788 1.152 1,150 221 265 218 1,650 370 1,804 47 138 942 2,267 244 1.750 1.623 1.707 511 2.119 1,318 1,737 Species Blue-gray gnalcatcher Black-tailed gnalcatcher Eastern bluebird tiflounfain bluebird Veery Gray-cheeked thrush Swainson's thrush Hermit thrush Wood thrush Amencan robin Varied thrush Wrentit Gray catbird Northern mockingbird Sage thrasher Brown thrasher Curve-billed thrasher California thrasher Sprague's pipit Cedar waxwing Phainopepla Loggerhead shnke European starling White-eyed vireo Scientific name Polioptila caerulea Trend 103 P- ns ns 0.00 ns 006 ns No. of outes 1.233 Black swift Chimney swift White-throated swift Broad-tailed hummingbird Rufous hummingbird P melanura Sialia siatis S. currucoides Catharus luscescens C minimus C usiulalus C gultatus Hylocichia mustelina Turdus migratorius Ixoreus naevius -0.22 252 0.56 -106 -4.46 000 57 1,633 422 964 43 Red-headed woodpecker ns 707 Acorn woodpecker Golden-lronted woodpeck Red-bellied woodpecker Yellow-bellied sapsucker 2.10 -188 1.03 2.16 0.01 0 00 0.01 006 912 1,510 2,588 148 Nuttall's woodpecker Downy woodpecker Chamaea lasciala Dumelella carolmensis Mimus polyglottos Oreoscoples monlanus Toxostoma rulum T curvirostre T. redivivum Anthus spragueii Bombyalla cedrorum Phainopepla miens Lanius ludovicianus Sturnus vulgaris -1.39 -0 42 ns ns 113 1,941 Yellow-shafted flicker -0.98 116 0.03 1,694 Red-shafted flicker ns 244 Olive-sided flycatcher Western wood-pewee -119 -359 0.01 0.00 1,917 100 Eastern wood-pewee Yellow-bellied flycatcher Acadian flycatcher Alder flycatcher Willow flycatcher -4 06 -3 52 2.36 253 -3.20 -0 99 0.05 0 02 0.00 005 0.00 83 140 1627 104 1364 Least llycatcher 0.02 2727 Hammond's flycatcher Vireo griseus -0.15 ns 945 Dusky llycatcher Solitary vireo Warbling viteo V solilarius V gilvus 3 28 0.00 954 Pacific-Slope flycatcher 1.31 150 0.01 ns 1740 Eastern phoebe Philadelphia vireo Red-eyed vireo Tennessee warbler V philadelphicus 191 Ash-throated flycatcher Great crested flycatcher V. olivaceus Vermivora peregrina 1.39 4 21 0.01 ns 2020 341 Brown-crested flycatcher Orange-crowned warbler Nashville warbler Northern parula V. celata -0.71 ns 346 Cassin's kingbird V rulicapilla 135 ns 673 Western kingbird Parula americana 0.82 ns 970 Eastern kingbird Scissor-tailed flycatcher Yellow warbler Chestnut-sided warbler fvlagnolia warbler Dendroica petechia D. pensylvanica 0 94 -0.60 005 ns 2161 788 Horned lark D magnolia 2 80 000 527 Purple martin Cape May warbler D- tignna 2.95 ns 239 Tree swallow Myrtle warbler D coronala 141 0-09 575 Violet-green swallow Audubon's warbler Black-throated gray warbler D.c. auduboni D. nigrescens 0,08 2 32 ns 0 07 386 Northern rough-winged ns ns ns 190 swallow Townsend's warbler Hermit warbler D. townsendi 1,63 ns 145 Bank swallow D. occidentalis 0 79 ns 82 Cliff swallow Black-throated green warble Blackbumian warbler Pine warbler D. virens -0,45 ns 637 Barn swallow H. nistica Perisoreus canadensis Cyanocitta slelleri C cristata Aphelocoma coerulescens 0.37 •1.28 0.39 -181 1.27 ns ns ns 0.00 0.04 2,701 350 328 1,986 272 D fusca 0 87 ns 511 Gray |ay D. pinus 2,12 0.00 797 atelier's jay Prairie warbler D discolor -2 15 0.00 773 Blue jay Bay-breasted warbler Blackpoll warbler Black-and-white wattler D castanea D striata Mniotilta varia -0,04 ns 216 Scrub jay -0 33 0.91 ns 178 Pinyon |ay Gymnorhinus cyanocephalus -1.65 -1.34 ns 132 ns 1126 Black-billed magpie Pica pica Corvus brachyrhynchos C. ossitragus C. cryploleucus 0.05 577 Amencan redstart Ovenbird Setophaga rulialla Seiunjs aurocapillus -0 58 0.55 ns ns 1299 Amencan crow 0.85 2.93 -2.48 0.06 0.01 ns 0.00 2,578 466 87 1,202 1278 Fish crow Northern waterthrush S noveboracensis 0.49 ns 615 Chihuahuan raven Kentucky warbler Mourning warbler Oporomis lormosus -0.77 ns 685 Common raven C. corax Parus alricapillus P carolinensis 3.66 0 Philadelphia 015 ns 538 Black-capped chickadee 1.89 -0.67 0.00 ns 1.433 862 MacGillivray's warbler Common yellowthroat 0. tolmiei -0.58 ns 309 Carolina chickadee Geolhlypis Irichas -0 48 ns 2361 Mountain chickadee P gambeli eP mfescens P mornalus P bicolor Pb aincnstatus 0 07 •1.54 -2.30 0.64 2.06 ns ns 0.01 ns 003 291 133 180 1,289 64 97 250 Hooded warbler Wilsonia cilnna 1.49 053 ns ns 608 Chestnut-backed chickadt Wilson's warbler Canada warbler W pusilla 525 Plain titmouse W. canadensis -0.73 ns 504 Tufted titmouse Black-crested titmouse Yellow-breasted chat Summer tanager Scarlet tanager Westem tanager Icleria virens Piranga mbra -0 43 -0.19 ns ns 1273 761 Verdin Auriparus tiavicep Psallriparus minimus Sitta canadensis S- pusilla Campylorhynchus brunnelcapillus Salpinctes obsoletus Thryothonjs ludovicianus Thryomanes bewickii Troglodytes aedon T troglodytes Regulus salrapa R. calendula -1.38 -1.13 ns ns P olivacea P ludoviciana 0.22 ns 1257 Bushtit -0.31 ns 472 Red-breasted nuthatch 2.48 -1.30 -0.89 0.00 ns ns 872 290 136 509 Northern cardinal Cardinalis cardinalis -0 21 ns 1591 Brown-headed nuthatch Pyrrhuloxia C sinualus -0.73 ns 61 Partus wrpn Rose-breasted grosbeak Pheucticus ludovicianus -0 19 ns 1146 \jO\jlUi VYICU Black-headed grosbeak P melanocephalus -0.32 ns 509 Rock wren -168 004 Blue grosbeak Guiraca caerulea 186 000 1014 Carolina wren 1.01 -0 35 1.55 2.25 -0.01 0.03 ns 0.00 ns ns 1,118 594 1,924 659 541 656 Lazuli bunting Passerina amoena 0.14 ns 417 Bewick's wren Indigo bunting P. cyanea -0.57 ns 0.00 1725 House wren Painted bunting Pans -3.21 -158 269 Winter wren Dickcissel Green-tailed towhee Spiza amencana Pipilo chtorurus 0.02 791 Golden-crowned kinglet 0.41 ns 212 Ruby-crowned kinglet -131 ns Rufous-sided towhee P erythrophlhalmus -1.99 0.00 1951 Our Living Riwoiincs — BinJs 21 Species Scientific name Trend p. No. of routes Species Red-winged blackbird Tricolored blackbird Eastern meadowlark Western meadowlark Yellow-headed blackbird Brewer's blackbird Great-tailed grackle Boat-tailed grackle Common grackle Bronzed cowbird Brown-headed cowbird Orchard oriole Baltimore onole Bullock's oriole Scott's oriole Pine grosbeak Purple finch Cassin's finch House finch Red crossbill Scientific name Agelaius phoeniceus A. tricolor Slurnella magr^a Trend -106 4.83 -218 001 ns 000 ns ns 0.06 rJo.of outes 2.760 69 1,742 1.334 649 1,006 198 California towhee P californicus -0 22 ns 0.00 0,00 113 83 171 Brown towhee P. fuscus -2,67 Cassin's sparrow Aimophila cassinii -285 Chipping sparrow Spizella passenna ■0.04 -1.31 ns 0,02 2.300 444 S. neglecia Xanlhocephalus xanlhocephalus Euphagus cyanocephalus Ouiscalus mexicanus 0. major 0 quiscula ■0.56 153 ■1,15 Clay-colored sparrow S pallida Brewer's sparrow Field sparrow S. bmweri S pusilla -3.68 -325 ■0.25 -3,42 0.00 000 ns 000 376 1,581 1.488 935 Vesper sparrow Pooecetes gramineus Chondesles grammacus 7 40 2,52 -1 44 000 0.05 000 ns 006 Lark sparrow 118 2,196 55 2.780 Black-throated sparrow Amphispiza bllirteata A belli Calamospiza melanocorys ■3.78 -2 43 0.02 ns 225 210 Sage sparrow Molothrus aeneus M. ater -1,12 ■0 88 Lark bunting ■2,86 0,03 359 Savannah sparrow Passerculus sandwicher^sis -0 57 ns 1,461 Icterus spurius 1 galbula ■1.38 0 26 0,03 ns 1,313 1,594 Baird's sparrow Ammodramus bairdii A savannarum ■1.52 ■4 48 ns 0 00 134 1,479 Grasshopper sparrow l.g- bullockii ■0.81 ns 614 Fox sparrow Passerella iliaca 0.44 ■080 ns 0,09 224 2,079 1 pansorum Pinicola enucleator Carpodacus purpureus C. cassinii 2 26 ns 113 Song sparrow Melospiza melodia M. lincolnii 6,36 -1 19 1,27 0,01 152 Lincoln's sparrow 3.99 0,02 420 783 0 05 ns 921 235 Swamp sparrow M georgiana 050 ns White-throated sparrow Zonolrichia albicollls -1,44 0,01 635 C mexicanus -014 ns ns 1,420 438 White-crowned sparrow I leucophrys ■191 001 274 Loxia cun/irostra 2,13 Slate-colored junco Junco hyemalis ■0.47 ns 008 545 341 White-winged crossbill L leucoplera -552 0 09 155 Oregon |unco Jh. oregonus -1,23 Pine siskin Lesser goldfinch Carduelis pinus C psallria 0,38 -1,22 ns ns 778 281 For liirthtT information: Gray-headed junco J.h. caniceps 2.04 8.32 ns 50 68 Bi-uce G. Peterjohn NflcCown's longspur Calcarius mccownii 000 American goldfinch C- tristis ■1.06 0.03 ns 0.00 2,165 596 2,557 National Biological Set^/ice Chestnut-collared longspur C. omatus 0.62 ns 153 Evening grosbeak House sparrow 'ns-not significant Coccothrausles vespedinus ■037 Patu.xent Environmental Science Bobolink Dolichonp oryzivorus ■1,33 0,01 1,147 Passer domeslicus -1.65 Center Laurel, MD 20708 Many studies have foLiiid significant changes, pfiniarily declines, in popula- tions of bleeding birds throughout the United States. Most studies have focused on birds that migrate to the Neotropics for winter. Speculations about causes of observed declines have primarily implicated habitat fragmentation and loss (e.g.. deforestation) in Central and South America. The National Audubon Society's Christmas Bird Counts (CBC). begun in the winter of 1900-01. provide the data need- ed to discern consistent population trends in birds wintering throughout the United States. For this study we used the CBC data to examine population trends of songbirds with ranges that apparently are limited by lower tem- peratures in the North. We chose these species to track populations of birds that could be in peril in the future. These birds potentially will be more quickly affected by changing climate than other birds, and we need baseline informa- tion on them to document possible conse- quences of global climatic change. The species that are indeed declining need to be monitored because the possible synergistic effects of declining populations and changing climate could result in local and even regional extinc- tions. Methods We examined 30 years of CBC data (winters of 1959-60 to 1988-89) for 50 songbirds whose northern range edges are associated with January minimum temperatures (Root 1988b). For each songbird species or subspecies at each count site, we calculated the number of individ- uals seen per counting effort (e.g.. hours of observation). Yearly averages for each of the conterminous states were determined from these values for each species. Data were used from all count sites that were censused at least 25 of the 30 years. For details on the method we used to calculate population trends, see Geissler and Noon ( 1 98 1 ) and contact us. All of our con- clusions rest on very conservative analyses. Trends Of the 50 songbirds examined. 27 (54%) exhibited a statistically and biologically signifi- cant trend in at least one state (Fig. I). Of these 27 species. 16 (59%) had populations declining in more states than states in which they were increasing; 12 exhibited only declines and 4 had a population increase in at least one state. Ten (37%) of the 27 species had populations increasing in more states than states exhibiting declines, with 7 exhibiting only population increases. One (4%) species had populations increasing and decreasing in the same number of states. In general, the populations of birds that eat seeds from grasses and forbs (e.g.. spanows and meadowlarks) seem to be declining more fre- quently than those of birds that eat seeds from shrubs and trees, or berries (e.g.. tufted titmouse [Parus bicolor] and cedar waxwing [Bombycilla Winter Population Trends of Selected Songbirds by Terry L. Root University of Michigan Larry McDauiel National Center for Atmospheric Research Binl.s — Our Liviiii; Rc.\ CD 5 o CO CTi c 5 ^ n 3 t~> i fl> T3 ■n ■D E JD F m 5 S §. ^ 3 O > R o s ? r < O ^ CO S ■c ■^ 15 F m Decrease Fig. 1. Nuniher ot states with popiilalioti trends either Jeclining or increasing for 27 songbirds. cedronint]) (Fig. 1 ). This situation may be due to tlie fact that the grassiantj and early succession- al habitats are being modified, while ornamental fruiting bushes, shrubs, and trees planted in urbanized areas may be benefiting the increasing species (Beddall 1963). The explanation, how- ever, is certainly more coinplex than this, given that some birds do not fit the pattern. For exam- ple, the American pipit {Antlnts nihcsccus), which eats berries, crustaceans, and mollusks (Ehrlich et al. 1988), is decreasing in four states and increasing in none (Fig. 1 ). To evaluate the areas of the conterminous states showing increases or decreases in their bird populations, we counted the number of species showing a population change in each state and then calculated the percentage with respect to the number of the 27 species occur- ring in each state (Fig. 2). A total of 24 (309f ) of the states has greater than .'1% of these wintering bird species showing positive population trends, while 32 (67%) show declines of similar magni- tudes. Mapping the percentages (Fig. 3) indicates that the largest increase is in South Carolina, with the far western states, those in the north- central region, and a scattering of states in the eastern portion of the conterminous states show- ing positive population trends. The largest decreases (Fig. 3) are in South Carolina, Georgia, Florida, Alabama, Louisiana, and Delaware. The Pacific states, those in the Fig. 2. Number and percentage of 27 birds showing deehning and increasing population trends. Our /,/r//;v Rcmiuk t's — Hinis 20,0-30 "^, ^r^ Great Plains, and the southeastern portion of the conterminous states generally show the greatest declines, though the actual reasons for these population changes will need to be examined in more detail. Ceilainly, the pattern of extensive declines in most of the southern coastal states is quite alarming. Additionally, regions of the country that could be particularly influenced by global cli- matic change are the southern coasts (because of increased stonns and degradation of coastal wetlands; IPCC 1990). and the Great Plains (owing to a significant decline in soil moisture; Leathemian 1992). Hence, the populations of birds in these areas need to be closely moni- tored to ensure preservation actions are taken before the combined effects of population declines and climate change result in extinc- tions. More studies and monitoring are warrant- ed to understand the possible consequences of these patterns. The analyses presented here can also be used to investigate population trends of target species across the country. Compare, for instance, the trends by state for the American tree spanow [Spizellii arhorea: one of the most declining birds examined) and the cedar waxwing (one of the most increasing birds) with maps of their winter range and abundance patterns (Root 1988a). This comparison reveals that significani population trends, whether positive or negative, seem to occur primarily aU)ng these species" northern range boundaries and in many coastal states. Such analyses could help target specific regions of the country where population trends of key (e.g., threatened) species need watching. References Beddall. B.C. 1963. Range expansions of the cardinal and other birds in the northeastern states. Wilson Bidl. 7.S: 140- 1,58. Ehrlich. P.R.. D.S. Dohkin. and D. Whcye. 1988. The bird- er's handbook. Simon and Schuster. New York. 785 pp. Geissler. PH.. and B.R. Noon. 1981. Estimates of avian population trends from the North America Breeding Bird Survey. Pages 42-.51 in C.J. Ralph and J.M. Scott, eds. Estimatmg the numbers of terrestrial birds. Studies in Avian Biology 6. IPCC. 1990. Climate change: the IPCC scientific assess- ment, (also see Climate change 1992; the supplementary report to the IPCC scientific assessment.) Intergovern- mental Panel on Climate Change. Cambridge University Press. New York. NY. 364 pp. Leathemian, S.P. 1992. Sea level rise: implications and responses. Pages 256-263 in S.K. Majumdur. L.S. Kalkstein. B. Yamal, E.W. Miller, and L.M. Rosenfeld. eds. Global climate change: implications, challenges and mitigation measures. Pennsylvania Academy of Science. Philhpsburg. NJ. Root. T.L. 1988a. Atlas of wintering North American birds. University of Chicago Press. IL. 312 pp. Root, T.L. 1988b, Environmental factors associated with avian distributional boundaries. Journal of Biogeography 15:489-505. Fig. 3. Percentage of 27 birds showing positive and negative trends. For further information: Terry L. Root University of Michigan School of Natural Resources and Environment 430 E. University Ann Arbor, MI 48109 Populations of many North American land- birds, including forest-inhabiting species that winter in the Neotropics, seem to be declin- ing (Robbins et al. 1989; Terborgh 1989). These declines have been identified through broad-scale, long-term survey programs that identify changes in abundance of species, but provide little information about causes of changes in abundance or the health of specific populations in different geographic locations. Population health is a measure of a popula- tion's ability to sustain itself over time as deter- mined by the balance between birth and death rates. Indices of population size do not always provide an accurate measure of population health because population size can be main- tained in unhealthy populations by immigration of recruits from healthy populations (Pulliam 1988). Poor population health across many pop- ulations in a species eventually results in the decline of that species. Early detection of popu- lation declines allows managers to coirect prob- lems before they are critical and widespread. Demographic data (breeding productivity and adult survival) provide the kind of early warning signal that allows detection of Breeding Productivity and Adult Survival in Nongame Birds 24 Binh — Oiii Liiiiii; Ri'suunes by Thomas E. Martin National Biological Sen'ice David F. DeSante The Institute for Bird Populations Charles R. Paine Montana Cooperative Wildlife Research Unit Therese Donovan University of Montana Randall Dettmers Ohio Cooperative Research Unit James Manolis Minnesota Cooperative Fish and Wildlife Research Unit Kenneth Burton The Institute fin- Bird Populations iMihcalthv populations in terms of productivity or survival probJL-nis (Marlui and Guepel 1993). In addition, demographic data can help deter- mine whether population declines are the result of low breedmg productivity or low survival in migration or winter Breeding productivity data also can help identify habitat conditions associ- ated with successful and failed breeding attempts. Such information is critical for devel- oping habitat- and land-management practices that will maintain healthy bird populations (Martin 1992). Here, we provide examples of the kinds of information that can be obtained by bioad-scale demographic studies. Demographic Programs The Monitoring Asian Productivity and Survivorship (MAPS) and Breeding Biology Research and Monitoring Database (BBIRD) programs were developed to gather the demo- graphic data needed to provide early and locali- ty-specific warning signals of population prob- lems. MAPS uses large, stationary mistnets to capture and examine young and adult birds for between-year changes and to determine long-term trends in adult population size, pro- ductivity, and adult survival. BBIRD locates and monitors bird nests to study changes in nesting success, determine causes of nesting failure (e.g., weather, habitat, nest predation, or nest parasitism), and identify habitat conditions associated with successful reproduction. Though both programs are new. they are grow- ing rapidly. We present example data to demon- strate initial results and burgeoning potential of these programs for the future. MAPS Initiated in 1989 and coordinated by The Institute for Bird Populations. MAPS is a coop- erative effort among federal and state agencies. private organizations, and bird banders to oper- ate a standardized continent-wide network of mist-netting and banding stations during the breeding season (DeSante 1992; DeSante et al. 1993a. " 1993b). A typical MAPS station involves about ten 12-m (39-ft) mistnets over a 20-ha (49-acre) area. All birds captured throughout the breeding season are identified to species, age. and sex. and are banded with U.S. Fish and Wildlife Service bands. As of 1992. 170 stations were in operation and more than 94.000 captures of more than 200 bird species were recorded. The number of adult birds captured is used as an index of adult population size while the proportion of young provides an index of posttledgling productivity (Baillieetal. 1993). BBIRD The BBIRD program, initiated in 1992. pro- vides detailed information on nesting productiv- ity and habitat needs of nongame birds at a national scale. BBIRD is a cooperative effort among biologists studying nesting productivity at local sites across the country. Participants fol- low a standard field protocol to obtain raw data on nesting productivity, causes of reproductive failure, vegetation measures at several spatial scales, and point counts (bird counts). Data Uom each local site are overseen by individual independent investigators who can obtain com- parative information from other sites. In addi- tion, overview analyses to identify national and regional trends are conducted at the Montana Cooperative Wildlife Research Unit. BBIRD study sites are in large forested blocks to minimize fragmentation effects and prinide baseline information on productivity in undisturbed habitats as well as in auxiliary sites that have no habitat restrictions (e.g.. grazed, fragmented, or logged sites). The BBIRD pro- gram now includes 23 sites in 17 states. Over S.OOO nesis of more than 150 bird species were monitored during the first 2 years of the pro- gram. Variation in Productivity The data provided by MAPS and BBIRD suggest that weather may be an important influ- ence on population dynamics at large and even continental scales. Prior data from constant-effort mist-netting in scrub habitat on the west coast have suggested that avian pro- ductivity may peak during average weather con- ditions and may he depressed when weather conditions deviate from average (DeSante and Geupel 1987). These facts are especially impor- tant because one of the most important ecologi- cal results of global climate change may be a greater annual variability in both local and large-scale weather conditions. Changes in indices of adult population size and postfledging productivity from the first 4 years of MAPS are presented for all species pooled and for each target species caught at 10 or more stations in 1992 in the Northeast and Northwest regions. These data indicate that pro- ductivity varied greatly from year to year, pre- sumably a result of large-scale weather condi- tions (e.g.. precipitafion and temperature) just before and during the breeding seasons. Productivity was poor across most of North America, but especially in the eastern third of the continent in 1990. Adult population sizes declined significantly in the East in 1991. pre- sumably a result of the poor productivity in 1990. In 1992 productivity was poor again in Our Li\ini^ Rfsoiirit-s — Biiil.s 25 the East hut giKui in the West. These results sug- gest that produclivily in a given year may inllu- ence population sizes and population dynamics in subsequent years for many species over a large area. BBIRD data likewise suggest that weather may substantially alTect nesting pn)ducti\ily. Unusually wet weather conditions were report- ed at 6 of 14 BBIRD sites in 1992 when nest success of several species, including wood thrush (Hylocichhi iniistelina) and red-eyed vireo {Vireo olivaceiis). was lower in 1992 than in 1993 (Table I ). These same two species also had reduced breeding productivity based on MAPS data. They produced fewer young per successful nest in 1992 than in 1993, a fact which also may be related to weather; some research suggests that clutch size as well as fledging success can be affected by weather conditions and may even provide a particularly sensitive measure of a species' tolerance to changing climatic conditions (e.g., Rotenherry and Wiens 1989). Further research may show that climatic variability is an important influ- ence on the population trends of species. Table 1. Wood tlimsli and red-eyed vireo nest Mieeess based on Mayficid ( 1%I. 1975) estimates at midwestem BBIRD sites during 1492 and 1993 (numhcrs of nests are in parentheses). State Wood thrush Red-eyed vireo 1992 1993 1992 1993 Ohio 23,0(52) 33,1(194) 6.6(19) 33,7 (83) Arkansas 45.6(11) 58.0(15) 35.3 (35) 42,1 (36) Minnesota 190(51) 23,0 (25) Habitat-specific Differences Forest fragmentation, where large forest blocks are cut and interspersed with open habi- tat, is believed to be particularly detrimental for breeding nongame birds. For example, BBIRD data show that fragmentation was associated with lower nest success in several species at midwestern BBIRD sites. Ovenbirds {Sciunis aurocapilliis) were particularly sensitive to fragmentation effects; their reduced nest suc- cess resulted primarily from increased preda- tion, although the parasitism rates of brown- headed cowbird (Molothnis titer) were also higher in fragments. No clear effect of fragmen- tation was noted for red-eyed vireos. although nest success differed substantially among unfragmented sites, potentially reflecting more subtle differences in habitat suitability or land- scape-level effects (Table 2). Adult Survival in Two Eastern Thrushes Analysis of 3 years ( 1 990-92 ) of MAPS data for veery (Cathariis fiisce.scens) and wood thrush indicated low and substantially different State Ovenbird Red-eyed vireo Fragmented Unfragmented Fragmented Unfragmented Ohio 13 7(35) 33 1(45) 30 0(52) 24 6(50) Wisconsin 19.8(30) 42,6(51) 26,4(13) 50.8(13) Aikansas 519(41) 38,7(71) Minnesota 44,5 (159) 21,0(76) iP < 0.06) adult survival probabilities from IWO to 1991. According to Breeding Bird Survey data, veery populations declined by l.O^f per year between 1966 and 1991. while wood thrush populations showed a statistically greater decline of 2.0% per year (Peteijohn and Sauer 1993). This difference in population declines is mirrored by survival indices; MAPS estimates of wood thrush survival are half that of the veery. possibly because of differences in adult survival over winter. This possibility is especially interesting because wood thrushes winter in Mexico and Central America where a greater proportion of the tropical forests have been cleared than in South America where veeries winter. Differences in estimated survival of the two species, however, could simply reflect different life-history traits (e.g., wood thrushes having lower adult survival associated with higher fertility; Martin in press). Estimated survival differences could also result from dif- ferences in breeding-site fidelity, which is relat- ed to nest success; a variety of evidence shows that birds disperse more in breeding seasons that follow nesting failure, potentially biasing survival estimates. Further nest-monitoring data frotn North America and survivorship data from both North America and the Neotropics are needed to identify causes of population declines in these and other Neotropical migratory land- birds. Trends Preliminary results from the MAPS and BBIRD programs suggest that population trends of nongame landbirds are influenced by Table 2. Ovenbird and red-eyed vireo nest success based on Maytleld (1961. 197.5) estimates at fragmented and unfragmented midwestcni BBIRD sites during 1942 and 1993 (numbers of nests are in parentheses). IVlonitonng of nests, such as this one belonging to a red-faced war- bler (CardeUina ruhrifnms). pro- vides information on breeding pro- ductivity. Binis — Oiu LniDfi Rimhiicis For further information: Thomas E- Martin National Biological Senice Cooperative Wildlife Research Lhiit LIniversity of Montana Missoula, MT?98I2 weatlier-induced prciduclivity problems, sur- vival pioblcins dining migration or wintei'. and degradation of breeding habitat. These results emphasize the impoilance of national programs such as MAPS and BBIRD in providing base- line information on both continental and local habitat-specific processes that intluence avian population dynamics. Ultimately, these data on breeding productivity and adult survival and their underlying environmental determinants will provide information critical for managing North American landbirds. References Baillie. S,R.. R.E. Green. M. Body, and ST. Buckland, 199.^. An evaluation of Ihe constant effort sites scheme. British Trtisl lor Ornithology. Thetford. 10.^ pp. DeSante, D.F. 1992. Monitoring Avian Productivity and Survivorship (MAPS): a sharp, rather than blunt, tool for monitoring and assessing landhird populations. Pages .SII--S2I ill DC McCullough and R.H. Barrett, eds. Wildlife 21)1)1: populations. Elsevier Applied Science. London. DeSante. D.F.. and G.R. Geupel. 1987. Landhird productiv- ity in central coastal California: the relationship to annu- al rainfall, and a reproductive failure in 19X6. Condor 89:6-^6-65.^. DeSante. D.F.. K.M. Burton, and O.E. Williams. 1993a. The Monitoring Avian Productivity and Survivorship IMAPS) program second annual report (1990-1991). Bird Populations 1:68-97. DeSante, D.F.. O.E. Williams, and K.M. Burton. I99.^b. The Monitoring Avian Productivity and Survivorship (MAPS) program: overview and progress. Pages 208-222 in DM. Finch and P.W. Stangel, eds. Status and manage- ment of Neotropical migratory birds. Gen. Tech. Rep, RM-229. U.S, Forest Service. Rocky Mountain Forest and Range E.xperiment Station. Fort Collins. CO. Martin. T.E. 1992. Breeding productivity considerations: what are the appropriate habitat features for manage- ment? Pages 4.'>,'i-473 in J.M. Hagan and D.W. Johnston, eds. Ecology and conservation of Neotropical migrants, Smithsonian Institution Press, Washington, DC. Martin, T.E. Variation and covariation of life history traits of birds in relation to nest sites, nest predation. and food. Ecological Monographs, In press. Martin, T.E.. and G.R. Guepel, 199.3. Nest-monitonng plots: methods for locating nests and monitoring success. Journal of Field Ornithology 64:507-519. Mayfield. H, 1961. Nesting success calculated from expo- sure, Wilson Bull, 73:255-261, Mayfield, H. 1975. Suggestions for calculating nest success, Wilson Bull, 87:456-466, Peterjohn, B,G,, and J,R, Sauer, 1993. North American Breeding Bird Survey annual summary 1990-1991, Bird Populations 1:52-67, Pulliam, H,R, 1988, Sources, sinks, and population regula- tion, American Naturalist 132:652-661, Robbins, C.S,. J,R, Sauer, R,S. Greenberg, and S, Droege, 1989, Population declines in North American birds that migrate to the Neotropics, Proceedings of the National Academy of Science 86:7658-7662. Rotenberry, J.T., and J, A, Wiens, 1989, Reproductive biolo- gy of shrubsteppe passerine birds: geographical and tem- poral variation in clutch size, brood size, and fledging success. Condor 91:1-14. Terborgh, J, 1989. Where have all the birds gone? Es,says on the biology and conservation of birds that migrate to the American tropics. Princeton University Press, NJ. 207 pp. Canada Geese in North America by Donald H. Riisch Richard E. Malecki National Biological Service Robert Trost U.S. Fish and Wildlife Service Canada geese [Bninta canadensis) are piob- ably more abundant now than at any time in history. They rank first among wildlife watchers and second among harvests of waterfowl species in North America. Canada geese are also the most widely distributed and phenotypi- cally (visible characteristics of the birds) vari- able species of bird in North America. Breeding populations now exist in every province and ter- ritory of Canada and in 49 of the 50 United States. The size of the 12 recognized subspecies ranges from the 1.4-kg (3-lb) cackling Canada goose {B.C. minima) to the 5.0-kg ( 1 1-lb) giant Canada goose (B.C. maxima; Delacour 1954; Bellrose 1976), Market hunting and poor stewardship led to record low numbers of geese in the early 1900"s, but regulated seasons including clo- sures, refuges, and law enforcement led to restoration of most populations. Winter surveys were begun to study population trends and set responsible harvest regulations for these long-lived and diverse birds. Winter surveys begun in 1936-37 probably represent the oldest continuing index of migratory birds in North America. Surveys Sporadic counts of migrating and wintering Canada geese from the ground were supple- mented by regular tallies from the air in the early 195()'s. Winter surveys began because the subarctic and arctic nesting areas of many sub- species were still unknown and aerial surveys of these remote areas were impractical. The well-designed spring surveys of Canada geese that began in the 1970"s with the Eastern Prairie population have now expanded to include several others (Office of Migratory Bird Management 1993). Spring surveys estimate numbers of each population at the time of year when subspecies are reproductively isolated and geographically separated. The smaller sub- species of Canada geese nest farther north (arc- tic and subarctic regions of Alaska and Canada), and most winter farther south (gulf states and Mexico) than do the larger subspecies. Status and Trends Most aggregations of wintering geese were overharvested in the early 1900"s. Those (fin l,i\iiii^ RcMitfK fs — Hirtis subspecies that nested in temperate regions closer to humans were most heavily hunted. By 1930 the giant Canada geese, which nested in the northern parts of the deciduous forest and tall-grass prairie, were believed extirpated. Numbers of the large geese that nested in the Great Plains and Great Basin ^B.c. luajfuti) were also severely reduced. Small Canada geese from the remote arctic and subarctic breeding ranges fared somewhat better, possibly because of less exposure to unregulated exploitation, but were also reduced in ntniibcr. Although hunting depleted numbers of Canada geese, human activity also created new habitats for these birds. Agriculture led to the clearing of forests and the plowing of prairies, creating the open landscapes preferred by geese. Cereal grains and pastures provided new food sources for geese, and the development of mechanical combines and pickers created an increased supply of waste grain (Hine and Schoenfeld 1968). In addition, uniform hunting regulations and improved wildlife law enforce- ment curtailed goose harvests after the signing of the Migratory Bird Treaty in 1916, and most goose populations increased over the next sev- eral decades (Figure). National wildlife refuges provided key sanctuaries and further assisted recovery of Canada goose numbers. The giant Canada goose was "rediscovered" by Harold C. Hanson, a biologist of the Illinois Natural History Survey; the publication of his book The Giant Canada Goose in 1965 initiat- ed a restoration effort that became one of the great success stories of wildlife management. These large aeese were restored to their fonner 36 40 44 48 52 56 60 64 68 72 76 80 84 88 92 Year range in the Mississippi and Central flyways and now breed in all states east of the Mississippi River. Research and improved scientific manage- ment led to better understanding of diversity, distribution, and population dynamics of Canada geese in the 1970's. Awareness of dif- ferences in distribution and migration among the subspecies allowed managers to effectively control goose harvests. Improved management led to stable or increasing numbers of Canada geese in most populations (Table). The Mississippi Flyway Giant, Hi-line, Rocky Mountain, and Western Prairie/Great Plains populations, all composed mainly of large sub- species (B.C. maxima and mofptti), grew at about twice the rate of other populations that contained mainly smaller subspecies. The pop- ulation numbers of the large geese that breed in the states of the Atlantic Flyway have also increased dramatically, but this trend was masked by declining numbers of 2eese in Figure. Total numlx'rs of Canada geese counted on winter surveys, 14.16-93. Year Population* AP SJBP MVP Max(MF) EPP WP/GP TGPP SGPP H-LP RMP DSKY CCG 1969-70 775,2 106,9 324 7 508 106 6 1512 442 258 22 5 1970-71 675.0 127.3 292,3 64.4 126,3 133,2 148,5 40,5 25,3 19,8 1971-72 7002 117,6 293,9 55,8 1574 160,9 160,9 314 366 179 1972-73 712.0 101,3 295,9 54,2 181,4 148.4 259.4 35.6 37,1 15,8 1973-74 760,2 136,0 2779 576 2058 160.5 153 6 24,5 42 8 18,6 1974-75 819.3 101.0 304.4 57,0 197,1 133,5 123,7 41,2 46,7 26.5 1975-76 7845 115,5 304,9 62 1 2044 203,7 2425 556 516 23,0 1976-77 923.6 129.8 478,5 58,5 254,2 171,3 210,0 67,6 54,3 24.1 1977-78 833.2 1804 575,5 60,1 270 2 2155 134 0 65,1 59 0 24,0 1978-79 823.6 142.7 434,5 77,1 207,2 187.6 163,7 33,8 62,7 25.5 1979-80 780.1 127.0 394,9 86,4 1718 165,9 2130 67 3 77 3 22,0 64,1 1980-81 955.0 120.3 367,4 102,9 150,9 257,7 168,2 94,4 93,8 23,0 127,4 1981-82 7026 118,5 250,9 1076 1453 1750 284,7 156 0 81 9 64,3 177 87 1 1982-83 888.7 129,9 303,7 149,9 213,4 242.0 171,8 173,2 75,9 68,2 17,0 54,1 1983-84 822,4 1299 3528 103,9 163 1 150,0 279,9 143,5 39,5 55 5 101 26,2 1984-85 814.2 129,3 477,2 151,7 168,4 230,0 207,0 179,1 76,4 90,3 7,5 25,8 1985-86 905,4 158,0 6189 180,1 169 0 115,0 198,2 1810 698 683 12,2 32 1 1986-87 754.8 129,8 514,6 231,9 183.4 324,0 163.2 190,9 98,1 71,5 51,4 1987-88 737,9 158 8 564 6 225 9 2285 272,1 315,8 139 1 66,8 714 12,2 54,8 1988-89 660.7 170.2 734,6 252,2 184,5 330,3 224.2 284,8 100,1 73,9 11.8 69,9 1989-90 733,8 159,4 1098 2 2843 3249 271,0 159,0 378,1 1059 1024 11,7 76 8 1990-91 706.9 142,2 939,7 345,1 218,4 390,0 315.5 508,5 116,6 867 110,2 1991-92 654,5 107,2 7668 234 8 1894 3419 2804 6202 140,5 1157 18,0 1046 1992-93 569,2 104,4 673,4 282,6 146,4 318,0 238,7 328,2 118,5 99,5 16,6 149.3 "Populations are Atlantic (AP), Southern James Bay (SJBP). Mississippi Valley (MVP), Mississippi Western Praine/Greal Plains (WP/GP), Tall-grass Praine (TGPP). Short-grass Prairie (SGPP), Hi Cackling Canada Goose (CCG) Flyway Giant (Max|MF)), Eastern Prairie (EPP), line (H-LP). Rocky Mountain (RMP), Dusky (DSKY). and Table. Canada goose population indices (in j.llOD's) based on sur- veys conducted during fall and winter, ]9W-9i. 28 Bmls — Our Li\ ini; Rf\('iirci's For further inrorniution: Donald H. Ru;,ch National Biological Service Wisconsin Cooperati\c Wildlife Research Unit University of Wisconsin Madison, WI 5J706 Canada's eastern subarctic regions. Although small geese with long migrations have generally not fared as well as large geese with short migrations, some small geese ha\'e responded well to intensive management. Introduced Arctic fo.xes (Alope.x kigopiis) depleted populations of the Aleutian Canada goose (B.C. leucopaivia). and the subspecies was nearly extinct by 1440. About 300 were rediscovered in the Aleutians on Buldir Island in 1962 (Jones 1963). Sub.sequent removal of fo.xes and translocation of wild gee.se have led to increases to about 750 geese in 1975 and more than 11.000 in 1993. Heavy hunting caused numbers of cackling Canada geese to plummet to record lows in the early I980"s, but intensive research (Raveling and Zezulak 1992) and harvest control have brought about a sustained recovery (Table). Recent genetic studies of Canada geese sup- port the existence of two major groups that last shared a common ancestor about 1 million years ago. The large-bodied group [B.c. ccimidcnsis. intehoi: maxima, moffitti. fulva. occidentalis) is mainly continental in distribution, while the small-bodied group (luitcliinsii. tavcnwri. mini- ma, leuc(tpareia) breeds in coastal Alaska and Arctic Canada (Rusch et al. in press). The future of the.se diverse stocks of Canada geese depends upon information adequate to pemiit simultaneous protection of rare forms, responsible subsistence and recreational hunt- ing of abtmdant populatit)ns, and control of nui- sance Canada geese in urban and suburban envi- ronments. Delineation of breeding ranges and spring surveys that monitor numbers of pairs and their productivity offer the most realistic approach to population management and the conservation of this remarkable diversity of geese. Ranges of most populations have been described, and spring surveys are in place for some. Development and continuation of spring surveys for each subspecies ol' Canada geese are prerequisites for their conservation and man- agement. The species can no doubt be perpetu- ated without spiing surveys, but without contin- ued monitoring, management, and conserva- tion, it is likely that rare forms will disappear, opportunities for subsistence and recreational hunting will diminish, and nuisance problems caused by large geese living near humans will increase. Rt'fcrences Bellrose. F.C. 1476. Ducks, geese and swans of North •America. Stackpole. Harrishurg. PA. 544 pp. Dclacour, J.T. IQ.'i4. The waterfowl of the world. Vol. I. Country Life. Ltd.. London. 251 pp. Hanson. H.C. 1965. The giant Canada goose. Southern llhnois University Press. Carbondale. 226 pp. Hnic. R.L.. and C. Schoenfeld. eds, 1968. Canada goo.se management. Dcnbar Educational Research Services. Madison. WI. 194 pp. loncs. R.D.. Jr I96.V Buldir Island, site of a reinnant popu- lation of Aleutian Canada geese. Wildfowl 14:80-84. Office of Migratory Bird Management. 1993. Status of waterfowl and fall night forecast. U.S. Fish and Wildlife Service. Washington. DC, 37 pp. Raveling, D.G.. and D.S. Zezulak. 1992. Changes in distri- bution of cackling Canada geese in autumn. California Fish and Game 78:65-77. Rusch. D.H.. DD, Hamburg. M.D. Samuel, and B.D. Sullivan, eds. 1994. Biology and management of Canada geese. Proceedings of the 1991 International Canada Goose Symposium. In press. Canada Geese in the Atlantic Flyway by Jay B. Hestbeck National Biological Service Large changes have occurred in the geo- graphic wintering distribution and sub- species composition of the Atlantic Flyway population of Canada geese {Braiita canaden- sis) over the last 40 years. The Atlantic Flyway can be thought of as being partitioned into four regions: South. Chesapeake, mid-Atlantic, and New England. Wintering numbers have declined in the southern states (Noilh Carolina, South Carolina, Georgia, Florida), increased then decreased in the Chesapeake region (Delaware. Maryland, Virginia), and increased markedly in the mid-Atlantic region (New York, New Jersey, Pennsylvania, West Virginia) (Serie 1993: Fig. 1). In the New England region (Maine, New Hampshire. Vermont, Massachusetts, Rhode Island, Connecticut), wintering numbers increased from around 6,000 during 1948-50 to between 20,000 and 30,000 today (Serie 1993). Overall, the total number of wintering geese reached a peak of 955,000 in 1981 and has since declined 40% to 569,000 in 1993. Compounding these distributional changes in wintering numbers, the subspecies composition has also changed. The Canada goose population is composed of migrant geese (primarily B.c. 48 53 58 I I I I ! I I I I I I I I I I I 63 68 73 78 83 88 93 Year Fig. 1. Midwinter number of Canada geese in mid- Atlantic. Chesapeake, and South regions of the Atlantic Flyway. 1948-93 (Midwinter Survey. U.S. Fish and Wildlife Service. Office of Migratory Bird Management) Our Liviiifi Ri'siHines — Binl\ caiuuh'ii.sis and B.c. interior) that breed in the subaretic regions of Canada and resident geese (primarily Be. maxima and B.C. inoffitti) that breed in southern Canada and the United States (Stotts 1983). The number of resident geese in Maine to Virginia has increased considerably from maybe^ 50.000 to 100.000 in 1981 (Cono\er and Chasko 1985) to an average of 560.000 in 1992-93 (H. Heusman. Massachusetts Division of Fisheries and Wildlife, personal communication). This rapid increase in resident geese suggests that the migrant population has declined more than the 40% decline observed in total wintering geese from 1981 to 1993. Population Changes Changes in population numbers result from changes in production, survival, and movement, acting singly or in combination. Consequently, understanding the reason for population changes involves detecting variation in survival, production, and movement over time and relat- ing that variation to changes in wintering num- bers. During the 1970's. the decrease of winter- ing geese in the South and increase in the Chesapeake region appeared to result from increased survival of geese in the Chesapeake and possibly from movement or short-stopping of geese from the South to the Chesapeake (Trost et al. 1986). Short-stopping occurs when migrant geese winter in a more northern loca- tion than their traditional, more southern, migration terminus. During the I980"s. the decrease of wintering geese in the Chesapeake appeared to result from an 11% decrease in average survival from 1963- 74 to 1984-88 (Hestbeck^l994a). This decrease in survival conesponded to a 36% increase in average harvest rate for the Atlantic Flyway fronri963-74 to 1984-88 (Fig. 2). Overall, the flyway harvest rate, as a 3-year average, increased from 19% in 1962-64 to 34% in 1982- 84, and then slowly declined to 31% by 1990- 92. The eastern Canada harvest rate has slowly increased from 4.2% in 1968-70 to 8.1% in 1990-92. The slight decline in the harvest rate in the flyway since 1982-84 has been partially off- set by harvest rate increases in eastern Canada. The decrease in number of geese wintering in the Chesapeake region in the 1980"s was not related to changes in production. Production for migrants, measured from the Canadian data, remained constant over the period of population decline in the Chesapeake (Fig. 3). Average pro- duction recently declined during 1991-92 for geese harvested in Quebec. I also used harvest age ratios for the mid-Atlantic and Chesapeake regions to test for differences in production between these regions (Hestbeck 1994b). If the changes in vsintering number lesuUed Irom changes in production, the average annual change in the age ratios would be higher for the mid-Atlantic region than for the Chesapeake region. The average annual changes were not different between these regions, however, indi- cating that regional production differences were not present. The decrease in number of geese wintering in the Chesapeake region in the 1980's was not caused by migrant geese short-stopping in the mid-Atlantic instead of returning to the Chesapeake. From neck-band data, the proba- bility of returning or moving to the different regions was estimated and indicated that, although geese traditionally returned to the same wintering area, they also changed winter- ing areas from year to year (Hestbeck 1994b). In years with harsher winters, geese wintered farther south than during milder winters (Hestbeck et al. 1991). Overall, the probability of returning or moving to the Chesapeake region was higher than the probability of return- ing or moving to any other region. When popu- lation size, survival, and movement were com- bined to estimate net movement among regions, the estimated net movements among regions were small and did not correspond to the changes in numbers of wintering geese. Taken t-lsiiig ricck-bandcd guosc (Branta caiuulensis). 0,40- Fig. 2. Hanest rate of Canada geese in ttie Atlantic Flyway. \^b2- 92 (Harvest and Midwinter Surveys, U.S. Fish and Wildlife Service. Office of Migratory Bird Management) and eastern Canada. 1968-92 (Harvest Survey. Canadian Wildlife Service. National Wildlife Research Centre). .iO Birds — Our Liviiii; Resiiiirccs Fiy. 3. Priiduction ratio of Canada geese in Quebec and Atlantie regions of eastern Canada. 1Q75- 93 (Waterfowl Parts Collection Survey. Canadian Wildlife Service. Atlantic Region. Sackville. N.B.). 2.5 For further information: Jay B. Hestheck National Biological Service Massachusetts Cooperative Fish and Wildlife Research Unit University of Massachusetts Box 34220 Amherst, MA 01003 Quebec 00- 75 87 93 Year resLilt.s suggested that the together, these increases hi llie luimber of wintering geese in the mid-Atlantic region did not result from short-sliipping of geese. The increase of wintering geese in the mid- Atlantic most likely resulted from expanding resident populations. Resident geese generally have larger body si/es. allowing them to winter farther north than smaller-bodied migrant geese (Lefebvre and Raveling 1967). Resident and migratory-resident geese may selectively remain in the mid-Atlantic region. In addition, the resident population may be increasing faster than the migrant population because survival and production appear higher for residents than for migrants. Residents survive better partly because they are familiar with areas of food and refuge and may avoid lumting areas (Johnson and Castelli 1994). Production may be higher for resident than migrant geese because the cli- mate is less variable and milder with a longer growing season in southern Canada and the United States than in the subarctic. Resident geese may also reach reproductive age earlier than migrant geese because the southerly grow- ing season is longer, providing greater food resources. References Conover, MR,, and GO. Chasko. 1985. Nuisance Canada goose problems in the eastern United Slates. Wildlife Society Bull. l3:22S-23-V Hestbeck. J.B. 1994a. Survival of Canada geese banded in winter in the Atlantic Flyway. Journal of Wildlife Management 58(4l: 748-756. Hestbeck, J.B. 1994b. Changing number of Canada geese wintering in different regions of the Atlantic Flyway. In D.H. Rusch. D.D. Humburg. M.D. Samuel, and B.D. Sullivan, eds. Proceedings of the 1991 International Canada Goose Symposium. Milwaukee. Wl. In press. He.stbeck. J.B., J.D. Nichols, and R.A. Malecki. 1991. Estimates of movement and site fidelity using mark- resight data of wintering Canada geese. Ecology 72:523- 53.V Johnson, F.A.. and P.M. Castelli. 1994. Demographics of Canada geese breeding in southeastern Canada and the northeastern United States. In D.H. Rusch. D.D. Humburg. M.D. Samuel, and B.D. Sullivan, eds. Proceedings of the 1991 International Canada Goose Symposium. Milwaukee. WI. In press. Lefebvre. E.A.. and D.G. Raveling. 1967. Distribution of Canada geese in winter as related to heat loss at varying en\ironmental temperatures. Journal of Wildlife Management 3 1 :538-546. Serie. J. 1993. Watertbwl harvest and population survey data. U.S. Fish and Wildlife Service, Office of Migratory Bird Management, Laurel, MD. 68 pp. Stotts, V.D. 198.^. Canada goose management plan for the Atlantic Flyway, 1983-95. Part 2. History and cuiTent sta- tus. The Atlantic Flyway Waterfowl Council, niimeo. Trust, R.E., R,A. Malecki, L.J. Hindman, and D.C. Luszcz. 1986. Survival and recovery rates of Canada geese from Maryland and North Carolina 1963-1974. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 40:454-464. Arctic Nesting Geese: Alaskan Populations by Jerry Hupp Robert Steliii Craig Ely Dirk Derksen National Biological Service North American populations of most goose species have remained stable or have increased in recent decades (USFWS and Canadian Wildlife Service 1986). Some popula- tions, however, have declined or historically have had small numbers of individuals, and thus are of special concern. Individual populations of geese should be maintained to ensure that they provide aesthetic, recreational, and ecolog- ical benefits to the nation. Monitoring and man- agement effoils for geese should focus on indi- vidual populations to ensure that genetic diver- sity is maintained (Anderson et al. 1992). Alaska is the only state with viable breeding populations of arctic geese. Five species ( 1 1 subspecies) nest in Alaska, and although these species also breed in arctic regions of Canada or Russia, most geese of the Pacific Flyway origi- nate in Alaska or use Alaskan habitats during migration. Alaskan geese are often hunted for subsistence by Alaskan Natives. While data for some areas are lacking, pop- ulations of greater white-fronted geese (Anser albifrons jronuilis) and medium-sized Canada geese (Bninta canadensis) in interior and north- ern Alaska appear stable or have increased (King and Derksen 1986). Although only a small number of lesser snow geese {Chen caendescens caeridescens) nest in Alaska, sub- stantial populations occur in Canada and Russia. Populations of Pacific black brant (B. hernicla nii;rica)is). emperor geese (C. canagi- ca). greater white-fronted geese, and cackling Canada geese (B.C. minima) on the Yukon- Kuskokwim Delta (YKD) of western Alaska have declined from their historical numbers and are the focus of special management efforts (USFWS 1989). In addifion, populations of tule white-fronted geese (A.«. gambeli), Aleutian Canada geese (B.c. leucopareia), Vancouver Our Liviiii; Resources — Birtis . Resoiinrs — Birds .fy (1980-92) tor the Atlantic. Mississippi, and Central tlvways (Fig. 2). Production in the Pacific Flyway exhibited a substantial decline from 2.40 in 1 963-70. to 1 .7S in 1 97 1 -79. and to 1.60 in 1980-92. Likewise, survival would be lower during 1980-92 if population declines were caused by declines in sur\ival. Comparisons of average survival rates between 1980-92 and earlier peri- ods were possible for only a limited number of areas because few pintails were banded in many regions. In the area encompassing northern Alberta, northeastern British Columbia, and southwestern Northwest Territories, average survival during 1980-92 was higher than the average for earlier periods for adult males (80% versus 68%). young males (68% versus 53%). and adult females (69% versus 64%). In south- em Alberta, average survival during 1980-92 was higher than the average for earlier periods for adult males (74% versus 70%) and young females (86% versus 55%). Survival remained constant between 1980-92 and earlier periods for all age-classes of pintails banded in southern Saskatchewan and southern Manitoba. In the Dakotas. average survi\'al duiing 1980-92 was higher for only adult males (77% versus 66%). These data reveal that possible declines in pintail survival did not cause the population declines observed during the 1980's. Overall, survival was higher during 1980-92 than during earlier periods for adult males that winter in the Pacific. Central, and Mississippi flyways and for young females that winter in the Pacific Flyway. Survival remained constant between time periods for adult females and young males in the Pacific, Central, and Mississippi flyways. Given the small changes in production and survival, pintail numbers should stabilize in the Central and Mississippi flyways and possibly the Atlantic Flyway. In the Pacific Flyway, how- ever, the survival increases of young females has not compensated for the overall decrease in production. During the 1980's the Canadian prairies on the average received less precipitation, resulting in reduced availability of pintail breeding habi- tat. Hopes for increased pintail population size have been based, in part, on the expectation that increased precipitation in the western Canadian prairies would result in increased breeding habi- tat and production. Female-based age-ratio data suggest, though, that increased production is unlikely to occur even with increased precipita- tion because pintail production remained low even when water was plentiful. Average age- rafios for the Pacific Flyway when water in the western Canadian prairies was above average (total May ponds for southern Alberta and Mississippi Central Pacidc southern Saskatchewan exceeding 2.68 million) steadily declined frotn 3.11 in the 196()"s. to 2.03 in the m7()'s. atid 1.86 in the 1980"s. Consequently, a fundamental change appears to have occurred in pintail productivity on western Canadian prairies, meaning that we cannot base pintail management on the hope that increased precipitation will result in a return to the higher levels of production experi- enced in the I960's. Researchers suspect that the production decline may be related to the fact that the shal- low-water breeding habitat favored by pintails is most susceptible to agricultural drainage. By 1989. 78%' of the pothole margins (the transi- tion zone where potholes meet farmland) and 22% of wet basins were degraded by agricultur- al activity in prairie Canada (F.D. Caswell and A. Didiuk, Canadian Wildlife Service, personal communication). Increased intensification of agricultine may also contribute to lower pro- duction on the prairies through increased graz- ing and cropping, increased nest destruction, and increased use of agricultural chemicals (Ducks Unlimited 1990). Further research on the western Canadian prairies is necessary to determine specific causes of production declines in pintails and to determine methods to increase production. References Ducivs Unlimited. 1990. Sprig: population recovery strategy for ttie northern pintail. Ducks Unlimited. Inc.. Long Grove. IL. 30 pp. Hestbeck. J.B. 1993. Overwinter distribution of northern pintail populations in North America. Journal of Wildlife Management 57:582-589. Johnson. D.H.. and J.W. Grier. 1988. Determinants of breeding distributions of ducks. Wildlife Monograph 100. 37 pp. Smith. R.I. 1968. The social aspects of reproductive behav- ior in the pintail. Auk 85:381-396. Smith. R.I. 1970. Response of pintail breeding populations to drought. Journal of Wildlife Management 34:943-946. Fig. 2. Average production of pm- tails in Atlantic. Mississippi. Central, and Pacific flyways for 1963-70, 1971-79. and 1980-92 (Waterfowl Parts Collection Survey. U.S. Fish and Wildlife Service. Office of Migratory Bird Management). For futher information: Jay B. Hestbeck National Biological Service Cooperative Fish and Wildlife Research Unit University of Massachusetts Amlierst. MA 01003 40 Birds — Our Li\ini; Risoiirces Canvasback Ducks by William L. Holiiiiaii G. Michael Haramis Dennis G. Jorde Carl E. Korschgen John Takekawa National Biological Service Ciiiivasbacks (Aythya valisineria) are unique tn North America and are one of our most widely recognized waterfowl species. Unlike other ducks that nest and feed in uplands, diving ducks such as canvasbacks are totally dependent on aquatic habitats throughout their life cycle. Canvasbacks nest in prairie, parkland, subarctic, and Great Basin wetlands; stage during spring and fall on prairie marshes, northern lakes, and iHvers; and winter in Atlantic. Pacific, and Gulf of Mexico bays, estuaries, and some inland lakes. They feed on plant and animal foods in wetland sediments. Availability of prefened foods, especially energy-rich subtenanean plant parts, is probably the most important factor influencing geographic distribution and habitat use by canvasbacks. In spite of management efforts that have included restrictive harvest regulations and fre- quent hunting closures in all or some of the fly- ways (Anderson 1989). canvasback numbers declined from \'-)>f' to 1993 and remain below the population goal (540.000) of the North American Waterfowl Management Plan (USFWSand Canadian Wildlife "Service 1994). Causes for this apparent decline are not well understood, but habitat loss and degradation, low rates of recruitment, a highly skewed sex ratio favoring males, and reduced survival of canvas- backs during their first year are considered important constraints on popidation growth. Population size = 620.540 - 2,873 (year) /■2 = 011.P=0014 55 58 64 67 73 Year 76 79 82 85 91 93 Figure. Estimated breeding popu- lation of canvasbacks, 1955-93 (data from the U.S. Fish and Wildlife Service, Office of Migratory Bird Management). Status and Trends Canvasback population trends are monitored by means of annual Breeding Waterfowl and Habitat Surveys and Midwinter Waterfowl Inventories (MWI). Readers should refer to cited literature for additional information regarding methods. Canvasback Numbers and Distribution Between 1955 and 1993 population indices for canvasbacks fluctuated between 353,700 and 742.400 and averaged 534,000 ducks (Figure), The population showed a general rate of decline of 0.6% per year during the period; however, because population estimates are imprecise, annual differences are difficult to detect. For example, a population change of more than 3()'7f would be needed to detect a sig- nificant difference between years with 90% confidence. The winter distribution of canvasbacks has changed since the 1950"s, when most canvas- backs (79%) were found wintering in the Atlantic or Pacific tlyways. The proportion of the continental population wintering in the Central and Mississippi flyways increased from 21% in 1955-69 to 44% in 1987-92 as a result of declines in canvasback numbers at Chesapeake Bay and San Francisco Bay and increases in the Gulf of Mexico region. Only about 23,000 canvasbacks winter in Mexico, but numbers may be increasing (Office of Migratory Bird Management, unpublished data). Shifts in winter distribution probably reflect regional differences in habitat availabili- ty, but may also indicate differences in survival and recruitment. Sex Ratios Canvasbacks have a highly skewed sex ratio favoring males. Sex ratios of wintering canvas- backs in Louisiana (1.6-1.8 males:female: Woolington 1993) and San Francisco Bay (2.2 malesit'emale; J. Takekawa, unpublished data) are lower than those observed in the Atlantic Flyway (2.9-3.2 males:female), but sex ratios apparently decreased in two mid-Atlantic states between 1981 and 1987 (Haramis et al. 1985. 1 994). Based on recent ( 1 987-92 ) MWI and sex ratio data, we calculated that the continental sex rafio for canvasbacks likely lies between 2.0 and 2.5 males:female. Survival Annual survival rates of female canvasbacks (56%-69%) are lower than those of males (70%-82%; Nichols and Haramis 1980). Survival rates also vary geographically (survival is greater in the Pacific Flyway than in the Atlantic; Nichols and Haramis 1980) and are positively related to body mass in early winter (Haramis et al. 1986). Survival of females in their first year probably is reduced relative to that of adults. Assuming that all surviving females return to their natal areas to breed, return rates for female canvasbacks breeding in southwestern Manitoba suggest that only 21% of hens survive their first year compared to 69% annual survival of older hens (Seine et al. 1992). Nichols and Haramis (1980) found no asso- ciation between canvasback harvest regulations and survival. However, an analysis of return Our Liviiif; Resources — Birds 41 rates lor lenialc canvasbacks in southwestern Manitoba indicated that sufvival of immatures was signilicantiy related to harvest (M.G. Anderson. Ducks Unhmited-Canada. inipub- hshed data). The canvasback season was closed in the Atlantic. Central, and Mississippi flyways during 1 986-03. but about 8.000 birds were har- vested annualls in Canada and 10. 000 in the Pacific Flyway. There is also a substantial ille- gal harvest of canvasbacks at some sites maramis et al. 1993; Korschgen et al. 1993; W.L. Hohnian. unpublished data). However, the current level of hunting-related mortality is probably not limiting population growth. Rather, annual variation in recruitment and degradation and loss of breeding, migrational. and wintering habitats are more likely inlluenc- ing population size. Time-specific Survival Rates and Sources of Mortality Survival rates for adults in spring and sum- mer are unknown. In spite of a nationwide ban on the use of lead shot by waterfowl hunters, ingestion of spent lead shotgun pellets by water- fowl is common and likely will remain so for many years. More than 50% of spring-migrat- ing canvasbacks captured at a major staging area on the Mississippi River had elevated blood lead levels (Havera et al. 1992). Lead- exposed birds have reduced body mass, fat, and protein (Hohman et al. 1990), so their subse- quent survival and ability to reproduce and per- form activities such as courtship, migration, or molt, may be compromised. Nest success (i.e., embryonic survival) ot canvasbacks is highly variable, especially for birds nesting on the prairies. For example, nest success in southwestern Manitoba in wet years was 54%-60%, but in dry years averaged only 17% (Serie et al. 1992). In spite of habitat loss and degradation, ranges in nest success observed in southwestern Manitoba were simi- lar in 1961-72 (21%-62%; Stoudt 1982) and 1974-80 (17%-60%; Serie et al. 1992). Mammalian predation, especially by mink (Mustela vison) and raccoon (Procyon lotor). is an important factor affecting the nest success of prairie-nesting canvasbacks. Moitality of prefledged ducklings is high, especially during the first 10 days (C.E. Korschgen. unpublished data). In northwestern Minnesota, estimated survival rates for duck- lings up to 10 days old ranged from near zero to 70%, but differed between sexes during the first 25 days of life (male > female; C.E. Korschgen, unpublished data). Predation and weather were the primary sources of duckling mortality. Survival of young between fledging and fall migration is unknown; however, production estimates calculated from harvest information (0.16-1.07 young:adult) suggest that recruit- ment rates for canvasbacks generally are low compared to other ducks. Survival rates for fall-migrating canvasbacks have not been studied, but survival rates have been estimated at several major wintering sites. Adult and immature females had high winter survival at Chesapeake Bay (83%- 100%; Haramis et al. 1993) and coastal Louisiana (> 95%; Hohman et al. 1993). Winter survival was lower at Catahoula Lake. Louisiana (57%- 92%), where canvasbacks were not only shot illegally but where substantial numbers of birds were also exposed to lead (W.L. Hohman, unpublished data). Habitat Trends Historically, climate, grazing, and fire were major factors affecting habitats of prairie-nest- ing waterfowl. Since settlement, however, human activities, especially those related to agriculture, have had a major impact on the quantity and quality of breeding habitats. Nationwide, over 53% of original wetlands have been lost. Wetland losses in states where canvasbacks histoiically nested range from less than V7c (Alaska) to 89% (Iowa); however, deeper wetlands preferred by nesting canvas- backs probably have been drained to a lesser extent than shallower wetlands. Northern lakes used by canvasbacks for molting and staging before fall migration prob- ably have been least affected by human and nat- ural perturbations. Nonetheless, disturbances related to commercial and recreational activi- ties, nutrient enrichment of lakes resulting from sewage discharges and agricultural runoff, introductions of herbivorous fish, and alteration of lake levels for generation of hydroelectric power have reduced the suitability and use of some traditional staging areas in the southern boreal forest region. Canvasback {AMhya vulismeria). 42 Birds — Oiii Liviiif; Re Most oflhe traditional stopover habitats used hy migrating eanvasbaci^s no longer provide suitable feeding and resting opportunities (Kahl 1 99 1 ). For example, of the more than 40 former migration stopover areas in the upper portion of the Mississippi Flyway. only Lake Christina in west-central Minnesota, two pools on the Upper Mississippi River, and two areas on the Great Lakes have peak populations of more than 5,000 canvasbacks (Korschgen 1989). Restoration efforts begun in 1987 at Lake Christina were successful in reestablishing submersed aquatic vegetation and canvasback use. Habitat on the Upper Mississippi River increased in extent from the mid-1960"s to the late I980's. However, reciird drought in 1988-89 and exten- sive flooding in 1993 in the Upper Mississippi River basin have caused major declines in habi- tat quality and abundance. In the Great Lakes region, increased bird use of Lake St. Clair and Long Point on Lake Erie coincided with improved water quality and increased production of submersed aquatic plants, especially wildcelery (Vallisneria ameri- caiui). These improvements are attributed to regulation of water discharges into the Great Lakes and perhaps the proliferation of zebra mussels (Dreisseua polymorpha). In the Pacific Flyway, coastal habitats used by migrating canvasbacks have not changed greatly since the 1930's, although development has increased in some areas (e.g., Puget Sound). Whereas use of .some inland sites (e.g.. Great Salt Lake, Utah; Malheur National Wildlife Refuge (NWR). Oregon; and Stillwater NWR. Nevada) declined duiing the 1970"s or I980's, canvasback use of Klamath Basin NWR, Oregon-California, and Pyramid Lake, Nevada, has increased. Degradation of water quality in the Chesapeake Bay caused by nutrient enrichment, turbidity, and sedimentation reduced the abun- dance of aquatic plant and animal foods most important to canvasbacks in winter (Haramis 1991). Declining availability of plant foods caused canvasbacks to shift to mostly animal foods. Canvasback numbers declined in response to loss of aquatic plants in the Chesapeake Bay, but increased in North Carolina and Virginia where preferred plant foods were still abundant (Lovvorn 1989). Aquatic plants are now declining in the coastal areas of North Carolina and other wintering areas throughout the Atlantic Flyway. Unless the widespread decline of aquatic plant foods is reversed, the number of canvasbacks wintering in the Atlantic Flyway is not likely to increase. San Francisco Bay is the most important wintering area for canvasbacks in the Pacific Flyway. Urban development there has greatly reduced available habitat. In remaining habi- tats, canvasbacks are exposed to high levels of ein ironmental contaminants (Miles and Ohlendorf 1993). Canvasbacks make extensive use of salt evaporation ponds in northern San Francisco Bay (Accurso 1992). These ponds recently came under public ownership, but their management as tidal salt marshes will probably reduce their use by canvasbacks. Increasing numbers of canvasbacks have been observed recently on wetland easements and sewage lagoons in the northern San Joaquin Valley. Increased numbers of canvasbacks are win- tering in the Gulf of Mexico region, especially at Catahoula Lake, where, since 1985, peak numbers (up to 78,000 birds) have equaled or exceeded counts on traditional wintering areas such as Chesapeake Bay and San Francisco Bay. Birds appear to be attracted to Catahoula Lake because of its abundant plant foods and stable flooding regime (Woolington and Emfinger 1989). These birds are at risk of lead poisoning, however, because of the high density of spent lead shot contained in lake sediments. Information Gaps Information needs for improved manage- ment of canvasbacks include banding or radio- telemetry data sufficient to provide habitat information and estimates of region-specific rates of survival, band recovery, and recruit- ment; survival rates of immature birds between hatch and anival on wintering areas; and cross- seasonal effects of winter nutrition and contam- inant exposure on reproduction. References Accurso. L.M. 1992. Distribution and abundance of winter- ing waterfowl on San Francisco Bay. 1988-1990. M.S. thesis. Huniboldl State University, Acadia, CA. 252 pp. Anderson. M.G. 1989. Species closures — a case study of wintering watertbwl on San Francisco Bay. 1988-1990. M.S. thesis. Humbolt Stale University, Acadia. CA. 252 pp. Haramis. CM. 1991. Canvasback. Pages 17.1-17.10 m S.L. Funderburk. J. A. Mihursky, S.J. Jordan, and D. Riley. eds. Habitat requirements for Chesapeake Bay living resources. 2nd ed. Living Resources Subcommittee, Chesapeake Bay Program. Annapolis. MD. Haramis, G.M., E.L. Derieth. and W.A. Link. 1994. Flock sizes and .sex ratios of canvasbacks in Chesapeake and North Carolina. Journal of Wildlife Management 58: 12.^- 1.^0. Haramis. G.M., J.R. Goldsberry, D.G. McAuley, and E.L. Derieth. 1985. An aerial photographic census of Chesapeake and North Carolina canvasbacks. Journal of Wildlife Management 49:449-454. Haramis. G.M.. D.G. Jorde. and CM. Bunck. 1993. Survival of hatching-year female canvasbacks wintering on Chesapeake Bay. Journal of Wildlife Management 57:763-770. Haramis, CM.. J.D. Nichols. K.H. Pollock, and J.E. Hines. 1986. The relationship between body mass and survival of wintering canvasbacks. Auk 103:506-514. Our Liviiii; Rffiimnts — Birds 4J Havera. S.P.. R,M, Wliitton, and R.T. Sliealy. 1992. Blood lead and ingested shot in diving ducks during spring. Journal ot'Wildlite Management 5fi;3.^9-?45. Hohnian. W.L.. R.D. Pntchert. J.L. Moore, and D.O. Schaeffer 1993. Survival of female canvasbacks winter- ing in coastal Louisiana. Journal of Wildlife Management 57:758-762. Hohman, W.L.. R.D. Pritchert. R.M, Pace, D.W. Woolniglon, and R. Helin. 1990, Influence of ingested lead on body mass of wintering canvasbacks. Journal of Wildlife Management 54:21 1-215. Kahl, R, 1991. Restoration of canvasback migrational stag- ing habitat in Wisconsin. Tech. Bull. 172. Department of Natural Resources, Madison, Wl. 47 pp. Korschgen. C.E. 1989. Riverine and deepwater habitats for diving ducks. Pages 157-189 in L.M. Smith. R.L. Pedcrson. and R.M. Kaminski, eds. Habitat management for migrating and wintering waterfowl in North America. Texas Tech University Press, Lubbock. Korschgen. C.E., K, Kenow, J. Nissen. and J. Wetzel. 199.^. Final report: canvasback hunting mortality and hunter education efforts on the Upper Mississippi River National Wildlife and Fish Refuge. U.S. Fish and Wildlife Service. LaCrosse. WL 50 pp. Lovvom. J.R. 1989. Distributional responses of canvas- backs to weather and habitat change. Journal of Applied Ecology 26:113-130. Miles, A.K.. and H.M. Ohlendorf. 1993. Environmental contaminants in canvasbacks wintering on San Francisco Bay. California, California Fish and Game 79:28-38, Nichols, J.D.. and CM. Haramis. 1980. Inferences regard- ing survival and recovery rates of winter-banded canvas- backs. Journal of Wildlife Management 4: 1 64- 1 73. Serie, J,R„ D,L. Trauger, and J.E. Austin. 1992. Influence of age and selected environmental factors on reproductive performance of canvasbacks. Journal of Wildlife Management 56:546-555. Stoudt, J,H, 1982. Habitat use and productivity of canvas- backs in southwestern Manitoba, 1961-72, U,S, Fish and Wildlife Service Special Sci, Rep, Wildlife 248, 31 pp, Woolington. D,W, 1993, Se.\ ratios of wintering canvas- backs in Louisiana. Journal of Wildlife Management 57:751-757. Woolington, D.W.. and J.W. Emfinger 1989. Trends in win- tering canvasback populations at Catahoula Lake, Louisiana. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 43:396-403, USFWS and Canadian Wildlife Service. 1994. North American waterfowl management plan 1994 update, expanding the commitment. U.S. Fish and Wildlife Service. Washington. DC. 40 pp. For further Information: William L. Hohman National Biological Service Southern Science Center 700 Cajundome Blvd. Lafayette. LA 70506 Moie than two million seabirds of 29 species nest along the west coasts of Califoinia, Oregon, and Washington, including three species listed on the federal list of threat- ened and endangered species: the brown pelican (Pelecanus occidentalis). least tern (Stcnia antillaruni). and marbled murrelet (Bnichynimphits marmoratiis). The size and diversity of the breeding seabird community in this region reflect excellent nearshore prey con- ditions; subtropical waters within the southern California Bight area; complex tidal waters of Strait of Juan de Fuca and Pugel Sound in Washington; large estuaries at San Francisco Bay, Columbia River, and Grays Harbor- Willapa bays; and the variety of nesting habitats used by seabirds throughout the region, includ- ing islands, mainland cliffs, old-growth forests, and artificial structures. Breeding seabird populations along the west coast have declined since European settlement began in the late 1700's because of human occupation of. commercial use of. and introduc- tion of mammalian predators to seabird nesting islands. In the I900"s. further declines occuned in association with rapid human population growth and intensive commercial use of natural resources in the Pacific region. In particular. severe adverse impacts have occurred from par- tial or complete nesting habitat destruction on islands or the mainland, human disturbance of nesting islands or areas, marine pollution, fish- eries, and logging of old-growth forests (Ainley and Lewis 1974; Bartonek and Nettleship 1979; Hunt et al. 1979; Sowls et al. 1980; Nettleship et al. 1984; Speich and Wahl 1989; Ainley and Boekelheide 1990; Sealy 1990; Ainley and Hunt 1 99 1 ; Carter and Morrison 1 992; Carter et al. 1992; Vermeeret al. 1993). Methods Population status of breeding seabirds on the west coast has been measured primarily through the determination of and trends in population size, based on counts of birds and nests at nest- ing colonies (e.g., Sowls et al. 1980). At-sea surveys also have been used to approximate population sizes for breeding and nonbreeding populations and species as well as their foraging distribution alongshore and offshore (e.g.. Briggs et al. 1987). Rather than just monitoring siTiall plots of nests on a few accessible islands to determine status and trends, relatively accu- rate and standardized censuses of entire coastal seabird breeding populations (except for certain nesting areas of difficult-to-census species) have been conducted annually or periodically to determine the overall status of many species breeding on the west coast (Figs. 1-4). However, we have considered census accuracy, natural variability, trends at well-studied colonies (e.g.. Farallon National Wildlife Refuge) and many other factors in assessing population status and trends. Status and Trends Storm-petrels (Hydrobatidae) Increasing numbers of Leach's storm-petrels (Oceanodroma leucorhoa) have been docu- mented recently in Oregon (R.W. Lowe, USFWS, unpublished data), although this Breeding Seabirds in California, Oregon, and Washington by Harry R. Carter David S. Gilmer National Biological Service Jean E. Takekawa Roy W. Lowe Ulrich W. Wilson U.S. Fish and Wildlife Service 44 Bints — Our Livinii Rt'simncs Fork-tailed storm-petrel (1,000's) 12 9 — 6-< Brown pelican (1,000's) 1 -2 0 ND Leach's storm-petrel ^3 Double-crested cormorant ND 12 9 - 6 — CM CO 3 5 0 (1,000's) 7 6 5- 4- 3- ■^ CO 1 - s - 0 Ashy storm-petrel Brandt's cormorant (10.000's) ^H CM MR 250- 200- Black storm-petrel Pelagic cormorant (1,000's) 1b0 100 50 0 s 0 0 0 0 75-80 89-91 79 88 78-82 91 CA OR WA w ■i CO S8 ID O to O S (D OJ ID "* to - CD 75-80 CA Year Fig. 1. Status and trends of breed- ing populations of storm-petrels, pelicans, and cormorants on the west coasts of California. Oregon, and Washington. Data for small inland populations of while peli- cans and double-crested cor- morants are not included. ND — no data available; 0 — no coastal nesting. Sources: CA (Hunt et al. IQTg^Sowls et al. 1980. Carter et al. 1992): OR (Varoujean and Pitman 1979; R.W. Lowe, unpub- lished data); and WA (Speich and Wahl 1989; U.W. Wilson, unpub- lished data). Also see Carter et al. (in press) for double-crested cor- morant. OR Year 78-82 91 WA increase probably represents greater survey effort (Fig. 1). They have dechneci in northern California because of the loss of burrow-nesting habitats due to soil erosion and defoilation by nesting cormorants (Carter et al. 1992). Ashy storm-petrels (O. homochwa) have declined recently at the world's largest known colony at the South Farallon Islands, possibly because of high gull predation (W.J. Sydeman, Point Reyes Bird Observatory, unpublished data). This decline is of concern because the small world population of this species (fewer than 10.000 breeding birds) nests entirely in California. Greater numbers of ashy and black storm- petrels (O. iiu'lania) have been documented recently in southern California, although this probably reflects greater survey efforts (Carter et al. 1992). In Fig. 1. similar numbers of fork- tailed storm-petrels (O. fiircata) are indicated over the past decade in Oregon and California because survey efforts confirmed very small numbers. Declines in California are suspected (Carter et al. 1992), but further work is required to establish trends. Pelicans (Pelecanidae) Brown pelicans have increased recently at the only two remaining colonies (West Anacapa and Santa Barbara islands) in the Channel Islands in southern California (Fig. 1), follow- ing severe pre- 1975 declines primarily due to eggshell thinning from marine pollutants (Anderson et al. 1975; Anderson and Gress 1983; Carter et al. 1992; F Gress and D.W. Anderson. University of California-Davis, per- sonal communication). Breeding success is still low and limited recovery may involve immigra- tion of birds out of Mexico. Concern exists for adverse effects of continuing low levels of marine pollutants, commercial fisheries, and the 1990 American Trader oil spill. Although the brown pelican has shown recent population increases, white pelicans have been extiipated from parts of interior California and have declined at inland colonies in northern California because of low reproduction related to water developments and drought (Carter et al. 1992; P. Moreno and D.W. Anderson. University of California-Davis, personal communication). Small colonies still exist at Sheepy Lake and Clear Lake in the Klaniath Basin area. These con- ditions also exist at other inland areas in Oregon. Washington, and Nevada, but problems seem fewer farther east. Cormorants (Phalacrocoracidae) Double-crested cormorants ( Plialacrocora.x aiiritiis) have increased dramatically in coastal regions of California and Oregon (Fig. 1) because of reduced human disturbance, reduced levels of marine pollutants in southern California, and recent use of artificial nesting areas in San Francisco Bay and Columbia River estuaries (Gress et al. 1973; Carter et al. 1992). They have not increased in Puget Sound because of high human disturbance and preda- tion by bald eagles [Haliaeetiis leucocepluilus), which has caused colony abandonments (Henny et al. 1989; Speich and Wahl 1989; Carter et al. in press; U.W. Wilson, unpublished data). Declines have been reported at interior colonies in California. Oregon, and Washington due to water developments, human disturbance at colonies, and large-scale shooting of birds at hatcheries (during smolt releases) and at aqua- cultural facilities (Carter et al. in press; R.W. Lowe, unpublished data; R. Bayer, personal communication; P. Moreno, unpublished data). Brandt's and pelagic cormorant {P. penicillatus and P. pelagicus) populations have fluctuated in response to El Nino conditions (Ainley and Boekelheide 1990; Ainley et al. 1994). At the South Farallon Islands, these cormorants appear very sensitive to El Nifio conditions, which result in quite poor reproduction and mortality Ohi Ltvtn^ Res(}itnv\ — Binls 45 of subadult and adult birds (Boekelheide and Ainley 1989; Ainley and Boekelheide 1990). Overall, numbers have remained stable or increased in most areas in the region (e.g.. Carter et al. 1992), whereas these birds now occur at lower abundance than previously at the South Farallon Islands (Ainley et al. 1994). Numbers have increased in southern California, but the birds ha\e suffered from gill-net and oil- spill mortality as well as human disturbance at colonies (H.R. Carter, unpublished data). Gulls, Terns, and Skimmers (Laridae and Rynchopidae) The predominant nesting gull on the west coast is the western gull (Lunis dccidcntalis). Numbers have increased, especially in California (Fig. 2). probably because of the bird's use of human and fishing refuse and reduced human disturbance. Numbers have reached saturation at the world's largest colony at the South Farallon Islands (Ainley et al. 1994); however, expansion is occuning at other major colonies in central and southern California (Carter et al. 1992). Glaucous- winged gulls (L glaitcesceus) have remained stable or increased in Puget Sound (Ll.W. Wilson, unpublished data). California gulls (L. culiforulciis) have recently expanded from interior colonies to nest in San Francisco Bay (Fig. 2: Carter et al. 1992; P. Woodin, San Francisco Bay Bird Observatory, unpublished data). They face seri- ous threats at inland colonies in interior California because of water developments. At the world's largest colony at Mono Lake, low water levels have resulted in the formation of land bridges to nesting islands, allowing access by coyotes (Canis latnins) in certain years (Jones and Stokes Associates 1993). Similar problems exist at other northern California colonies for many seabird and colonial water- bird species (W.D. Shuford, Point Reyes Bird Observatory, unpublished data). The status of California gulls at inland colonies in Oregon and Washington is not well known. Status and trends of inland colonies of ring-billed gulls [L. deknvarensis) in California, Oregon, and Washington are not known, although problems related to low water levels may occur at many colonies. Many thousands have nested recently in northern California (W.D. Shuford. unpublished data). Small num- bers (< 500 breeding birds) also nest along the Washington coast (Speich and Wahl 1989). Small numbers (< 10 breeding birds) of Heermann's gulls (L. heennuuni) nested in the early I980's along the central California coast but none are known to do so now. Franklin's gulls (L. pipixcan) recently nested in small numbers (< 100 breedins birds) at Lower California gull (1,000's) Western gull {10,000's) ND if 30- o o ^ 25- 20- 15- 10- 5- Glaucous-winged gull (1,000's) ND 12- 10- 8- 6 4 2- Black skimmer (100's) o ,_r 0 75-80 89-91 79 88 78-82 91 CA OR WA Year Caspian tern (1.000's) ■ I ■ - S - "" T- f aS 7 6 5 4 3 2 1 0— =^ 5 ^ 4 - 3 — 2 ■ — 35- 30- 25- 20 15 10 5 0- 25- 20- 15- Klamath Lake, California, but their status in the region is not known. Low thousands of Caspian. Forster's. least, and elegant terns (Sterna caspia. S. forsteh. S. uiitillaruiu, S. elegans) and black skimmers (Rynchops iiiger) now occur in the region through increases (especially along the southern California coast) due to colony protection and use of artificial nesting sites (Speich and Wahl 1989; Carter et al. 1992). Certain tern colonies have been eliminated or shifted (especially in San Francisco Bay) because of human distur- bance and red fox (Vulpes viilpes) or other mammalian predation (P. Woodin, unpublished data). Overall, least tern colonies in California appear somewhat stable because of extensive management. They undoubtedly occur at lower ND Forster's tern (1,000's) 0 — Least tern (100's) Elegant tern (lOO's) 0 75-80 89-91 79 8 CA OR Year 78-82 91 WA Fig. 2. Status and trends of breed- ing populations of gulls, terns, and skimmers. Small coastal popula- tions of gulls (Heermann's and ring-billed) and royal terns, as well as large or small inland popu- lations of gulls (ring-billed and California), terns (black, gull- billed, Caspian, and Forster's), and black skimmers are not included. ND — no data available: 0 — no coastal nesting. Sources: CA (Huntetal. 1979: Sowls et al. 1980: Carter etal. 1992): OR (Varoujean and Pitman 1979: R.W. Lowe, unpublished data): and WA (Speich and WM 1989: U.W. Wilson, unpublished data). Also see Carter et al. (in press) for dou- ble-crested cormorant. 46 Birds — Our Li\'ini^ Rt'sdurces 6 — 5 — 4 3 2 - 1 Common murre (100,000's) 15- Cassm's auklet (10.000's) Pigeon guillemot (1,000s) ND uo c^J C'J ND Rhinoceros auklet ■i (10,000's) H H 1 1 — ■Si ^- O _8_ M- ND 35 30 25 20 15 Xantus' murrelet (100's) 75-80 89-91 79 88 78-82 91 CA OR WA Year 75-80 89-91 79 88 78-82 91 CA OR WA Year Fig. 3. Status and irLMids of breed- ing populations ol several alcids ui California, Oregon, and Washington. Data lor marhled munelets and historical nesting hy ancient murrelels are not included. ND — no data available; 0 — no coastal nesting. Sources: CA (Huntetal. 1979; Sowls et al. 1980; Caner et al. 1992); OR (Varoujean and Pitman 1979; R.W. Lowe, unpublished data); and WA (Speich and Wahl 1989; U.W. Wilson, unpublished data). Also see Carter et al. (in press) for dou- ble-crested cormorant. ihati liistoiicul levels because of loss of nesting hiibital. which continues to be threatened (Carter et al. 1992: R. Jurek. California Department of Fish and Game, personal com- munication). Low numbers (< 100 breeding birds) of arctic terns {S. pamdisaea) have nest- ed in coastal Washington in the past but not now (Speich and Wahl 1989). .Small numbers (< 100 breeding birds) of gull-billed and royal terns (5. nllotica and S. maxima) recently colonized the southern California coast, although gull-billed terns have nested inland at the Salton Sea for a few decades. The status of black terns (Chlidoiiias iilger) is not known. Alcids (Alcidae) Pigeon guillemot (Cepphus columha) popu- lations have remained stable overall (Fig. 3). but major tluctuations have occurred in response to El Nino events at the South Farallon Islands and on the Oregon coast (Hodder and Graybill 1985; Ainley and Boekelheide 1990). A signifi- cant population and new nesting areas have been found recently in southern California, although higher numbers retlect both better sur- vey techniques and population increases (Carter et al. 1992). Ancient murrelets (Syiuhlihoramphus anuquus) nested on the Washington coast in the early 1900"s but no longer do (Speich and Wahl 1989). Cassin's auklets (Ftychoramphus dlciiticus) have declined at the largest known colony in the region at the South Farallon Islands, probably because of high gull predation and loss of bur- row-nesting habitat from soil erosion (Cailer et al. 1992; W.J. Sydcman. unpublished data). However, lower numbers also were found at Prince Island in southern California where numbers of nesting gulls are lower. Differences in survey techniques probably account for part of the lower numbers found recently, but other data on soil conditions, densities of nesting gulls, and gull predation suppon a decline at the South Farallon Islands (W.J. Sydeman. unpub- lished data). Hundreds also were killed in the 1984 Piierld RIcan and 1986 Apt:\ Houston oil spills (Ford et al. 1987; Page et al. 1990). Rhinoceros auklets {Cerorliinca monocera- ta) have increased throughout the region. Largest numbers occur at Protection and Destruction islands, but burrow occupancy has fluctuated widely between years (Wilson and Manuwal 1986; U.W. Wilson, unpublished data). The South Farallon Islands were recolo- nized after a 100-year absence in the early 1970"s (Ainley and Lewis 1974) and reached saturation levels by the late 1980's (Carter et al. 1992: Ainley et al. 1994). Nesting has recently extended to the Channel Islands (Carter et al. 1992). Thousands of rhinoceros auklets were killed in the 1986 Apex Houston oil spill (Page et al. 1990). The largest tufted puffin {Fnitercida cirrlia- tci) populations occur along the west coast of the Olympic Peninsula (Speich and Wahl 1989). but their status there is not well known. In Puget Sound, this species has declined substantially (U.W. Wilson, unpublished data). At small colonies in Oregon and California, their num- bers appear stable (Carter et al. 1992: Fig. 3). despite impacts due to El Nino at the South Farallon Islands (Ainley and Boekelheide 1990; Ainley et al. 1994). They have recently recolo- nized southern California where they have not nested since the early 1900"s (Carter et al. 1992). Common muiTcs {Uria cialge) are the domi- nant member of the breeding seabird communi- ty on the west coast but they have declined sub- stantially in central California and Washington (Figs. 3, 4) because of the combined effects of high mortality from gill-net fishing and oil spills plus poor reproduction during intense El Nino events. In central California, large histori- cal declines in the late 1800's and early 1900's almost led to the extinction of this population (Ainley and Lewis 1974). Population growth occuned. however, between the 1950"s and the 1970"s. producing about 230.000 breeding birds by 1980-82 (Takekawa et al. 1990). Over 70,000 murres were estimated to have been Out Living Rt'sourcfs — Biril.s 47 killed in gill nets in central California between 1979 and 19S7. before heavy fishing restrictions were imposed in 1987 to stop mortality (Takekawa et al. 1990). Additional moitalit\ (10.000+ murres) occurred during the 1984 Puerto Rican and 1986 Ape.x Houston oil spills (Ford et al. 1987; Page et al. 1990). At the South Farallon Islands, reproductive success was almost nil during intense El Niiio events in 198.^ and 1992 (Ainley and Boekelheide 1990: W.J. Sydeman. unpublished data). Because of these and other factors, the central California popula- tion declined by over biWc from 1982 to 1989 and has not recovered (Fig. 4; Takekawa et al. 1990; Carter et al. 1992;" Ainley et al. 1994; H.R. Carter, unpublished data). In Washington, mune numbers crashed dur- ing the 1982-83 El Niiio (Wilson 1991), although there was heavy mortality from gill nets at this time; mortality from gill nets still continues in Puget Sound. In addition, certain colonies have been disturbed by low-tlying air- craft, especially near military bases. Numbers of breeding murres in Washington are lower than indicated in Figs. 3 and 4 because many birds counted in colonies in recent years (and used to derive estimates) do not appear to be breeding (U.W. Wilson, unpublished data). Significant inortality occurred during the 1984 Arco Anchorage. 1988 Nestucca. and 1991 Tenyo Mciru oil spills. In the Nestucca spill alone, about 30,000 murres were estimated to have died (Ford et al. 1991). The Washington population of murres has been almost extirpat- ed over the last decade and has not recovered. In contrast, murre populations in Oregon and northern California have been stable or increas- ing to date, despite human disturbance at sever- al colonies (Takekawa et al. 1990; R.W. Lowe, unpublished data) and some losses of Oregon birds from oil spills and the use of gill nets in Washington. In addition, these areas were known to experience lower productivity through colony abandonment during intense El Nino conditions in 1993 (Fig. 4; H.R. Carter, unpub- lished data; J.E. Takekawa and R.W. Lowe, unpublished data). Thus, it appears clear that decline and lack of recovery of populations in central California and Washington have resulted primarily from human causes, especially gill nets and oil spills. Marbled murrelets probably have declined substantially throughout the region largely because of the direct loss of most (90% -95*^ ) of their old-growth forest nesting habitat to large- scale logging since the mid-1800"s (Carter and Morrison 1992; FEMAT 1994). About 10.000- 20.000 birds remain. In addition, hundreds of munelets have been killed in gill nets and oil spills in central California. Puget Sound, and off the Olympic Peninsula (Carter and Momson 1992; H.R. Carter, unpublished data), Murrelets appear to have vei-y low reproductive rates (based on nests examined and at-sea counts of juveniles), probably because of high avian nest prcdation in fragmented forests and possibly lower breeding success during intense El Nifio events. This species was listed as threatened in California, Oregon, and Washington in 1992, and is being considered carefully with regard to the future of old-growth forests and the timber industry in this region. Small populations in California, Oregon. and southwestern Washington are isolated and susceptible to extinction from various potential disturbances in the future. Washington W(10,000's) .-.-■■■I Oregon (100,000's) ND ND ND ND ND ND ND ND 25 20 15 Central California (10,000's) ND ND ND ND ND ND ND ND 79 80 81 82 83 84 85 87 88 90 91 92 93 Year The Xantus" murrelet (Synthliboramphus Inpoleucus) persists in very low numbers (2.000-5.000 breeding birds) only in southern California. Numbers breeding at the largest colony at Santa Barbara Island probably have declined between the mid-1970"s and 1991 (Fig. 3; Carter et al. 1992). The decline may have occuiTcd because of many factors, includ- ing census differences. Poor reproduction, how- ever, has occurred because of high levels of avian and mammalian predation and has proba- bly led to this decline. Other smaller colonies may disappear because of mortality from oil spills from offshore platforms in Santa Barbara Channel and oil tanker traffic into Los Angeles Fig. 4. Status and trends of breeding populations of common murres in Washington. Oregon, and central California. ND — no data available. Sources: WA (Wilson 1991; U,W. Wilson, unpublished data); OR (Varoujean and Pilman 1979; R.W. Lowe, unpublished data); and Central CA (Takekawa et al. 1990; Carter etal. 1992; H.R. Carter and J.E. Takekawa, unpublished data). 4S Biiils — Old Li\iiii; Rt'.sdiOicv harbor and other factors. Larger numbers of nesting birds are now suspected in southern CaUfomia (H.R. Carter, unpuhhshed data). A significant portion of the small world popula- tion of this species nests in southern California while the remainder nests on the northwest coast of Baja California, Mexico. This candi- date species may be considered for federal and state listing in the near future. Future Efforts Because of the continuing decline of and threats to seabirds on broad regional and local levels along the west coast, efforts to determine status and trends of seabirds must be extended beyond cunent levels. Long-tenn efforts must be shared among many federal and state agen- cies, universities, and private groups, including ( 1 ) the development of a coordinated long-term monitoring and research program, including data-base development and maintenance; (2) extending monitoring to all coastal and inland areas and species; (3) developing new method- ologies for surveying nocturnal species of mur- relets, auklets. and storm-petrels; (4) conduct- ing studies of specific conservation problems such as loss of nesting habitats (e.g.. old-growth forests), gill-net mortality (e.g.. Puget Sound), oil-spill mortality, human disturbance, water developments, and agricultural practices; (5) restoring lost or depleted seabird colonies and habitats; and (6) examining the possible long- tenn effects of human fisheries and global cli- mate change on seabird prey resources and nest- ing habitats. References .\inlev. DC. and RJ. Boekelheide. eds. 1990. Seabirds of the Farallon Islands: ecology, dynamics, and structure of an upwelling-system community. Stanford University Press. Stanford. CA. 450 pp. Ainley. D.G.. and G.W. Hant. Jr. IWI. The status and con- servation of seabirds in California. Pages 103-1 14 in J.P Croxall. ed. Seabird status and conservation: a supplement. International Council of Bird Presenation Tech. Bull. 11. Ainley. D.G.. and T.J. Lewis, 1974. The history of Farallon Island marine bird population. 1854-1972. Condor 76:432-446. Ainley. D.G.. W.J. Sydeman, S.A. Hatch, and U.W. Wilson. 1994. Seabird population trends along the west coast of North America: causes and extent of regional concor- dance. Studies in Avian Biology 15:1 19-133. Anderson. D.W., and F. Gress. 1983. Status of a northern population of California brown pelicans. Condor 85:79- 88. Anderson, D.W., J.R. Jehl. R.W. Risebrough. L.A. Woods. L.R. DeWeese. and W.G. Edgecomb. 1975. Brown peli- cans: improved reproduction off the southern California coast. Science 190:806-808. Bartonek. J.C, and D.N. Nettleship. eds. 1979. Conservation of marine birds of nonhem North America. U.S. Fish and Wildlife Service, Wildlife Res. Rep. II. 319 pp. Boekelheide. R.J.. and D.G. Ainley. 1989. Age. resource availability, and breeding effort in Brandt's cormorant. Auk 106:389-401, Briggs, K.T.. W.B. Tyler. D.B. Lewis, and D,R, Carlson, ^987. Bird communities at sea off California: 1475 to 1983. Studies in Avian Biology 1 1 , 74 pp. Carter, H.R.. and M.L. Morrison, eds. 1992. Status and con- servation of the marbled murrelet in North America. Proceedings of a 1987 Pacific Seabird Group Symposium. Proceedings of the Western Foundation of Vertebrate Zoology 5. Camanllo. C.\. 134 pp. Caner, H.R., G.J. McChesney, D.L. Jaques, C.S. Strong, M.W. Parker. J.E. Takekawa, D.L. Jory, and D.L. Whitworth. 1992. Breeding populations of seabirds in California. 1989-1991. Vol I, U.S. Fish and Wildlife Service. Dixon. CA. (Unpublished final report.) Carter. H.R.. A.L. Sowls. MS. Rodway. U.W. Wilson. R.W. Lowe, F. Gress. and D.W. Anderson. Status of the dou- ble-crested cormorant on the west coast of North America. Colonial Waterbirds. In press. Ford. R.G.. G.W. Page, and H.R. Carter. 1987. Estimating mortality of seabirds from oil spills. Pages 747-751 in Proceedings of the 1987 Oil Spill Conference. American Petroleum Institute. Washington. DC. Ford. R,G,, D,H, Varoujean, D.R. Warrick, W.A. Williams, D.B, Lewis. C.L. Hewitt, and J.L. Ca.sey. 1991. Seabird mortality resulting from the Neslmx-a oil spill incident winter 1988-89, Ecological Consulting Incorporated, Portland. OR. [Unpublished report.) Forest Ecosystem Management Assessment Team (FEMAT). 1994. Forest ecosystem management: an eco- logical, economic, and social assessment. U.S. Departments of Agriculture and Interior, Washington, DC Gress. F. R.W. Risebrough. D.W. Anderson, L.F. Kiff. and J.R. Jehl. Jr. 1973. Reproductive failures of double-crest- ed cormorants in southern California and Baja California. Wilson Bull. 85:197-208. Henny. C.J.. L.J. Blus. S.P Thompson, and U.W. Wilson. 1989, Environmental contaminants, human disturbance and nesting of double-crested cormorants in northwest- em Washington, Colonial Waterbirds 12:198-206, Hodder. J., and M.R. Graybill. 1985. Reproduction and sur- vival of seabirds in Oregon during the 1982-83 El Nifio. Condor 87:535-.54l. Hunt. G.L., R.L. Pitman. M. Naughton. K. Winnett. A. Newman, PR. Kelly, and K.T. Bnggs. 1979. Reproductive ecology and foraging habits of breeding seabirds. Pages I -399 in Summary of marine mammal and seabird surveys of the southern California Bight area 1975-1978. Vol. 3— Investigators' reports. Part 3. Seabirds— Book 2. University of California-Santa Cruz. For U.S. Bureau of Land Management. Los Angeles. CA. Contract AA550-CT7-36. )Unpublished report.) Jones and Stokes Associates. 1993. Environmental impact report for the review of Mono Basin water nghts ot the City of Los Angeles. Draft. May. (JS A 90-171.) Prepared for California State Water Resources Control Board, Division of Water Rights. Sacramento. CA. Nettleship. D.N.. G.A. Sanger, and PF Springer, eds, 1984, Marine birds: their feeding ecology and commercial fish- eries relationships. Proceedings of the Pacific Seabird Group Symposium. Canadian Wildlife Service Spec. Publ., Ottawa. Ontario. 220 pp. Page. G.W.. H.R. Carter, and R.G. Ford. 1990. Numbers of seabirds killed or debilitated in the 1986 Ape.x Hoiislon oil spill in central California. Pages 164-174 in S.G. Sealy, ed. Auks at sea. Proceedings of an International Symposium of the Pacific Seabird Group. Studies in Avian Biology 14. Sealy. S.G.. ed. 1990. Auks at sea. Proceedings of an International Symposium of the Pacific Seabird Group. Studies in Avian Biology 14. 180 pp. Our Liviiiii Rcsdidxex — Binis 49 Sowls. A.L.. A.R. DeGange. J.W. Nelson, and G.S. Lester. 1980. Catalog of California seabird colonies. U.S. Fish and Wildlife Service, FWS/OBS .^7/80. 371 pp. Speich. S.M., and T.R. Wahl. 1989. Catalog of Washington seabird colonies. U.S. Fish and Wildlife Service. Biological Rep. 88(fi). ."ilO pp. Takekaw^i. J.E., H.R. Carter, and TE. Harvey. 199(1. Decline of the common murre in central California, 198U-1986. Pages 149-163 in S.G. Sealy. ed. Auks at sea. Proceedings of an International Symposium of the Pacific Seabird Group. Studies in Avian Biology 14. Varoujean. D.H.. and R.L. Pitman. 1979. Oregon seabird survey 1979. U.S. Fish and Wildlife Service, Portland, OR. Unpublished report. Vermeer, K.. K.T. Briggs, K.H. Morgan, and D. Siegel- Causey, eds. 1993. The status, ecology, and conservation of marine birds of the North Pacific. Proceedings of a Pacific Seabird Group Symposium. Canadian Wildlife Service Spec. Publ. Ottawa. Ontario. 263 pp. Wilson, U.W. 1991. Responses of three seabird species to Fl Nino events and other wami episodes on the Washington coast, 1979-1990, Condor 93:S.'i3-8.S8. Wilson, U.W., and D.A. Manuwal. 1986. Breeding biology of the rhinoceros auklet m Washington. Condor 88:143- For further information: Harry R, Carter National Biological Service California Pacific Science Center 6924 Tremont Rd. Di.\on. CA 95620 Abiuit 100 million seabirds reside in marine walei'.s of Alaska during some pail ol' the year. Perhaps half this population is eomposed of 50 species of nonbreeding residents, visitors, and breeding species that use marine habitats only seasonally (Gould et al. 1982). Another 30 species include 40-60 million individuals that breed in Alaska and spend most of their lives in U.S. ten-itorial waters (Sowls et al. 1978). Alaskan populations account for more than 95% of the breeding seabirds in the continental United States, and eight species nest nowhere else in North Amenca"(USFWS 1992). Seabird nest sites include rock ledges, open ground, underground bunows. and crevices in cliffs or talus. Seabirds take a variety of prey from the ocean, including krill. small fish, and squid. Suitable nest sites and oceanic prey are the most important factors controlling the natur- al distribution and abundance of seabirds. The impetus for seabird monitoring is based partly on public concern for the welfare of these birds, which are affected by a variety of human activities like oil pollution and commercial fish- ing. Equally important is the role seabirds serve as indicators of ecological change in the marine environment. Seabirds are long-lived and slow to mature, so parameters such as breeding success, diet, or survival rates often give earlier signals of changing environmental conditions than popula- tion size itself. Seabird survival data are of inter- est because they reflect conditions affecting seabirds in the nonbreeding season, when most annual mortality occurs (Hatch et al. 1993b). Techniques for monitoring seabird popula- tions vary according to habitat types and the breeding behavior of individual species (Hatch and Hatch 1978, 1989; Byrd et al. 1983). An affordable monitoring program can include but a few of the 1.300 seabird colonies identified in Alaska, and since the mid-1970"s, monitoring efforts have emphasized a small selection of surface-feeding and diving species, primarily kittiwakes (Rissa spp.) and murres {Uria spp.). Little or no information on trends is available for other seabirds (Hatch 1993a). The existing monitoring program occurs largely on sites within the Alaska Maritime National Wildlife Refuge, which was established primarily for the conservation of marine birds. Data are collected by refuge staff, other state and federal agencies, private organizations, university faculty, and students. Status of Monitored Birds Kittiwakes Kittiwakes are small, pelagic (open sea) gulls that range widely at sea and feed on a vari- ety of small fish and plankton, which they cap- ture at the sea surface. Black-legged kittiwakes {RIssd tri(lactyla) have been studied intensively because they are widely distributed and easy to observe. Among 10 locations for which popula- tion trend data are available, 3 show significant declines since the mid-1970"s, 3 show increas- es, and 4 show no consistent trends (Fig. 1 ). The overall trend is unknown, although widespread declines are anticipated because of a downward Seabirds in Alaska by Scott A Hatch John F. Piatt National Biological Senice Dense colonic >! . Islands, western Gulf of Alaska. Ml iiuirres (Uriel cicilf;c) breed on bare cliff ledges — here on the Semidi 50 Birds — Our Livini^ Resources BLKI (897 birds) St. George Is. RLKI (3,926 birds) ^ St. Paul Is. RLKI (115 birds) 100- 75- 50- 25- 0- 100- 75- 50- 25- 0- Semldi Is. "blki ~ ^(480 birds!" vs C. Thompson BLKI (4,088 birds) C. Peirce BLKI (1,295 birds) ZT^ Buldir Is. 56 60 72 75 78 81 84 87 90 Year Fig. 1. Population trends of hiack-legged kitliwakes (BLKI) and red-legged kittiwakes (RLKI) at selected colonies in Alaska. The maximum count of birds or nests is indicated for each location. Dashed lines indicate significant regressions {P < 0.051 of data collected since 1970 iP is a mea- sure of the confidence that the decline or increase is statistically reliable. P < 0.05 indicates a high probability that the population trend depicted actually occurred). See Hatch et al. 1993a and references cited therein for data sources. trend in the production of offspring (Fig. 2); some large colonies fail chronically. On Middleton Island, for example, breeding has been a total or near-total failure in 10 of the last 12 years (1983-94; Hatch et al. 1993a; Hatch, unpublished data). The colony is declining at an average rate of T7c per year (equal to adult mor- tality), suggesting there is no recruitment (Hatch et al. 1993b). If survival estimates obtained on Middleton apply generally, the near-term future of kittiwakes is unfavorable because average productivity of 0.2 chicks per pair (Fig. 2) is inadequate to maintain populations. Where red-legged kittiwakes (/?. brevi- rosiris) have been monitored, they show popu- lation trends similar to black-legged kittiwakes (Fig. 1). In 1989 their population was down by 50% in the Pribilof Islands, but they were inore numerous at Buldir Island than in the mid-1970"s (Byrd and Williams 1993). Because most of the world population of red-legged kit- tiwakes breeds in the Pribilofs (75% on St. George Island), their decline at that location is cause for concern. 0.7 06 45 / / \ ,36 (colony years) 0 5 50 \33 04 Xse 03 \45 02 \ l^c 01 53 63 00 77 79 81 83 85 87 Year Fig. 2. Productivity (chicks fledged per nest built) of black- legged kittiwakes in Alaskan colonies. 1976-89. The number of colony-years included in each mean is indicated. See Hatch et al. 1993a for raw data. Murres Murres are large-bodied, abundant, and wide-ranging seabirds that feed mostly on schools of fish they pursue by diving underwa- ter, sometimes to depths of 100-200 m (330-650 ft). Repeated counts of one or both murre species (common murre, Uria acilge, and thick-billed murre, U. lomvia) are available for 1 2 locations in Alaska (Fig. 3). Since 1970 com- mon munes have declined significantly at two colonies, and thick-billed munes have declined at one. Murres (species not distinguished) increased at two colonies over the same period. Between the I950"s and the I970's, murres increased at one location (Middleton Island) and declined at another (Cape Thompson), but they have since been relatively stable at both colonies. In 1989 the Ex.xon Valdez oil spill killed substantial numbers of common murres at several colonies in the Gulf of Alaska (Piatt et al. 1990a). Available data are insufficient to identify overall trends. Murres are relatively consistent producers of young, averaging 0.5-0.6 chicks per pair annually in both species (Byrd et al. 1993). Threatened and Endangered Species No breeding seabirds are currently listed as threatened or endangered in Alaska. The short-tailed albatross (Diomedea albatnis), with fewer than 1 ,000 individuals surviving, breeds in Japan but visits Alaskan waters during most months of the year. The species is vulnerable to incidental take by commercial fishing gear, especially gill nets and longlines (Sherburne 1993). Three species that breed in Alaska were recently listed as category 2 (possibly qualify- ing for threatened or endangered status, but more information is needed for determination): the red-legged kittiwake, marbled muirelet {Brachyramphus mannorutiis). and Kittlitz's murrelet (B. hrevimsths). As noted previously, red-legged kittiwakes have declined substantial- ly on the Pribilof Islands (Fig. 1 ). Marine bird surveys conducted in Prince William Sound in 1972-73 and 1989-93 suggest a significant decline of marbled murrelets in that area (Klosiewski and Laing 1994). This finding is corroborated by Audubon Christmas Bird Counts from coastal sites in Alaska, which reveal a downward trend since 1972 (Piatt, unpublished data). Kittlitz's murrelet also showed a decline in the Prince William Sound surveys (Klosiewski and Laing 1994). With an estimated population of fewer than 20.000 birds range-wide (van Vliet 1993). this species is one of the rarest of auks (Family Alcidae). Both murrelets were adversely affected by the Exxon Valdez oil spill (Piatt et al. 1990a). Our Living Resources — Birds >/ Other Species Scant int'orniation is available to assess numerical changes for most seabird species in Alaska. We know that some species were seri- ously reduced or locally extirpated by foxes introduced to islands in the 1800"s and early i900"s. About 450 islands from southeastern Alaska to the western Aleutians were used as release sites for arctic (Alopex lagopus) and red foxes {Viilpes viilpes) (Bailey 1993). The species most affected included open-ground nesters such as gulls (Lanis spp.). tems {Stenui spp.l. and ful- mars {Fuliiuiriis iiUicialis). and bumming birds like ancient murrelets {Synrhlihdraniphits untiqii- iis). Cassin's auklets {Ptychonunphus alfiiticus). tufted puffins {Fnitercula cirrhata), and stomi-petrels iOceanodroma spp.). In spite of natural die-offs and eradication efforts, foxes remain on about 50 islands to which they were introduced (Bailey 1993). Recent counts suggest that fulmars are increasing at two of their major colonies (Semidi Islands and Pribilof Islands), and sever- al small colonies have been established since the mid-1970"s (Hatch 1993b). Counts of least and crested auklets {Aeihia piisilla and A. cristateUa) also indicate possible increases at two colonies in the Bering Sea (Piatt et al. 1990b: Springer etal. 19931 Red-faced cormorants (Pluilacroconix urilc) declined about 50% on the Semidi Islands between 1978 and 1993. while pelagic cor- morants (P. pelagiciis) increased on Middleton Island between 1956 and the mid-1970"s (Hatch, unpublished data). Glaucous-winged gulls ^Llll■lls gluucescens) increased on Middleton from none breeding in 1956 to more than 20,000 birds in 1993 (Hatch, unpublished data); this species has also shown marked increases following removal of introduced foxes at several sites in the Aleutian Islands (Byrd et al. 1994). Marine bird surveys in Prince William Sound (Klosiewski and Laing 1994) suggest that arctic tems {Sterna panuiisaea). glaucous-winged gulls, pelagic cormorants, homed puffins (Fnitercula cornicidata), and pigeon guillemots [Cepphus columba) have all declined in that area. Tems and guillemots have recently increased on several Aleutian Islands following fox removal (Byrd et al. 1994). Factors Affecting Seabirds Alaskan seabirds are killed incidentally in drift gill nets used in high seas (DeGange et al. 1993), and oil pollution poses a significant threat, as demonstrated by the Exxon Valdez. spill. There is little doubt, however, that the introduction of exotic animals, especially foxes. but also rats, voles, ground squirrels, and rabbits TBMU (1,335 birds) St. Matthew Is. COMU (1,528 birds) St, Lawrence Is. (1.123 murres) 100 75 50 25 0 100 75 50 25 0 100 75 50 25 0 100 75 50 25 0 Semidi Is- (3,117 murres) ^\^ Bluff (2,541 COIulU) C Peirce (2,749 COMU) xz C. Thompson St, George Is, (1,842 birds) TBMU C, Lisburne (23,428 murres) (19,613 birds) SI, Paul Is Buldir Is, (2,035 murres) COMU (2,933 birds) 56 60 70 73 76 79 82 85 56 60 70 73 76 79 82 85 88 91 Year has been the most damaging source of direct mortality associated with human activity (Bailey 1993). Unlike one-time catastrophes, introduced predators exert a continuous nega- tive effect on seabird populations. Changes in food supply, whether natural or related to human activity, are another important influence on seabird populations. The postwar period from 1950 to the 1990"s has seen explo- sive growth and constant change in commercial fisheries of the northeastem Pacific (Alverson 1992). Driving these changes, or in some cases possibly driven by them, are major shifts in the composition of marine fish stocks. In the Gulf of Alaska, for example, a shift occurred in the late 1970's and early 1980's toward greater abundance of groundfish (cod. Gadiis macro- cephaliis: various flatfishes; and especially walleye pollock, Theragra chalcogramma), possibly at the expense of small forage species such as herring (Clupea harengus). sandlance (Ammodytes hexaplerus). and capelin {Mallotiis vHlosiis: Alverson 1992) (Fig. 4). Coincident with these changes, diets of a variety of seabirds such as murres. murrelets, and kittiwakes have shifted from being predominantly capelin-based COMU TBMU murres regressions Fig. i. Population trends of com- mon muires (COMU) and tliicl<-billed muires (TBMU) at selected colonies in Alaska. Counts of "murres" included unspecified numbers of common and thick-billed murres. The max- imum count of individuals is indi- cated for each location. Dashed lines indicate significant regres- sions (P < 0.05) of data collected since 1970. See Hatch 1993a for data sources. 52 Birds — Our Living Restiurces 20 - Pollock Fig. 4. Temporal changes in marine fish stocks of the Gulf of Alaska: total pollock biomass (age 2+) from stock assessment surveys by the National Marine Fisheries Service, 197S-40 (above, Marasco and Aron 1991 ), and catch per unit effort of capelin in midwater trawls in Pavlov Bay, western Gulf of Alaska, 1972-92 (below; P. Anderson, NMFS, unpublished data). For further information: Scott A. Hatch National Biological Service Alaska Science Center Anchorage, AK 99503 to pollock-based (Piatl, unpublished data), Seabiid deeiines and bieeding failures corfe- spond to the shift, as do drastic declines in har- bor seals (Phoca vltiilina) and nonhern sea lions {Eiinieloplas jiihaiiis) in the Gulf of Alaska (MeiTick et al. 1987; Pitcher 1990). The wholesale removal of large quantities of fish biomass from the ocean is likely to have major, if poorly known, effects on the marine ecosystem. An emerging issue is whether fish harvests are altering marine ecosystems to the detriment of seabirds and other consumers like pinnipeds and whales. The relative role of fishing and natural envi- ronmental variation in regulating these systems is another matter for long-term research. In any case, seabird monitoring will continue to pro- vide valuable insights into marine food webs, especially changes that affect the ocean's top-level consumers, including humans. References Alverson. D.L. 1992. A review of commercial fisheries and the Steller sea lion (Emnelopias jiibatusY. the conflict arena. Reviews in Aquatic Sciences 6:203-256. Bailey, E.P. 1993. Fox introductions on Alaskan islands: his- tory, impacts on avifauna, and eradication. U.S. Fish and Wildlife Service. Resour Publ. 193. 54 pp. Byrd, G.V., R.H. Day. and E.P Knudson. 1983. Patterns of colonv attendance and censusing of auklets al Buldir Island, Alaska. Condor 85:274-280, Byrd, G.V.. and J.C. Williams. 1993. Red-legged kittiwake {RissLi breviroslris). Pages 1-12 in The birds of Nonh America, 60. A. Poole and F. Gill, eds. The Academy of Natural Sciences, Philadelphia; The American Ornithologists' Union, Washington, DC. Byrd, G,V., E.C, Murphy, G.W. Kaiser, A,Y. Kondratyev. and Y,V. Shibaev. 1993. Status and ecology of offshore fish-feeding alcids (murres and puffins) in the North Pacific. Pages 176-186 in K. Vermeer. K.T. Bnggs, K.H. Morgan, and D. Siegel-Causey, eds. The status, ecology, and conservation of marine birds of the North Pacific. Canadian Wildlife Sen'ice, Ottawa. Byrd, G.V., J.L. Trapp, and C.F Zeillemaker 1994. Removal of introduced foxes: a case study in restoration of native birds. Transactions of the 59th North American Wildlife and Natural Resources Conference. Wildlife Management Institute, Washington, DC. In press. DeGunge, A.R., R.H, Day, J.E. Takekawa, and V.M. Mendenhall. 1993. Losses of seabirds in gill nets in the North Pacific. Pages 204-211 in K. Vermeer. K.T. Briggs, K.H. Morgan, and D. Siegel-Causey, eds. The status, ecol- ogy, and conservation of marine birds of the North Pacific. Canadian Wildlife Service, Otlavva. Gould, RJ., D.J. Forsell. and C.J. Lensink. 1982, Pelagic dis- tribution and abundance of seabirds in the Gulf of Alaska and eastern Bering Sea. U.S. Fish and Wildlife Service FWS/OBS-S2/48. 294 pp. Hatch, S,A. 1993a, Population trends of Alaskan seabirds. Pacific Seabird Group Bull. 20:3-12. Hatch, S.A. 1993b. Ecology and population status of northern fulmars Fulnmnis ^latiaiis of the North Pacific. Pages 82-92 in K. Vemieer. K.T. Bnggs, K.H. Morgan, and D. Siegel-Causey, eds. The status, ecology, and conservation of marine birds of the North Pacific. Canadian Wildlife Service, Ottawa. Hatch, S,A., G.V. Byrd. D.B. Irons, and G.L. Hunt, Jr. 1993a, Status and ecology of kittivvakes (.Rissa tridactyla and R. breviroslris) in the North Pacific. Pages 140-153 in K. Vermeer, K.T. Briggs, K.H. Morgan, and D. Siegel-Causey, eds. The status, ecology, and conservation of marine birds of the North Pacific. Canadian Wildlife Service, Ottawa, Hatch, S.A., and M,A. Hatch. 1978. Colony attendance and population monitoring of black-legged kittiwakes on the Semidi Islands, Alaska. Condor 90^613-620. Hatch, S.A., and M.A. Hatch. 1989. Attendance patterns of murres at breeding sites: implications for monitoring. Journal of Wildlife Management 53:483-493. Hatch, S.A., B.D. Roberts, and B.S. Fadely. 1993b Adult sur- \ival of black-legged kittivvakes Rissa tridactyla in a Pacific colony. 1^7135:247-254. Klosiewski, S.R, and K.K. Laing. 1994. Marine bird popula- tions of Prince William Sound, Alaska, before and after the Exxon Vatdez oil spill, U.S. Fish and Wildlife Service, Anchorage, AK. 89 pp. Marasco. R„ and W. Aron, 1991, Explosive evoluuon — the changing Alaska groundfish fishery. Reviews in Aquatic Sciences4:299-315. Men-ick, R.L., T.R. Loughlin, and D.G. Calkins. 1987, Decline in abundance of the northern sea lion, Euinetopias jiibutiis. in Alaska, 1956-86. Fishery Bull. 85:351-365. Piatt, J.F„ C,J, Lensink. W. Butler, M. Kendziorek, and DR. Nysewander. 1990a. Immediate impact of the "Exxon Valdez" oil spill on marine birds. Auk 107:387-397. Piatt, J.F, B.D. Roberts, and S.A. Hatch. 1990b Colony attendance and population monitoring of least and crested auklets on St. Lawrence Island, Alaska. Condor 92:97-106. Pitcher, K.W. 1990. Major decline in number of harbor seals, Plioca vitidina richcirdsi. on Tugidak Island, Gulf of Alaska. Marine Mammal Science 6:121-134. Sherburne, J. 1993. Status report on the short-tailed albatross Diomedea albatnis. U.S. Fish and Wildlife Service, Ecological Services. Anchorage, AK. 58 pp. Sowls, AX., S.A. Hatch, and C.J. Lensink. 1978. Catalog of Alaskan seabird colonies. U.S. Fish and Wildlife Service FWS/OBS-78/78. 254 pp. Spnnger, A.M., A.Y. Kondratyev, H. Ogi, Y.V. Shibaev. and G.B. van Vliet. 1993. Status, ecology, and conservation of Synthliboramplms murtelets and auklets. Pages 187-201 in K, Vermeer, K.T. Briggs, K.H, Morgan, and D. Siegel-Causey, eds. The status, ecology, and conservation of manne birds of the North Pacific, Canadian Wildlife Service, Ottawa. USFWS. 1992. Alaska seabird management plan, U,S. Fish and Wildlife Service. Division of Migratory Birds, Anchorage, AK. 102 pp. van Vliet. G. 1993. Status concerns for the "global" popula- tion of Kittlitz's murrelet: is the "glacier murrelef ' reced- ing? Pacific Seabird Group Bull. 20:15-16. Out Ln'tiif^ Rt'siHiiVi's — BtrJs 5.1 Colonial walerbirds. that is, scabirds (gulls, terns, cormorants, pelicans) and wading birds (herons, egrets, ibises), have attracted the attention of scientists, conservationists, and the public since the turn of the century when plume hunters nearly drove many species to extinction. The first national wildlife refuge at Pelican Island, Florida, was founded to conserve a large nesting colony of the brown pelican {Pclccaniis occidentalis). The National Audubon Society also established a game warden system to mon- itor and protect important waterbird colonies. These efforts helped establish federal laws to protect migratory birds and their nesting habi- tats in Noilh America. Although the populations of many species rebounded in the early part of the 2()th century, major losses and alteration of coastal wetlands still threaten the long-term sustainability of many colonial waterbirds. A national, coordi- nated monitoring program is needed to monitor population status and trends in colonial water- birds (Erwin et al. 1993). The Canadian Wildlife Service has recently established a national seabird monitoring program (D. Nettleship. CWS, personal communication). In addition, better coordination and cooperation for monitoring waterbirds are needed on both their breeding grounds in North America and their wintering grounds in Latin America where wetland loss is also a critical problem (Erwin et al. 1993). This article summarizes the status and trends of selected waterbird species in North America, but excludes Alaska. Hawaii, and the Pacific coast, which are described else- where. Population Surveys Data on the population status of coloni; waterbirds come from many sources. The Breeding Bird Survey (Peterjohn and Sauei 1993) is useful as a visual index for the more widely distributed species that occur along coasts and across the interior of the United States and Canada (e.g.. great blue herons [Ardea herodias] and herring gulls [Larus cirgentalus]). but it is not effective for many waterbird species that nest in wetlands. Recently, Christmas Bird Count (CBC) data have been analyzed, providing an index to num- bers of wintering birds (J.R. Sauer, National Biological Service, personal communication). For waterbirds, these counts must be used with caution since water conditions can have a major effect on the feeding distribution of waterbirds during the count period in December. Thus, trends in CBC counts may indicate more about trends in wetland conditions than trends in pop- ulations of any particular waterbird species. More precise estimates of species" popula- tions at colony sites have been conducted over the years by state, federal, and private organiza- tions. Although a few states (e.g., Florida, Illinois, Massachusetts, Texas, and Virginia) have conducted annual surveys over a long peri- od for at least some species, there is little con- sistency among their methods and the frequen- cy of surveys (Erwin etal. 1985). Many data on breeding populations are kept at the state level, but these data seldom predate 1 980. precluding assessment of long-term trends in many of these long-lived species. Even though more than 50 species of colo- nial waterbirds breed in the United States, Canada, and Mexico, this article focuses on the 22 species for which sufficient data are avail- able to indicate population changes, at least at a regional level. Pelecaniformes Pelicans and their allies (cormorants, anhin- gas) suffered from DDT use, and their numbers plummeted to the point where the eastern and California brown pelicans became endangered. The eastern subspecies, however, was recently removed from the threatened list because of its rapid numerical and range increases (Table). The American white pelican {Pelecamis eiy- throrhynchos) has shown similar sharp increas- es in the western regions of Canada and the United States (Evans and Knopf 1993). Double- Colonial Waterbirds by R. Michael Erwin National Biological Service Common tern (Sterna hinindo). 54 Birds ■ Our Liviiii^ Resiiiines Table. Regional. natiniKil. and continental population statu;- and trends of selected colonial water- birds in the United States-' as reported by the Breeding Bird Survey. Christmas Bird Counts, and other sources. Population status BBS/CBC trend'' Species Region Early period Recent period % change % +/-routes Years References'^ Pelecaniformes American white pelican Eastern brown pelican Double-crested cormorant Continent US Canada Mexico U.S. US Continent US Canada U.S. 17,872 nests (1964) 14,103(1967-69) Sporadic (100 nesis) 7,800-8,300(1970-76) 22,299 nests (1980-81) 53,345(1985-86) 26.461 ( -f5.3" ■I-3.8'" NA ■1-6.5'" -t23" +11.5- +8 2- +0,6r" +0 6r" +0.64' 1966-91 BBS 1 1 1 1966-89 CBC (winter) 2 1966-91 BBS 1966-89 CBC (winter) Ciconliformes Great blue heron Great blue tieron Snowy egret Reddish egret Black-crowned night-heron White Ibis While-laced ibis Wood stork Continent US Canada US U.S. US Gull coast U.S. Southeast US U.S. Western U.S U.S. Southeast U.S. U.S. +1.5" +19 0.60- oer" 1,700-2,200 pr (1976-78) 1,370-1,900 pr (1989-90) 40,000-80,000pr(1967-71) 22,000-50,000 pr (1987-93) 4,500-5,500 pr (1967-75) 13,000-13,500 pr (19851 2,500-5,200 pr (1976-82) 6,729 pr (1993) +0,7 ns 0,54" +2,2— +2.0" +2.8 +5.0" +7.6" +1.3 ns 1966-91 1966-89 1966-89 1966-89 1966-89 1966-89 1966-89 BBS CBC CBC 3,4,5,6 CBC 7 CBC 8 CBC 9,10 CBC Charadrilformes Razorbill N, Gull St, Lawrence, Can, 16,200 birds (1960) 2,380 birds (1982) 11 Atlantic puflin Canada (Witless Bay) 300,000-340,000 pr(1973) 225,000 pr(1978-80) 11 U.S. 125 pr, (1977) 135 pr, (1993) 12 Great black-backed gull U.S. +3 6" 1966-89 CBC Hernng gull Atlantic coast U.S. 110,000 pr.(1978-82) < 100,000 pr (1988-92) 13 US +0.5 ns 1966-89 CBC Ring-billed gull Continent +7.9" +0.60"- 1966-91 BBS US +16.5" +0 58- Canada +5.7* +0.62"- US, +4.2- 1966-89 CBC Franklin's gull Continent -6.0 ns 1966-91 BBS US ■19 2- Canada -1.2 ns Gull-billed tern Mid-Atlantic US (VA-SC) 1,100-1,600 pr, (1977) 1,125-1625 pr, (1993) 14,15,16 Gulf coast U,S. (TX-AL) 1,200-2,100 pr. (1977) 3,000 pr, (1990) 3,4,5 US. -15- 1966-89 CBC Forsler's tern Continent -2,4 ns -0.58' BBS U.S. -3,2 ns -0.60" BBS Canada InsutI, data US +43- CBC Common tern Great Lakes U.S. 1,691 nests (1977) 1,916 nests (1989) 17,18 Roseate tern N Atlantic US. 2,855-3,285 pr (1976-80) 3,200 pr (1993) 19,20 U.S. Caribbean Uncertain pre-1975 1,900-2,500 pr, (1975-80) 13,18 Least tern (inlenorssp) Mississippi River 4,100-4,700 birds (1986-87) 6,833 birds (1991) 1986-91 21 Black tern Continent -3,9" -0.59"- 1966-92 BBS U.S, -5.6- -0 64"- Canada -3.4 -0.52 ns ^Excluding Alaska, Hawaii, and the Pacific coast states. ''Breeding Bird Survey trends statistically lest for an annual (% change) trend (Hq: trend = 0) and % ol increasing (+) or decreasing (-) routes (Hq no, routes + = no. routes-) Probability levels: 'P<0 10;" P<0,05: "* P<0 01 A lower P value means there is more confidence that the trend is real, A population trend change at the P< 0.10 level is considered statistically significant: ns = not significant Christmas Bird Count trends are conducted similar to annual BBS trend (J R Sauer. NBS. unpublished data). ^Sources: numbers reler to literature reference number; BBS = Breeding Bird Survey results (J,R. Sauer and B Peterjohn, NBS, personal communica- tion); CBC = Christmas Bird Count trend results (J R Sauer, personal communication), 1— Evans and Knopf 1993; 2— P Wilkerson, South Carolina Wildlife and Marine Resources Department; 3— Lange, in press; 4— Portnoy 1978; 5— Martin and Lester 1990; 6— Runde 1991; 7— P Frederick, University of Florida, unpublished data; 8— D, Manry, unpublished data; 9— Ogden etal 1987; 10— J. Ogden and M, Coulter, National Park Service, unpublished data; 11— Netlleship and Birkhead 1985: 12— B. Allen, Maine Department of Inland Fisheries and Wildlife, unpublished data; 13— Nisbel, in press; 14— Spendelow and Palton 1988: 15— Erwin 1979; 16— J. Parnell and P. Wilkerson, University of North Carolina and South Carolina Wildlife and Marine Resources Department, unpublished data, 17— Scharf et al, 1992; 18— Blokpoel and Tessier 1993; 19— Gochfeld 1983; 20— J,A, Spendelow, NBS, unpublished data; 21— E. Kirsch and J. Sidle, NBS, unpublished data. crested cormorant (Phalacrocorax aiiritiis) pop- ulations also declined during the 1940-70 peri- od, probably because of DDT and other pesti- cides; however, this species has increased dra- matically across Canada and the northern United States (Table). In the Great Lakes and elsewhere, this species' increases have attracted considerable attention because of the negative effects on fisheries and on the aquaculture industry (Blokpoel and Scharf 1991; Blokpoel and Tessier 1991; Nettleship and Duffy, in press). Our Livinf; Rt'iouive.s — Binl\ 55 Ciconiiformes Heron, egret, and ibis nesting colonies were reduced along much of the U.S. coastline in the early 1900"s as a result of the millinery trade; however, the species have all recovered their former ranges. Great blue herons are the most abundant and ubiquitous of the wading birds in North America: all indications suggest that their populations have increased, especially in the United States (Butler 1992; Table). One reason for this trend may be that winter survival has increased as herons feed heavily at aquaculture facilities in the southern United States. The reddish egret (Egretta rufescens) is list- ed as a species of management concern to the USFWS (OMBM 1994).^It nests in small num- bers along the gulf coast and in southern Florida (Table). Reddish egrets seem to have declined some in Texas (Lange. in press) and Louisiana (Portnoy 1978; Martin and Lester 1990; Figure), but the data are not adequate in Florida to assess trends. Snowy egrets (E. lliiila) were prized by plume traders at the turn of the century, and the species suffered dramatic population declines; however, by the 1970"s these egrets had recov- ered their former range. More recently, their populations declined in some Atlantic regions such as Virginia (Williams et al. 1990) and southern Florida (Robertson and Kushlan 1974; Ogden 1978; Table). The black-crowned night-heron {Nycticorax nycticorax), which occurs across all of North America, may be declining in pails of Canada, south to Texas (Davis 1993) and perhaps Virginia (Williams et al. 1990; Table). Ibises are more nomadic in their breeding distribution than are other wading birds. White ibis (Endocimus albiis) have declined markedly in southern Florida as a result of hydrologic changes in the Everglades (Robertson and Kushlan 1974; Ogden^ 1978). Their breeding distribution has shifted northward, and large colonies exist in Georgia and the Carolinas (Ogden 1978; Bildstein"l993). Over the entire southeastern United States the species may not have undergone major changes, although state estimates have been enatic (twofold changes in 2-3 years; Table). The white-faced ibis {Plciicidis chilli) was formerly (1987) on the USFWS management concern list, but is not on the 1994 national list (OMBM 1994). Population data for the central and western populations (noncoastal) indicate a marked increase in the numbers of these ibis from the early 1970's to 1985 (D. Manry, per- sonal communication; Table). Wood storks (Mycteria americcma). which have been federally listed as endangered since 1984, nest from Florida north to South Carolina in the United States, in Cuba, and in enormous numbers in the river deltas of eastern Mexico, especially the Usumacinta-Grijalva Delta. Stork colonies have shifted north from the Everglades to central and northern Florida. Georgia, and South Carolina since the 1970"s (Robertson and Kushlan 1974; Ogden 1978; Ogden et al. 1987). Recent inventories of nesting populations in the United States indicate a modest increase in numbers over the past 10-15 years (Table; Figure). Because of the mobility of wood storks and ibis, monitoring them requires a regional approach to ensure standardization in survey timing and methods. Individual state inventories are inadequate to address many highly mobile species. Charadriiformes This order of colonial-nesting waterbirds includes the alcids (murres, puffins, auks), shorebirds, gulls, terns, and black skimmers {Ryiichops niger). Although some species of alcids and terns were nearly extirpated by hunters or millinery traders during the early 19()()"s. they rebounded well in many areas. Alcid populations are rare in the eastern United States. In maritime Canada, however, alcid numbers are substantial (Nettleship and Birkhead 1985; Erskine 1992), though there is concern over Canada's razorbill (Alca tarda) populations, which declined by more than 75% from 1960 to 1982 (Nettleship and Birkhead 1985). These declines may be the result of con- flicts with commercial fisheries. Canadian populations of Atlantic puffins (Eratercula arctica) have declined a great deal in some areas. The largest Atlantic puffin colony in North America is at Witless Bay, Newfoundland (61% of continental breeding total); this colony has declined by 25%-35% from 1973 to 1980 (Nettleship and Birkhead 1985). Again, competition between birds and commercial fisheries (capelin) may be causing much of the decline. In Maine, a successful transplant program has been in effect for more than a decade to reintroduce nesting Atlantic puffins onto several coastal islands (Kress and Nettleship 1988); numbers remain small, how- ever (Table). Gull populations have increased substantial- ly from the middle part of the century to the pre- sent (Buckley and Buckley 1984; Nisbet, in press). Great black-backed gulls {Lxirus mari- mts) have increased in some mid- Atlantic states but have probably declined in Maine (Nisbet, in press; Table). Herring gull populations probably peaked around 1980 at about 1 lO.OtJO pairs along the northeastern U.S. coastline, but popu- lations may have declined during the 1980"s ^- endangered Wood stork I of concern 4-- 76-82 93 Roseate tern, North Atlantic population ^30 I ■_ B^S ■ mm 20 ^'^T^ 76-80 Interior least tern 93 65- 55- o 45- 35- 86-87 20- P^ Reddisli egret S 15 ±^ 76-78 89-90 Black tern ■%v. ■ii^ltal 66 71 76 81 86 91 Year Figure. Trends of selected colo- nial waterbirds either endangered or on the U.S. Fish and Wildlife Service's list of species of man- agement concern in the lower 48 states (excluding the Pacific coa.st). Black tern trends are count indices from the Breeding Bird Survey ( mean or average number of birds per route). Lighter color shows range of variation in estimates. 56 Birds — 6*///" Living Re.soiirccs (Nisbet. in press): BBS and CBC data do not show any change (Table). Changes in landfill practices that have reduced food supplies along the northeastern coast may have reduced winter survival and slowed the population growth of this species. In the Great Lakes, however, her- ring gulls have shown a dramatic increase since the^late 1970"s. Ring-billed gulls (L. JcUnvarenis) continue to increase across the northern tier of states. Canada, and the Great Lakes (Blokpoel and Scharf 1991: Blokpoel and Tessier 1991; Table). The BBS and CBC data suggest signifi- cant increases in the LInited States and Canada (Table). Refuge and resource managers are con- cerned over the reported decline in the Franklin's gull it. pipixcaii). an interior, marsh- nesting species that may be vulnerable to agri- cultural pesticides (White and Kolbe 1985). The BBS trends indicate that the numbers of this species significantly declined in the United States from 1966 to 1991. However, adding 1992 and 1993 data indicates a nonsignificant decline in the United States, which raises the question of the value of BBS data for this tlock- feeding species (J.R. Sauer. personal communi- cation). Gull-billed terns (Sterna lulullca] are a species of special concern to many coastal states and were on the fomier (1987) USFWS management list. Recent population figures from Texas (Lange. in press). Louisiana (Martin and Lester 1990). and the mid- Atlantic region (Virginia to South Carolina) suggest that the population is reasonably stable over the long term but en'atic from year to year (Table). The Forster's tem (S. forsteri) nests both along coasts and across the interior of the north- ern tier of states and Canadian provinces. State surveys do not suggest declines in most states from New Jersey (CD. Jenkins. New Jersey Division of Fish. Game and Wildlife, personal communication) to Virginia (Erwin 1979). Data are insufficient in the Great Lakes to assess trends. The trends from the BBS and CBC are contradictory, with breeding trends indicating declines and wintering trends a significant increase. This species is en"atic in its nesting and probably not sampled well by either of these surveys. Common terns (S. luniiulo). while abundant and increasing along the U.S. northeastern coast (Buckley and Buckley 1984), are considered endangered, threatened, or a species of special concern in six Great Lakes states and Ontario (Blokpoel and Schaif 1991; Scharf et al. 1992). Even though tern numbers increased from 1977 to 1989 in the U.S. Great Lakes (Table), the number of their colony sites has declined from 31 to 23. Competition with the ring-billed gull is a major factor in this decline (Schaif et al. 1992). The roseate tern (5. doiii^allii) is an endan- gered species (since 1987) and breeds in two populations in the western Atlantic. The west- ern North Atlantic population includes the mar- itime provinces south to Long Island. New York (with a few possibly from New Jersey to Georgia); the U.S. Neotropical population is confined to Puerto Rico, the Virgin Islands, and southern Florida. In the northern population, the number of breeding pairs ranged from 2.855 to 3.285 pairs during the 1976-80 period (Gochfeld 1983) to 3.200 estimated pairs in 1993 (J. Spendelow. National Biological Service, personal communication: Table; Figure). In the southern U.S. population, pair estimates from the 1976-79 period range from about 1.900 (Gochfeld 1983) to about 2.600 pairs in the Florida Keys. Puerto Rico, and the Virgin Islands (Blokpoel and Tessier 1993; Table). Earlier records are sparse in this region, making trends difficult to determine. The least tem iS. aittilUiniin) is di\ided into three subspecies in the United States and Canada: the interior {S.a. athalassos) and California {S.a. hwwni) subspecies are listed as endangered. In the Mississippi River drainages, the interior least tern seems to have increased from the 1986-87 period to 1991 (E. Kirsch and J. Sidle. NBS. unpublished data; Table: Figure). The 1993 fioods probably prevented recent nesting in many river stretches. The black tem (Clilidoiila.s iiiger) is listed as either endangered or a species of concern in many northern states, including New York. Iowa. Illinois. Wisconsin. Ohio, and Indiana. Its population has decreased at the BBS continen- tal and U.S. levels from 1966 to 1992 (Table; Figure). From 1982 to I99I. BBS data indicate a significant increase in Canada with continued decrease in the United States. This suggests a species" displacement to the north, possibly a result of changes in wetland conditions in the northern tier of the United States. A confound- ing factor may also be that the Canadian surveys have been more intensive for this species in recent years. References Bildstein. K.L. 1993. White ibis: wetland wanderer. Smithsonian Institution Press, Washington. DC. 242 pp. Blokpoel. H.. and W.C. Scharf. 1991. Status and conser\a- tion of seabirds nesting in the Great Lakes of North America. Pages 17-41 in J. Croxall, ed. Status and con- servation of the world's seabirds. International Council for Bird Preservation. Cambridge. England. Blokpoel. H., and G.D. Tessier 1991. Distnbution and abundance of colonial waterbirds nesting in the Canadian portions of the lower Great Lakes system in 1990. Canadian Wildlife Ser\'ice Tech. Rep. Series 117. 16 pp. Blokpoel. H.. and G.D. Tessier. 1993. Atlas of colonial waterbirds nesting on the Canadian Great Lakes. 1989- 1991. Part 1. Cormorants, gulls, and island-nesting terns Our Lniiif- Rfsoi}is gallopavo). Life History According to most accounts, wild turkeys were quite abundant at the time of European colonization of North America. Wild turkeys became a major food of these settlers as they moved westward across the forested eastern United States. Turkeys were also used for cloth- ing, ornamentation, and food by many Native American tribes. As the nation grew in the I800"s, wild turkey numbers dwindled. The birds were harvested without restraint and mar- keted for human consumption. In addition, their forest habitat was cleared for agriculture and wood products. In the early I900"s. population numbers continued to decline. By 1920, wild turkeys were extiipated from 18 of the 39 states of their ancestral range (Mosby and Handley 1943). Fig. 1. Distnbiition of ttie wild turkey in the United States and Mexico in 1989 (Stangel et al. 1992). (Jiir Liiu!}^ Rt'SDiines — Birds 71 After the early 1900's little change occuired in wild turkey distribution and populations until after World War 11 when resources were direct- ed to restoring and managing the nation's wildlife populations, including the wild turkey. A technique that many state agencies believed to be promising, but did not work, was artificial propagation of game-farm or pen-raised turkeys. Turkeys raised in captivity were not properly imprinted on (recognition and attach- ment) wild hens and did not have the experience and survival skills necessaiy to live and repro- duce in the wild. Restoration through trapping wild turkeys in the wild and relocating them was the proper solution, but this technique was not easily accomplished with the wary bird. Development of the rapidly propelled cannon net, originally designed for capturing waterfowl, was a major factor in relocating large numbers of wild turkeys for restoration. Thousands of wild turkeys were captured or moved with this tech- nique or variations of it: in addition, drop nets and immobilizing drugs were used. Several other factors contributed to the return of the wild turkey: the maturing of the eastern forests, which had been almost elimi- nated: increased knowledge from research: spread of sound management practices; and bet- ter protection of new flocks vulnerable to poaching. The restoration of the wild turkey is a great wildlife management success story. In the early part of this century only tens of thousands of wild turkeys were found in a few remote areas. By 1959 the total population approached one- half million (Kennamer et al. 1992), and by 1994 almost all of the forested eastern United States and much of the forested West had been restocked (Fig. 1 ), with the total population now probably approaching 4 million (Fig. 2). At pre- sent, there are viable wild turkey populations with hunting seasons in every state but Alaska, and the annual harvest exceeds one-half million turkeys. The state wildlife management agen- cies, aided by the National Wild Turkey Federation and supported by sportmen's dollars, undertook a tremendous task and achieved dra- matically successful results (Dickson 1992). Turkey hunting continues to be pursued by mil- lions of dedicated hunters. Future population expansion is expected to be somewhat limited. Most suitable turkey habi- tat has been stocked, and, generally, populations in these areas have already gone through their high-productivity phase. Population expansion is also limited because appropriate habitat will be lost as the human population expands. References Dickson. J.G.. ed. 1992. Tlie wild turkey: biology and man- agement. Stackpole Book>,. Hairisburg. PA. 46.^ pp. Kennamer, J.E.. M. Kennamer. and R. Brenneman. 1992. History. Pages 6-17 iii J.G. Dickson, ed. The wild turkey; biology and management. Stackpole Books. Harrisburg, PA. Mttshy. H.S.. and CO. Handley. I94.\ The wild turkey in Virginia: its status, life history and management. Virginia Division of Game and Inland Fisheries, Richmond. P-R Project. 281 pp. Schorger. A.W. 1966. The wild turkey: its history and domestication. University of Oklahoma Press. Nonnan. 62.5 pp. Stangel, PW.. J.I. Smith, and P.L. Leberg. 1992. Systematics and population genetics. Pages 18-28 in J.G. Dickson, ed. The wild turkey: biology and management. Stackpole Books. Harrisburg, PA. 59 70 80 86 90 Year Fig. 2. Estimated U.S. wild turkey population, 1959-90 (from Kennamer et al. 1992). For further information: James G. Dickson U.S. Forest Service Wildlife Habitat Laboratory PO Box 7600. SFA Station Nacogdoches, T.X 75962 The mourning dove (Zenaida macwuni) is one of the most widely distributed and abundant birds in North America (Droege and Sauer 1990). It is also the most important U.S. game bird in terms of numbers harvested. The U.S. fall population of mourning doves has been estimated to be about 475 million (Tomlinson et al. 1988: Tomlinson and Dunks 1993). The breeding range of the mourning dove extends from the southern portions of the Canadian Provinces throughout the continental United States into Mexico, the islands near Florida and Cuba, and scattered areas in Central America ( Aldrich 1993: Fig. 1 1. Although some mourning doves are nonmigratory, most migrate south to winter in the United States from northern California to Connecticut, south throughout most of Mexico and Central America to western Panama. Within the United States, three areas contain breeding, migrating, and wintering mourning dove populations that are largely independent of each other (Kiel 1959). In 1960 three areas were established as separate management units: the Eastern (EMU), Central (CMU), and Western (WMU:Fig. 1). The two main tools used to manage mourn- ing doves are an annual breeding population survey (known as the Mourning Dove Call- count Survey: Dolton 1993a, b) and harvest sur- veys. The Call-count Survey provides an annu- al index to population size as well as data for determining long-term trends in dove popula- tions. State harvest surveys and the National Migratory Bird Harvest Information Program, begun in 1992, estimate dove harvest. In addi- tion, recoveries from banded doves have pro- vided vital information for managing the species (Hayne 1975: Dunks et al. 1982; Tomlinson et al. Mourning Doves by David D. Dolton U.S. Fish and Wildlife Service 72 Birds — Our Livini; Resfurces Breeding and wintering range Mam wintering range Nontiern limit of wintering range Fig. 1. Breeding and wintering ranges of mourning doves and mourning dove management units in the United States. Status and Trends The Eastern Management Unit includes 27 states— 30% of the U.S. land area. The 1993 population indices were 18.3 doves heard and 14.9 doves seen per route (Dolton 1993b; Fig. 2). Both estimates are above the long-term trend estimates. Between 1966 and 1993. the popula- tion has been relatively stable. Dove harvest in the EMU was relatively constant from 1966 to 1987. with between 27.5 million and 28.5 mil- lion birds taken. The latest estimate, a 1989 sur- vey, indicated that the harvest had dropped to about 26.4 million birds shot by an estimated 1.3 million hunters (Sadler 1993). The Central Management Unit consists of 14 states containing 46% of the U.S. land area. Of the three units, the CMU has the highest mourn- ing dove population index. The 1993 index for the unit of 23.9 doves heard per route is slight- ly below the long-term trend estimate (Dolton 1993b; Fig. 2). For doves seen, the estimate of 26.8 is also below what was expected. Even though there appears to be an increase in doves seen and a slight decrease in doves heard between 1966 and 1993, in statistical terms there is no significant trend indicated for either count. Although hunting pressure and harvest varied widely among states, dove harvest in the CMU generally increased between 1966 and 1987 to an annual average of about 13.5 million birds. In 1989 almost 11 million doves were taken by about 747,000 hunters (Sadler 1993). The Western Management Unit comprises seven states and represents 24% of the land area in the United States. The 1993 population indices of 9.3 doves heard and 8.5 doves seen per route are slightly above their long-term trend estimates (Dolton 1993b; Fig. 2). Significant downward trends in numbers of doves heard and seen for the unit occuned between 1966 and 1993. From 1987 to 1993, however, a significant positive trend occuned in the unit although the indices were still below those of the 1960's. After a decline in the dove breeding population, dove harvest in the WMU declined significantly. In the early I970's, about 7.3 million doves were taken by an estimated 450.000 hunters. By 1989, the harvest had dropped to about 4 million birds shot by about 285,000 hunters (Sadler 1993). In summary, mourning dove populations in the EMU and CMU are relatively stable. Although the population of doves in the WMU declined from a high in the mid-l960"s. it appears that it stabilized during the past 7-10 years. U.S. dove harvest appears to be decreas- ing. The mourning dove remains an extremely important game bird, however, especially since more doves are harvested than all other migra- tory game birds combined. A 1991 survey indi- cated that the mourning dove provided about 9.5 million days of hunting recreation for 1.9 million people (USFWS and U.S. Bureau of Census 1993). Year-to-year population changes are normal and expected. Although populations are rela- tively stable in the Eastern and Central Management units, declining long-term trends in the past two decades are cause for concern in the Western Unit and in local areas elsewhere. A combination of factors may have been detri- mental to dove populations in some areas: habi- tat and agricultural changes including loss of nesting habitat through reclamation and indus- trial and urban development, changes in agri- cultural practices that may have reduced food sources, and possibly overharvest of doves in local areas. In California, for example, many live oak trees have been cut for wood products resulting in a loss of nesting habitat. Reclamation projects or lowered water tables eliminated thousands of acres of mesquite nest- ing habitat in Arizona. Since many doves from the WMU winter in Mexico during a 5- to 6- month period each year, agricultural changes there may negatively affect doves. In the CMU, agricultural changes were eval- uated and compared with dove population trends in the eastern group of states (R.R. George, Texas Parks and Wildlife Department, unpublished data); mounting dove population Uiir Livina Resouici's — Buds 73 indices appeared to be most closely correlated with changes in number of farms (positive) or farm si/e (negative). In addition, an analysis identified number of farms and acres of soy- beans, oats, and sorghum over time as good indicators of the number of doves heard. Early records indicate that mourning doves were present, although not abundant, when the United States was settled by colonists (Reeves and McCabe 1993). The resulting clearing of forests, introduction of new food plants, grazing and trampling by livestock that promoted seed- producing plants used by doves, and the cre- ation of stock ponds providing more widely dis- tributed drinking water in the arid West all ben- efited the mourning dove so that they are prob- ably more numerous now than in colonial times. These birds are quite adaptable and readily nest and feed in urban and rural areas. The mourning dove has recently even expanded its range northward. References Aldrich. J.W. 1993. Classification and distribution. Pages 47-54 in T.S. Basketl. M.W. Sayre, R.E. Tomlinson. and R.E. Mirarchi. eds. Ecology and management of the mourning dove, Stackpole Books. Hairisburg. PA. Dolton. D.D. 199.3a. The Call-count Survey: historic devel- opment and cuirent procedures. Pages 23.^-2.52 in T.S. Baskett. M.W. Sayre. RE. Tomlmson. and RE, Mirarchi. eds. Ecology and management of the mourning dove. Stackpole Books, Hamshurg. PA, Dolton. D.D. 1993b. Mourning dove breeding population status, 1993. U.S. Fish and Wildlife Service, Laurel, MD. 16 pp. Droege, S., and J.R. Sauer. 1990. North American Breeding Bird Survey annual summary 19S9. U.S. Fish and Wildlife Service Biological Rep, 90(8). 16 pp. Dunks. J.H.. RE. Tomlinson, H.M, Reeves, D.D. Dolton. C.E, Braun. and T.P, Zapatka, 1982, Migration, harvest, and population dynamics of mourning doses handed in the Central Management Unit. 1967-77. U.S. Fish and Wildlife Service Special Sci. Rep.— Wildlife 249. 128 pp. Hayne. D.W. 1975. E.xperimental increase of mourning dove bag limit in Eastern Management Unit, 1965-72. Southeastern Association of the Game and Fish Commissioners Tech. Bull. 2. 56 pp. Kiel. W. H.. Jr. 1959. Mourning dove management units — a progress report. U.S. Fish and Wildlife Service Special Sci. Rep.— Wildlife 42, 24 pp. - heard EMU long-term trend CMU WMU 66 68 70 72 74 76 78 80 82 84 Year 90 92 Reeves. H.M,. and R.E. McCabe. 1993. Historical perspec- tive. Pages 7-46 //( T.S. Baskett, M,W. Sayre, R.E. Tomlinson, and R.E. Mirarchi, eds. Ecology and man- agement of the mourning dove. Stackpole Books. Hamsburg, PA. Sadler, K.C. 1993. Mourning dove harvest. Pages 449-458 //; T.S. Baskett, M.W. Sayre. R.E. Tomlinson, and R.E. Mirarchi, eds. Ecology and management of the mourning dove. Stackpole Books. Hairisburg. PA. Tomlinson, R.E.. D.D. Dolton. H.M. Reeves. J.D. Nichols, and L.A. McKibben. 1988. Migration, harvest, and pop- ulation characteristics of mourning doves banded in the Western Management Unit. 1964-77. U.S. Fish and Wildlife Service Tech. Rep. 13. 101 pp. Tomlinson. R.E., and J.H. Dunks. 1993. Population charac- teristics and trends in the Central Management Unit. Pages 305-340 in T.S. Baskett. M.W. Sayre, R.E. Tomlinson, and R.E. Mirarchi, eds. Ecology and man- agement of the mourning dove. Stackpole Books, Harrisburg, PA. USFWS and U.S. Bureau of the Census. 1993. 1991 National survey of fishing, hunting, and wildlife -associ- ated recreation. U.S. Government Printing Office. Washington, DC. 124 pp. Fig. 2. Population indices of mourning doves in the Eastern (EMU), Central (CMU), and Western (WMU) Management units, 1966-93. For further information: David D. Dolton U.S. Fish and Wildlife Service Office of Migratory Bird Management 1 1500 Amencan Holly Dr. Laurel. MD 20708 The common raven {Coitus corax) is a large black passerine bird found throughout the northern hemisphere including western and noilhern Noilh America. Ravens are scavengers that frequently feed on road-killed animals, large dead mammals, and human refuse. They kill and eat prey including rodents, lambs (Larsen and Dietrich 1970). birds, frogs, scorpi- ons, beetles, lizards, and snakes. They also feed on nuts, grains, fruits, and other plant matter (Knight and Call 1980; Heinrich 1989). Their recent population increase is of concern because ravens eat agricultural crops and animals whose populations may be depleted. Ravens are closely associated with human activities, frequently visiting solid-waste land- fills and garbage containers at parks and food establishments, being pests of agricultural crops, and nesting on many human-made struc- tures. In two recent surveys in the deserts of California (FaunaWest Wildlife Consultants 1989; Knight and Kawashima 1993), ravens were more numerous in areas with more human influences, and were often indicators of the degree to which humans affect an area. Annual Breeding Bird Surveys (BBS) con- ducted nationwide by the U.S. Fish and Wildlife Service (USFWS) indicated that raven Common Ravens in the Southwestern United States, 1968-92 by William I. Boarman Kristin H. Berry National Biological Service 74 Birds ' Our Liviiif; Resources Fig. 1. Juvenile desert tortoise shell found beneath an aetive raven nest. The hole in the shell was probably pecked open by a raven to eat the organs. populations in several parts of the country sig- nificantly increased during 1965-79 (Robbins et al. 1986). This increase concerns resource man- agers because ravens teed on agricultural crops and animal species of interest to humans. For instance, in the deserts of the southwestern United States, ravens prey on young desert tor- toises {Gopherus agassizii'. Berry 1985; Fig. 1), which in the Mojave and Colorado deseils are listed as a threatened species by the USFWS (Federal Register 1990). Because of high levels of raven predation on tortoises, the Bureau of Land Management has taken action to reduce this predation (BLM 1990. 1994). We report here on a 24-year trend in raven abundance along roadsides in the deserts of the southwest- ern United States and surrounding regions, where increasing raven populations interest resource management agencies (BLM 1990; USFWS 1994).^ Our analysis of BBS 1968-92 data focuses on arid lands and neighboring habitats in California. Nevada. Utah, and Arizona. We used data from 137 39.2-km (24.5-mi) routes within the following BBS strata: Great Basin Desert; mountain highlands of Arizona; Sonoran- Colorado Desert; Mojave Desert; basins and ranges, including portions of the northern Mojave and Great Basin deserts; Central Valley; and southern California grasslands, California foothills (southern California routes only), and Los Angeles ranges combined into one (coastal southern California). Status and Trends Between 1968 and 1992, the latest year for which data were available, raven populations increased significantly {P < 0.01) throughout the study area (Fig. 2), in spite of relatively high variances among routes. Raven sightings increased 76-fold in the Central Valley of California, 14-fold in the Sonoran-Colorado Deseit, and 10-fold in the Mojave Desert over the 24-year period. Statistically significant but lower increases in raven populations were expe- rienced in the heavily urbanized coastal south- em California strata. The results for the moun- tain highlands stratum are questionable because of a low number of routes (;; = 7; B. Peterjohn. NBS. personal communication). In three studies, raven numbers were highest along powerlines, intermediate along highways, and lowest in open desert areas (Austin 1971; FaunaWest Wildlife Consultants 1989; Knight and Kawashima 1993). These reports and obser- vations of raven use of human-based resources for food, water, and nesting substrate (Knight and Call 1980; FaunaWest Wildlife Consultants 1989; Heinrich 1989) suggest that high raven populations are a result of human subsidies (Boarman 1993). Increased raven populations may be a con- cern for threatened and endangered species if increased numbers of ravens result in greater predation. In California alone, there are 96 threatened or endangered species, some of which are or may be at risk of increased raven predation if raven populations continue to grow. On San Clemente Island, ravens are a predator of the endangered San Clemente Island logger- head shrike (iMfiius htdoviciamis meamsi). and along coastal California they prey on endan- gered populations of the California least tern {Sterna cmtllkirum bnnviii: Belluomini 1991). The carcasses of II chuckwallas {Sciumnuiliis obesus), a candidate species for listing as threat- ened or endangered by the USFWS. were recently found beneath one raven nest (personal observation). This finding may be a rare occur- rence, but if raven populations continue to increase, more ravens may begin to prey on chuckwallas. We are conducting more research to understand the foraging ecology and popula- tion biology of ravens and their effects on their prey populations. This research will help us determine how much of a threat ravens pose to the region's biodiversity and learn how to reduce these effects. Fig. 2. A 24-year trend in the average (mean) number of raven sightings within each stratum studied. Our Lniiii^ Rc.\5 in 1993 ("Table 1 ). Status in .Jackson County, Mississippi The population decline of the Mississippi sandhill crane retlects the loss of the mesic and hydric pine savanna once abundant in the area. Savannas occur on coastal terraces, elevated ridges, and uplands. Fire frequency and intensi- ty, combined with soil type and hydrology, pro- vide successional regulation of the savanna. Woody, forested communities replace the savanna without fire. Before ditching, the fiat topography of the terraces allowed sheet flow of water across the terraces and supported exten- sive areas of open savanna. When the refuge was established, about 75% of the crane savan- nas had been destroyed (by residential or com- mercial development) or changed to one of sev- eral different forest types. Only 59c of the orig- inal savanna type that supported the cranes remains on the Gulf Coastal Plain. For this rea- son. Mississippi sandhill cranes now occur only on the refuge and adjacent private lands in southeastern Mississippi. The Mississippi sandhill crane population nests only on the 7,813-ha ( 19,300-acre) refuge. The only other large tract of remnant savanna that might be suitable nesting habitat exists southeast of the refuge on the proposed Grand Bay National Wildlife Refuge. Savanna used by the Mississippi sandhill crane exists as highly fragmented remnants that the refuge must man- age to provide nesting, foraging, and roosting sites (Table 2). Mortality and natural recruitment may also restrict population viability. Predation (primari- ly mammalian) causes high mortality during the first year of life. Other factors that may limit populations include tumors, contaminants, microbial pathogens, and parasites. The preva- lence of tumors in the wild Mississippi sandhill crane population far exceeds that expected in other birds and mammals. Table 2. Mississippi sandhill crane nesting sites on refuse, hv habitat. Type of habitat Number Percentage Open savanna 82 49 Swamp edges 62 38 Pine plantations 12 7 Forest edges 8 5 Cleared lands 2 1 Our LIvinii Rt'suurces — Blni\ 77 Research Needs Research needs include assessing the effects of prescribed burns and other mechanical tech- niques on habitat restoration and crane use; assessing the effects of water levels, water-level fluctuations, and hydrology on crane nesting and fledging success; determining the level of propagation and captive release conditioning needed to maintain population size during restoration; developing genetic management to protect the gene pool; and determining disease and contaminant sources for tumors and poor reproductive success in captive and wild Hocks. References Aldrich. J. 1972. A new subspecies of sandliill cranes from Mississippi. Proceedings of the Biological Society of Washington 8.'i(5):63-70. Dessauer, H.C.. G.F. Gee. and J.S. Rogers. 1992. Allozyme evidence for crane systematics and polymorphisms wilh- m populations of sandhill, sarus. Siberian, and whooping cranes. Molecular Phylogenetics and Evolution 1(4):279- 288. Jarvi. S.I.. G.F. Gee. MM. MUler. and W.E. Briles. 1994. Detection of haplotypes of the major histocompatibility complex in Florida sandhill cranes. Journal of Heredity. In press. For further information: George F. Gee National Biological Service Patuxent Environmental Science Center Laurel. MD 20708 The piping plover {Charadriiis melodiis) is a wide-ranging, beach-nesting shorebird whose population viability continues to decline as a result of habitat loss from development and other human disturbance (Haig 1992). In 1985 the species was listed as endangered in the Great Lakes Basin and Canada and threatened in the northern Great Plains and along the U.S. Atlantic coast. The U.S. Fish and" Wildlife Service (USFWS) is proposing that birds in the northern Great Plains also be listed as endan- gered. Each year, many breeding areas are censused and some winter surveys are conducted. In 1991 biologists from Canada, the United States, Mexico, and various Caribbean nations cairied out a simultaneous census of piping plovers at all known breeding and wintering sites. Census goals were to establish baseline population lev- els for all known piping plover sites and to cen- sus additional potential breeding and wintering sites (Figure). Status This census covered 2,099 sites, resulting in the highest number of breeding and wintering piping plovers ever recorded. It will be repeated three or four more times over the next l.'i-20 years for more accurate assessment of popula- tion trends. Winter Census The total number of wintering birds (3,451) reported constituted 63% of the breeding birds (5.486) counted (Tables I. 2). Most birds (55%; A' = 1.898) were found along the Texas coast where the census concentrated on birds in previ- ously uncensused stretches of Laguna Madre's back bays. The highest concentration of birds in local sites was also reported in Texas (Haig and Plissner 1993). Although the 1991 census dis- covered more wintering birds than had been pre- viously reported, a large proportion of piping plovers were not seen in the winter census. Better census efforts in Louisiana, northern Cuba, and on many of the smaller Caribbean islands may reveal additional winter sites. Previous reviews of their distribution did not indicate that birds moved farther south than the Caribbean (Haig and Oring 1985). Relatively few birds are seen on the Atlantic coast in win- ter, a contrast to the 36% of plovers that breed along the Atlantic coast. Thus, the largest gap in our understanding of piping plover distribution during winter appears to be in locating winter sites for Atlantic coast breeders. Breeding Census All known piping plover breeding sites were censused in 1991 (Table 2). Piping plovers were widely distributed in small populations across their breeding range (Figure); most adults (63.2%) bred in the northern Great Plains and prairies of the United States and Canada. Thirty- six percent were found on the Atlantic coast and Piping Plovers by Susan Haig National Biological Senice Jonathan H. Plissner Umversity of Georgia Editor's note: This paper is largely a synopsis of a paper by Haig and Plissner (1993) in Condor. ^-^^C~^~^ Breeding No. of Winter \ \ -^ census birds census ! / 1-10 e LsC^ 11-50 ■ ^^N ° 51-100 ■ \Vv§ 101-200 201 ■ 300 ■ ■ Figure. Distribution of piping plovers throughout the annual cycle in 1991. 78 Birds — Uur Living Resoiinvs Table 1. Numbers of wintering piping plovers and sites where birds occurred in IWl. Location Birds Sites U.S. Atlantic North Carolina South Carolina Georgia Florida Total 20 51 37 70 178 9 30 U.S.Gulf Florida 481 31 Alabama 12 1 Mississippi 59 7 Louisiana Texas Total 750 1.904 3,206 23 64 126 Mexico Gulf 27 4 Caribbean Bahamas 29 1 Turks and Caicos 0 0 Cuba 11 1 Jamaica 0 0 Puerto Rico 0 0 Cayman Islands 0 0 Total 40 2 Combined total 3,451 162 less than 1 '7f occuiTed on the Great Lakes. Sites with the highest concentrations of breeding birds also were found in the northern Great Plains (also known in Canada as the Great Prairie): however, each local population consist- ed of only a small (less than 8**) proportion of the total breeding population. Local populations were even smaller on the Atlantic coast. Migration Areas Atlantic coast piping plovers are commonly seen on east coast beaches during spring and fall migration. Migration routes of inland birds are poorly understood, however. Only a few occur- rences of piping plovers have been reported at seemingly appropriate inland migration sites such as Kirvvin National Wildlife Refuge in Kansas. Cheyenne Bottoms Wildlife Management Area in Kansas, and Great Salt Plains National Wildlife Refuge in Oklahoma. It appears that inland birds may fly nonstop to gulf coast sites. Trends Because simultaneous, species-wide census- es were not conducted in the past, assessing pop- ulation trends is difficult. Examination of long- term census data at specific sites is useful in some cases. Most midcontinent sites that have been monitored for 10 years or more have expe- rienced a decline (Table 3). The cumulative effects of problems in the prairies have been modeled, and results indicate that piping plovers in the Great Plains are now declining by 7% annually (Ryan et al. 1993). a devastating trend for the species. Atlantic coast numbers remain stable; however, there has been unprecedented effort to protect piping plovers along the U.S. Atlantic coast. Results from previous censuses (Table 3) should be considered rough population estimates; as is true with many bird species, we have little information regarding the intensity of census efforts in those population estimates. Threats In the northern Great Plains, water-level reg- ulation policies on the major rivers (e.g.. Platte, Missouri) serve as a direct source of chick mor- tality and an indirect source of habitat loss through vegetation encroachment and flooding (Schvvalbac'h 1988; Sidle et al. 1992). We know that because 2()9f of northern Great Plains (Great Prairie) birds use river sites, loss of pro- ductivity on rivers such as the Missouri can Table 2. Piping plover breeding census. 1991, Location Adults Sites where piping plovers occurred Atlantic Coast Canada New Brunswick 203 24 Newfoundland 7 1 Nova Scotia 113 34 Prince Edward Island 110 20 Quebec 76 11 St, Pierre/Miquelon 4 2 Canada Atlantic total 513 92 US, Maine 38 8 Massachusetts 293 50 Rhode Island 47 7 Connecticut 67 7 New York 338 69 New Jersey 280 22 Delaware 10 3 Maryland 35 1 Virginia 270 14 North Carolina 86 14 South Carolina 2 1 US, Atlantic total 1,466 196 Atlantic total 1,979 288 Great Lakes Duluth. MN 0 0 Wisconsin 1 1 Michigan 39 14 Long Point, Ontario 0 0 Great Lakes total 40 15 Northern Great Plains/Prairie Canada Praine Alberta 180 27 Saskatchewan 1.172 71 Manitoba 80 12 Lake of Woods, Ontario 5 1 Canada Prairie total 1,437 111 U,S, Great Plains Montana 308 39 North Dakota 992 115 South Dakota 293 47 Lake of Woods, MN 13 1 Colorado 13 4 Nebraska 398 106 Iowa 13 2 Kansas 0 0 Oklahoma 0 0 US, Great Plains total 2,030 314 Combined totals Canada 1.950 203 United States 3,536 525 Total 5,486 728 Our Liriiii^ Rtwcmxcs — Blnls 79 significantly affect annual productivity for the species. A similar threat to piping plovers occurs on Lake Diefenbaker in Saskatchewan, the largest piping plover breeding site in the world, where each year water levels are raised soon after parents ha\e laid their clutches, resulting in a loss of all nests. Avian and mammalian predation is a problem throughout the species" breeding range, although population numbers appear to be stabilizing on the Atlantic coast and the Great Lakes as a result of using predator exclosures over nests (Rimmer and Deblinger 1990; Mayer and Ryan 1991; Melvin et al. 1992). Human disturbance contin- ues to be a problem on the Atlantic coast (Strauss 1990), and in the Great Lakes, piping plovers may also be suffering from a lack of viable habi- tat (Nordstrom 1990). Comparison of food avail- ability at northem Great Plains sites with Great Lakes sites indicated lower diversity and abun- dance of invertebrates on the Great Lakes. Finally, recent evidence suggests that Great Lakes birds may be suffering from high levels of toxins (i.e.. PCB's). which may be a prime factor in low productivity and population growth (USFWS, East Lansing. Michigan, personal communication). The discovery of the high proportion of win- tering piping plovers on algal and sand flats has significant implications for future habitat pro- tection. Current development of these areas on Piping plover [Charadrius melodiis). Laguna Madre in Texas and Mexico, increased dredging operations, and the continuous threat of oil spills in the Gulf of Mexico will result in serious loss of piping plover wintering habitat. In summary, piping plovers suffer from many factors that may cause their extinction in the next 50 years. Most devastated are the Great Lakes and northem Great Plains birds whose viability is severely threatened. Unfortunately, recovery is hindered by a lack of knowledge about the winter distribution, status of winter sites, adequate water-management policy in western breeding sites, and direct human distur- bance on the Atlantic coast. Location 1st est. 2nd est. 1991 census % Change 1st est. 1991 % Change Year No. Year No. 2nd est. 1991 Atlantic Coast 30 56 1984 1983 1982 4 28 12 7 20 38 ■72 Newloundland 1968 +75 Cadden Beach, Nova Scotia 1976 ■64 -21 -29 Maine 1976 48 80 40 ■f217 Rhode Island 1945 1983 20 47 ■41 + 135 Connecticut 1980 1983 34 200 67 ■t68 +97 Long Island, NY 1939 1,000 1983 338 -66 +69 New Jersey 1980 1978 118 80 1983 1984 64 18 280 ■1-137 +338 Delaware 10 •88 -44 Maryland 1972 85 1984 25 35 ■59 +40 Great Lal( ol'the land area of Pueilo Rico had been converted from forest to agriculture (Snyder et al. 1987); less than \% of the old-growth forest remained after more than 400 years of European civilization. At this time, the parrot population must have been low, but no data exist. By 1937 U.S. Forest Service (USFS) rangers estimated the Puerto Rican par- rot population at about 2,000 birds (Wadsworth 1949). A few years later, panots were found only in the Luquillo Mountains, formerly a for- est reserve of the Spanish Crown and now man- aged by the USFS. This area contained the last forest habitat suitable for Puerto Rican paiTots. Population surveys of the Puerto Rican par- rot were not conducted until the 1950's. Early estimates of the parrot population in Puerto Rico are based on few written records and gen- eral observations (Snyder et al. 1987). knowl- edge of the parrot's biology, and e.Ktrapolation of population surveys conducted by Rodriguez- Vidal (1959). During the I950"s, Rodriguez- Vidal of the Puerto Rico Department of Agriculture and Commerce conducted the first extensive study of the Puerto Rican panot. He reported a population of 200 Puerto Rican parrots by the mid-1950"s (Fig. 2). About 20 years later the population had dwindled to 14 individuals that inhabited an isolated rain forest of the Luquillo Mountains. Puerto Rican parrot (Amazoiui vil- lata). In 1968 Kepler, U.S. Fish and Wildlife Service (USFWS), organized parrot surveys by placing observers at strategic sites, including overlooks from prominent rocks, road-cuts, and building roofs. Snyder et al. (1987) improved the survey method in 1972 by constructing 10 treetop lookouts in areas of major parrot use. Parrot surveys are conducted from these plat- forms during the breeding season and pre- and postbreeding season (Snyder et al. 1987). Observers collect information on parrot num- bers, directions, and their distance from the platform by the time of day. By 1993 this tree- top lookout system was expanded to 38 plat- forms (Vilella and Garcia 1994). In 1968 implementation of the Puerto Rican Parrot Recovery Plan began: it is a cooperative effort of scientists and managers of the Puerto Rico Department of Environmental and Natural Resources, USFS (Caribbean National Forest and International Institute of Tropical Forestry). USFWS Puerto Rican Parrot Field Office, and the National Biological Service. After the recovery program began, the parrot population increased to^47 bird's by 1989 (Wiley 1980; Lindsey et al. 1989; Meyers et al. 1993); how- ever, about 5Q'7( of the population was destroyed by Humcane Hugo that same year. A small population of 22-24 individuals remained in late 1989 (Fig. 2). Since then, the population recovered to 38^-39 by early 1994 (F.J. Vilella, USFWS, personal communication). After the hurricane, the number of successful nesting pairs increased from a maximum of 5 to 6 pairs from 1991 to 1993 (Meyers et al. 1993; Vilella and Garcia 1994). Research and Management Puerto Rican parrots declined in relation to the increasing human population (Fig. 1). Conversion of forests to agriculture and loss of forest habitat, on which the species depended for food and nest cavities, was the primary cause for decline. Shooting parrots for food or protection of crops and capture for pets were secondary causes for decline. The remnant par- rot population in the Luquillo Mountains was further stressed when trails and roads were cre- ated and when human uses of the forest timber were encouraged in the early 1900"s (Snyder et al. 1987). Storms before the arrival of Europeans probably had little effect on the par- rot population because the population was more widespread, and hurricanes tend to affect only a small geographic area. Severe hurricanes in 1898, 1928. 1932. and 1989 reduced small, now-isolated populations even further. The apparent ability of the population to rebound after these storms is suggested by increases in the panot population and in nesting pairs after Our Living Resource's — BlnJs ,S'5 2000 37 50 Fig. 2. Population trends of the Puerto Rican parrot in the 2()th century. Hurricane Hugo hit the island in 1989 (Meyers etal. 1993). Intense research and management strategies during the last 27 years have prevented the extinction of the Puerto Rican parrot. Much of the effort to rebuild the population has involved research and management of nesting sites (Wiley 1980; Snyder^'et al. 1987; Lindsey et al. 1989; Wiley 1991 ). Predators, such as black rats (Rattiis rattus) and pearly-eyed thrashers (Margarops fiiscatus), have been controlled (Snyder et aj. 1987). Bot fly (Phihmus spp.) infestations of nestlings are still a minor prob- lem (Lindsey et al. 1989). Management of nests by fostering captive-reared young into wild nests, guarding nests, controlling honey bees (Apis meUifera). improving and maintaining existing nest cavities, and creating enhanced nesting cavities should increase the population of the Pueilo Rican panot (Wiley 1980; Lindsey et al. 1989; Wiley 1991; Lindsey 1992; Vilella and Garcia 1994). Hurricanes will continue to threaten the wild population of the Puerto Rican parrot. Researchers estimate that storms equal to the intensity of Hugo (sustained winds of 166 km/h or 104 mi/h) occur at least every 50 years in northeastern Puerto Rico (Scatena and Larsen 1991). The risk of extinction caused by huni- canes will be reduced by establishing a geo- graphically separated wild population (USFWS 1987). Introduced parrots and parakeets are com- mon in Puerto Rico, including some of the genus Amazona. Monitored populations of these non-native birds have increased from 50% to 250% during 1990-93 (J.M. Meyers, National Biological Service, unpublished data). If they expand their ranges to include older forests, these populations may pose a threat to the Puerto Rican parrot by introducing diseases and by competing for resources. At present, none of the introduced Amazona populations are found near the Luquillo Mountains; howev- er, orange-fronted parakeets {Anitinga cunicii- laris) have foraged and nested in these moun- tains at lower elevations (J.M. Meyers, NBS, unpublished data). As the Puerto Rican parrot population increases, it is possible that suitable nesting sites may limit population growth. Before this occurs, research and management should concentrate on increasing the wild population. The ability of the Puerto Rican panot to expand its population in a manner similar to the exotic parrots in Puerto Rico, in a variety of natural and human-altered environments, should not be underestimated and may be the key to its recovery. References IjiiJsey, G.D. 1992. Nest guarding from observational blinds: strategy for improving Puerto Rican parrot nesi success. Journal of Field Ornithology 63:466-472. Lindsey. G.D.. M.K. Brock, and M.H. Wilson. 1989. Current status of the Puerto Rican parrot conservation program. Pages 89-99 in Wildlife management in the Caribbean islands. Proceedings of the Fourth Meeting of Caribbean Foresters. U.S. Department of Agriculture, Institute of Tropical Forestry. Rio Piedras, Puerto Rico. Little. E.L.. Jr.. and F.H. Wadsworth. 1964. Common trees of Puerto Rico and the Virgin Islands (reprint). Agriculture Handbook 249. U.S. Department of Agriculture. Washington. DC. 556 pp. Meyers. J.M.. F.J. Vilella. and W.C. Ban-ow. Jr. 1993. Positive effects of Hurricane Hugo: record years for Puerto Rican parrots nesting in the wild. Endangered SpeciesTech. Bull. 27:1.10. ' Rodriguez-Vidal. J.A. 1959. Puerto Rican partot study. Monographs of the Department of Agriculture and Commerce I. San Juan. Puerto Rico. 15 pp. Scatena. F.N.. and M.C. Larsen. 1991. Physical aspects of Hurricane Hugo in Puerto Rico. Biotropica 23:317-323. Snyder. N.R.F. j'^W. Wiley, and C.B. Kepler. 1987. The par- rots of Luquillo: natural history and conservation of the Puerto Rican partol. Western Foundation of Vertebrate Zoology. Los Angeles. CA. 384 pp. USFWS. 1987. Recovery plan for the Puerto Rican parrot. Amazona vinata. VS. Fish and Wildlife Service. Atlanta. GA. 69 pp. Vilella. F.J.. and E.R. Garcia. 1994. Post-hurricane manage- ment of the Puerto Rican parrot. In J.A. Bissonette and PR. Krausman. eds. International Wildlife Management Congress Proceedings. The Wildlife Society. Washington, DC. In press. Wadsworth. F.H. 1949. The development of the forested land resources of the Luquillo Mountains. Puerto Rico. Ph.D. dissertation. University of Michigan. Ann Arbor. 481 pp. Wiley. J.W. 1980. The Puerto Rican parrot (Amazona villa- la): its decline and the program for its conservation. Pages 133-159 in R. E. Pasquier. ed. Conservation of new world parrots. International Council for Bird Preservation Tech. Publ. I. Smithsonian Institute Press. Washington. DC. Wiley. J.W. 1991. Status and conservation of parrots and parakeets in the Greater Antilles. Bahama Islands, and Cayman Islands. Bird Conservation International 1:187- 214. For further information: J. Michael Meyers National Biological Service Patuxent Environmental Science Center PO Box N Palmer. Puerto Rico 00721-0501 USA S6 Biuls — Our Living Rt'siiiirccs Red-cockaded Woodpeckers by Ralph Costa U.S. Fish and Wildlife Senice Joan L. Walker U.S. Forest Service Table. Number of red-cockaded woodpecker active clusters, by state and land ownership category, for various years between 1990- 94.* The led-cockaded woodpecker (RCW; Picoidcs horealis) is a teiritorial. nonmigra- tory. cooperative breeding species (Lennartz et al. 1987). Ecological requirements include habi- tat for relatively large home ranges (34 to about 200 ha or 84 to about 500 acres; Connor and Rudolph 1941); old pine trees with red-heart disease for nesting and roosting (Jackson and Schardien 1986); and open, parklike forested landscapes for population expansion, dispersal (Connor and Rudolph 1991), and necessary social interactions. Historically, the southern pine ecosystems, contiguous across large areas and kept open with recuiTing fire (Christensen 1981 ), provided ideal conditions for a nearly continuous distribution of RCWs throughout the South. Within this extensive ecosystem red-cockaded woodpeckers were the only species to excavate cavities in liv- ing pine trees, thereby providing essential cavi- ties for other cavity-nesting birds and mammals, as well as some reptiles, amphibians, and inver- tebrates (Kappes 1993). The loss of open pine habitat since European settlement precipitated dramatic declines in the bird's population and led to its being listed as endangered in 1970 (Federal Register 35: 16047). We obtained historic RCW distribution data, aiTanged by state and county, from published sources (Jackson 1971; Hooper et al. 1980), and interviews with various red-cockaded wood- pecker experts. Current distribution and abun- dance data were obtained from natural resource agencies and knowledgeable biologists. Most records were reported between January 1993 and March 1994. and most represent direct cen- sus data. Specific references are available from R.Costa (Table). Several terms are used to describe red-cock- aded woodpecker abundance. "Group"" refers to birds that cooperate to rear the young from a sin- gle nest. It usually consists of a breeding male and female, and zero to four helpers, usually the group's male offspring from previous breeding seasons. For reporting purposes, single bird Ownership State Federal State Private Total Alabama 150 8 25 183 Arkansas 35 0 121 156 Florida 1,063 128 94 1,285 Georgia 431 2 218 651 Kentucky 5 0 0 5 Louisiana 422 10 73 505 Mississippi 152 0 22 174 Nortii Carolina 408 162 163 733 Oklahoma 0 9 1 10 South Carolina 456 39 186 681 Tennessee 1 0 0 1 Texas 218 26 61 305 Virginia 0 0 5 5 Total 3.341 384 969 4,694 ■For iniormation on references, contact R Costa. Red-cockaded woodpecker {Picoiiles borealis). groups (usually male) are tallied. The collection of cavity trees used by a group for nesting and roosting is the "cluster."" Although single tree clusters do occur, typically each cluster consists of 2 to more than 15 cavity trees and may occu- py 2 to more than 4 ha (5 to more than 10 acres). Each group normally occupies and defends only one cluster. "Population"" refers to the aggrega- tion of groups that are more distant than 29 km (18 mi) from the nearest group. A single isolat- ed group may constitute a population. Historical Distribution and Abundance The historical range of this species covered southeast Virginia to east Texas and north to por- tions of Tennessee. Kentucky, southeast Missouri, and eastern Oklahoma (Figure). The range included the entire longleaf pine ecosys- tem, but the birds also inhabited open shortleaf. loblolly, and Virginia pine forests, especially in the Ozark-Ouachita Highlands and the southern tip of the Appalachian Highlands. Red-cockaded woodpecker abundance was described variously as fairly common (Woodruff 1907), locally common (Murphey 1939), com- mon (Chapman 1895), or abundant (Audubon 1839). Occasional occurrences were noted for New Jersey (Hausman 1928). Pennsylvania (Gentry 1877). Maryland (Meanly 1943). and Ohio (Dawson and Jones 1903). t hii Lning Resources — Blnls H7 The distribution map (Figure) displays only counties for which specimens or reHable sources can he cited. The gaps in the distribution undoubtedly contained red-cockaded wood- peckers in the past. Most counties without doc- umented occurrences are found in the longleaf pine-shortleaf pine-loblolly pine-hardwoods transition areas in the east gulf region (Figure), where richer soils and rolling topographies were associated with intense agriculture and inter- rupted lire regimes. Such areas possibly sup- ported smaller populations that were quickly lost with the forest clearing and therefore were never recorded. Status and Causes of Decline Red-cockaded woodpeckers survive as very small (1-5 groups) to large (groups of 200 or more) populations. There are at least small pop- ulations in most states with historical occur- rences (Table). Except for a population of about 90 groups in southern Arkansas and northern Louisiana, the largest populations are found within the historical longleaf pine ecosystem. Other populations outside the longleaf pine range consist of fewer than 20 groups in single or several adjacent counties. Within the longleaf range, there are 4 populations with more than 200 groups and 1 1 populations with more than 100 groups; all but one are found on federal lands. The remaining longleaf pine-associated populations are small and isolated. Such small populations are threatened by adverse effects of demographic isolation, increased predation and cavity competition, and stochastic (random) nat- ural events such as hunicanes. The decline of the red-cockaded woodpecker coincided with the loss of the longleaf ecosys- tem. As forests were cleared, birds were isolated in forest tracts where unmerchantable trees were left. Aerial and ground photographs from the 1930"s show that scattered medium to large trees (0.4-2 per ha or 1-5 per acre) were left in many stands. The culled trees (undoubtedly including red-cockaded woodpecker cavity trees) provided residual nesting and foraging habitat for the birds. In some places these trees remain and are used by red-cockaded woodpeckers today. Since the I950"s. on lands managed for for- est products, the forest structure and composi- tion changed in conjunction with clearcutting. short timber rotations, conversion of longleaf stands to other pine species, and "clean" forestry practices (removal of cavity, disea.sed. or defec- tive trees). These practices eliminated much of the remaining red-cockaded woodpecker habi- tat. Additionally, aggressive fire suppression promoted the development of a hardwood mid- story in pine forests. The adverse impacts of a dense midstory on RCW populations are well- documented (Connor and Rudolph 1989; Costa andEscano 1989). Figure. Distribution of red-cocl<- aded woodpeckers by county and state. Most liistorical RCW records are cited from Jackson 1971 and Hooper et al. 1980. For information on references, contact R. Costa. 8S Binis — Our Li\iiif; Resources Recent Developments and the Future The Red-Lockaded Woodpecker Recovery Plan (USFWS 1985) specifies that rangewide recovery will he achieved when 15 viable popu- lations are established and protected by ade- quate habitat management programs. The recov- ery populations are to be distributed across the major physiographic provinces and within the major forest types that can be managed to sus- tain viable populations. Each recovery popula- tion will likely require 400 breeding pairs (or 500 active clusters, as some clusters are occu- pied by single birds or contain nonbreeding groups) to ensure long-term population viability ^Reed et al. 1993: Stevens, in press). At a densi- ty of 1 group/80-120 ha (200-300 acres; USFWS 1985; USPS 1993), landscapes of at least 40,000 ha (100,000 acres) will be needed to support viable populations. Most forested pine areas large enough to supply this habitat are on public, mostly federal, lands. With two exceptions (Hooper et al. 1991; USPS, Apalachicola National Forest, PL, unpublished data), there is no evidence that red- cockaded wiKidpecker populations can expand to viable levels without considerable human intervention. Conversely, numerous population extirpations have been documented (Baker 1983; Costa and Escano 1989; Cox and Baker, in press). Ensuring the survival of the species, even in the short term (50 years), will require landscape-scale habitat and population manage- ment to provide the forest structure and compo- sition needed for nesting and foraging habitat and population expansion; and to manage limit- ing factors (primarily a lack of suitable cavity trees, cavity competition, and demographic iso- lation) that can extiipate small populations. Both strategies are part of management guidelines drafted by several federal land stewards (USPS 1993; U.S. Army 1994; USFWS 1994). These ecosystem management plans promote practices that minimize landscape fragmenta- tion, retain suitable numbers of potential cavity trees well distributed throughout the landscape, and restore the original forest cover by planting the appropriate pine species. They recommend the use of growing-season fires to control hard- woods, create open forest conditions, and begin to restore the understory plant communities of the pine ecosystems. Stabilization and growth of small high-risk populations will be aided by cre- ating artificial red-cockaded woodpecker cavi- ties (Copeyon 1990) and translocating juvenile birds from stable larger populations into small ones (Rudolph et al. 1992). Technologies that minimize or eliminate predation and competi- Uon problems are available (Carter et al. 1989). During the past 4-7 years, several popula- tions have stabilized or increased (Gaines et al., in press; Richardson and Stockie, in press) as a result of implementing conservation biology principles — that is, integrating available tech- nology with the species" life history and ecolog- ical requirements. The limited number of juve- nile birds, however, may hinder recovery progress in all populations simultaneously. References Audubon. J.J. 1839. Ornithological biography. Vol, ^. A. and C. Black. Edinburgh. Baker. WW. 1983. Decline and extirpation of a population of red-cockaded woodpeckers in northwest Florida. Pages 44-45 in D.A. Wood., ed. Red-cockaded Woodpecker Symposium II Proceedings. Florida Game and Freshwater Fish Commission. Tallahassee. Caller. J.H., 111. J.R. Walters. S.H. Everhart, and PD. Doerr. 1989 Restrictors for red-cockaded woodpecker cavities. Wildlife Society Bull. 17:68-72. Chapman. FM. 189.5. Handbook of birds of eastern North America. D. Appleton and Co.. New York. 431 pp. Christensen, N.L. 1981. Fire regimes in southeastern ecosys- tems. U.S. Forest Service Gen. Tech. Rep. WO-26: 112- 1.36. Connor. R.N.. and DC. Rudolph. 1989. Red-cockaded woodpecker colony status and trends on the Angelina. Davy Crockett and Sabine National forests. U.S. Forest Service. Southern Forest Experiment Station. Res. Paper SO-250. 15 pp. Connor. R.N., and D.C. Rudolph. 1991. Forest habitat loss, fragmentation, and red-cockaded woodpecker popula- tion. Wilson Bull. 1(13 (3): 446-457. Copeyon. C.K. 1990. A technique for constructing cavities for the red-cockaded woodpecker. Wildlife Society Bull. 18:303-311. Costa. R.. and R.E. E.scano. 1989. Red-cockaded woodpeck- er status and management in the Southern Region in 1986. U.S. Forest Service Southern Region Tech. Publ. R8-TP 12.71 pp. Cox. J., and WW. Baker In press. Distribution and status of the red-cockaded woodpecker in Florida: 1992 update. Red-cockaded Woodpecker Symposium HI: species recovery, ecology and management. Stephen F. Austin State University. Nacogdoches. TX. Dawson. W.L.. and L. Jones. 1903. The birds of Ohio. Vol. I. The Wheaton Publishing Co., Columbus, OH. 671 pp. Gaines. G.D.. W.L. Jarvis. and K. Laves. In press. Red-cock- aded woodpecker management on the Savannah River Site: a management/research success story. Red-cockaded Woodpecker Symposium HI: species recovery, ecology and management. Stephen F Austin State University, Nacogdoches. TX. Gentry. T.G. 1877. Life-histories of birds of eastern Pennsylvania. Vol. 2. J.H. Choate. Salem. MA. Hausman. L.A. 1928. Woodpeckers, nuthatches, and creep- ers of New Jersey. New Jersey Agricultural Experiment Station Bull. 470:'l -48. Hooper. R.G., D.L. Krusac. and D.L. Carlson. 1991. An increase in a population of red-cockaded woodpeckers. Wildlife Society Bull. 19:277-286. Hooper. R.G.. L.J. Niles. R.F Harlow, and G.W. Wood. 1982. Home ranges of red-cockaded woodpeckers in coastal South Carolina. Auk 99{4):675-682. Hooper. R.G.. A.F. Robinson, and J. A. Jackson. 1980. The red-cockaded woodpecker: notes on life history and man- agement. U.S. Forest Service. Southeastern Area. State and Private Forestry, Gen. Rep. SA-GR 9. 8 pp. Jack.son. J.A. 1971. The evolution, taxonomy, distribution, past populations and current status of the red-cockaded woodpecker. Pages 4-29 in R.L. Thompson, ed. The Our Liviiii; Resources — Binls S9 Ecology and Management of the Red-cockaded Woodpecker. Proceedings of a Symposium. Bureau of Sport Fislienes and Wildlife and Tall Timbers Research Station. Tallahassee. FL. Jackson. J. .A., and B.J. Schardien. 1986. Why do red-cock- aded woodpeckers need old trees? Wildlife Society Bull. l4:.M8-.^22. Kappes. J.J. 1943, Interspecific mteractions associated with red-cockaded woodpecker ca\ ities at a north Florida site. M.S. thesis. University of Florida, Gainesville. 7.^ pp. Lennartz, M.R., R.G. Hooper, and R.F. Harlow. 1987. Sociality and cooperative breeding of red-cockaded woodpeckers iPicoiiles borealis). Behavioral Ecology and Sociobiology 20:77-88. Meanly. R.M. I94_V Red-cockaded woodpecker breeding in Maryland. Auk 60: 105. Murphey. E.E. 19.39. Dryobates borealis (VieiliotI, in A.C. Bent. Life histories of North American woodpeckers. Smithsonian Institution U.S. National Museum Bull. 174:72-79. Reed. J.M.. J.R. Walters. T.E. Emigh. and D.E. Seaman. 1993. Effective population size in red-cockaded wood- peckers: population and model differences. Conservation Biology 7(2 ):.302-.W8. Richardson. D.. and J. Stockie. In press. Intensive manage- ment of a small red-cockaded woodpecker population at Noxubee National Wildlife Refuge. Red-cockaded Woodpecker Symposium 111: Species Recovery. Ecology and Management. Stephen F. Austin State University. Nacogdoches. T.\. Rudolph. D.C.. R.N. Connor. D.K. Carrie, and R.R. Schaefer 1992. Experimental reintroduction of red-cock- aded woodpeckers. Auk 109(4):914-916. Stevens. E.E. In press. Population viability for red-cockaded woodpeckers. Red-cockaded Woodpecker Symposium III: Species Recovery. Ecology and Management. Stephen F. Austin State University. Nacogdoches. TX. U.S. Army. 1994. Management guidelines for the red-cock- aded woodpecker on army installations. U.S. Army Legal Services Agency. Arlington. VA. 19 pp. USPS. 1993. Draft environmental impact statement for the management of the red-cockaded woodpecker and its habitat on national forests in the Southern Region. U.S. Forest Service. Southern Region. Atlanta. GA. 460 pp. USFWS. 1985. Red-cockaded woodpecker recovery plan. U.S. Fish and Wildlife Service. Atlanta. GA. 88 pp. USFWS. 1994. Draft strategy and guidelines for the recov- ery and protection of the red-cockaded woodpecker on national wildlife refuges. U.S. Fish and Wildlife Service. Atlanta. GA. 50 pp. Woodruff. E.S. 1907. Some interesting records from south- ern Missouri. Auk 24:348-349. For further information: Ralph Costa U.S. Fish and Wildlife Service Red-cockaded Woodpecker Field Office Department of Forest Resources Clemson University 261 LehotskyHali Box 341003 Clemson. SC 29634 The southwestern willow flycatcher (Eiupid(mii\ iraillii twriiuus) occurs, as its name implies, throughout most of the south- western United States (Fig. 1). It is a Neotropical migrant songbird, i.e.. one of many birds that return to the United States and Canada to breed each spring after migrating south to the Neotropics (Mexico and Central America) to winter in milder climates. In recent years, there has been strong evidence of declines in many Neotropical migrant songbirds (e.g.. Finch and Stangel 1993). including the southwestern willow flycatcher (Federal Register 1993). The flycatcher appears to have suffered significant declines throughout its range, including total loss from some areas where it historically occurred. These declines, as well as the potential for continued and addi- tional threats, prompted the U.S. Fish and Wildlife Service (USFWS) to propose listing the southwestern willow flycatcher as an endan- gered species (Federal Register 1993). The southwestern willow flycatcher is one of four distinct races of willow flycatchers that breed in North America. All races breed in shrubby or woodland habitats, usually adjacent to, or near, surface water or saturated soil. Riparian areas — woodland and shrub areas along streams and rivers — are particularly favored. In fact, the southwestern willow fly- catcher is a riparian obligate, breeding only in riparian vegetation. It prefers tall, dense wil- lows and Cottonwood habitat where dense vege- tation continues from ground level to the tree canopy. Southwestern willow flycatchers appear to breed in stands of the exotic and inva- sive tamarisk {Tamarix spp.) only at locations above 625 m (2.051 ft) elevation (Federal Register 1993). and where the tamarisk stands have suitable structural characteristics (Fig. 2). Thus, many areas dominated by tamarisk are not suitable flycatcher habitat. Being a riparian obligate, the southwestern willow flycatcher is pailicularly sensitive to the alteration and loss of riparian habitat (including tamarisk inva- sion), which is a widespread and pervasive problem throughout the Southwest. Because of the decline and precarious status of southwestern willow flycatchers, it is impor- tant to document the status of the species, where it occurs, how many individuals are present, and where they are successfully breeding. Information on trends is also important in man- aging and protecting the species. Grand Canyon Southwestern Willow Flycatchers in the Grand Canyon by Mark K. Sogge National Biological Service Fig. 1. Breeding distribution of the southwestern willow flycatcher Dotted line represents areas where distribution is uncertain. 90 Birds — Our Lniiii^ Rc\onrci's - catcher breeding tcmtciry in tamarisk habitat along the Colorado River in the Grand Canyon. National Park, the USFWS, and the U.S. Bureau of Reclamation have been regularly monitoring the status of the southwestern wil- low tlycateher in the Grand Canyon since 1982. The National Biological Service's Colorado Plateau Research Station at Northern Arizona University has conducted this monitoring since 1992. The Grand Canyon is one of the few areas with such a long record of willow flycatcher population data; the only others are the Santa Margarita and Kern rivers in southern California. Methods Our monitoring program invohed intensive surveys of about 450 km (280 mi) of the Colorado River in Arizona between Glen Canyon Dam (Lake Powell) and upper Lake Mead. This portion of the river flows from ele- vation 945 m (3,100 ft) at the dam to 365 m ( 1.200 ft) at Lake Mead. We walked through or tloated along all potential southwestern willow flycatcher habitat patches along the river corri- dor and looked and listened for willow tly- ■V^- '"W-y. Fig. 3. Surveyor broadcasting taped vocalizations and looking for response from willow flycatchers. ^^ catchers. Although willow flycatchers look very similar to several other llycatchers, they can be readily identified by their distinctive "tltz-bew" song. To increase the chance of detecting resi- dent llycatchers. we played a tape recording of willow flycatcher songs and calls (Fig. 3) as we moved through our survey areas. This technique usually elicits a response from any resident southwestern willow flycatchers that may be present (Tibbitts et al. 1994). We conducted sur- veys from May through July at about 160 habi- tat patches each year (1992 and 1993). and made repeated trips to each site (Sogge et al. 1993). Status and Trends Surveys conducted between 1982 and 1991 looked only at the upper 1 14 km (71 mi) of the river and counted primarily singing males. Within this same stretch, we detected only two singing male willow flycatchers in 1992, and three in 1993. These willow flycatchers were found only in the dense riparian habitat domi- nated by tamarisk, but including some willows along the river corridor above 860 m (2,800 ft) elevation. The breeding population of south- western willow llycatchers in the Grand Canyon was very low: we found only one nest in 1992, and only three in 1993. Worse yet, each of the three 1993 willow flycatcher nests was brood-parasitized by brown-headed cowbirds (Molothnis (Iter), and none produced young willow flycatchers. With such a small breeding population, and the potential for severe loss of breeding effoil due to cowbirds. there is con- cern over the continued survival of the species within Grand Canyon. Based on comparison with past willow fly- catcher surveys in the Grand Canyon (river mi 0-71: Brown' 1988, 1991), willow flycatchers have declined since the mid-1980"s (Fig. 4). Because we could conduct more surveys and our methods were more likely to detect fly- catchers than the pre- 1992 surveys (conducted without using tape playback), the population decline of the southwestern willow flycatcher in Grand Canyon may be even more dramatic than our data indicate. We did find willow flycatchers in areas of the river corridor where surveys had not been previously conducted: three in 1992 and five in 1993. Two other willow flycatchers were also found during separate bird studies on the river corridor. These birds were found in tamarisk (above 530 m; 1,900 ft) or willow (below 530 m; 1,900 ft) habitats. None of these willow fly- catchers established territories or bred, howev- er, and most were probably migrants simply passing through the area (Sogge et al. 1993). Our Liiiiii^ Ri'.stmnt'.s — Binl.s 91 Fig. 4. Tlic luimhers of singing male soulhwestcrn wilKm tlycalchers and flycatcher nests detected in the Grand Canyon (river mi 0 to 71). 1982-9.^. Dotted lines represent years when surveys were not conducted. The lov\ bleeding population, historical declines, and potentially limited piodLictivily in the Grand Canyon retlect the plight of the southwestern willow flycatcher throughout its range. Declines have been noted virtually everywhere the flycatcher occurs, and threats to its survival are widespread and immediate. As human activities such as urbanization, water diversion, agriculture, and grazing in riparian areas continue in the Southwest, so do the loss and alteration of riparian habitat. Vital winter- ing habitat in Mexico and Central America is also being lost to similar human activities. Brood parasitism by brown-headed cowbirds is another significant threat to southwestern wil- low tlycatchers within the Grand Canyon and in many other areas. In fact, cowbirds may be one of the greatest threats in areas where breeding habitat is protected, such as the Grand Canyon and other national parks and protected areas. Cowbirds lay their eggs in the nests of other birds (the host), who subsequently abandon the nests or raise the cowbird chicks. Female cow- birds will sometimes remove or destroy host eggs, and cowbird chicks often monopolize the parental care of the hosts. Thus, cowbird para- sitism can reduce the number of host young pro- duced, and in some cases, cowbirds may be the only young successfully raised by the host. Such effects have been recorded for southwest- em willow flycatchers in the Grand Canyon and in other areas as well (Federal Register 1993). Conversely, control and removal of cowbirds have resulted in local increases in southwestern willow flycatchers and other songbirds. Cowbird brood parasitism is related to riparian loss and fragmentation because cowbird para- sitism is highest in fragmented habitats. The southwestern willow flycatcher is a unique and valuable part of the riparian com- munity in the Southwest. Although recent and planned future surveys provide important status and distributional information on the flycatcher in the Grand Canyon and a few other areas with- in Arizona, there is a critical need for basic sur- veys and ecological research (including the effect of brown-headed cowbirds) on this species throughout most of its range, particular- ly in New Mexico, southern Utah, and Colorado. As a riparian obligate species whose continued existence is directly tied to the future of our remaining riparian habitats, its precarious status and historic decline help illustrate the need for riparian preservation and management. Such management is important not only for the southwestern willow flycatcher, but also for all plant and animal species that make up and depend on these valuable riparian areas. References Broun, B.T 1988. Breeding ecology of a willow flycatcher population in Grand Canyon. Arizona. Western Birds I9(ll:25-.V^. Brown. B.T. 1991. Status of nesting willow flycatchers along the Colorado River from Glen Canyon Dam to Cardenas Creek, Arizona. U.S. Fish and Wildlife Service Endangered Species Rep. 20. 34 pp. Federal Register. 1993. Proposal to list the southwestern willow flycatcher as an endangered species, and to des- ignate critical habitat. U.S. Fish and Wildlife Service 23 July 1993. Federal Register .'i8:39495-39522. Finch. D.M.. and RW. Stangel. 1993. Status and manage- ment of Neotropical migratory birds; 1992 September 21-25; Estes Park. CO. Gen. Tech. Rep. RM-229. U.S. Forest Service. Rocky Mountain Forest and Range Experiment Station. Fon Collins. CO. 422 pp. Sogge. M.K.. T.J. Tibbitts. and S.J. Sferra. 1993. Status of the southwestern willow flycatcher along the Colorado River between Glen Canyon Dam and Lake Mead — 1993. Summary report. National Park Service Cooperative Park Studies Unit. Northern Arizona University. U.S. Fish and Wildlife Service, and Arizona Game and Fish Depailment. 69 pp. Tibbitts. T.J.. M.K. Sogge. and S.J. Sferra. 1994. A survey protocol for the southwestern willow flycatcher iEiiipidoiutx Iraillii exrimus). National Park Service Tech. Rep. NPS/NAUCPRS/NRTR-94/04. 24 pp. Southwestern flycatcher {Empidoimx traillii extimus). For further information: Mark K, Sogge National Biological Service Colorado Plateau Research Station Northern Arizona University Box 5614 Flagstaff. AZ 86011 '■^■M Mammals Overview Many mammalian popula- tion studies have been ini- tiated to determine a species' biological or eco- logical status because of its perceived econom- ic importance, its abundance, its threatened or endangered state, or because it is viewed as our competitor. As a result, data on mammalian populations in North America have been amassed by researchers, naturalists, trappers, farmers, and land managers for years. Inventory and monitoring programs that pro- duce data about the status and trends of mam- malian populations are significant for many rea- sons. One of the most important reasons, how- ever, is that as fellow members of the most advanced class of organisms in the animal king- dom, the condition of mammal populations most closely reflects our condition. In essence, mammalian species are significant biological indicators for assessing the overall health of advanced organisms in an ecosystem. Habitat changes, pailicularly those initiated by humans, have profoundly affected wildlife populations in North America. Though Native Americans used many wildlife species for food, clothing, and trade, their agricultural and land- use practices usually had minimal adverse effects on mammal populations during the pre- European settlement era. In general, during the post-Columbian era, most North American mammalian populations significantly declined, primarily because of their inability to adapt and compete with early European land-use practices and pressures. Habitat modification and destruction during the settlement of North America occurred very slowly initially. Advances in agriculture and engineering accelerated the loss or modification of habitats that were critical to many species in climax communities. These landscape transfor- mations often occurred before we had any knowledge of how these environmental changes would affect native flora and fauna. Habitat alterations were almost always economically driven and in the absence of land-use regula- tions and conservation measures many species were extiipated. In addition to rapid and sustained habitat and landscape changes from agricultural and silvi- cultural practices, other factors such as unregu- lated hunting and trapping, indiscriminate predator and pest control, and urbanization also contributed significantly to the decline of once- bountiful mammalian populations. These prac- tices, individually and collectively, have been directly conelated with the decline or extinction of many sensitive species. The turn of the century brought a new focus on conservation efforts in this country. Populations of some species, such as the white- Science Editor Benjamin N. Tuggle U.S. Fish and Wildlife Service Chicago Illinois Field Office Harrington, Illinois 60010 94 Monnuiils — Our Livnti^ Resources tailed deer {Odocoileus viri>iiiiii)iiis). showed marked recovery after regulatory and conserva- tion strategies began. Ardent wildlife manage- ment and conservation programs, started pri- marily for game species, have increased our knowledge and understanding of species and habitat interactions. Conservation programs have also positively affected many species that share habitat with the target species the pro- grams are designed to aid. To complement these efforts, however, integrated regulatory legisla- tion and conservation policies that specifically help sustain nontarget species and their habitats are still imperative. The increased emphasis on the importance of managing for biological diversity and adopt- ing an ecosystem approach to management has enhanced our efforts to move from resource- management practices that are oriented to sin- gle species to strategies that focus on the long- term conser\ation of native populations and their natural habitats. Thus, an integrated and comprehensive inventory and monitoring pro- gram that coordinates data on the status and trends of our natural resources is critical to suc- cessfully manage habitats that support a diverse array of plant and animal species. This section provides knowledge on the sta- tus and trends of some higher vertebrate species that occupy some of this country's most diverse ecosystems. Many articles discuss historical and present species distribution, while others discuss the need for further research to fill our gaps of knowledge regarding the species. The articles cover a range of mammal species, some that have benefited greatly from past conserva- tion efforts, and others that are now threatened or endangered, with the effort to recover them just beginning. Some species have been directly affected by habitat loss or modification, others by past hunting and trapping pressures. We should not forget that our survival depends on wildlife, particularly higher verte- brates, nor should we forget that the status of wildlife populations serves as an advance indi- cator of overall environmental quality. Marine Mammals hy Anne Kinsinger National Biological Service Summarized from National Oceanic and Atmospheric Administration (1994) At least .^5 species of marine mammals are lound along the U.S. Atlantic coast and in the Gulf of Mexico: 2 seal species. I manatee, and 32 species of whales, dolphins, and por- poises (see Table 1 for status of selected species). Seven of these species are listed as endangered under the Endangered Species Act (ESA). At least 50 species of marine mammals are found in U.S. Pacific waters: 11 species of seals and sea lions; walrus; polar bear; sea otter; and 36 species of whales, dolphins, and por- poises; 1 1 species are listed as endangered or threatened under the ESA (see Table 2 for the status of .selected species). Table I. Status of selected Atlantic and Gulf of Mexico coast species of marine niammaf Species and geographic area Abundance Status Trends Official status in designated U.S. waters Fin whale, NE U S 5,200 Humpback whale, NWAtlantic 5,100(2.888-8,112) 350 Northern right whale, NW Atlantic Pilot whales, NE U.S. Bottlenose dolphin NE U.S. coastal type Unknown NE U.S. offshore type Gulf of Mexico (offshore and coastal types) Whitesided dolphin, NE U.S. Spotted dolphin, NE US Harbor porpoise. Gull of Maine 47,200 Harbor seal. NE US 26,000 Beaked whales (six species in U.S. waters) Unknown 10.000-13,000 35.000-45,000 27,600 200 Unknown Unknown Possibly 65% of 1850 population Probably <5°o of original number Unknown Possibly down by 50% 1987-88 Unknown Possibly down by 50°i 1987-88 Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Unknown Endangered' Endangered' Endangered' Unknown Depleted" Unknown Unknown Unknown Unknown Increasing Proposed as threatened' Unknown "Endangered Species Act. "Marine Mammal Protection Acf NMFS Assessments The National Marine Fisheries Service (NMFS). an agency within the National Oceanic and Atmospheric Administration (NOAA), con- ducts research and status studies on many of these marine mammals under the authorities of the Magnuson Fisheries Conservation and Management Act, the Marine Mammal Protecnion Act (MMPA), and the ESA. The results of the status sur\eys include information required by the MMPA and the ESA on abun- dance (population size); status (as compared with historical levels or current viability); trends (changes in abundance); and status in U.S. waters. These results, published annually by NOAA, are the basis for this summary (NOAA 1994). Estimates of abundance in U.S. waters are available for many, though not all, marine mam- mal species. Information on status and trends, however, is extremely limited because so little is known of the basic life history of many marine mammal species that scientists can determine neither status nor whether a population estimate represents a healthy, sustainable population. Moreover, long-term trends in many populations cannot be determined because historical popula- tion data are not available. The NMFS provides assessments for 139 stocks (i.e., populations of species or groups of species that are treated together for manage- ment) of marine mammals; the status of 120 stocks is unknown, and trend data are only (Jul Lniiit; Rcsdiiices — Manuiuils 95 available for 19 stocks. The recently reautho- rized MMPA requires the NMFS to conduct periodic assessments of marine mammal stocks that occur in U.S. waters, For this reason, better status and trends data are likely to become available over the next few years. Abimdance and status data for selected marine mammals are summarized in Table I (Atlantic species) and Table 2 (Pacific species). Trend data are mixed, but a number of conser- vation success stories have come from marine mammals. The bowhead and grey whales have shown significant population increases, as have California sea lions, the northem elephant seal, harbor seals in California, Oregon, Washington, and the Northeast, and the southern sea otter. These increases are largely the result of prohi- bition of commercial whaling by the International Whaling Commission (IWCl and by protection enacted under the MMPA and ESA. Other marine mammal populations, such as the Steller sea lion and the common dolphin in the eastern tropical Pacific, are still declining. Causes of decline in marine mammal popula- tions include bycatch associated with commer- cial fishing, illegal killings, strandings, entan- glement, disease, ship strikes, altered food sources, and possibly exposure to contaminants. Table 2. Status ol selected PacifiL ciiast species of iiianne mammals Population Trends Whales The eastern North Pacific stock of grey whale (Eschrichtius robustus) is rising (Fig, 1 ) and is one success story in species restoration. The NMFS estimates that the historical popula- tions of grev whales in 1896 were around 15,000-20"!^00b. While current population levels are below the estimated carrying capacity of 24,000, they appear higher than historical levels and represent a substantial gain. The population growth rate between 1968 and 1988 was 3.3% per year. After 3 years of review, on 15 June 1994. this species was removed from protection (delisted) under the ESA, an indication of suc- cessful management. 8 20 ° rio da»a Species and area Abundance Status Trends Official status in des- ignated U.S. waters Fin wliale Humpback whale. E Pacific Northern right wtiale Bowhead whale, W. Arctic Grey whale 935 -1,400 Unknown 7,500 20,869(19,200- 22,700) Unknown Probably less than 1 5% of 1850 population Unknown About 40% of 1848 population size Recovered to tiislorical 1845 abundance levels Unknown Unknown Unknown Increasing at 3. 1%/yr, 1978-88 Increasing at 3 3%/yr, 1968-88 Endangered' Endangered" Endangered' Endangered" Removed from ESA listing June 1994 E. tropical Pacific dolphins NE spotted 731,000 Depleted Declining W/S spotted 1,298,000 Unknown Stable Coastal spotted 30,000 Unknown Stable E spinner 631,800 Depleted, 44% of late 1950's population Stable Depleted" Whitebelly spinner 1,019,000 Unknown Stable N common 476,300 Unknown Declining Central common 406,100 Unknown Stable S common 2,210,900 Unknown Stable Common (pooled) 3,093,300 Unknown Stable Striped 1,918.000 Unknown Stable Harbor porpoise SE Alaska W Gulf of Alaska N California Central California Inland Washington Oregon/Washington Hawaiian monk seal 2,052 1,273 10,000 3,806 3,298 23,701 1,550 Declined 50% since 1 950's Unknown, pup counts declining to vanable Endangered' California sea lion (CA, OR, WA) 111,016 Unknown Increasing 10,2%/yr since 1983 Harbor seal Alaska California OregonWashington 63,000 23,113 45,713 Unknown Increasing? Declining Increasing Increasing Northern lur seal Pnbilol Islands 982,000 <40%of 1950's population No significant trend Depleted" since 1983 on St Paul Is. San Miguel 6,000 Increasing Steller sea lion 116,000 < 22% of late 1950's population Declined 73% since 1 960 Threatened" Northern Pacific Fig. 1. Estimated population of grey whales, 1967-90 (NOAA 1994). 'Endangered Species Act "lylarine (Mammal Protection Act, The bowhead whale (Balaena mysiiceiiis) is an endangered species that has shown a signifi- cant increase since the IWC adopted new rules in 1980 regulating its harvest for subsistence puiposes by Native Americans (Fig. 2). The total prewhaling (before the mid-1800"s) popu- lation of the bowhead whale is believed to have been 12,000-18,000; NMFS e.stimates that by 1900 it was pi'obably in the low thousands. The current population of 7,500 is about 40% of its estimated 1848 population level (Table 2), more than 3 times the population low reached in 1980. The bowhead whale population has been growing by about 3% per year since 1978. The endangered western North Atlantic pop- ulation of right whales (Eiibalaemi glacialis) is considered by NMFS to be the only northern hemisphere right whale population with a sig- nificant number of individuals, about 300-350 animals (Table 1). Other stocks are considered virtually extinct: only five to seven sightings have been made in the last 25 years. Estimates of the pre- 1 8th century population are as high as 96 Mdiitmah — Our tiring Rcsaurces ^ 6 Fig. 2. Actual cniints of bcmhead whales. l978-9U(NOAA 1W4|. For further information: Michael Payne National Marine Fisheries Service Office of Protected Resources F/PR2 1335 East-West Highway Silver Spring, MD 20910 78 79 81 82 83 84 85 Year 87 88 89 90 91 92 93 10,000. NMFS believes that human influences sueh as ship strikes and net entanglements are affecting about 60% of the population. The agency notes that the annual loss of even a sin- gle right whale has measurable effect on the population, by greatly inhibiting recovery of the species. Dolphins and Porpoises The coastal migratory stock of Atlantic bot- tlenose dolphin {Tiirsiops inmcutus) is listed as depleted under the MMPA (Table 1). This coastal stock incurred a loss of up to 50% dur- ing a 1987-88 die-off. Long-term trends are unknown, but the stock may require as many as 50 years to recover. Harbor porpoises (Phocoena phocoeua) occur on both U.S. coasts and are faring rela- tively well. The northwestern Atlantic harbor poipoise is found from Newfoundland, Canada. to Florida. The NMFS 1991-92 population esti- mate of the Gulf of Maine population is 47,200 (Table 1 ), but estimates of abundance for other populations do not exist. NMFS has found that harbor porpoise mortality from sink gill-net fisheries along the east coast of North America from Canada to North Carolina appears large compared with the species" natural reproduction rates. Management actions are being taken to address this issue, but long-term trends are unknown. On the west coast. NMFS's com- bined population estimate for northern California, Oregon, and Washington coastal stocks is 45.713. The NMFS assesses 10 stocks of eastern tropical Pacific dolphins. Although population trends for most populations cannot be detected, the northeastern stocks of offshore spotted dol- phin and the common dolphin may be declining (Table 2). These two stocks, as well as the east- em spinner and the striped dolphin, are inciden- tally taken in the international fishery for yel- lowfin tuna in the tropical Pacific waters off Mexico and Central America. Although mortali- ty has been reduced in recent years, populations are still declining, or at best not increasing. Seals and Sea Lions According to the NMFS. harbor .seal iPhoca vitulina) populations have increased recently throughout much of their range because of pro- tection by the MMPA. Recent NMFS surveys estimate that at least 26.000 harbor seals inhabit the Gulf of Maine (Table 1 ). Populations of California harbor seals are also increasing; a recent survey resulted in a count of about 23.000 harbor seals residing in the Channel Islands and along the California mainland (Table 2). an increase from about 12.000 in 1983. The popu- lation of harbor seals in Oregon and Washington has been estimated at 45.700, and is also increasing. Harbor seal counts in the Central Gulf of Alaska, however, have declined signifi- cantly in the past two decades; numbers are cur- rently estimated by NOAA at 63,000 seals. The northern fur seal iCulUtrhinus ursinus) is considered depleted under the MMPA. Production on one of its major breeding areas. Alaska's Pribilof Islands, dropped more than 60% between 1955 and 1980, but has since sta- bilized. The cunent population is less than 40% of the mid-1950"s level; no significant trend in the Pribilof Islands population has been noted since 1983 (Table 2). The northern sea lion or Steller sea lion [Eiimetopias jiihutiis) is listed as threatened under the ESA. Species numbers have declined shaiply throughout its range in the last 34 years (Table 2). The number of adults and juveniles in U.S. waters dropped from 154.000 in 1960 to 40,000 in 1992. a reduction of 73%. Most of this decline occuned in Alaska waters, and is believed due to a combination of factors, including incidental kills, illegal shooting, changes in prey availability and biomass, and perhaps other unidentified factors. The U.S. population of California sea lions (Zaiophiis caUfomiamis) is increasing at a rate of about 10% annually. In 1990. NMFS esti- mated that the U.S. population was 111,000 individuals (Table 2). A number of human-relat- ed interactions, such as incidental take during fishing, entanglement, illegal killing, and pollu- tants, result in sea lion deaths. Reference NOAA. 1994. Our living ocean: report on the status of U.S. living marine resources. 1993. NOAA Tech. Memorandum NMFS-F/SPO-15. National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Silver Spring. MD. 136 pp. Our l.nhifi Resources — Mammals 97 The Indiana bat {Myotis sodalis) is an endan- gered species that occurs throughout much of the eastern United States (Fig. I ). Although bats are sometimes viewed with disdain, they are of considerable ecological and economic importance. Bats consume a diet consisting largely of nocturnal insects and thereby are a natural control for both agricultural pests and insects that are annoying to humans. Furthermore, many forms of cave life depend upon nutrients brought into caves by bats in the form of guano or feces (Missouri Department of Conservation 1991). • Priority 1 liibernacuia ' D Range of bat Fig. 1. Range of tlie Indiana bat and locations of Priority 1 liibernacuia [see text for definition.s). Indiana bats use distinctly different habitats during summer and winter. In winter, bats con- gregate in a few large caves and mines for hiber- nation and have a more restricted distribution than at other times of the year. Nearly 85% of the known population winters in only seven caves and mines in Missouri. Indiana, and Kentucky, and approximately one-half of the population uses only two of these hibemacula. In spring, females migrate north from their hibemacula and form maternity colonies in pre- dominantly agricultural areas of Missouri, Iowa, Illinois, Indiana, and Michigan. These colonies, consisting of 50 to 150 adults and their young, normally roost under the loose bark of dead, large-diameter trees throughout sum- mer; however, living shagbark hickories (Cciiya ovata) and tree cavities are also used occasion- ally (Humphrey et al. 1977; Gardner etal. 1991; Callahan 1993; Kurta et al. 1993). As a consequence of their limited distribu- tion, specific summer and winter habitat requirements, and tendency to congregate in large numbers during winter. Indiana bats are particularly vulnerable to rapid population reductions resulting from habitat change, envi- ronmental contaminants, and other human dis- turbances (Brady et al. 1983). Additionally, because females produce only one young per year, recovery following a population reduction occurs slowly. Concerns arising froin the high potential vulnerability and slow recovery rate have led to a long-term population monitoring effort for this species. Bat Census Design The first rangewide census of wintering Indiana bats was made in 1975. All subsequent population data were gathered according to standardized cave census techniques established by the Indiana Bat Recovery Team in 1983 (Brady et al. 1983). Data presented in this arti- cle are based upon counts made at 2-year inter- vals at Priority I hibemacula, which are caves where winter populations exceeding 30,000 bats have been recorded. We chose to use data only from Priority I caves because they contain the majority of bats in the population. During midwinter cave censuses, bats hanging singly and in small clusters of up to 25 were counted indi\ idually. The number of bats in larger clus- ters was determined by multiplying the surface area of the cluster by bat density (Fig. 2). Bat Populations: Trends and Recovery Prospects Before the I970"s. the population status of Indiana bats was poorly understood because the locations of many of their winter hibemacula were unknown, and the counts that were con- ducted were made irregularly and inconsistent- ly. The 1975 census established a benchmark of nearly 450.000 bats using Piiority 1 hibemacu- la. Since 1983 the number of bats tallied has declined significantly, reaching a low of 347,890 during the most recent census in 1993 (Fig. 3). Indiana Bats by Ronald D. Drobney National Biological Service Richard L. Clawsoii Missouri Department of Conser\'ation Fig. 2. Hibernating cluster of Indiana bats 98 Mtimiikils — Our Liviiii; Resources Kentucky 83 85 87 89 Year 91 93 Fig. 3. State and national trends lor Indiana bats. H)S.^-43 For further information: Ronald D- Drobney National Biological Service Missouri Cooperative Fish and Wildhte Research L'nit 1 12 Stephens Hall University of Missouri Columbia. MO 65211 Althotigh the national trend indicates a 22*^ decline during the past 10 years, this decrease has mn been consistent across the species" win- ter range (Fig. 3). Most of the decrease in the lO-year national census results can be account- ed for by a precipitous .^4'7r decline in the num- ber of bats counted in Missouri. A more favor- able pattern has been noted in Indiana, where numbers have increased, and in Kentucky, where the population has remained relatively stable. Recovery efforts have included placing gates or fences across cave entrances to eliminate dis- turbances to hibernating bats. These exclusion devices have not halted population declines, suggesting that other factors are negatively influencing bat populations. Another potential threat is the loss of habitat used by maternity colonies. Maternity roost sites in dead trees exposed to sunlight and locat- ed in upland forests and near streams are partic- ularly important. Losses of these sites through streamside deforestation and stream channeliza- tion pose significant threats to population recovery. Pesticides and other en\ ironmenial contami- nants represent additional hazards. Indiana bats are exposed to lingering residues of chlorinated hydrocarbon pesticides such as aldiln and hep- tachlor. These products have been banned since the l97(J"s. but persist in the soil and in insects upon which bats feed. Potential detrimental effects of the new generation of pesticides, including organophosphates, are unknown. The long-term prognosis for Indiana bat populations is uncertain. The fact that wintering populations appear to be increasing in Indiana and are remaining relatively stable in Kentucky provides the basis for some optimism. A better understanding of their summer habitat require- ments and factors affecting survival and repro- duction is needed so that more effective recov- ery efforts can be fomiulated. It is important to recognize, however, that even if the factors that are negatively influencing Indiana bat popula- tions are removed, recovery will occur slowly because this species has a low reproductive rate. References Brady. J.T.. R.K, LaVal. TH. Kunz. M.D. Turtle. D.E. Wilson, and R.L. Clawson. \9H^. Recovery plan for the Indiana bat. U.S. Fish and Wildlife Service. Washington. DC. 94 pp. Callahan. E.V. 194.^ Indiana bat summer habitat require- ments. M.S. thesis. Uni\ersity of Missouri. Columbia. 74 pp. Gardner, J.E.. J.D. Gamer, and J.E. Hofmann. 1991. Summer roost selection and roosting behavior of Myotis sdiliilis (Indiana bat) in Illinois. Final report. Illinois Natural History Survey. Illinois Department of Conservation. Champaign. 56 pp. Humphrey, S.R.. A. R. Richter. and J.B. Cope. 1977. Summer habitat and ecology of the endangered Indiana bat. Myotis soJulis. Journal of Mammalogy 58:334-.^46. Kurta. A., D. King. J. A. Teramino, J.M. Stnbley, and K.J. Williams. 1993. Summer roosts of the endangered Indiana bat [Myoris sotlalis) on the northern edge of its range. American Midland Naturalist 129:132-138. Missouri Department of Conservation. 1991. Endangered bats and their management in Missouri. Missouri Department of Conservation. Jefferson City. 8 pp. Gray Wolves by L. David Mech National Biological Service Daniel H. Fleischer University of Montana Clifford J. Martiiika National Biological Service The gray wolf (G//;/.v lupus) originally occu- pied all habitats in North America north of about 20° north latitude (in Mexico), except for the southeastern United States, where the red wolf (C. rufus) lived. By I960 the wolf was exterminated by federal and state governments from all of the United States except Alaska and northern Minnesota. Until recently. 24 sub- species of the gray wolf were recognized for North America, including 8 in the contiguous 48 states. After the gray wolf was listed as an endangered species in 1967, recovery plans were developed for the eastern timber wolf (C./. lycaon). the northern Rocky Mountain wolf (C.l. irremotus). and the Mexican wolf (C/. bcii- le}i). The other subspecies in the contiguous United States were considered extinct. The Eastern Timber Wolf Recovery Plan (U.S. Fish and Wildlife Service 1992) set as cri- teria for recovery the following conditions: a viable wolf population in Minnesota consisting of at least 200 animals, and either a population of at least 100 wolves in the United States with- in 160 km (100 tni) of the Minnesota popula- tion, or a population of at least 200 wolves if farther than 160 km (100 mi) from the Minnesota population. The Northern Rocky Mountain Wolf Recovery Plan (U.S. Fish and Wildlife Service 1987) defined recovery as when at least 10 breeding pairs of wolves inhab- it each of three specified areas in the noilhern Rockies for 3 successive years. The Mexican Wolf Recovery Plan (U.S. Fish and Wildlife Service 1982) called for a self-sustaining popu- lation of at least 100 Mexican wolves in a 12,800-kni- (4,941-mi-) range. A recent revision of wolf subspecies in North America (Nowak 1994), however, reduced the number of subspecies originally occupying the contiguous 48 states from eight to four. It classified the wolf currently inhabit- ing northern Montana as being C.l. occidental- is. primarily a Canadian and Alaskan wolf. It considered C.l. nuhilus to be the wolf remaining in most of the range of the former northern Rocky Mountain wolf and the present range of the eastern timber wolf: this leaves the eastern timber wolf extinct in its former U.S. range, sur- Our LIvinii Rt'scnniw — M{inuniil.\ 99 viving now only in southeastern Canada. The new classification may have implications for the recovery criteria propounded by the Eastern Timber Wolf and Northern Rocky Mountain Wolf recovery plans. The reclassification did not change the status of the Mexican wolf. This article is based on a review of the liter- ature and recent personal communications. Most of the studies cited depended primarily on the use of aerial radio-tracking and observation (Mech 1974: Mech et al. 1988). Population Status by Region Lake Superior Region After wolves were protected in 1974 by the Endangered Species Act of 1973. their numbers and distribution in Minnesota increased, and indi\iduals began recolonizing Wisconsin (Mech and Nowak 1981). The population increased in Wisconsin and began recolonizing Michigan (Hammill 1993). The Minnesota pop- ulation increased at about 3% per year (Fuller et al. 1992); its distribution continues to increase (Paul 1994). The best estimate of its cunent size is 1.740-2.030 wolves. Wisconsin and mainland Michigan each supported an estimated 30+ wolves in early 1994 (A. P. Wydeven. Wisconsin Department of Natural Resources, personal communication; J. Hammill, Michigan Department of Natural Resources, personal communication), and Isle Roy ale National Park about 14 wolves (Peterson 1994). As wolves increased in Minnesota, they also began dispersing westward into North and South Dakota (Licht and Fritts 1994). The only records from these states involve 10 wolves killed from 1981 through 1992, but the possibility remains that small populations may occur in some of the more remote areas. Sufficient prey certainly exist there, so if dispersing wolves from Minnesota and Manitoba are not killed by humans, they should be able to breed and start populations. Western United States Wolves were virtually absent in the western United States (other than an occasional animal that disperses from Canada) from the mid- 1930"s through 1980 (Ream and Mattson 1982). The nearest breeding population through this period was probably in Banff National Park, Alberta. Wolves were completely protected in extreme southeastern British Columbia in the 1960's (Pletscher et al. 1991). This led to recol- onization of the area and adjacent northwestern Montana, and in 1986 a den was documented in Glacier National Park, Montana (Ream et al, 1989). This population, which straddles the Canadian border, has since grown to four packs and about 45 wolves. Three breeding packs have been reported elsewhere in western Montana (Fritts el a 1994), all probably founded by animals that dis- persed from Glacier National Park. Additionally, an animal that dispersed from Glacier is in northeastern Idaho, and a wolf shot in 1992 just south of Yellowstone National Park was genetically related to Glacier wolves (Fritts et al. 1994). Animals that have dispersed, pri- marily from the Glacier area, have begun back- filling the area between Glacier National Park and Jasper National Park, Alberta (Boyd et al. 1994). This connection to larger wolf popula- tions in Canada will enhance the viability of the U.S. population. Although occasional wolves have been sighted in Wyoming and Washington and numerous sightings have been reported from central Idaho, no reproduction has been docu- mented in these states, with the possible excep- tion of litters in Washington in 1990 (S.H. Fritts, U.S. Fish and Wildlife Service, personal communication). An environmental impact statement on the reintroduction of wolves to Yellowstone and central Idaho was completed in early 1994. Factors Impeding Wolf Recovery In small populations, the death of any indi- vidual can seriously impede recovery, meaning that factors that may not affect larger popula- tions may hinder recovery of smaller ones. Such factors hindering the recovery of wolves include illegal and accidental killing of wolves by humans, canine parvovirus (Mech and Goyal 1993: Johnson et al. 1994; Wydeven et al. 1994), sarcoptic mange (A. P. Wydeven et al., Wisconsin Department of Natural Resources, personal communication), possibly Lyme dis- ease (Thieking et al. 1992), and heart worm {Dirofilaria immitis: Mech and Fritts 1987). Of these, only killing by humans is subject to human control. I Gray wolf iCaiiis lupus). lUU Mammals — Our Livim; Renmrces For further information: L. David Mech National Biological Service North Central Forest Experiment Station 1992 Folwell Ave. St. Pai]l,MN 55108 Future Outlook All wolf populations in the contiguous 48 states are increasing. Minnesota wolves occupy all suitable areas there and even have been col- onizing agricultural regions where the Eastern Timber Wolf Recovery Team felt they should not be (U.S. Fish and Wildlife Service 1992). Thus, in 1993. the Department of Agriculture's Animal Damage Control Program destroyed a record 139 wolves for livestock depredation control (Paul 1994). As wolf populations con- tinue to grow in other newly colonized areas, there may be an increasing need for control of those wolves preying on livestock (Fritts 1993). Because the public has so strongly supported wolf recovery and reintroduction. it may be dif- ficult for many to understand the need for con- trol. Thus, strong efforts at public education will be required. References Boyd. D.K., PC, Paquet. S. Donelon. R.R. Ream. D.H. Pletscher, and C.C. White. 1994. Dispersal characteristics of a recolonizing wolf population in the Rocky Mountains. In L.D. Carbyn. S.H. Fritts. and D.R. Seip. eds. Ecology and conservation of wolves in a changing world. Canadian Circumpolar Institute. Edmonton. Alberta. In press. Fritts. S.H. 199.^. The downside of wolf recovery. International Wolf 3( 1 ): 24-26. Fritts. S.H., E.E. Bangs. J. A. Fontaine. W.G. Brewster, and J.F. Gore. 1994. Restoring wolves to the northern Rocky Mountains of the United States. In L.D. Carbyn. S.H. Fritts. and D.R. Seip. eds. Ecology and conservation of wolves in a changing worid. Canadian Circumpolar Institute. Edmonton, Alberta. In press. Fuller, T.K.. WE. Berg. G.L. Radde. M.S. Lenarz. and G.B. Joselyn. 1992. A history and current estimate of wolf dis- tribution and numbers in Minnesota. Wildlife Society Bull. 20:42-5.'i. Hammill. J. 199.'(. Wolves in Michigan: a histoncal perspec- tive. International Wolf 3:22-23. Johnson, M.R., D.K. Boyd, and D.H. Pletscher. 1994. Serology of canine parvovirus and canine distemper m relation to wolf tCanis lupus) pup mortalities. Journal of Wildlife Diseases 30:270-273. Licht. D.S.. and S.H. Fntts. 1994. Gray wolf \Canis lupus) occurrences m the Dakotas. American Midland Naturalist 132:74-81. Mech, L.D. 1974. Current techniques in the study of elusive wilderness carnivores. Pages 315-322 in Proceedings of the 11th Intemation,al Congress of Game Biologists. National Swedish Environment Protection Board, Stockholm, Mech. L,D,. and S.H. Fritts. 1987. Parvovirus and heartworm found in Minnesota wolves. Endangered Species Tech. Bull. 12(-S-6):5-6. Mech. L.D.. S.H. Fritts. G. Radde. and W.J. Paul. 1988. Wolf distnbution in Minnesota relative to road densitv. Wildlife Society Bull, 16:85-88. Mech. L.D,. and S,M. Goyal. 1993. Canine parvovirus effect on wolf population change and pup survival. Journal of Wildlife Diseases 29:330-"333. Mech. L.D.. and R.M, Nowak, 1981. Return of the gray wolf to Wisconsin, Amencan Midland Naturalist 105:408-409. Nowak. R.M. 1994. Another look at wolf ta.xonomy. In L.D. Carbyn. S.H. Fritts. and D.R. Seip, eds. Ecology and con- servation of wolves in a changing world. Canadian Circumpolar Institute, Edmonton, Alberta. In press. Paul. W.J. 1994. Wolf depredation on livestock in Minnesota: annual update of statistics 1993. U.S. Department of Agriculture. Animal Damage Control. Grand Rapids, MN. 10 pp. Peterson, R.O. 1994. Out of the doldrums for Isle Royale wolves? International Wolf 4(2):19. Pletscher. D,H.. R.R. Ream. R. Demarchi. W.G. Brew,ster. and E.E. Bangs. 1991. Managing wolf and ungulate popula- tions in an international ecosystem. Transactions of the North American Wildlife and Natural Resources Conference 56:539-549, Ream. R.R.. M.W, Fairchild. D.K. Boyd, and A.J. Blakesley. 1989. First wolf den in western U.S. in recent history. Northwestern Naturalist 70:39-40. Ream. R.R., and U.I. Mattson. 1982. Wolf status in the north- em Rockies. Pages 362-381 in F.H. Harrington and PC. Paquet, eds. Wolves of the wodd. Noyes Publishing. Park Ridge. NJ. Thieking. A,. S,M, Goyal. R.F Berg, K.L. Loken, L.D. Mech, and R.P, Thiel, 1992. Seroprevalence of Lyme disease in Minnesota and Wisconsin wolves. Journal of Wildlife Diseases 28:177-182, U.S. Fish and Wildlife Service. 1982. Mexican wolf recovery plan. USFWS. Albuquerque. NM. 103 pp. U.S. Fish and Wildlife Service. 1987. Northern Rocky Mountain wolf recovery plan. USFWS. Denver. CO. 119 PP- U.S. Fish and Wildlife Service, 1992. Recovery plan for the eastern timber wolf, USFWS. Twin Cities. MN, 73 pp, Wydeven. A.P. R.N. Schultz. and R.P Thiel. 1994. Gray wolf monitoring in Wisconsin — 1979-1991. In L.D. Carbyn. S.H. Fritts, and D.R, Seip. eds. Ecology and conservation of wolves in a changing world. Canadian Circumpolar Institute, Edmonton, Alberta. In press. Black Bears in North America by Michael R. Vaughaii National Biological Service Michael R. Pelton University of Tennessee Habitat loss, habitat fragmentation, and unrestricted harvest have significantly changed the distribution and abundance of black bears {Ursus americaniis) in North America since colonial settlement. Although bears have been more carefully managed in the last 50 years and harvest levels are limited, threats from habitat alteration and fragmenta- tion still exist and are particularly acute in the southeastern United States. In addition, the increased efficiency in hunting techniques and the illegal trade in bear parts, especially gall bladders, have raised concerns about the effect of poaching on some bear populations. Because bears have low reproductive rates, their popula- tions recover more slowly from losses than do those of most other North American mammals. Black bear populations are difficult to inven- tory and monitor because the animals occur in relatively low densities and are secretive by nature. Black bears are an important game species in many states and Canada and are an important component of their ecosystems. It is important that they be continuously and careful- ly monitored to ensure their continued exis- tence. Our Livuii; Ri'soiincs — Maimncis 101 Black Bear Survey Data Information on the distribution and status of black bears in North America came from sever- al unpublished reports and scientific publica- tions. Tntjfu- USA (McCracken et al. 1995) reports periodically on the status of black bears in North America. Two reports on the status and conservation of the bears of the world were pre- sented at meetings of the International Conference on Bear Research and Management in 1970 and 1989 (Cowan 1972; Senheen 1990). Finally, much of the information for this report is from data collected by survey for a report by the International Union for the Conservation of Nature and Natural Resources/Species Survival Commission (lUCN/SSC) Bear Specialist Group (Pelton et al. 1994). Range and Status Black bears historically ranged over most of the forested regions of North America, includ- ing all Canadian provinces, Alaska, all states in the conterminous United States, and significant portions of northern Mexico (Hall 1981; Fig. 1 ). Their current distribution is restricted to rela- tively undisturbed forested regions (Pelton 1982; Pelton et al. 1994; Fig. 2). Black bears can still be found throughout Canada with the exception of Prince Edward Island (extirpated in 1937), and in at least 40 of the 50 states; their status in Mexico is uncertain (Leopold 1959; Fig. 2). In the eastern United States black bear range is continuous throughout New England but becomes increasingly fragmented from the mid- Atlantic down through the Southeast (Maehr 1984). In the Southeast, most populations are now restricted to the Appalachian mountain chain or to coastal areas intemiittently in all states from Virginia to Louisiana (J. Wooding, Florida Freshwater Fish and Game Commission, unpublished data). Recently, 1 1 Canadian provinces and territo- ries reported stable black bear populations, and 10 provinces and territories estimated popula- tion sizes totaling about 359,000-373,000 (Pelton et al. 1994; McCracken et al. 1995; Table 1 ). Bears are legally harvested in all Canadian provinces and territories; total annual mortality from all sources (e.g., hunting, road kills, nuisance kills) is estimated at more than 23.000 (Pelton etal. 1994). Province Population estimate Trend Alberta 39,600 Stable Britisti Columbia 121,600 Stable Manitoba 25.000 Stable New Brunswick Unknown Stable/declining* j Newloundland 6.000-10,000 Stable Northwest Territories 5,000+" Stable ;| Nova Scotia 3,000 Stable Ontario 65,000-75,000 Stable/increasing i Quebec 60,000 Stable Sasl Prairie dog control campaigns, like this one in Arizona, circa 1913. contributed to the decline of the hlack-footed ferret. For further infurniation: Dean E. Biggins National Biological Service Midcontinent Ecological Science Center 4.'il2 McMarry Ave. Fort Colhns. CO S(),«i2.S small- to medium-sized veilebrates on praiiie dog complexes, as well as the degree of depen- dence on piairie dogs of selected associated species; examine the effect of complex size, as well as constituent colony sizes, numbers, and juxtaposition on diversity and abundance of associated species; investigate the recent histo- ry of plague on selected complexes to determine the relation between complex size (and mor- phology) and resistance to decimation by plague; and develop methods for reestablishing prairie dog colonies and reconstructing com- plexes in suitable areas where prairie dogs have been extirpated. The black-footed ferret cannot be reestab- lished on the grasslands of North America in viable self-sustaining populations without large complexes of prairie dog colonies. The impor- tance of this system to other species is not com- pletely understood, but large declines in some of its species should serve as a warning. The case of the black-footed ferret provides ample evidence that timely preventive action would be preferable to the inefficient "salvage" opera- tions. Furthermore, there is considerable risk of ineversible damage (e.g., genetic impoverish- ment) with such rescue efforts. References Biggins. D.E.. B.J. Miller. L. Hanehury. R, Oakleaf. A. Farmer. R. Crete, and A. Dood. 199.^. A technique for evaluating black-footed ferret habitat. Pages 73-88 in J.L. Oldemeyer. D.E. Biggins. B.J. Miller, and R. Crete, eds. Management of prairie dog complexes for the reintro- duction of the black-footed ferret. U.S. Fish and Wildlife Service Biological Rep. 13. Biggins. D.E.. M.H. Schroeder. S.C. Forrest, and L. Richardson. I98.'i. Movements and habitat relationships of radio-tagged black-footed ferrets. Pages 11.1-11.17 in S.H. Anderson and D.B. Inkley. eds. Proceedings of the Black-footed Ferret Workshop. Wyoming Game and Fish Department. Cheyenne. Caipenter. J.W., and C.N. HiUman. 1978. Husbandry, repro- duction, and veterinary care of captive ferrets. Proceedings of the American Association of Zoo Vetennarians Workshop. Knoxville. TN. 1979:36-47. Clarke. D.C. 1988. Prairie dog control — a regulatory view- point. Pages 1 19-12(1 in D.W. Uresk and G. Schenbeck. eds. Eighth Great Plains Wildlife Damage Control Workshop Proceedings. U.S. Forest Service Gen. Tech. Rep. RM-1.'S4. FoiTest. S.C. D.E. Biggins. L. Richardson, T.W. Clark. T.M. Campbell III. K.A. Fagerstone. and E.T. Thome. 1988. Population attributes for the black-footed ferret {Muswla /(;,i;M/it'.s) at Meeteetse, Wyoming, 1981-1985. Journal of Mammalogy 69(2):261-273. Hillman. C.N.. and R.L, Linder. 1973. The black-footed fer- ret. Pages 10-20 in R.L. Linder and C.N. Hillman. eds. Proceedings of the Black-footed Ferret and Prairie Dog Workshop. South Dakota State University Publications. Brookings. Lnider. R.L.. R.B. Dahlgren, and C.N. Hillman. 1972. Black-footed ferret-prairie dog interrelationships. Pages 22-37 in Proceedings of the Symposium on Rare and Endangered Wildlife of the Southwestern U.S. New Mexico Department of Game and Fish. Santa Fe. Marsh. R.E. 1984. Ground squirrels, prairie dogs and mar- mots as pests on rangeland. Pages 195-208 in Proceedings of the Conference for Organization and Practice of Vertebrate Pest Control. ICl Plant Protection Division. Femherst, England. O'Brien. S.J.. J.S. Martenson. M.^. Eichelberger. E.T. Thome, and F. Wright. 1989. Biochemical genetic vari- ation and molecular systematics of the black-footed fer- ret, Musti'la nigripes. Pages 21-33 in Conservation biol- ogy and the black-footed ferret. Yale University Press, New Haven. CT. Sharps. J. 1988. Politics, prairie dogs, and the sportsman. Pages 117-118 in D.W. Uresk and G. Schenbeck. eds. Eighth Great Plains Wildlife Damage Control Workshop Proceedings. U.S. Forest Service Gen. Tech. Rep. RM- 154. Williams, E.S.. E.T. Thome. M.J.G. Appel. and D.W. Belitsky. 1988. Canine distemper in black-footed ferrets {Musteki nigripes) from Wyoming. Joumal of Wildlife Diseases 24:385-398. American Badgers in Illinois by Barbara Ver Steeg Illinois Natural History Survey Richard E. Warner University of Illinois The American badger {Ta.xidca ki.xiis) is a medium-sized carnivore found in treeless areas across North America, such as the tall- grass prairie (Lindzey 1982). Badgers rely pri- marily on small burrowing mammals as a prey source; availability of badger prey may be affected by changes in land-use practices that alter prey habitat. In the midwestem United States most native prairie was plowed for agri- cultural use beginning in the mid-1800's (Burger 1978). In the past 100 years. Midwest agriculture has shifted from a diverse system of small farms with row crops, small grains, hay, and livestock pasture to larger agricultural oper- ations employing a mechanized and chemical approach to cropping. The result is a more uni- form agricultural landscape dominated by two primary row crops, com and soybeans. The effects of such land-use alterations on badgers arc unknown. In addition, other human activi- ties such as hunting and trapping have no doubt had an impact on native vertebrates such as the badger. Our ongoing study was initiated to determine the distribution and status of badgers in Illinois. Trends in carnivore abundance are difficult to evaluate because most species are secretive or visually cryptic. Trapping records, one of the earliest historical data sources for furbearers, are virtually nonexistent for badgers in the 1800"s (Obbard et al. 1987). In Illinois, badgers have been protected from harvest since 1957. Furthemiore, population estimates derived from furbearer harvest data are complicated by mar- ket price bias (Erickson 1982). Thus, data for estimating long-term population trends in Illinois badgers are few and flawed. Our approach is to document and evaluate current Our Lh'iiif; RcvdH/'ccv — Mainiiuils 11)9 population parameters, behavior, and inabitat use in the context of present and historical habi tat quality and availability. Most research on badgers has been limited to the western United States. Although results have varied somewhat among these studies, average densities (estimated subjectively from mark-recapture and home range data) have ranged from 0.38 to 5 badgers/kiii- {0.98-12.9.S badgers/mi-). We use radio telemetry to colled intensive data at a field site in west-central Illinois. Preliminary results suggest that indi- vidual badger home range size in Illinois is an order of magnitude larger than that of western badgers, implying that badger density in Illinois is much lower The home range size estimates of two badgers in Minnesota were also larger than those reported for western states (Sargeant and Warner 1972; Lampe and Sovada 1981 ). More than 65% of the Illinois landscape is under intensive row-crop agriculture (Neely and Heister 1987). Although badger prey exist throughout Illinois, available prey in row crops is limited to small species such as the deer mouse {Pcnwiy.sciis manicidatits). which occur in low uniform densities. Important prey species reported in the West, such as ground squinels (Spennophihis spp.), have average densities similar to Illinois deer mice, but they are much larger animals and may be concentrated into easily hunted loose colonies (Messick and Homocker 1981; Minta 1990). In Illinois, badgers appear to use most fre- quently cover types that are relatively undis- turbed by plowing, including hayfields, pas- tures, and linear habitats such as roadsides and fencelines. These habitats offer the greatest con- centration of small mammalian prey and the lowest frequency of agricultural disturbance. If badgers are limited by available prey, it is pos- sible that the current badger population density is lower than when native prairie and its accom- panying prey species" populations dominated the landscape. Although badgers are legally protected in Illinois, human-induced mortality such as vehi- cle collisions and agricultural accidents take a toll on populations. Large predators that might prey on adult badgers, such as the black bear (Ursus awericaniis). gray wolf (Canis lupus). and mountain lion {Felis concolor), have been extirpated since the 19th century (Hoffmeister 1989). However, our study shows that predation by coyotes {Canis latrans) and domestic dogs significantly affects juvenile badgers; fewer than 70% of juveniles survive to dispersal, reducing overall recruitment. The badger"s range may be expanding east- ward from its fomier boundaries within the Midwest; observations of range expansion in Missouri, southern Illinois. Indiana, and Ohio American badger (Taxidea tuxus). suggest that agricultural practices have converted previously forested acres to more suitable badger habitat (Moseley 1934; Leedy 1947; Mumford 1969; Hubert 1980; Mumford and Whitaker 1982; Long and Killingley 1983; Gremillion- Smith 1985; Whitaker and Gammon 1988). Our study revealed that badgers are distrib- uted and breeding throughout Illinois. The dynamics of badger range expansion are diffi- cult to pinpoint, in part because of the cryptic nature of the species. In Illinois and probably the agricultural Midwest in general, individual badgers move over such large areas that live sightings or indications of badger presence are few and far between. Oppoitunistic observa- tions to evaluate local badger distribution underestimate geographic range; thus, a focused regionwide attempt to evaluate badger range in the Midwest might demonstrate a wider distri- bution than expected. Badgers in Illinois appear to be a species with intermediate status: though they are neither abundant nor of high economic value, they are widely distributed and have adapted to a greatly altered environment. Understanding what factors cause a species such as the badger to become more or less abundant is vitally important in con- servation biology and wildlife management. References Burger. G.V. 1978. Agriculture and wildlife. Pages 89-107 in H.P. Brokaw. ed. Wildlife and America. Council on Environmental Quality. Washington. DC. Erickson, D.W. 1982. Estimating and using furhearer harvest information. Pages 53-66 in G.C. Sanderson, ed. Midwest furhearer management. Central Mountains and Plains Section of The Wildlife Society. Wichita, KS. Gremillion-Smith. C. 1985. Range extension of the badger {Tuxiiiea mxii.s) in southern Illinois. Transactions of the Illinois Academy of Science 78:1 1 1-1 14. Hoffmeister, D.F. 1989. Mammals of Illinois. University of Illinois Press. Urbana, IL. 348 pp. Hubert. G.F., Jr. 1980. Badger status evaluation. Illinois Department of Conservation. Job Completion Report. Federal Aid Project W-49-R-34. Study XII. 12 pp. Lampe. R.P., and M.A. Sovada. 1981. Sea.sonal variation in home range of a female badger (Taxiilai laxiis). Prairie Naturalist 15:55-58. Leedy, D.L. 1947. Spermophiles and badgers move east- ward in Ohio. Journal of Mammalogy 28:290-292. no Mammals— Oia Living Resources For furtlier information: Barbara Ver Steeg Illinois Natural History Survey 607 E. Peabody Dr Champaign, IL MS20 Lindzey. F.G. ms2. The North American badger Pages 653-663 in J. A. Chapman and G.A. Feldhammer. eds. Wild mammals of North America. Johns Hopkins University Press, Baltimore, MD, Long, C.A.. and C.A, Killingley. 1983. The badgers of the world. Charles C. Thomas Publishers, Springfield, IL. 404 pp. Messick, J.P, and M.G. Homocker. 1981. Ecology of the badger in southwestern Idaho. Wildlife Monograph 76. 53 pp. Minta. S.C. 1990. The badger, Ta.xiilea raxas. (Caniivora: Mustelidae): spatial-temporal analysis, dimorphic terri- torial polygyny, population characteristics, and human influences on ecology. Ph.D. thesis. University of California. Davis. 317 pp. Moseley, E.L. 1934. Increase of badgers in northwestern Ohio. Journal of Mammalogy 15; 156-158. Mumford, R.E. 1969. Distnbution of the mammals of Indiana. Indiana Academy of Science Monograph I. 114 pp. Mumford, RE., and J.O. Whitaker, Jr. 1982. Mammals of Indiana. Indiana Universitv Press, Bloomington, IN. 537 pp. Neely, R,D.. and C.G. Hcister. compilers. 1987. The nalur- al resources of Illinois: introduction and guide Illinois Natural History Survey Special Publ. 6. 224 pp. Obbard, M.E., J.G. Jones, R. Newman. A. Booth, A.J. Satterthwaite, and G. Linscombe. 1987. Furbearer har- vests in North America. Pages 1007-1038 in M. Novak, J. A. Baker ME. Obbard, and B. Malloch, eds. Wild furbearer management and conservation in North Amenca. The Ontario Trappers Association and the Ministry of Natural Resources, Toronto, Ontario. Sargeant, A.B., and D.W. Warner 1972. Movements and denning habits of a badger Journal of Mammalogy 53:207-210. Whitaker, J.O., Jr, and J.R. Gammon. 1988. Endangered and threatened vertebrate animals of Indiana; their distri- bution and abundance. Indiana Academy of Science Monograph 5. 122 pp. California Sea Otters by James A. Estes Ronald J. Jameson James L. Bodkin David R. Carlson National Biological Service Int'ormation on the .size. dLStribution. and pm- ductivity of the CalifoiTiia sea otter population is broadly relevant to two federally mandated goals: removing the population's listing as thieatened under the Endangered Species Act (ESA) and obtaining an "optimal sustainable population" under the Marine Mammal Protection Act. E.xcept for the population in cen- tral California, sea otters (Enliydni lutris) were hunted to extinction between Prince William Sound. Alaska, and Baja California (Kenyon 1969). Wilson et al. (1991). based on variations in cranial morphology, recently assigned sub- specific status {E. I. nereis) to the California sea otter. Furthermore, mitochondrial DNA analysis has revealed genetic differences among popula- tions in California. Alaska, and Asia (NBS, unpublished data). In 1977. the California sea otter was listed as threatened under the ESA, largely because of its small population size and perceived risks from such factors as human disturbance, compeliiion Sea otter (Enliydra lulns). with fisheries, and pollution. Because of unique threats and growth characteristics, the California population is treated .separately from sea otter populations elsewhere in the North Pacific, Survey Design Data on the size and distribution of the California sea otter population have been gath- ered for more than 50 years. In 1982 we devel- oped a survey technique in which individuals in most of the California sea otter's range are counted from shore by groups of two observers using binoculars and spotting scopes. Supplemental data for each sighting include group size, activity, number and size of pups, and habitat. Areas that cannot be counted from shore are surveyed from a low-flying aircraft, Rangewide surveys are done in late spring and mid-autumn. Population Trends, 1914-93 The California sea otter population has increased steadily through most of the 1900"s (Fig. I ), Rate of increase was about 5* per year until the mid-1970's. Although only one survey was completed between 1976 and 1982, the col- lective data suggest that population growth had ceased by the mid-1970"s. and that the population may have declined by as much as 30% between the mid-1970"s and early 1980"s. Counts made since 1983 have increased at about 5%-6% per year. In spring 1993. 2.239 California sea otters were counted. The California sea otter's lineal range (dis- tance along the 9-m [5-fathom] isobath between the northernmost and southernmost sightings) has also increased, although more slowly and erratically than the population size (data sum- marized by Riedman and Estes 1990). The Our l.iviiix Ri'siiiiiTfs — Mammals III 24 34 44 54 64 Year 94 Fig. 1. Trends in abundance of the California sea otter population. 1914-93. direction of range expansion was predoininale- ly southward before 1981. but northward there- after. Comparison between spring surveys con- ducted in 1983 and 1993 (Fig. 2) is sufficient to draw several conclusions. First, the population's range limits changed little during this 10-year period. e\en though large numbers of individu- als accumulated near the range peripheries. Second, population density increased through- out this time, although rates of increa.se were lowest near the center of the range. Finally, the relative abundance of individuals has remained largely unchanged (compare Fig. 2a [1983] with Fig. 2b |1993], noting the similarity in forms of distributions for kilometer segments 10-21). Although the number of dependent pups counted in spring surveys almost doubled between 1983 and 1993, the geographic range within which these pups were bom has changed very little (Fig. 2). Rate of annual pup produc- tion ranged from 0.14 to 0.28, but in most years it varied between 0.18 and 0.21. There are no obvious trends in rate of annual pup production between 1983 and 1993. Although the incre- mental change in the population from one year to the next appeared positively related to the annual number of births, this relationship can- not be shown to be statistically significant. Implications From the mid-1970"s to the early 1980's. the California sea otter population ceased growing and probably declined. Entanglement mortality in a coastal set-net fishery was the likely cause of this decline (Wendell et al. 1985). Restrictions were imposed on the fishery in 1982. and the population apparently responded by resuming its prior rate of increase. The maximum rate of increase for sea otter populations is about 20% per year. Except for the California otters, all increasing populations for which data are available have grown at about this rate (Estes 1990). These patterns, coupled with the absence of any size- or density-related reduction in growth rates, make the relatively slow rate of increase in the California popula- tion perplexing. Although the ultimate reason for disparate growth rates among sea otter populations is unknown, we believe that causes relate more to increased mortality than diminished reproduc- tion. While it is difficult to compare popula- tion-level reproductive rates between sea otters in Alaska and California, longitudinal studies of Spring 1983 census 200 175 125 ■ 100 - 75 ■ 50 25 3 5 7 9 11 13 15 17 19 21 23 25 27 29 -- Independents Spring 1 993 census ■ Pups II ,1 III II I.. 5 7 9 11 13 15 17 19 21 23 25 27 20-km segment, north (1) to south (29) 29 Fig. 2. Distribution and abun- dance of California sea otters in 1983 (a) and 1993 (b). Data are from the spring surveys. 112 Maiuiuals — ()///■ Llvlni^ Rt'Siuirct'S For further information: J.A. Esles National Biological Service University of California Santa Cruz, CA 95U64 marked individuals in tiie two regions indicate that both age of first reproduction and annual birth rate of adult females are similar. Furthermore, the close similarity between the theoretical maximum rate of increase and observed rates of population increase for sea otters in Washington, Canada, and portions of Alaska suggests that mortality from birth to senescence in these populations is quite low. In contrast, rates of mortality in the California sea otter are comparatively high, with an estimated 40%-50% of newborns lost before weaning (Siniff and Ralls 1991; Jameson and Johnson 1993; Riedman et al. 1994). This alone would significantly depress a population's potential rate of increase. Furthermore, the age composi- tion of beach-cast carcasses in California indi- cates that most postweaning deaths occur well in advance of physiological senescence (Pietz et al. 1988; Bodkin and Jameson 1991 ). These pat- terns likely explain the depressed rate of increase in the California sea otter population. Although the demographic patterns of mor- tality in California sea otters are becoming clear, the causes of deaths remain uncertain. There is growing evidence for the importance of predation by great white sharks {Carcharodon carchcirias). Contaminants may also be having a detrimental effect on California sea otters, although as yet there is no direct evidence for this. However, polychlorinated biphenyl (PCB) and DDT levels, known to be high in the California Current, are also high in the liver and muscle tissues of California sea otters (Bacon 1994). Of particular concern are that average PCB levels in California sea otters approach those that cause reproductive failure in mink, which are in the same family as otters; and preweaning pup losses are especially high in primiparous {sec glossary) females. This latter point may be significant because environmental contaminants that accumulate in fat can be transferred via milk in extraordinarily high con- centrations, especially to the first-born young in species such as the sea otter which has pro- longed sexual immaturity. References Bacon, C.E. 1994. An ecotoxicological comparison of organic contaminants in sea otters [Enhxdra liitris) among populations in California and Alaska. M.S. thesis. University of California, Santa Cruz, .'i-'i pp. Bodkin. J.L.. and R.J. Jameson. 1991. Patterns of seabird and marine mammal carcass deposition along the central California coast. 1980-1986. Canadian Journal of Zoology 69(.'S):II49-II55. Estes. J.A. 1990. Growth and equilibrium in sea otter popu- lations. Journal of Animal Ecology 59:.^8,'i-40l. Jameson, R.J., and A.M. Johnson. I99_V Reproductive char- acteristics of female sea otters. Marine Mammal Science 9(2): I. "56- 1 67. Kenyon. K.W. 1969. The sea otter in the eastern Pacific Ocean. North American Fauna 68:1-352. Pietz. P.. K. Ralls, and L. Perm. 1988. Age determination of California sea otters from teeth. Pages 106-1 15 //; D.B. Siniff and K. Ralls, eds. Population status of California sea oilers. Final report to the Minerals Management Service, U.S. Department of the Interior 14-12-001-3003. Riedman. M.L., and J.A. Estes. 1990. The sea otter [Enhydra liilris): behavior, ecology, and natural history. U.S. Fish and Wildlife Service Biological Rep. 90(14). 1 26 pp. Riedman M.L.. J.A. Esles. M.M. Staedler. A. A. Giles, and D.R. Carlson. 1994. Breeding patterns and reproductive success of California sea otters. Journal of Wildlife Management 58:-39 1 -399. Sinift D.B., and K. Ralls. 1991. Reproduction, survival, and tag loss in California sea otters. Manne Mammal Science 7(3):2ll-229. Wendell, F.E., R.A, Hardy, and J.A. Ames. 1985. Assessment of the accidental take of sea otters, Enhydra liitris. in gill and trammel nets. Marine Research Branch, California Department of Fish and Game. 30 pp. Wilson. D.E., M.A. Bogan, R.L. Brownell, Jr., A.M. Burdin, and M.K. Maminov. 1991. Geographic variation in sea otters, Enlndra lulris. Journal of Mammalogy 72( I ):22-36. White-tailed Deer in the Northeast by Gerald L. Storm National Biological Service William L. Palmer Pennsylvania Game Commission Populations of white-tailed deer (Odocoileus virginianiis) have changed significantly during the past 100 years in the eastern United States (Halls 1984). After near extirpation in the eastern states by 1900, deer numbers increased during the first quarter of this century. The effects of growing deer populations on forest regeneration and fami crops have been a con- cern to foresters and farmers for the past 50 years. In recent years, deer management plans have been designed to maintain deer populations at levels compatible with all land uses. Confiicts, however, between deer and forest management or agriculture still exist in the Northeast. Areas that were once exclusively forests are now a mixture of forest, farm, and urban environments that create increased interactions and conflicts between humans and deer, including deer-vehi- cle collisions. Management of deer near urban environments presents a unique challenge for local resource managers (Porter 1991 ). This report describes trends in abundance of white-tailed deer in the northeastern United States, relationships between harvest and popu- lation estimates, and conflicts between deer and other resources. Data Surveys We contacted biologists in each of 13 north- eastern states to acquire estimates of deer popu- lation size, harvest, and deer-vehicle collisions. We featured harvest data for antlered deer from Our L/i (Ht; Resources — Mammals //.? all 13 states to describe deer abundance during 1983-92, as well as data from selected states to describe relations between deer harvests and population size. Biologists in the northeastern states also pro- vided information on trends in reported con- flicts between deer and land use and other nat- ural resources. We detemiined the proportion of states that expressed conflicts for particular cat- egories such as deer and agriculture, deer and forestry, or deer and other resources. Population Estimates and Management Implications White-tailed deer populations have increased in all 13 northeastern states during 1983-92, based on either population estimates or number of antlered deer harvested. Population estimates for nine states indicated an increase from less than 1 .5 million in the early I980"s to 1.8 million in the early 1990's (Fig. I ). Deer density in the deer range of these states Even though states are responsible for managing deer within their boundaries, they do not control all land areas. The level of management for a state may be an eco- logical or political unit. However, states usu- ally lack data on deer and their habitats for small units such as municipalities, parks, refuges, or military facilities, and they are not directly responsible for management of these special areas. Presented here are exam- ples of two state parks, two national parks and a national historic site, and three nation- al wildlife refuges. Parks Ridley Creek and Tyler state parks in Pennsylvania provide two examples of where attempts have been made to manage high deer densities in and around urban areas. Such high densities pose significant problems because of deer feeding on orna- mental plants and deer-vehicle collisions. At Ridley Creek State Park, a 1,052-ha (2,600- acre) area near Philadelphia, hunters har- vested 97-344 deer per year during eight controlled hunts held between 1983 and 1992. From 160 to 491 deer were observed during annual counts made from helicopters (no count was made in 1990). A count of 491 in 1983 indicated that the deer density was in excess of 46. 7 deer/km- (121 deer/mi-) in the park. Hunter harvests resulted in a sig- nificant herd reduction, as 160 deer were counted in 1992 compared to 491 in 1983. Controlled hunts were conducted during 4 years— 1987, 1988, 1989, and 1991— at Tyler State Park in eastern Pennsylvania. The hunts in December 1987 and January 1988 yielded a kill of 487 deer; this number equates to 70.3 deer hai-vested per km- ( 182 deer/mi-) on the 692-ha (1,710-acre) park. During 1987, 455 deer were counted during aerial surveys compared to 49 during 1992, indicating that controlled hunts resulted in a significant reduction in deer abundance at Tyler State Park. National Parks The 2,335-ha (5,770-acre) Catoctin Mountain National Park, administered by the National Park Service in Maryland, has Deer Management at Parks and Refuges been noticeably affected by deer since at least 1 98 1 . Estimates of deer density indicat- ed an increase from 9.6 to 23.5 deer/kni- (25 to 61 deer/mi-) between 1986 and 1989. The presence of deer at this density has led to concern over the effect of deer on native plants, including rare species. The National Park Service is preparing an environmental assessment to review various management alternatives and to select a strategy to man- age deer at Catoctin Mountain Park. Unlike in state parks, harvest of deer from National Park Service lands is difficult, if not illegal, to implement; hence, management options are more limited. Estimates of deer abundance at Gettysburg National Military Park and Eisenhower National Historic Site from 1987 through 1992 indicated an increase from 721 to l.OlSdeeron a 2,862-ha (7,072- acre) area near Gettysburg in Adams County, Pennsylvania (Storm et al. 1992; Tzilkowski and Storm 1993). The 1992 populafion equates to a density of 35.5 deer/km- (92 deer/mi-), which is 10 times higher than that prescribed by the Pennsylvania Game Commission for Adams County. The deer herd at Gettysburg has been associated with high levels of damage to farm crops and for- est plant communities, as well as deer-vehi- cle collisions. An environmental impact statement is being prepared to develop a strategy for managing the Gettysburg deer population. Refuges The number of deer harvested by hunters increased twofold between 1983 and 1992 at each of the three national wildlife refuges examined. During 1992, the number of deer taken by hunters was 165 (17.8/km- [46/mi-]) for Eastern Neck, 210 (7.7/km- [20/mi-]) for Great Swamp, and 109 (4.2/km- [1 1/mi-]) at Montezuma. Although we did not obtain estimates of prehunt pop- ulations at these three refuges, if we assume that 35% of the population was killed, the prehunt herd size at the Great Swamp Refuge was 600 deer, which equates to 22 deer/km- (57 deer/mi-). Harvests by hunters appear to control deer at national wildlife refuges, despite the fact that each refuge manager has a unique set of cultural and biological attributes to consider in deer management. Although hunting is a viable deer management alter- native for most refuges, there is still a need to monitor the size of deer herds, determine the most suitable technique to survey deer at each refuge and the most useful demograph- ic data, and monitor plant communities to assess the effect of feeding by deer on plant resources. White-tailed deer fawn. References Storm, G.L.. D.F. Cottam. R.H. Yatiner. and J.D. Nichols. 1992. A comparison of two techniques for estimating deer density. Wildlife Society Bull. 20:197-203. Tzilkowski, W.M., and G.L. Storm. 1993. Detecting change using repeated measures analysis: white-tailed deer abundance at Gettysburg National Military Park. Wildlife Society Bull. 21:411-414. 114 Mammals — Our Livin)> Rfsauncs 85 86 87 88 89 90 91 92 Year Fig. 1. The trend in the size ot the white-tailed deer piipulation in nine northeastern states (Connecticut, Delaware, Maine, Massachusetts. New Hampshire. New York, Pennsylvania, Rhode Island, Vermont). 1983-92. Fig. 2. The harvest of antlered white-tailed deer (number per square mi or 259 ha of deer range) in 13 northeastern states in 1983 (first value) and in 1992 (second value); estimates for Virginia and West Virginia include young-of- the-year males (button bucks). has increasetj from 4..^ deei/kni- (11.1 deer/mi-) in 1983 lo 5.5 deer/km- (14.2 deer/mi-) in 1992. Density estimates ranged from 2.7 deer/km- (7.1 deer/mi-) in Rhode Island to 9.7 deer/km- (25.1 deer/mi-) in Pennsylvania. The total 1992 population of white-tailed deer in the Northeast (including estimates provided by personal communication with biologists from Maryland. New Jersey. Virginia, and West Virginia) was estimated at about 3.0 million. The total antlered (Fig. 2) and antlerless har- vest for all 1 3 states was estimated at 600.000 in 1983 and 900,000 in 1992. Managers manipu- late the harvest of antlei'ed to antlerless deer to obtain a desired population (i.e.. appropriate age and sex ratios). During the past decade, deer populations in the Northeast have continued to increase except in states that harvested marked- ly more antlerless than antlered deer. In Pennsylvania, for example, the deer population increased until the harvest of antlerless deer reached levels necessary to curb the upward trend in the population. In contrast, Massachusetts has consistently harvested more antlered than antlerless deer and the population 1983 value/1 992 value continues to increase. These two examples illus- trate how a prescribed harvest of antlerless deer can be used to achieve a population response that is consistent with each state's management objective. The magnitude of the antlerless and antlered deer harvest is a key factor for adjust- ing populations. The actual female-male ratio in the population, reproductive rates, and the sex- specitlc mortality caused by nonhunting factors also affect the population trends of each state. Ten of 1 3 states responded to the request for White-tailed deer tOildcoileiis viii;iniaiu(s). information on deer conflicts during the past decade; only two of these indicated no contlict between cuirent deer populations and land use or other natural resources. Four of the eight states with conflicts indicated increasing trends in agriculture-deer conflicts. Conflicts increased between deer and urban habitats in eight states, and vehicle-deer collisions increased in seven of the states. Seven states indicated they had prob- lems between deer and forest regeneration, and two of these states indicated the problem was becoming commoner. Seven states reported deer conflicts with parks and refuges; such problems included lack of forest regeneration as well as deer feeding on ornamental shrubs on private propeily. Four of these states indicated increas- ing trends in these kinds of problems. Conclusions and Present Outlook The trends in abundance of deer in north- eastern states are largely a function of regulated harvests by hunters. A significant amount of informadon on annual harvest by hunters and deer demographics is available in each north- easteiTi state. Thus, the process of managing white-tailed deer inay serve as a model to eval- uate monitoring techniques, population dynam- ics, and effects of wildlife on cultural and other natural resources. Managers of parks and refuges need better information to predict trends in regeneration and development of forests and the role of deer in forest regeneration. This will require the use of new and appropriate survey techniques (Wiggers and Beckemian 1993) and the ability to evaluate, interpret, and manage data acquired during long-term monitoring of deer and habi- tats used by deer (Tzilkowski and Storm 1993). Management goals can only be achieved throuah knowledge of trends in deer abundance Our Liviiif; Kesounes — Mammals 115 and a better understanding of public attitudes toward natural resources. References Halls. L.K., ed. 14X4. WhilL-lailed deer: ecology and man- agement. Slackpole Books. Harrisburg. PA. 870 pp. Porter. W.F. 1991. While-lailed deer in eastern ecosystems: implications for management and research in national parks. Natural Resources Report NPS/NRSUNY/NRR- 91/05. National Park Service. Denver. CO. 51 pp. Tzilkowski. W.M.. and G.L. .Storm. 199.^. Delecting change using repeated measuies analysis: while-tailed deer abundance al Gettysburg National Military Park. Wildlife Society Bull. 21:411-414. Wiggers, E.P.. and S.F. Beckerman. 199.^. Use of thermal infrared sensing to survey vvhile-lailed deer populations. Wildlife Society Bull n:26.V2f)S. For further information: Gerald L. Storm National Biological Service Pennsylvania Cooperative Fish and Wildlife Research Unit University Park. PA 16802 North American elk or wapiti (Cervus cla- pluis) represent how a wildlife species can recover even after heavy exploitation of popula- tions and habitats aix)und the turn of the centu- ry. This species is highly prized by wildlife enthusiasts and by the hunting public, which has provided the various state wildlife agencies with ample support to restore populations to previously occupied habitats and to manage populations effectively. Additionally, the Rocky Mountain Elk Foundation, founded in 1984. has promoted habitat management, acquisition, and proper hunting ethics among many segments of the hunting public. Current population size is estimated at 782.500 animals for the entire elk range (Rocky Mountain Elk Foundation 1989). Projections of population trends for the national forests and for the entire U.S. elk range are for continued increases through the year 2040 (Flather and Hoekstra 1989). This species occupies more suitable habitat than at any time in the century, and populations are at all-time highs (Figure). Elk populations in the United States primarily occupy federally managed lands, including national forests, pub- lic lands, national parks, and several wildlife refuges. Substantial populations occur on pii- vate holdings, including large ranches and reservations owned by Native Americans. Populations have been introduced into Michigan and Pennsylvania and recently have expanded in Nevada and California. In Canada, elk have increased their range into northern British Columbia since 1950 and occupy crown lands in Alberta. British Columbia, and Manitoba. Elk populations in the mountain parks of Jasper, Yoho, Kootenay, and Banff are an important part of the fauna, and the popula- tions in Elk Island National Park and Riding Mountain National Park have been extensively investigated. In Alberta and the western United States, an industry centered around ranching elk has proliferated in recent years. Perhaps the most spectacular improvement in elk populations is in Califoniia. where one population that originally consisted of about 600 individuals in the Owens Valley has now grown to over 2,500 Tule elk in 22 different populations (Phillips 1993). Aquiring habitat and reintroducing elk are the major reasons for the increase. Problems associated with elk management include the reduced life expectancies of males, which in some areas are attributable to hunting. This problem has been aggravated by increased access to formerly inaccessible habitat, allow- ing more hulls to be hunted. Additionally, elk have moved into more accessible habitats that provide less cover during hunting seasons. In some cases, hunting has increased enough to lower bull elk life expectancies even in areas where access has not increased. Means to address these issues include reductions in sea- son lengths, quotas on bulls either through hunter registration or limited-entry permit hunts, closures of extensive areas to vehicle access during the hunting season, and more integrated management of timber harvest to accommodate the needs of elk for escape cover. Such restrictions vary in their effectiveness, depending upon numbers and distribution of hunters, other human disturbances, and the amount and kind of forest involved. In open pine forests, for example, restricting access may be less effective than in denser fir forests, making other hunting regulations, such as limit- ed-entry hunts, necessary. Elk occupying open rangelands where conifer cover is poorly dis- tributed are largely subject to limited-entry hunting. Elk are sensitive to human activity North American Elk by James M. Peek University of Idaho Figure. Distribution of elk in North America as of 1978. based on information provided by provincial and state wildlife agen- cies (modified from Thomas and Toweill 1982. used with pennis- sion. Wildlife Management Institute). 116 AUmnnals — Our Living Re\i>urces For further information: James M. Peek University of Idaho Department of Fish and Wildhfe Resources Moscow, ID 83843 even in national paries where they are not hunt- ed and may become partially conditioned to human presence. Recreational, logging, graz- ing, seismic, and mining activities must be restricted to times and places where animals are least affected. As elk numbers have increased in farming areas, depredation on cash crops has also increased. Efforts to address this issue include special "depredation" hunts designed to move animals away from problem areas or to reduce populations, planting less palatable crops, fenc- ing hay and valuable crops to prevent access by elk, feeding elk, and hazing to discourage use. An integrated and specially tailored approach is often necessary to address this important prob- lem. Whether the high densities of elk that occur within Yellowstone National Park are perceived to be a problem depends upon one's viewpoint. CuiTent research on the condition of park plant communities heavily used by wintering elk sug- gests that factors interact to influence these communities. Grasslands that have been pro- tected for more than 30 years did not exhibit changes in productivity when compared with grazed grasslands (Coughenour 1991). On the other hand, when protected stands are compared with stands open to browsing, it appears that woody plants may have been adversely altered through prolonged heavy grazing (Chadde and Kay 1991). Past actions that affected plants include fire protection, concentrated grazing pressure by bison [Bison hisoii) in some areas, and altered grizzly bear (Ursiis circtos) feeding behavior. Within Yellowstone Park, the prospec- tive restoration of wolf (Canis lupus) popula- tions and changes in grizzly bear populations since the elimination of artifical food sources will undoubtedly affect elk populations that e.\ist primarily within the park. Natural changes in habitat across the west- ern elk range have largely benefited elk. Efforts to improve range conditions by modifying live- stock grazing practices will provide more for- age for elk, even if losses in woody plants may reduce the habitat quality for deer. Better live- stock management should also mean accommo- dating elk habitat use by providing ungrazed pastures within grazing allotments and by manipulating livestock grazing so plants retain their palatability to elk. As livestock is managed more effectively across western public lands, forage plants that wildlife use will benefit, thus also benefiting elk. On the other hand, some traditional high-quality elk winter habitats, which contain serai [see glossary) shrub ranges that developed after large fires earlier this century, are now growing into conifer stands. Some conifers like Douglas tlr {Pseiidotsuga menziesii) are palat- able and highly digestible for elk, and even pole-size stands can provide needed cover dur- ing severe winters or hunting seasons. As conifers dominate a larger proportion of the winter ranges and associated spring habitats, however, they shade out other species and habi- tat quality may deteriorate, eventually hurting elk populations. These long-term changes are not easily dealt with in short-term management efforts. Nevertheless, the future of elk populations in North America seems secure. Demand for hunt- ing as well as the nonconsumptive values of elk will ensure the success of substantial popula- tions. Elk populations will benefit from improved habitat conditions on arid portions of the range, improved livestock management, more effective integrated management of forest- ed habitats, and continued implementation of fire management policies in the major wilder- ness areas and national parks. References Chadde. S.W,. and C.E. Kay. 1991. Tall willow communi- ties on Yellowstone's northern range: a test of the "natur- al regulation" paradigm. Pages 231-262 in R.B. Keiter and M.S. Boyce, eds. The greater Yellowstone ecosys- tem. Yale University Press, New Haven, CT. Coughenour, M.B. 1991. Biomass and nitrogen responses to grazing of upland steppe on Yellowstone's northern win- ter range. Journal of Applied Ecology 28:71-82. Flather. C.H.. and T.W. Hoekstra. 1989. An analysis of the wildlife and fish situation in the United States: 1989-2040. U.S. Department of Agriculture Forest Service Gen. Tech. Rep. RM-178. 147 pp. Phillips. B. 1993. Good news for tules: Destanella Flat. Bugle 10:21-31. Rocky Mountain Elk Foundation. 1989. Wapiti across the West. Bugle 6:138-140. Thomas, J.W.. and D.E. Toweill, eds. 1982. Elk of North Amenca. Stackpole Books, Harrisburg, PA. 698 pp. Reptiles and Amphibians Overview Amphibians and reptiles are important elements of our national biological heritage and deserve special attention. They are crucial to the natural functioning of many ecological processes and key components of important ecosystems. In some areas certain species are economically consequential; others are aesthetically pleasing to many people, and as a group they represent significant segments of the evolutionary history of North America. Knowledge gained from past study of amphibian development and metamor- phosis has contributed immensely to our under- standing of basic biological processes and has directly benefited humans. The native herpetofauna of the continental United States includes about 230 species of amphibians (about 62% of which are salaman- ders and 38% frogs) and some 277 species of repfiles (about 19% turtles, 35% lizards, 45% snakes, and less than 1% crocodilians). If the list were expanded to include native species from Puerto Rico and the U.S. Virgin Islands in the Caribbean. Hawaii, the Trust Territory of the Pacific Islands, and the U.S. Territories in the Pacific, the amphibian list would increase by about 20 native species (all frogs) and another 5 non-native frog species. If the reptile inventory were expanded similarly, the list would increase by 2 turtles. 83 lizards, 1 8 snakes, and 1 croco- dilian. Another 2 species of turtles, 17 lizards, 2 snakes, and 1 crocodilian have been introduced. An updated summary of this information is scheduled for publication later this year (McDiamiid, unpublished data). Many U.S. reptile and amphibian checklists and field guides have been written over the past 50 years. The data for such summaries come from researchers working with various aspects of the biology of amphibians and reptiles and are found in many scientific publications. These summary field guides give the impression that the herpetofauna of the United States is well known and well studied. When we realize how little is known of the herpetofauna of compara- ble areas in South America, such an assumption is valid. A cursory review of U.S. data, howev- er, provides a somewhat different view. Since 1978 the total herpetofaunal diversity of the United States has increased by almost 12%, from 454 to 507 species. Much of that increase, though, has resulted from a new knowledge of complex groups of species (e.g., eastern pletho- dontid salamanders) through the application of molecular techniques to gain a better under- standing of the patterns of species formation and of the phylogenetic (evolutionary) history of certain groups. New species are still being Science Editor Roy W. McDiarmid National Biological Service National Museum of Natiiral History Washington, DC 20560 IIS Reptiles uiul Amphibians — Our Liviiii; Resoiirees discovered in reiutiveiy populated parts of liie counti7 (e.g., salamanders from California; D. Wake, Museum of Vertebrate Zoology. University of California, Berkeley, personal communication). Baseline information of the status and health of U.S. populations of amphibians and reptiles is remarkably sparse. No national program of monitoring populations of amphibians and rep- tiles, comparable to the North American Breeding Bird Survey (now coordinated by the National Biological Service), is operational. Programs in some states (e.g., Kansas. Illinois, Maryland. Wisconsin) have been moderately successful in monitoring amphibians, but clear- ly a national program is needed. Long-term data (more than 10 years) from specific sites in many habitats in different parts of the country were and are essential to detect continental or global patterns of change in the distribution and abun- dance of species' populations. A recent publica- tion (Heyer et al. 1994) recommended standard guidelines and techniques for monitoring amphibian populations and habitats; a similar volume on reptiles is planned. What remains is to establish a national program for such moni- toring studies; the Declining Amphibian Populations Task Force, a part of the Species Survival Commission of the World Conservation Union, together w ith the National Biological Service, should play major roles in establishing such programs for amphibians. Similarly, organizations that deal with the con- servation of turtles and crocodilians need to be expanded to develop an effective national mon- itoring program for reptiles. Habitat degradation and loss seem to be the most important factors adversely affecting amphibian and reptile populations in North America. The drainage and loss of small aquat- ic habitats and their associated wetlands have had a major adverse effect on many amphibian species and some reptiles. Many other factors in the decline of reptiles and amphibians have been implicated: most, perhaps all, are human-caused. For example. non-native species of gamefish introduced for sport have been implicated in the decline of frog populations in mountainous areas of some west- em states. Similarly, the introduction, acciden- tal or intentional, of other non-native species (e.g., bullfrogs in western states, anoline lizards in south Florida, and snakes in Guam) has harmed native species in other parts of the coun- try. Although populations of a few species have been severely impacted for diverse reasons (see the articles on California native frogs and the Tarahumara frog \Raua larahiiiiuinie]). it is not too late to prevent the extirpation of others. Certain management and conservation deci- sions based on adequate scientific data and careful planning ha\e proven successful (see articles on Coachella Valley fringe-toed lizard [Uiiui inomatci] and the American alligator [Alligator luississippiensis]). but too often these initiatives are reactive and occur only after a species is in trouble. Clearly, a better coordinated national pro- gram that looks at all species of amphibians and reptiles is desirable. Local and state programs to monitor amphibian and reptile populations are beginning; these efforts need to be expanded nationally. It is obvious that early detection of problems is crucial to successful remedial action. In many ways, a national program of monitoring amphibian and reptile populations is like preventive medicine; the earlier a problem is detected, the greater the likelihood of suc- cessful treatment and the lower the cost. A proactive national program based on standard- ized scientific methodology and applied across all species and habitats will go a long way toward ensuring that amphibians and reptiles remain a healthy component of our national bio- logical heritage. They are too important overall to receive anything less. Reference Heyer. W.R.. M.A. Donnelly, R.W. McDiarmid, L.-A.C. Hayek, and M.S. Foster, eds. 1994. Measunng and mon- itoring biological diversity: standard methods for amphibians. Smithsonian Institution Press. Washington. DC. 364 pp. l\irtles by Jeffrey E. Lovich National Biological Service Turtles have existed virtually unchanged for the last 200 million years. Unfortunately, some of the same traits that allowed them to survive the ages often predispose them to endangerment. Delayed maturity and low and variable annual reproductive success make tur- tles unusually susceptible to increased mortality through exploitation and habitat modifications (Brooks et al. 1991; Congdon et al. 1993). In general, turtles are overlooked by wildlife managers in spite of their ecological signifi- cance and importance to humans. Turtles are, however, important as scavengers, herbivores. and carnivores, and often contribute significant biomass to ecosystems. In addition, they are an important link in ecosystems, providing disper- sal mechanisms for plants, contributing to envi- ronmental diversity, and fostering symbiotic associations with a diverse array of organisms. Adults and eggs of many turtles have been used as a food resource by humans for centuries (Brooks et al. 1988; Lovich 1994). As use pres- sures and habitat destruction increase, manage- ment that considers the life-history traits of tur- tles will be needed. Our L/\ i/ji; Rcsruirccx — Kcpliles and Amphihums 119 Documenting Turtle Population Status 1 ie\iev\ed the population trends of turtles in the United States by examining most references (Ernst et al. 1994) that document the trends of tuitle species and populations. Because few long-term studies (lasting more than one gener- ation of the species examined) have focused on turtles, data on population fluctuations over time are generally unavailable (but see Gibbons 1990; Congdon et al. 1993). Techniques for conducting population studies of turtles and analyzing the data are summarized in Gibbons (1990). ^ Although we know less than desired about the actual extent of population fluctuations in most turtle populations, we do know that many turtles in the United States are at great risk of decline and extinction. Of the 55 native turtle species in the United States and its offshore waters. 25 (45*7^) require conservation, and 21 (38%) are protected or are candidates for pro- tection under the Endangered Species Act. Of the 1 1 species and subspecies listed as candi- dates for protection under the ESA. 4 are con- sidered declining, and 7 have unknown popula- tion statuses (Table). All tortoises and marine turtles require conservation action. Of the remaining 46 turtle species (aquatic and semi- aquatic fornis), 16 (35%) require conservation action. The percentage of U.S. turtles requiring conservation action (45%) is similar to that of the world (41%; lUCN/SSC Tortoise and Freshwater Turtle Specialist Group 1991 ). Although no turtles in the United States are known to have become extinct since European colonization (Honegger 1980). many species have experienced significant declines in num- bers and distribution during the last 100 years. For example, several bog turtle (Clenunys muh- lenhergii) populations in western New York, and all populations in western Pennsylvania, are apparently extirpated (Collins 1990; Ernst et al. 1994). Some populations of the spotted turtle (C guttata} have also shown dramatic declines (Lovich 1989). Even wide-ranging, formerly common species such as the common box turtle (Terraiieue Carolina: Ernst et al. 1994). desert tortoise {Gopherus agassizii: USFWS 1993). gopher tortoise (G. polyphemiis: McCoy and Mushinsky 1992), common slider {Trachemys scrlpta: Warwick 1986). and the alligator snap- ping turtle {Macwclemys tewwiiickii: Pritchard 1989) have declined significantly, underscoring the importance of monitoring "common" Family and species Common name Status* Ctjelonildae Sea turlles Caretta caretta Loggerhead Threatened Chelonia mydas Green sea turtle Endangered or threatened according to population or geographic area Eretmochelys imbricala Hawksbill Endangered g;' Lepidochelys kempii Kemp's ridley Endangered i. olivacea Olive ridley Endangered or threatened according to population or geographic area Chelydridae Snapping turtles Macrodemys temminckii Alligator snapping turtle Unknown but vulnerable; C^ candidate Dermochelyidae Lealherback sea turtles Dermochelys coriacea Leatherback Endangered Emydidae Semi-aquatic pond turlles Clemmys insculpta Wood turtle May become threatened if trade not brought under control C marmorala Western pond turtle Declining; C- candidate C. muhlenbergii Bog turtle Unknown; are or may be threatened by intemalional trade; C^ candidate Emydoidea blandingii Blanding's turtle Declining, C- candidate Graptemys barbouri Barbour's map turtle Unknown; C^ candidate G caglei Cagle's map turtle Unknown G. flavimaculata Yellow-blotctied map turtle Threatened, but insufficiently known; may be threatened by international trade G oculilera Ringed map turtle Threatened; restncted distribution Malaclemys terrapin Diamondback terrapin Some populations unknown, others declining; C^ candidate; listing applies to population or geographic area Pseudemys alabamensis Alabama red-bellied turtle Endangered; restricted distribution P. rubrivenlris Red-bellied turtle Endangered, according to population or geographic area Kinoslernidae Mud and musk turtles Kinosternon llavescerts Yellow mud turtle Unknown; C^ candidate; listing applies to population or geographic area K hirtipes [Mexican rough-footed mud turtle Unknown; C^ candidate; listing applies to population or geographic area Slernolherus depressus Flattened musk turtle Threatened Tesludinidae Tortoises Gopherus agassizii Desert tortoise Some populations threatened, others are C^ candidates; may become threatened If trade not brought under control. Status of Sonoran Desert population unknown G. berlandieri Texas tortoise IVlay become threatened it trade not brought under control Receiving some conservation action G. poiyphemus Gopher tortoise Declining Some populations threatened, others are C^ candidates; may become threatened if trade not controlled. Receiving some conservation action Trionychidae Sottshell turtles Apalone spinifera Spiny sottshell turtle Are or may be affected by international trade Table. U.S, turtle species in need of conservation. C^ ~ Possibly qualifying for threatened or endangered status, but more information is needed for determination. 120 ReptiUw iinj AinphihiLins — i)tfi' Lntni^ Resources Barbour's iiui(> lurtle (Graplemys harbouri) is restricted to the Apalachicola River system of Alabama. Florida, and Georgia. The species is a candidate for listing under the Endangered Species Act. species (Dodd and Fiunz 1993). The alarming decline of marine turtle populations is discussed later in this section. Perhaps the best data on long-term popula- tion changes in turtles are for the diamondback terrapin {Malaclemys terrapin), a species exploited heavily during the 19th century as a gourmet food (McCauley 1945; CaiT 1952). Terrapin populations declined rapidly, causing some states to set seasons and limits for their protection as early as 1878. The market for ter- rapin meat eventually waned, and terrapin pop- ulations recovered somewhat because their habitat remained largely intact. Unfortunately, some terrapin populations may be declining again because of renewed regional harvesting (Garber 1988). increased habitat destruction, mortality from vehicles, and drowning in crab traps (Ernst et al. 1994). Some turtle species, such as members of the map turtle genus Graptemys. have restricted ranges (Lovich and McCoy 1992) that place them at extreme risk of extinction. In addition, the popularity of many species, particularly tor- toises, as pets, contributes to the decline of wild populations (lUCN/SSC 1989: Ernst et al. 1994). Disease also appears to contribute to population declines in some turtles (Balazs 1986; Dodd 1988; Jacobson et al. 1991) and even seems a major challenge to the recovery of the federally threatened desert tortoise (USFWS 1993). Because of individual longevity, delayed maturity, and long generation times of turtles, long-term studies are required to monitor the dynamics of turtle populations (Gibbons 1990); recovery of most threatened species will be slow. Programs in which hatchlings are propa- gated in captivity and later released into the wild will do little to assist the recovery of turtles until the ultimate causes of decline are correct- ed (Frazer 1992). Efforts to conserve turtles in the United States should be concentrated in areas of high species diversity, where many species have lim- ited distributions, and where populations are at great risk. Ni)table high-risk areas include shal- low wetlands inhabited by freshwater turtles and coastal zones occupied by sea turtles. The most significant area of turtle endemism in the United States is along the Coastal Plain of the Gulf of Mexico (Lovich and McCoy 1992). Eleven species of turtles in the southeastern United States, where diversity is high (Iverson and Etchberger 1989; Iverson 1992), require conservation action, adding to the importance of implementing immediate conservation pro- grams in that region. References Balazs. G.H. 1986. Fibropapillomas in Hawaiian green tur- tles. Marine Turtle Newsletter .^9: 1-,^. Brooks, R.J.. G.R Brown, and D.A. Galbraith. 1991 . Effects of a sudden increase in natural mortality of adults on a population of the common snapping turtle (Chelydra ser- pcnimci). Canadian Journal of Zoology 69:1314-1.^20. Brooks. R.J., D.A. Galbraith. E.G. Nancekivell. and C.A. Bishop. 1988. Developing guidelines for managing snap- ping turtles. Pages 174-179 in R.C. Szaro, K.E. Severson, and D.R. Patton, tech. coords. Management of amphib- ians, reptiles, and small mammals in North America. U.S. Forest Service Gen. Tech. Rep. RM-166. Carr. A.F. 19.S2. Handbook of turtles. The turtles of the United States, Canada, and Baja California. Comstock Publishing Associates, Cornell University Press, Ithaca, NY. 542 pp. Collms, D.E. 19911. Western New York bog turtles: relicts of ephemeral islands or simply elusive' Pages 151-153 in R.S. Mitchell, C.J. Sheviak, and D.J. "Leopold, eds. Ecosystem management: rare species and significant habitats. Proceedings of the Fifteenth Annual Natural Areas Conference. New York State Museum Bull. 471. Congdon. J.D.. A.E. Dunham, and R.C. Van Loben Sels. 1993. Delayed sexual matunty and demographics of Blanding's turtles (Emydoiileu blandingii): implications for conservation and management of long-lived organ- isms. Conservation Biology 7:826-833. Dodd. C.K.. Jr 1988. Disease and population declines in the flattened musk turtle Slemolbenis depressus. American Midland Naturalist 119:394-401. Dodd, C.K.. Jr. and R. Franz. 1993. The need for status information on common herpetofaunal species. Herpetological Review 24:47-49. Ernst. C.H., J.E. Lovich. and R.W. Barbour 1994. Turtles of the United States and Canada. Smithsonian Institution Press. Washington, DC. In press. Frazer, N.B. 1992. Sea turtle conservation and halfway technology. Conservation Biology 6:179-184. Garber, S.B. 1988. Diamondback terrapin exploitafion. Plastron Papers 17(6): 18-22. Gibbons, J.W., ed. 1990. Life history and ecology of the slider turtle. Smithsonian Institution Press, Washington, DC. 368 pp. Honegger, R.E. 1980. List of amphibians and reptiles either known or thought to have become extinct since 1600. Biological Conservation 19:141-158. Our Liviiii; Rrsoiincs — Reptiles iiihl Amphihians 121 lUCN/SSC. 19Sy, The conscnation biology of tortoises. Occasional Papers ot tiie Internalional Union for the Conservation of Nature and Natural Resources. Species Survival Commission (SSC) 5. 204 pp. lUCN/SSC Tortoise and Freshwater Turtle Specialist Group. 1991. Tortoises and freshwater turtles: an action plan for their conservation. 2nd ed. International Union for the Conservation of Nature and Natural Resources, Gland. Switzerland. 48 pp. Iverson, J.B. 1992. Global coiTelates of species richness in turtles. Herpetological Journal 2:77-Sl. Iverson. J.B.. and C.R. Etchberger |9,S9. The distnhutions of the turtles of Flonda. Florida Scientist S2: 1 19-144. Jacobson, E.R., J.M. Ga.skin. M.B. Brown. R.K. Harris, C.H. Gardiner. J.L. LaPoite, HP. Adams, and C. Reggiardo. 1991. Chronic upper respiratory tract disease of free-ranging desert tortoises (Xerohutes agassizii). Journal of Wildlife Diseases 27:296-316. Lovich. J.E. 1989. The spotted turtles of Cedar Bog. Ohio: historical analysis of a declining population. Pages 23-28 in R.C. Glotzhober. A. Kochman. and W.T. Schultz, eds. Proceedings of Cedar Bog Symposium II. Ohio Histoncal Society. Lovich. J.E. 1994. Biodiversity and zoogeography of non- niarine turtles in Southeast Asia. Pages 381-391 //; S.K. Majumdar, F.J. Brenner, J.E. I.ovich, J.F. Schalles. and E.W. Miller, eds. Biological diversity: problems and challenges. Pennsylvania Academy of Science. Ea,ston, PA. In press. Lovich, J.E.. and C.J. McCoy. 1992. Review of the Graptemv.s piilchni group (Reptilia, Testudines, Emydidae 1. with descriptions of two new species. Annals of Carnegie Museum 61:293-315. McCauley. R.H. 1945. The reptiles of Maryland and the District of Columbia. Privately printed, Hagerstown, MD. 194 pp. McCoy. E.D.. and H.R. Mushinsky. 1992. Studying a species in decline: changes in populations of the gopher tortoise on federal lands in Florida. Florida Scientist 55:116-124. Pritchard, P.C.H. 1989. The alligator snapping turtle: biolo- gy and conservation. Milwaukee Public Museum, Wl. 104 pp. USFWS. 1993. Draft recovery plan for the desert tortoise (Mojave population). U.S. Fish and Wildlife Service, Portland. OR. 170 pp. Warwick, C. 1986. Red-eared tenapin laniis and conserva- tion. Ory.x 20:237.240. For further information: Jeffrey E. Lovich National Biological Service Midcontinent Ecological Science Center Palm Springs Field Station 63-500 Garnet Ave. PO Box 2000 North Palm Springs, CA 92258 Five species of marine turtles frequent the beaches and offshore waters of the south- eastern United States: loggerhead (Cciretta caretta). green (Clwloma mychis). Kemp's rid- ley {Lepidochelys keinpii). leatherback (Dermochelys coriacea). and hawksbill (Eretmochelys liiihricata). All five are repoiled to nest, but only the loggerhead and green turtle do so in substantial numbers. Most nesting occurs from southern North Carolina to the middle west coast of Florida, but scattered nest- ing occurs from Virginia through southern Texas, The beaches of Florida, particularly in Brevard and Indian River counties, host what may be the worid's largest population of log- gerheads. Marine turtles, especially juveniles and subadults. use lagoons, estuaries, and bays as feeding grounds. Areas of particular importance include Chesapeake Bay. Virginia (for logger- heads and Kemp's ridleys); Pamlico Sound. North Carolina (for loggerheads); and Mosquito Lagoon, Florida, and Laguna Madre, Texas (for greens). Offshore waters also support impoilant feeding grounds such as Florida Bay and the Cedar Keys, Florida (for green turtles), and the mouth of the Mississippi River and the north- east Gulf of Mexico (for Kemp's ridleys). Offshore reefs provide feeding and resting habi- tat (for loggerheads, greens, and hawksbills). and offshore currents, especially the Gulf Stream, are impoilant migratory corridors (for all species, but especially leatherbacks). Most marine turtles spend only part of their lives in U.S. waters. For example, hatchling log- gerheads ride oceanic currents and gyres (giant circular oceanic surface cunents) for many years before returning to feed as subadults in southeastein lagoons. They travel as far as Europe and the Azores, and even enter the Meditenanean Sea, where they are susceptible to longline fishing mortality. Adult loggerheads may leave U,S. waters after nesting and spend years in feeding grounds in the Bahamas and Cuba before returning. Nearly the entire world population of Kemp's ridleys uses a single Mexican beach for nesting, although juveniles and subadults, in particular, spend much time in U.S. offshore waters. The biological characteristics that make sea tuilles difficult to conserve and manage include a long life span, delayed sexual maturity, differ- ential use of habitats both among species and life stages, adult migratory travel, high egg and juvenile mortality, concentrated nesting, and vast areal dispersal of young and subadults. Genetic analyses have confirmed that females of most species retuiTi to their natal beaches to nest (Bowen et al. 1992; Bowen et al. 1993). Nesting assemblages contain unique genetic markers showing a tendency toward isolation from other assemblages (Bowen et al. 1993); thus, Florida green turtles are genetically differ- ent from green turtles nesting in Costa Rica and Brazil (Bowen et al. 1992), Nesting on warm sandy beaches puts the turtles in direct conflict with human beach use, and their use of rich off- shore waters subjects them to mortality from commercial fisheries (National Research Council 1990). Marine turtles have suffered catastrophic declines since European discovery of the New World (National Research Council 1990). In a relatively short time, the huge nesting assem- Marine Turtles in the Southeast by C. Kenneth Dodd, Jr. National Biological Sen ice 122 Rcplilfs and Amplubians — Our Lnifii^ Rcxources blages in the Cayman Islands, Jamaica, and Bennuda were decimated. In the United States, commercial turtle fisheries once operated in south Texas (Doughty 1984), Cedar Keys, Florida Keys, and Mosquito Lagoon; these fish- eries collapsed from overexploitation of the mostly juvenile green turtle populations. Today, marine turtle populations are threatened world- wide and are under intense pressure in the Caribbean basin and Gulf of Mexico, including Cuba, Mexico, Hispaniola, the Bahamas, and Nicaragua. Subadult loggerheads are captured extensively in the eastern Atlantic Ocean and Meditenanean Sea. Thus, marine turtles that hatch or nest on U.S. beaches or migrate to U.S. waters are under threats far from U.S. jurisdic- tion. Marine turtles can be conserved only through international efforts and cooperation. Information on the status and trends of southeastern marine turtle populations comes from a variety of sources, including old fishery records, anecdotal accounts of abundance, beach surveys for nests and females, and trawl and aerial surveys for turtles offshore. Surveys for marine turtles are particularly difficult because most of their lives are spent in habitats that are not easily surveyed. Hence, most status and trends information comes from counting females and nests. Few systematic long-term (more than 10-20 years) surveys have been con- ducted; the most notable are the nesting surveys at Cumberland Island and adjacent barrier islands in Georgia (TH. Richardson. University of Georgia, unpublished data), and beaches south of Melbourne in Brevard County. Florida (Ehrhart et al. 1993). Beach monitoring is fairly widespread in many areas of the Southeast, but coverage varies considerably among beaches and field crews. The only long-term sampling of lagoonal or bay populations occurs at Mosquito Lagoon and Chesapeake Bay, although short- duration surveys have sampled Florida Bay, Pamlico Sound, and Laguna Madre. Trawl sur- veys of inlets and ship channels and aerial sur- veys of offshore waters have been undertaken periodically. Loggerhead and Green Turtles The number of turtles nesting fluctuates sub- stantially from one year to the next, making intei-pretation of beach counts difficult. The Florida nesting populations of loggerheads and green turtles appear stable based on 12 years of data from east-central Florida (Ehrhail et al. 1993; Fig. 1). The green turtle nesting popula- tion may be increasing because of protective measures over the last 20 years or so. although the number of nesting females is still low (assuming 3-5 nests per female). North of Florida, nesting loggerhead numbers are declin- ing 3i'7c-9% a year in Georgia and South Carolina (National Research Council 1990). The main cause of mortality is drowning in shrimp and flsh nets (National Research Council 1990). although turtle excluder devices (TEDs; Fig. 2a) have helped reduce mortality (Fig 2b; Henwood et al. 1992). Large juveniles are most susceptible to drowning, and this is a critical life stage in the population dynamics of sea turtles (Crouse et al. 1987). Few data are available for lagoonal turtles, although similar numbers have been captured in Mosquito Lagoon and Chesapeake Bay from one year to the next. Loggerhead and green tur- tle populations, both adult and subadult. have undoubtedly declined from historical levels because of Iseach development and disturbance, the collection of eggs, and destructive fishing 82 83 84 85 86 87 88 89 90 91 92 93 Nesting season (year) 82 83 84 85 86 87 88 89 90 91 92 93 Nesting season (year) Fig. 1 a. Loggerhead nest totals in south Brevard County, Florida, 1982-93. b. Green turtle nest totals in south Brevard County, Florida. 1982-93. From Ehrhart et al (1993). Our Liviiifi Ri'Sdiincs — Reptiles ami Aiiiphihum\ I2i practices. Most high-level nesting occurs on the remaining inide\eloped or lightly developed beaches. Even there, plans for development and disorientation from lights pose serious and con- tinuing problems. Kemp's Ridley At one lime, more than 40,000 females nest- ed in a single mass nesting (termed "arribada") in Tamaulipas, Mexico. Several arribadas prob- ably occurred each year. Since 1947 a drastic reduction in the number of nesting females caused the near extinction of this species (Ross et al. 1989). Today only about 400-500 turtles nest each year despite stringent protection of the nesting beach. The principal threat to this species is incidental take during shrimp fishing. Leatherback and Hawksbill The leatherback and hawksbill are rare nesters in the southeastern United States, but offshore waters are important for feeding, rest- ing, and as migratory coiTidors. The status and trends of these species in U.S. offshore waters are unknown, although they are severely threat- ened throughout the Caribbean. Leatherbacks are taken by trawlers or are otherwise entangled in nets. Hawksbills are sought, especially in Cuba, for their shell, which is used for jewelry and similar items. The solitary nesting habits of hawksbills make them particularly difficult to monitor. Summary Sea turtles are threatened by beach develop- ment, light pollution, ocean dumping, incidental take in trawl and longline fisheries, disease (especially fibropapillomas), and many other variables. Because sea turtles are long-lived species, trends are difficult to monitor. Present methods of beach monitoring are extremely labor-intensive, expensive, and biased toward one segment of the population. Very little is known about marine turtle life-history and habi- tat requirements away from nesting beaches, and virtually nothing is known about male tur- tles. Because the effectiveness of measures aimed at protecting turtles may not be seen for decades, known conservation strategies should be favored over unproven mitigation schemes. Acquiring nesting habitat should be encour- aged. One of the most important management measures to protect sea turtles, especially of the juvenile and subadult size class, in the south- eastern United States. Caribbean, and western Atlantic Ocean is the use of TEDs to minimize drowning in commercial fisheries. Mature -- Funnel Finfish deflector Deflector grid Finfisti opening Fig. 2a. Schematic of a turtle excluder device (TED). From Watson et al. (1986). females should also be protected because of their importance to future reproduction. Researchers need to identify migratory routes, feeding and developmental habitat, and ways to minimize adverse impacts during all life-histo- ry stages. References Bowen. B.. J.C. Avise. J.I. Richardson. A.B. Meylan. D. Margaritoulis. and S.R. Hopkins-Murphy. 1993. Population structure of loggerhead turtles (Carettu caret- la) in the northwestern Atlantic Ocean and Mediterranean Sea. Conserxation Biology 7:834-844. Bowen. B.W.. A.B. Meylan. J.P. Ross. C.J. Limpus, G.H. Balazs, and J.C. Avise. 1992. Global population structure and natural history of the green turtle iCIieloiiia mydas) in terms of matriarchal phvlogenv. Evolution 46:865- 881. Crouse. D.T.. L.B. Crowder. and H. Caswell. 1987. A stage- based population model for loggerhead sea turtles and miplications for conservation. Ecology 68:1412-1423. Doughty. R.W. 1984. Sea turtles in Te.xas; a forgotten com- merce. Southwestern Historical Quarterly 88:43-70. Ehrhart. L.H.. W.E. Redfoot, R.D. Owen, and S.A. Johnson. 1993. Studies of marine turtle nesting beach productivity in central and south Brevard County. Florida, in 1993. Report to Florida Department of Environmental Protection. Institute of Manne Research. St. Petersburg. 20 pp. Henwood, T., W. Stuntz. and N. Thompson. 1992. Evaluation of U.S. turtle protective measures under exist- ing TED regulations, including estimates of shrimp trawler related mortality in the wider Caribbean. National Oceanic and Atmospheric Administration Tech. Memorandum NMFS-SEFSC-303. 15 pp. National Research Council. 1990. Decline of the sea turtles. Causes and prevention. National Academy Press, Washington. DC. 259 pp. Ross. J. P.. S. Beavers. D. Mundell, and M. Airlh-Kindree. 1989. The status of Kemp's ridley. Center for Marine Conservation. Washington. DC. 5 1 pp. Watson. J.W., J.F. Mitchell, and A.K. Shah. 1986. Trawling efficiency device: a new concept for selective shrimp trawling gear. Marine Fisheries Review 48:1-9. Atlantic Ocean 30 25 ■° 20 ^ 15 Gulf ^M m — Hflexico ^ § o o o o TEDs No TEDs Fig. 2b. Incidental capture of sea turtles in inshore and offshore waters of the United States before and after regulations requiring the use of TEDs on the U.S. shrimp fleet. From Henwood et al. (1992). For further information: C. Kenneth Dodd. Jr National Biological Service Southeastern Biological Science Center 7920N.W. 7P'St. Gainesville. PL 32653 J24 Reptiles and Amphihuiiis — Our Livui^ Resources Amphibians by R. Bruce Bury P. Stephen Corn C. Kenneth Dodd, Jr. Roy W. McDiannid Norman J. Scott, Jr. National Biological Service Amphibians are ecologically important in most freshwater and terrestrial habitats in the United States: they can be numerous, func- tion as both predators and prey, and constitute great biomass. Amphibians have certain physio- logical (e.g., permeable skin) and ecological (e.g.. complex life cycle) traits that could justi- fy their use as bioindicators of environmental health. For example, local declines in adult amphibians may indicate losses of nearby wet- lands. The aquatic breeding habits of many ter- restrial species result in direct exposure of egg. larval, and adult stages to toxic pesticides, her- bicides, acidification, and other human-induced stresses in both aquatic and terrestrial habitats. Reported declines of amphibian populations globally have drawn considerable attention ("Bury ct al. 19S(); Bishop and Petit 1992; Richards et al. 1993; Blaustein 1994; Pechmann and Wilbur 1994). Approximately 230 species of amphibians, including about 140 salamanders and 90 anu- rans (frogs and toads) occur in the continental United States. Because of their functional importance in most ecosystems, declines of amphibians are of considerable conservation interest. If these declines are real, the number of listed or candidate species at federal, state, and local levels could increase significantly. Unfortunately, because much of the existing infomiation on status and trends of amphibians is anecdotal, coordinated monitoring programs are greatly needed. Faunal Comparisons North American amphibian species exhibit two major distributional patterns, endemic and - Dis|unct populations of same species O 01 concern or stale-protected ■ Federally protected A Extirpated US. population of Tarahumara frog (Rana tarahumarae) Figure. Distribution of U.S. endemic amphibian species to be more broadly dispersed. widespread. Endemic species (Figure) tend to have small ranges or are restricted to specific habitats (e.g., species that occur only in one cave or in rock talus on a single mountainside). Declines are documented best for endemic species, partly because their smaller ranges make monitoring easier. Populations of endemics are most susceptible to loss or deple- tions because of localized activities (Bury et al. 1980; Dodd 1991). Examples of endemic species affected by different local impacts include the Santa Cruz long-toed salamander {Anibystoiiia mucrodactylum croceiim) in California, the Texas blind salamander (Typhlomolge rathbuni) in Texas, and the Red Hills salamander {Pluieognatluis hubrichti) in Alabama; these three species are listed as feder- ally threatened or endangered. The number of endemic species that have suffered losses or are suspected of having severe threats to their continued existence has increased in the last 15 years (Table). In pail, the increa.se reflects descriptions of new species with restricted ranges, but the accelerating pace Table. The number of amphibian species showing docu- mented or perceived dechnes in 1980 (Bury et al. 1980) and 1994. Distribution pattern Number of species 1980 1994 Endemic or relict 33 52 Widespread 5 33 those west of the 100th meridian tend of habitat alteration is the primary threat. The ranges of most endemics in the western states (26 species) are widely dispersed across the landscape. In contrast, endemics in the east- em and southeastern states (25 species) tend to be clustered in centers of endemism, such as in the Edwards Plateau (Texas), Interior (Ozark) Highlands (Arkansas, Oklahoma), Atlantic Coastal Plain (Texas to Virginia), and uplands or mountaintops in the Appalachian Mountains (West Virginia to Georgia). Widespread species often are habitat gener- alists. Many were previously common, but have shown regional or rangewide declines (Hine et al. 1 98 1; Com and Fogelman 1984; Hayes and Jennings 1986; Table). Reported declines of widespread species often lack explanation, per- haps because these observations have only recently received general attention or because temporal and spatial variations in population sizes of many amphibians are not well under- stood. Some reports are for amphibians in rela- tively pristine habitats where human impacts are not apparent. A few examples of declines in widespread species illustrate the threats they face across the country: Our l.iviiif; Rcsdiurcx — Replilcs ami Amphibians 125 • Aiiiphihians predominate in small lorest streams of the Pacific Northwest. Because timber is har- vested without adequate streamside protection, many populations ol the tailed I'rog {A.siciphiis tniei) and torrent salamanders {RhyacoUilon spp.) have been severely affected; some popula- tions soon will warrant consideration for listing. • The western toad (Bufo boreas) once was com- mon in the Rocky Mountains, but now occurs at fewer than 20% of known localities from south- em Wyoming to northern New Mexico. • Many salamander and frog populations in the southeastern United States have been negatively affected, some severely, because of degradation of stream habitats (e.g.. the hellbender, Cnptohnimiiiis allegcmiensis) and conversion of natural pinewood and hardwood forests and asso- ciated wetlands (e.g., gopher frog, Raiia capita) to plantation forestry, agriculture, and urban uses. • Leopard frogs {Rana spp.). which are used in teaching and research institutions, were once abundant in most of the United States. Populations in this diverse group have declined, sometimes significantly, in midwestem. Rocky Mountain, and southwestern states. Causes of Declines No single factor has been identifieid as the cause of amphibian declines, and many unex- plained declines likely result from multiple causes. Human-caused factors tnay intensify natural factors (Blaustein et al. 1994b) and pro- duce declines from which local populations cannot recover and thus ihey go extinct. Known or suspected factors in those declines include Western load {Bufo boreas). destruction and loss of wetlands (Bury et al. 1980); habitat alteration, such as impacts from timber harvest and forest management (Com and Bury 1989; Dodd 1991; Petranka et al. 1993): introduction of non-native predators, such as sportfish and bullfrogs, especially in western states (Hayes and Jennings 1986; Bradford 1989); increased variety and use of pesticides and herbicides (Hine et al. 1981); effects of acid precipitation, especially in east- ern North Ainerica and Europe (Freda 1986; Beebee et al. 1990; Dunson et al. 1992); increased ultraviolet radiation reaching the ground (Blaustein et al. 1994a): and diseases resulting from decreased immune system func- tion (Bradford 1991; Carey 1993; Pounds and Crump 1994). A Success Story: The Barton Springs Salamander A success story from the Edwards Plateau in Texas illustrates the importance of baseline ecological data, current science, and the types of partnerships essential for conservation of amphibians. The recently described Barton Springs salamander (Eurycea sosonim) occurs only in three springs within about 300 m (984 ft) of each other within the city limits of Austin. This salamander has one of the smallest known distributions of any North American verte- brate. Pools associated with the two primary springs had been developed as municipal swimming and wading pools, and standard cleaning procedures had eliminated most salamanders. With cooperation of city authorities and local volunteers, pool main- tenance practices detrimental to the sala- mander were modified, and populations of the salamander seem to be increasing and expanding their ranges within the spring sys- tem. Barton Springs salamander {Eurycea sosonim). 126 Reptiles iiHil Ainphibiiins — Ihir Li\iiiii Resutiiees For further information: R. Bnice Bury National Biological Service 200 S.W. 35th St. Corvallis, OR 97333 Amphibian populations also may vary in size because of natural factors, pailicularly extremes in the weather (Bradford 1983: Com and Fogelman 1984). The size of amphibian populations may vary, sometimes dramatically, from year to year, so what is perceived as a decline may be part of long-term tluctuations (Pechmann et al. 1991). The effect of global cli- mate change on amphibians is speculative, but it has the potential for causing the loss of many species. Monitoring Needs A profound need exists for natiimal coordi- nation of regional inventories and population studies, including a national effort to monitor amphibians on parks, forests, wildlife refuges, and other public lands. Only through long-temi studies will better data on population changes through time and between sites become avail- able. Such data are essential to evaluating the status and trends of amphibian species in the United States. Some regional surveys and inventories exist but only for a few species; these studies should be expanded into a coordi- nated effort with long-term inonitoring of popu- lations at many sites across the country as the goal. In addition, more research is needed to determine the impact of natural and human- caused factors on the different life-history stages and environments of amphibians. Also, the assumption that amphibians are good indi- cators needs to be tested rigorously (Pechmann and Wilbur 1994). Likewise, understanding the dynamics of populations between habitats and regions, and the roles amphibians play in aquat- ic and terrestrial ecosystems is essential. Detailed work on the ecology of species and the factors implicated in declines needs to continue. References Beebee. T.J.C.. R.J. Hower. A.C. Stevenson. S.T. Patnck. P.G. Appleby. C. Hetcher, C. Marsh. J. Natkanski. B. Rippey. and R.W. Battarbee. 1990. Decline of the natter- jack toad Bufo calnmitci in Britain: palaeoecological. documentary, and experimental evidence for breeding site acidification. Biological Consenation 53:1-20. Bishop. C.A.. and K.E. Petit, eds. 1992. Declines in Canadian amphibian populations: designing a national monitoring strategy. Canadian Wildlife Service Occasional Paper 76:1-120. Blaustein. A.R. 1994. Chicken Little or Nero's fiddle? A perspective on declining amphibian populations. Herpetologica 50:85-97. Blaustein, A.R,. PD. Hoffman. D.G. Hokit, J.M. Kiesecker. S.C. Walls, and J.B. Hays. 1994a. UV repair and resis- tance to solar UV-B in amphibian eggs: a link to popula- tion declines'' Proceedings of the National Academv of Sciences 91:1791-1795. " Blaustein. A.R.. D.B. Wake, and W.P Sousa. 1994b. Amphibian declines: judging stability, persistence, and susceptibility of populations to local and global extinc- tion. Conservation Biology S:60-71. Bradford, D.F. 1983. Winterkill, oxygen relations, and ener- gy metabolism of a submerged dormant amphibian, Runa nuiseosii. Ecology 64:1 171-1 183. Bradford. D.F. 1 989. Allotopic distribution of native frogs and introduced fishes in high Sierra Nevada lakes of California: implication of the negative effect of fish introductions. Copeia 1989:775-778. Bradford, D.F. 1991. Mass mortality and extinction in a high-elevation population of Rciiia miiscosa. Journal of Herpetology 5:174-177. Bury, R.B.. C.K. Dodd. Jr.. and CM. Fellers, 1980, Conservation of the Amphibia of the United States: a review, U.S. Fish and Wildlife Service Res. Publ. 134:1- Carey. C. 1993. Hypothesis concerning the causes of the disappearance of boreal toads from the mountains of Colorado. Conservation Biology 7:355-362. Corn. P.S.. and R.B. Bury. 1989. Logging in western Oregon: responses of headwater habitats and stream amphibians. Forest Ecology and Management 29:39-57. Corn. PS,, and J.C. Fogelman, 1984, Extinction of montane populations of the northern leopard frog tRaiui pipiens) in Colorado, Journal of Heijietology 18:147-152, Dodd. C.K.. Jr 1991. The status of the Red Hills salaman- der Phaeognatlms Imbnchti. Alabama. USA. 1976-1988. Biological Conservation 55:57-75. Dunson, W.A., R.L. Wyman, and E.S. Corbett. 1992. A symposium on amphibian declines and habitat acidifica- tion. Journal of Herpetology 16:349-352. Freda. J. 1986. The influence of acidic pond water on amphibians: a review. Water. Air. and Soil Pollution 30:439-450. Hayes. M.P., and MR, Jennings, 1986, Decline of ranid frog species in western North America: are bullfrogs iRaiia calesheiana) responsible'? Journal of Herpetology 20:490-509, Hine. R,L.. B.L. Les. and B.R Hellmich, 1981. Leopard frog populations and mortality in Wisconsin. 1974-76. Wisconsin Department of Natural Resources Tech. Bull. 122:1-39. Pechmann. J,H,K,. D,E, Scott. R,D, Semlitsch, J,P Caldwell. L,J, Vitt. and J,W. Gibbons, 1991, Declining amphibian populations: the problem of separating human impacts from natural fluctuations. Science 253:892-895, Pechmann. J,H,K,. and H,M, 'Wilbur. 1994. Putting declin- ing amphibian populations in perspective: natural tluctu- ations and human impacts. Herpetologica 50:65-84. Petranka. J.W.. M.E. Eldridge. and K.E. Haley. 1993. Effects of timber harvesting on southern Appalachian salamanders. Conservation Biology 7:363-370. Pounds. J. A., and M.L. Crump. 1994. Amphibian declines and climate disturbance: the case of the golden toad and harlequin frog. Conservation Biology 8:72-85, Richards. S,J„ K.R. McDonald, and" R.A. Alford. 1993. Declines in populations of Australia's endemic tropical rainforest frogs. Pacific Conservation Biology 1:66-77. Our I.iviiii; Resources — Rcpnics ami Amphihians 127 The American alligator (Alligator mississip- piensis) is an integral component of wetland ecosystems in Florida. Alligators also provide aesthetic, educational, recreational, and eco- nomic benefits to humans. Because of the com- mercial value of alligator hides for making high-quality leather products, alligator hunting was a major economic and recreational pursuit of many Floridians from the mid-1800"s to 1970. The Florida alligator population varied considerably during the 1900"s in response to fluctuating hunting pressure caused by unstable markets for luxury leather products. The declining abundance of alligators during the late 195()"s and early 1960's led to the 1967 classification of the Florida alligator population as endangered throughout its range. Federal and international regulations imposed during the 1970"s and 198(rs helped control trade of alli- gator hides, and illegal hunting of alligators was checked. The Florida alligator population responded immediately to protection and was reclassified as threatened in 1977 and as threat- ened because of its similarity in appearance to the American crocodile {Crocodylus acutus) in 1985 (Neal 1985). Assessments of Florida's alligator popula- tion were based on sporadic surveys before 1974 (Wood et al. 1985). The Florida Game and Fresh Water Fish Commission implemented annual night-light surveys that used spotlights to detect alligator eyeshine in 1974 to provide a more objective basis for assessing population trends (Wood et al. 1985). Although all areas were not sampled every year, these data are the best available for alligator populations in Florida and are useful for estimating population trends (Woodward and Moore 1990). Because survey areas were not a random sample of all alligator habitat in Florida, trend results are applicable only to deepwater habitats and navi- gable wetlands. Design of Alligator Surveys, 1974-92 We conducted night-light counts (Woodward and Marion 1978) with high-intensity spotlights from boats on 54 areas throughout Florida (Fig. 1) during 1974-92 (Woodward and Moore 1990). The number of areas surveyed in any year ranged from 7 in 1974 to 43 in 1980. In 1983 the number of areas surveyed was reduced to 22 to allow observers to conduct replicate counts on areas each year (Fig. 1 ). Eighteen of the 22 areas were subjected to alligator harvests of some type. American Alligators in Florida by Allan R. Woodward Florida Game and Fresh Water Fish Commission Clinton T. Moore U.S. Fish and Wildlife Service Fig. 1. Locations of survey areas for night-light counts alligators in Florida, 1974-92. We analyzed observed densities of alligators per kilometer (0.62 mile) of shoreline to esti- mate trends for each area during the periods 1974-92 and 1983-92. Size classes correspond- ed to the overall population, juveniles (0.3-1.2 m [ 1 -4 ft] ). harvestable sizes {1.2m or longer [4 ft or longer]), and adults (1.8 m or longer [6 ft or longer]; hatchlings less than 0.3 m long [1 ft] were excluded from trend analysis). Count densities represent only alligators observed during the survey. Most (more than 65%) alligators were submerged during surveys and not detected (Murphy 1977: Brandt 1989; Woodward and Linda 1993). Alligators in wet- lands adjacent to surveyed areas may have been undetected (Woodward and Linda 1993). Counts, however, do provide a relative measure of alligator abundance that is useful for estimat- ing population trends, provided that rates of detection do not vary annually. Status and Trends From 1974 to 1992, the density of alligators on surveyed wetlands increased an average 41% Alligators at dusk. Payne's Praine State Preser\'e. Florida. 128 Reptiles ami Amphibians — Our Living Resources or 1.9% annually. Average annual densities of harvestable alligators increased 2.7%, while average annual densities of adults increased 2.5%. The 0.5% average annual increase in counts of juvenile alligators during 1974-92 was not significant. These trends confirm that the Florida alligator population increased dur- ing the apparent recovery of the 1970"s and I980"s (Neal 1985). We observed cyclic pat- terns in abundance over time for all size classes (Fig. 2). Cyclic population levels may represent varying availability of counted alligators due to fluctuations in water level not fully accounted for in our analyses. They may also reflect pop- ulation changes brought about by periodic droughts or. to a lesser extent, severe winters. 0.3 m -1,2m (1-4 ft) 1.8 m or longer (6 ft or longer) 74 76 78 80 82 84 86 90 92 Year Fig. 2. Annual indice.s (mean number of alligators deteeted per linear kilometer 10.62 mi] of sur- vey route) and smoothed trend estimates (Cleveland 1979) for three size classes of the statewide alligator population in Florida, 1974-92. From 1983 to 1992. observed densities of adult alligators declined 3.2% per year, but we did not detect such trends in other size classes (Fig. 2). It is too early to draw conclusions con- cerning the influence of harvests on alligator populations since legal harvesting began in 1987 because of the variable nature of night- light alligator counts and the uncertain effects of wariness. Relatively stable populations of juveniles and harvestable alligators indicate that hatchling recruitment (replenishment) is suffi- cient to replace alligators lost through harvest. Consequently, alligator harvests do not seem to have negatively affected the Florida alligator population as a whole. Historically, the Florida alligator population was threatened by habitat loss and excessive illegal hunting (Hines 1979), but recently envi- ronmental contamination has been associated with population declines. Wetland drainage and alteration during the I900"s destroyed alligator habitat and permanently reduced alligator pop- ulations in some wetlands, particularly in fresh- water marshes (Neal 1985). State legislation, most recently the Wetlands Protection Act of 1984 (Florida Statutes 403.91), has significant- ly protected remaining wetlands, but alteration and loss of wetlands persist. Between the mid- 1970"s and mid-1980's, 10,542 ha (26,030 acres) of wetlands per year were lost to agricul- ture and other development (Frayer and Hefner 1991 ). Thus, habitat loss remains a threat to alli- gator populations. Illegal hunting is now negligible and has been replaced by regulated, managed harvests. Florida implemented a nuisance alligator con- trol program in 1978 in response to increasing problem alligators during the I970"s (Hines and Woodward 1980). Because the nuisance alliga- tor program targets individual alligators, the removal of these animals is unlikely to measur- ably affect alligator populations (Hines and Woodward 1980; Jennings et al. 1989). The state game commission introduced managed harvests of alligators and their eggs in 1987 to create conservation incentives by enhancing economic value of wild alligators (Wiley and Jennings 1990). Studies of the effects of harvest on alligator populations demonstrated that har- vests are sustainable at certain rates (Jennings et al. 1988: Woodward et al. 1992). Annual moni- toring and effective control of harvest rates ensure that populations will not suffer long- term depletion. More recently, environmental toxins have been implicated in the shaip decline of the alli- gator population on Lake Apopka. Florida's third-largest lake (Woodward et al. 1993; Guillette et al. 1994). Widespread pollution of wetlands by potentially toxic petrochemicals and metals may threaten the long-term viability of other alligator populations within Florida. For the present, the status of the Florida alliga- tor population is secure; however, continued habitat loss and toxic contamination will nega- tively affect alligator populations and may eventually compromise their conservation. References Brandt, L.A. 1989. The status and ecology of the American alligator iAIU^alor mississippiensis) in Par Pond. Savannah River Site. M.S. thesis. Florida International University. Fort Lauderdale. 89 pp. Cleveland. W.S. 1979. Robust locally weighted regression and smoothing scatteiplots. Journal of the American Statistical Association 74:829-836. Frayer. W.E.. and J.M. Hefner. 1991. Flonda wetlands: sta- tus and trends. 1970's to 1980's. U. S. Fish and Wildlife Service. Atlanta. 33 pp. Guillette, L.J.. Jr.. T.S. Gross. G.R. Masson. J.M. Matter. H.F Percival. and A.R. Woodward. 1994. Developmental abnormalities of the gonad and abnormal sex hormone concentrations in juvenile alligators from contaminated and control lakes in Florida. Environmental Health Perspectives 102:680-688. Our Livini^ Resource.': — Reptiles and Ainpliilmms 129 Mines, T.C. 1474. The past and presenl status of the American alligator in Florida. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 33:224-232. Mines. T.C and A.R. Woodward. 1980. Nuisance alligator control in Flonda. Wildlife Society Bull. 8:234-241. Jennings. M.L.. M.F Percival, and A.R. Woodward. 1988. Evaluation of alligator hatchling and egg removal from three Florida lakes. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 42:283-294. Jennings. M.L.. A.R. Woodward, and D.N. David. 1989. Florida's nuisance alligator control program. Pages 29- 36 in S.R. Craven, ed. Proceedings of the Fourth Eastern Wildlife Damage Control Conference. Madison. WI. Murphy. T.M. 1977. Distribution, movement, and popula- tion dynamics of the American alligator in a thermally altered reservoir. M.S. thesis. University of Georgia. Athens. 64 pp. Neal. W. 1985. Endangered and threatened wildlife and plant.s; reclassification of the American alligator in Florida to threatened due to similarity of appearance. Federal Register 50( 1 19 1:25.672-25,678. Wiley. E.N.. and M.L. Jennings. 1990. An overview of alli- gator management in Florida. Pages 274-285 in Proceedings of the Tenth Working Meeting Crocodile Specialist Group. lUCN The Worid Conservation Union. Gland. Switzerland. Wood. J.M.. A.R. Woodward. S.R. Mumphrey. and T.C. Mines. 1985. Night counts as an index of American alli- gator population trends. Wildlife Societv Bull. 13:262- 273. Woodward, A.R., and SB. Linda. 1993. Alligator popula- tion estimation. Final Report, Florida Game and Fresh Water Fish Commission, Tallahassee. 36 pp. Woodward, A.R., and W.R. Manon. 1978. An evaluation of night-light counts of alligators. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 32:291-.302. Woodward, A.R., and C.T. Moore. 1990. Statewide alligator surveys. Final Report, Flonda Game and Fresh Water Fish Commission, Tallahassee. 24 pp. Woodward, A.R., C.T. Moore, and M.F Delany. 1992. Experimental alligator harvest. Final Report, Florida Game and Fresh Water Fish Commission. Tallahassee. 118 pp. Woodward. A.R.. M.F. Percival. M.L. Jennings, and C.T. Moore. 1993. Low clutch viability of American alligators on Lake Apopka. Florida Scientist 56:52-63. For further information: Allan R. Woodward Florida Game and Fresh Water Fish Commission 4005 S. Main St. Gainesville, FL 32601 The Coastal Plain of the southeastern United States contains a rich diversity of reptiles and amphibians (herpetofaiina). Of the 290 species native to the Southeast. 1 70 ( 74 amphib- ians, 96 reptiles) are found within the range of the remnant longleaf pine ( Finns pahislris) ecosystem (Fig. 1 ). Many of these species are not found elsewhere, particularly those amphib- ians that require temporary ponds for reproduc- tion. Many Coastal Plain species are listed fed- erally or by states as endangered or threatened or are candidates for listing (Fig. 1 ). Examples include the flatwoods salamander {Ambystoma cingulatum), striped newt (Notophthabniis per- striatus), Carolina and dusky gopher frogs (Rana capita capita and R.c. sevosa). eastern indigo snake {Drymarchan corais couperi). gopher tortoise (Gophenis polyphemus), eastern diamondback rattlesnake (Cratahis adaman- teiis). and Florida pine snake (Pitiiophis melanoleucus mngitus). Studies in the Southeast Information on the status and trends of the Coastal Plain herpetofauna comes from limited studies of selected species or populations, most- ly within the last decade. The only intensive long-term quantitative and community-based studies have been at the Savannah River Site on the upper Coastal Plain of South Carolina. Most other studies have been distributional surveys for species such as Red Hills salamanders (Phaeognathns luibhchti). gopher frogs, striped newts, flatwoods salamanders, gopher tortoises, and Florida scrub lizards (Sceloponis woodi). Few studies have reported detailed habitat requirements for suspected declining species throughout their range. Surveys generally range 1-2 years in duration. Other trend information is derived from studies conducted by university scientists, private organizations, or state resource agencies. Concern for the future of the entire herpetofaunal community in the Southeast rests mostly on the well-documented loss of the old-growth longleaf pine ecosystem, although few community-based heipetofaunal surveys have been undertaken in this habitat. Status The tire-adapted longleaf pine community once stretched from southeastern Virginia to eastern Texas (Fig. 2). At present, less than 14% of the historical 282,283 km- (70 million acres) longleaf pine forest remains (Means and Grow 1985; Noss 1989), and most of it is on private land. Less than 1% is old-growth forest. Conversion of longleaf pine forests for agricul- ture, timber plantations, and urban needs (Ware et al. 1993) is accelerating (Fig. 3) and probably threatens the continued existence of many amphibian and reptile species, particularly in southern Georgia and Florida. For example, longleaf pine forests in Florida declined from 30,756 km- (7.6 million acres) in 1936 to only 3,845 km- (0.95 million acres) in 1989, an 88% decrease (Cerulean 1991). In southeastern Georgia the longleaf pine forest declined 36% (to 931 km- [230,000 acres]) between 1981 and 1988 (Johnson 1988). Most of this conversion has been from second- or third-growth longleaf pine stands to slash or loblolly pine plantation forestry. Reptiles and Amphibians in the Endangered Longleaf Pine Ecosystem by C. Kenneth Dodd, Jr. National Biological Service 130 Reptiles and Anipltihiaii.s— Our Lniiii; Resources I Reptiles S amphibians m range of Longleaf pine ET/R/D Fig. 1. Reptiles and amphibians within the southeastern Coastal Plain. Green bars = total number; Gold bars = number of species in need of conservation and manage- ment. E = endangered, T = threat- ened. R = rare. D = declining. Fig. 2. Historical distribution of the longleaf pine ecosystem in the southeastern Coastal Plain. Chart shows the present total number of species of amphibians and reptiles in various southeastern states. The effects of the loss of the longleaf pine ecosystem on the herpetofaunal community have never been assessed directly, but several species are known to have been affected. For example, the number of gopher tortoises, a key species within the longleaf pine ecosystem, has declined by an estimated 80% during the last 100 years (Auffenberg and Franz 1982), More than 300 invertebrates and 65 vertebrates use gopher tortoise burrows (Jackson and Milstrey 1989; Fig. 4), so an 80% reduction in gopher tortoises could represent a substantial reduction in the biodiversity of the longleaf pine ecosys- tem. Amphibians that breed in temporary ponds have been particularly affected both because of direct habitat destruction and the slower loss of wetland breeding sites by ditching. Breeding, foraging, and overwintering sites are also affected by certain types of forest plantation site preparation. Only five populations of striped newts remain in Georgia (Dodd 1993; L. LaClaire, USFWS, personal communication); the tlatwoods salamander has disappeared from the eastern section of its range; gopher frogs are nearly extirpated in North Carolina. Alabama, and Mississippi; and dusky salamanders (Desiiioi^iuiilius spp.) appear to have declined or disappeared in coastal South Carolina and peninsular Florida. On the other hand, the long-term communi- ty studies at the Savanna River Site, where the destructive effects of plantation forestry are not prevalent, do not reveal declining trends, although some amphibian populations there fluctuate widely from one year to the next in 80- 60- "40- 20- TTTi- rir rrp MC SC GA FL AL MS LA TX Longleaf pine Urban areas Human population 15 13 11 Fig. 3. Trend m loss of longleaf pine forest in relation to urban development and increases in human population in Florida, 19.^0-90 I Cerulean 1991; used with pemiission from The Nature Conservancy). both numbers and reproductive output (Pechmann et al. 1991). A 5-year study on a north Florida biological preserve disclosed declining amphibian numbers, but the study coincided with a severe regional drought (Dodd 1992). In west-central Florida, amphibian com- munities have changed composition because of Hg. 4. The distribution of the gopher tortoise (Gophenis pohphemus) in the southeastern United States. The chart shows the number of species of various taxa known to use its burrow and the number of plant taxa described from the longleaf pine-wiregrass ecosystem. Our Ijvinii Rt'soiini's — Rci^iUw and Ainpluhuius IM urbanization (Delis 1993), but the long-term effects of the change are unknown. The overall status of the Red Hills salamander (federal threatened list) remained the same from 1976 to 198S (Dodd 1991 ), although habitat loss contin- ued from plantation forestry. Virtually no data exist for tenestrial reptile populations or com- munities except for the gopher tortoise. Anecdotal information for all tenestrial reptiles suggests population declines, particularly in areas affected by imported red fire ants {Solt'iiopsis iiivicUi). Local centers of amphibian and reptile diver- sity need to be identified within the remaining longleaf pine community. Surveys, basic life- history studies of sensitive species, and long- term monitoring of amphibian and reptile popu- lations need to be initiated. Many species that are restricted to wetland and upland habitats appear to be declining, but precise baseline data are lacking. Factors impeding the identification of population trends include the longevity of many species, the effects of periodic natural events such as drought, and what appear to be random population fluctuations. At the same lime, when the known extent of habitat loss is coupled with declining trends elsewhere (Blaustein and Wake 1990; Wyman 1990) that result from unknown or hypothesized causes (UVB light, acidity, heavy metals, estrogen- mimicking compi>unds, roads, habitat fragmen- tation), the study and monitoring of amphibian and reptile populations in remnant southeastern longleaf pine forests will become especially imperative. References Auffenberg. W.. and R. Franz. 1982. The status and distrib- ution of tlie gopher tortoise {Gopherus polyphemus). North American tortois- ll.-S. Fish and Wildlife Pages 95- 1 26 in R.B. Bury, cd es: conservation and ecology. Service Res. Rep. 12. Blaustein, A.R., and D.B. Wake. 1990. Declining amphibian populations: a glotial phenomenon? Trends in Ideology and Evolution .');2(13-2()4. Cerulean, S.I. 1991. The preservation 2(100 report. Flonda's natural areas — what have we got to lose'.' The Nature Conservancy. Winter Park, PL. 74 pp. Delis, PR. 1993. Effects of urbanization on the community of anurans of a pine fiatwood habitat in west central Florida. M.S. thesis. University of South Florida. Tampa. 47 pp. Dodd. C.K., Jr 1991. The status of the Red Hills salaman- der Pluu-ognarhns hiibrichri. Alabama, USA, 1976- 1 98S. Biological Conservation 55:57-75. Dodd, C.K.. Jr 1992. Biological diversity of a temporary pond herpetofauna in north Florida sandhills. Biodiversity and Conservation 1:125-142, Dodd. C.K.. Jn 1993. Distribution of striped newts iNoiophllialmiis perstriatus) in Georgia. Report to U.S. Fish and Wildlife Service, Jacksonville, FL. 52 pp. Jackson, D.R., and E.G. Milstrey. 1989. The fauna of gopher tortoise burrows. Florida Nongame Wildlife Program Tech. Rep. 5:86-98. Johnson, T.G. 1988. Forest statistics for southeast Georgia. 1988. USDA Forest Service Resour Bull. SE-104. \53 PP- Means, D.B., and G. Grow. 1985. The endangered longleaf pine community. ENFO (Florida Conservation Foundation) Sept: 1-12. Noss, R.F. 1989. Longleaf pine and wircgrass: keystone components of an endangered ecosystem. Natural Areas Journal 9:21 1-213. Pechmann, J.H.K., D.E. Scou. R.D. Semlitsch. J.P Caldwell, L.J. Vitt, and J.W. Gibbons. 1991. Declining amphibian populations: the problem of separating human impacts from natural tluctuations. Science 253:892-895. Ware. S., C. Frost, and PD. Doerr. 1993. Southern mixed hardwood forest: the former longleaf pine forest. Pages 447-493 //) W.H. Manin, S.G. Boyce. and Ar. Echtemacht, eds. Biodiversity of the southeastern United States. Lowland terrestrial communities. John Wiley and Sons, New York. Wyman, R.L. 1990. What's happening to the amphibians? Conservation Biology 4:350-352. For further information: C. Kenneth Dodd, Jr National Biological Service Southeastern Biological Science Center 7920 N.W. 7P"St. Gainesville. FL 32653 Many recent declines and extinctions of native amphibians have occurred in cer- tain parts of the world (Wake 1991; Wake and Morowitz 1991 ). All species of native true frogs have declined in the western United States over the past decade (Hayes and Jennings 1986). Most of these native amphibian declines can be directly attributed to habitat loss or modifica- tion, which is often exacerbated by natural events such as droughts or floods (Wake 1991 ). A growing body of research, however, indicates that certain native frogs are particularly suscep- tible to population declines and extinctions in habitats that are relatively unmodified by humans (e.g., wilderness areas and national parks in California; Bradford 1991; Fellers and Drost 1993; Kagarise Sherman and Morton 1993). To understand these declines, we must document the current distribution of these species over their entire historical range to learn where they have disappeared. In 1988 the California Department of Fish and Game commissioned the California Academy of Sciences to conduct a 6-year study on the status of the state's amphibians and rep- tiles not currently protected by the Endangered Species Act. The study's puipose was to deter- mine amphibians and reptiles most vulnerable to extinction and provide suggestions for future research, management, and protection by state, federal, and local agencies (Jennings and Hayes 1993). This article describes the distribution and status of all native true frogs in California as determined by the California Fish and Game study. Native Ranid Frogs in California by Mark R. Jennings National Biological Service 132 Reptitci mill Ainpliihuins — 0:ir Lniiit; Rfsoiirces Status All species studied have suffered declines in distribution and abundance, largely because of habitat loss or modification from farming, graz- ing, logging, urban development, suppression of bru.sh fires, and flood-control or water-devel- opment projects. The species have also been affected by the widespread introduction of ver- tebrate and invertebrate aquatic predators. Northern Red-legged Frog {Rana aurora aurora) This frog, restricted to lower elevations (300 m |984 ft]) of the north coast region of California (Fig. 1 ), has disappeared from about 15% of its historical range in California. It is not in danger of extinction in the state. Fig. 1. Historical and current distribution of the northern red-legged frog. California red-legged frog, and Cascades frog in California based on 2,068 museum records and 302 records from other sources. Dots indicate locality records based on verified museum specimens. Squares indicate locality records based on venfied sightings (e.g.. field notes, photographs, pubhshed papers). Red dots and green squares denote localities where native frogs are extant. Gold dots and blue squares indicate where native frogs are presumed extinct. Figure modified from Jennings and Hayes (1993). California Red-legged Frog (/?.«. draytonii) This frog was originally found over most of California below 1,524 m (500 ft) and west of the deserts and the Sierra Nevada crest (Fig. 1 ). Although the California red-legged frog has now disappeared from about 75% of its histori- cal range in the state, around the turn of the cen- tury it was abundant enough to support an important commercial fishery in the San Francisco fish markets (Jennings and Hayes 1984). California red-legged frogs have almost completely disappeared from the Central Valley and southern California since 1970 and are cur- rently proposed for listing as endangered by the U.S. Fish and Wildlife Service (Federal Register 1994). Cascades Frog {R. cascadae) The Cascades frog was originally found in northern California above 230 m (755 ft: Fig. I ). where it was historically very abundant. Since the mid-1970's, the species extensively declined, disappearing from about 50% of its range in the state. No habitat loss hypothesis adequately explains why this frog survived with cuiTcnt land-use practices for over 50 years before its decline. It is still abundant in California only in the northern third of its range on lands under federal ownership. Foothill Yellow-legged Frog [R. boylii) This frog was originally found over most of California below 1 .829 m (6,000 ft), west of the deserts and the Sierra-Cascade crest (Fig. 2). In many locations before 1970, populations con- tained hundreds of individuals (Zweifel 1955), but the frog has now completely disappeared from southern California and from about 45% of its historical range over the entire state. Most populations were apparently healthy until the mid-1970"s. when a population crash occurred in southern California and the Sierra Nevada foothills after several years of severe floods and drought, which may have been responsible for the declines, although it is not certain. Because this species was an important component of the food web in many streamside ecosystems, its loss has probably negatively affected several organisms, such as garter snakes (Thamnophis spp.), which historically relied upon it as a major food source. Spotted Frog (R. pretiosa) The spotted frog was historically recorded only from scattered localities in the extreme northeastern part of California below 1,372 m (4.500 ft), where it was apparently restricted to large marshy areas filled by warmwater (more than 20°C [68°F]) springs (Fig. 2). It has now Our Z./\'mi,' Riwimnrs — Rejnilo, and Amphihiuns I3J disappeared from about 99% of its range, and is only known from one location in the state. It appears to be on the verge of extinction in California. Yavapai Leopard Frog (R. yavapaiensis) This frog was originally found along the Colorado River and in the Coachella Valley of southeastern California (Fig. 2). It has not been seen in the state since the niid-l960"s and now seems to be extinct at all sites examined. This leopard frog has been replaced in California by the introduced bullfrog (R. catesbeicma) and the Rio Grande leopard frog {R. berlaudieri), which are able to thrive in human-modified reservoirs and canals in the Yavapai leopard frog's original range (Jennings and Hayes 1994). Mountain Yellow-legged Frog {R. inuscosa) This species was historically abundant in the Sierra Nevada at elevations largely above 1.829 m (6.000 ft), and also in the San Gabriel, San Bernardino, and San Jacinto mountains of southern California above 369 m ( 1,210 ft; Fig. 3). The mountain yellow-legged frog has disap- peared from about 509c of its historical range in the Sierra Nevada and about 99% of its histori- cal range in southern California. Some researchers believe that the widespread intro- duction of non-native trout into high-elevation lakes is the major reason for the decline of this species in the Sierra Nevada (Bradford 1989: Bradford et al. 1993). The species, however, experienced massive die-offs in many parts of its range during the 1970"s (Bradford 1991) after several years of severe floods and drought, and continues to decline in relatively pristine areas such as wilderness areas and national parks. Such observations indicate that present land- management practices of setting aside large tracts of land for the "protection of biodiversi- ty" may not be adequate for ensuring the con- tinued survival of this species. Already, the loss of this frog over large areas has negatively affected organisms such as the western terrestri- al garter snake {Thamnopliis elegans). which relied upon it as a major food source (Jennings et al. 1992). To keep these populations from extinction, resource managers may need to ini- tiate active management efforts for mountain yellow-legged frogs (such as fish eradication programs in selected high-elevation lakes, fenc- ing of riparian zones to exclude livestock graz- ing, and relocating hiking trails and camp- grounds away from sensitive riparian habitats). Northern Leopard Frog (R. pipiens) This frog was historically recorded from scattered localities below 1,981 m (6.500 ft) in Northern red-lesaed trog (Rana aurora aiavra). Fig. 2. Historical and current distribution of ttie foottiill yellow-legged frog, spotted frog, and Yavapai leopard frog in California based on 3,.^ 16 museum records and 171 records from other sources. Dots indicate locality records based on verified museum specimens. Squares indicate locality records based on verified sightings (e.g.. field notes, photographs, published papers). Red dots and green squares denote localities where native frogs are e.\tant. Gold dots and blue squares indicate where native frogs are presumed e.xtinct. Figure modified from Jennings and Hayes (1993). 134 Rc'inHc.s liud Amphihuins — Our Liviii}^ Rcstntires Fig. 3. Historical and current distribution of the mountain yellow-legged frog, and presumed native populations of the nonhem leopard frog in California based on 2.565 museum records and 673 records from other sources. Dots indicate locality records based on verified museum speci- mens. Squares indicate locality records based on venfied sightings (e.g.. field notes, photographs, published papers). Red dots and green squares denote localities where native frogs are extant. Gold dots and blue squares indicate where native frogs are presumed extinct. Figure modified from Jennings and Hayes ( 1993). the eastern part of California (Fig. 3). Some populations were introduced into the state with- in the past 100 years (Jennings and Hayes 1993). most around the turn of the century (Storer 1925). This species has disappeared from about 95% of its range in California and is now found only in one national wildlife refuge near the Oregon border. Most localities where this frog was historically found have not changed appreciatively during the past 50 years, so the reasons for the species' decline and dis- appearance remain a mystery. For further information: Mark R. Jennings National Biological Service Alaska Science Center Piedras Blancas Field Station PO Box 70 San Simeon, CA 93452 References Bradford. D.F. 1989. Allotopic distribution of native frogs and introduced fishes in the high Sierra Nevada lakes of California: implication of the negative effects of fish introductions. Copeia l989(3):775-778. Bradford. D.F. 1991. Mass mortality and extinction in a high elevation population of Rana miiscosa. Journal of Herpetology 25(2):I74-177. Bradford, D.F. D.M. Graber, and F Tabatabai. 1993. Isolation of remaining populations of the native frog. Rana muscosa. by introduced fishes in Sequoia and Kings Canyon National Parks. California. Conservation Biology 7(41:882-888. Federal Register 1994. Endangered and threatened wildlife and plants; proposed endangered status for the California red-legged frog. Federal Register 59(221:4888-4895. Fellers. G.M.. and CA. Drosl. 1993. Disappearance of the Cascades frog Rana cascadae at the southern end of its range. California, USA. Biological Conservation 65(2):177-I81. Hayes. M.P.. and M.R. Jennings. 1986. Decline of ranid frog species in western North America: are bullfrogs (Rana catesheiaiia) responsible' Journal of Herpetology 20(4):490-509. Jennings. M.R.. and M.P Hayes. 1984. Pre-1900 overhar- vest of the California red-legged frog I.Raim aurora dray- toniiy. the inducement for bullfrog {Rana catesheiaiia) introduction. Herpetologica 41(1 ):94-l03. Jennings. MR., and M.P. Hayes. 1993. Amphibian and rep- tile species of special concern in California. Final report submitted to the California Department of Fish and G.ime. Inland Fisheries Division. Rancho Cordova, under Contract (8023). 336 pp. Jennings. M.R.. and M.P. Hayes. 1994. Decline of native ranid frogs in the desert southwest. In PR. Brown and J.W. Wright, eds. Proceedings of the Conference on the Herpetology of the North American Deserts. Southwestern Herpetologists Society. Spec. Publ. 5. In press. Jennings. W.B.. D.F Bradford, and D.F Johnson. 1992. Dependence of the garter snake Thamnophis elegans on amphibians in the Sierra Nevada of California. Journal of Herpetology 26(4):503-505. Kagarise Sherman. C. and M.L. Morton. 1993. Population declines of Yosemite toads in the eastern Sierra Nevada of California. Journal of Herpetology 27(2):186-I98. Storer. T.I. 1925. A synopsis of the amphibia of California. University of California Publications in Zoology 27:1- 343. Wake, D.B. 1991. Declining amphibian populations. Science 253( 5022 ):860. Wake. D.B.. and H.J. Morowitz. 1991. Declining amphibian populafions — a global phenomenon' Findings and rec- ommendations. Alytes 9( 1 1:33-42. Zweifel. R.G. 1955. Ecology, distribution, and systematics of frogs of the Rana boylei group. University of California Publications in Zoology 54(4):207-292. Oiti Livini^ Rt'sourci's — Reptiles ami Aniphibiuns IJ5 The desert tortoise [Gopherus uiiussizii) is a widespread species of the southwestern United States and Mexico. Within the United States, desert tortoises Uve in the Mojave. Colorado, and Sonoran deserts of southeastern California, southern Nevada, southwestern Utah, and western Arizona (Fig. 1 ). A substan- tial portion of the habitat is on lands adminis- tered by the U.S. Department of the Interior. The U.S. government treats the desert tor- toise as an indicator or umbrella species to mea- sure the health and well-being of the ecosys- tems it inhabits. The tortoise functions well as an indicator because it is long-lived, takes 12-20 years to reach reproductive maturity, and is sen- sitive to changes in the environment. In 1990 the U.S. Fish and Wildlife Service listed the species as threatened in the northern and west- ern parts of its geographic range (Fig. 1) because of widespread population declines and overall habitat loss, deterioration, and fragmen- tation. Because some populations exhibit signifi- cant genetic, moiphologic (see glossary), and behavioral differences, the Desert Tortoise Recovery Team identified six distinctive popu- lation segments (Fig. I ) for critical habitat pro- tection and long-term conservation within the Mojave and Colorado deserts (e.g.. Lamb et al. 1989: USFWS 1994). The population segments are representative of distinctive climatic, floris- tic, and geographic regions. Surveys The primary sources of information on sta- tus and trends of desert tortoise populations are from study plots established by the U.S. Bureau of Land Management and state fish and game agencies. More than 30 permanent study plots, each of which is 2.6 km- or larger ( I mi- or more), are surveyed at intervals ranging from 2 to 10 years. Study plots provide data on popula- tion characteristics, including density, size-age class structure, sex ratios and numbers of breed- ing females, recruitment of juveniles into the adult population, causes of death, and mortality rates (Berry 1990). Researchers use mark- recapture techniques to conduct 60-day surveys in spring for live and dead tortoises. Trends for habitat condition on study plots are measured by using quantitative data on native and exotic annual and perennial vegeta- tion (Berry 1990). Associated data on past and recent human activities or influences include numbers of visitors per season; density of dirt roads, trails, and vehicle tracks; levels and types of livestock grazing; and acreage disturbed by mining and mineral development and utility corridors. The data base for the six population seg- ments varies considerably; some segments con- tain several plots that have been sampled for 1 1 - 17 years, whereas others have few plots that have been sampled only I or 2 years (Berry 1990; USFWS 1994). Trends Condition and trends in tortoise populations vary within and between population segments. One measure of population condition is change in density. Examples of changes in density for nine study plots in California and Nevada are shown in Fig. 2 (Berry 1990; D.B. Hardenbrook, Nevada Division of Wildlife, and S. Slone, Bureau of Land Management, person- al communication). The greatest declines in Desert Tortoises in the Mojave and Colorado Deserts by Kristin H. Berry Philip Medica National Biological Service v\ \ \ Nevada 1 ( California \ eastern Mojave Desert northeastern / Mojave / Desert / Utah upper Virgin River I western Mojave Desert ( / A m \ S^C ^j V eastern Colorado Desert r t J [ \ northern Colorado Desert Sonoran Desert 1 \ Arizona r- densities, for all size classes and for breeding females (up to 90%), occurred in the western Mojave segment between the 1970"s and I990"s. Similar declines (30%-60%) also occurred in the eastern Colorado Desert seg- ment between 1979 and 1992, with the greatest declines registered at the Chuckwalla Bench plot (Fig. 2). Moderate declines of 20%-25% were reported from some sites in the eastern Mojave Desert segment (Piute Valley and Goffs). The northeastern Mojave also exhibited declines on some plots (e.g.. Ivanpah Valley and Gold Butte). In contrast, the northern Colorado Desert population segment showed indications of growth in the breeding adults at one plot (Ward Valley), and the upper Virgin River seg- ment appears stable (USFWS 1994). Fig. 1. Li.S. range of tfie desert tortoise (Gapherus agassizii). Tfie six population segments for desert tortoises federally listed as tfireat- ened occur in parts of the Mojave and Colorado deserts that lie north and west of the Colorado River. r^cscit toiloisc iOopheriis ui;as' sizii). 136 Reptiles and Amphibians — Onr Living Resaiirces 300- ®lvanpah Valley: (^ Desert Tortoise Natural Area: northeastern Mojave Desert, ^ western Mojave Desert, CA CA (1979-90) (1979-92) ©Chuckwalla Bencti: eastern Colorado Desert, CA (1979-92) (K\ Ward Valley: northern Colorado Desert, CA (1980-91) ©Goffs: eastern Mojave Desert, CA (1980, 1990) ©Piule Valley: eastern Moiave Desert, NV 250- (1983, 1983; ©Sheep Mountain: eastern Mojave Desert, NV (1984, 1992) /TT\ Gold Butte: northeastern Mojave Desert, NV (1986, 1990) Trout Canyon: eastern Mojave Desert, NV (1987,1992) 200- 150- 100- 50- k i=l 80 Year 90 80 Year 90 Year 90 Fig. 2. Examples of changes in desert tortoise population densities at nine study sites in California and Nevada. Tfie midpoint for density estimates of all sizes of tortoises (orange line) is shown by a dot on a bar representing the 959c confidence interval (CD; the midpoint for density estimates for adult tortoises only (red lines) is depicted by a square on a bar rep- resenting the 95% CI. Causes of declines vary by site. Causes of population declines differed somewhat within and between population seg- ments, but were primarily related to human activities. Higher than normal losses or mortal- ity rates were attributed to many causes, such as illegal collecting, vandalism, upper respiratory tract disease or shell disease, predation by com- mon ravens, crushing by vehicles both on and off roads, and trampling by livestock (BLM 1988; USFWS 1994). For example. 14.6'7r- 28.9% of desert tortoise carcasses collected from western Mojave plots in the 1970"s and early 1980's showed signs of gunshots (tortois- es were shot while still alive), but only 0%- 3.1% of carcasses from the less-visited eastern Mojave and northern Colorado deserts showed such signs (Berry 1986). Deaths from vehicles on paved roads were also highest in the western Mojave. where densities of dirt roads and vehi- cle trails are higher than elsewhere. Of particular concern is the recent appear- ance of a highly infectious and usually fatal upper respiratory tract disease caused by the bacterium Mycoplasma agassizii. The disease, apparently introduced through the release of captive tortoises (Jacobson 1993), has caused 80 Year 90 the deaths of thousands of wild tortoises in the Mojave Desert during the last few years (K.H. Berry, unpublished data). Fragmented and deteriorated habitats also affect population vitality. Populations in areas with high levels of exotic annual plants are declining at substantially higher rates than those in less disturbed areas. In summary, tortoise populations occurring in relatively undisturbed and remote areas with little vehicular access and low human visitation generally were stable, or exhibited lower rates of decline than tortoise populations in areas with high levels of disturbance, high vehicular access, and high human visitation. References Berry. K.H. 1986. Incidence of gunshot deaths in desert tor- toises in California. Wildlife Society Bull. 14:127-132. Berry. K.H. 1990. The status of the desert tortoise in California in 1989 (with amendments to include 1990- 1992 data sets). Draft report from U.S. Bureau of Land Management to U.S. Fish and Wildlife Service, Region I.Portland. OR. BLM. 1988. Desert tortoise habitat management on the pub- lic lands: a rangewide plan. U.S. Bureau of Land Management. Washington, DC. 23 pp. Oi(r Liviiifi Resources — Reptiles anil Amphibians I.U Jacohson. E.R. 199.V Implications of infectious diseases for captive propagation and introduction progratiis of threat- ened/endangered reptiles. Journal of Zoo and Wildlite Medicine 24(3):245-255. Lamb. T., J. Avise, and J.W. Gibbons. 1984. Phylogeo- graphic patterns in mitochondrial DNA of the desert tor- toise {Xerohcites iigassizi) and evolutionary relationships among the North American gopher tortoises. Evolution 43(11:76-87. USFWS. 1994. Desert Tortoise (Mojave Population) Recovery Plan. U.S. Fish and Wildlife Service. Portland. OR. 77 pp. + appendices. For further information: Kristin H. Berry National Biological Service Riverside Field Station 6221 Bo.x Springs Blvd. Riverside. CA 92507 Fringe-toed lizards (Unia spp.l inhabit many of the scattered windblown sand deposits of southeastern California, southwestern Arizona, and northwestern Mexico. These lizards have several specialized adaptations: elongated scales on their hind feet ("fringes") for added traction in loose sand, a shovel-shaped head and a lower jaw adapted to aid diving into and mov- ing short distances beneath the sand, elongated scales covering their ears to keep sand out, and unique morphology (form or structure) of inter- nal nostrils that allows them to breathe below the sand without inhaling sand particles. While these adaptations enable fringe-toed lizards to successfully occupy sand dune habi- tats, the same characteristics have restricted them to isolated sand "islands." Three fringe- toed lizard species live in the United States: the Mojave {U. scopaiiu). the Colorado Desert (U. nokitii), and the Coachella Valley {U. inonniki}- Of the three, the Coachella Valley fringe-toed lizard has the most restricted range and has been most affected by human activities. In 1980 this lizard was listed as a threatened species by the federal government. In 1986 the Coachella Valley Preserve sys- tem was established to protect habitat for the Coachella Valley fringe-toed lizard. This action set several precedents: it was the first Habitat Conservation Plan established under the revised (1982) Endangered Species Act and the newly adopted Section 10 of the act, it estab- lished perhaps the only protected area in the world set aside for a lizard, and its design was based on a model of sand dune ecosystem processes, the sole habitat for this lizard. Three disjunct sites in California, each with a discrete source of windblown sand, were set aside to protect fringe-toed lizard populations: Thousand Palms, Willow Hole, and Whitewater River. Collectively, the preserves protect about 2% of the lizards' original range. Eight years after the establishment of the preserve system, few Coachella Valley fringe- toed lizards exist outside the boundaries of the three protected sites. Barrows (author, unpub- lished data) recently identified scattered pockets of windblown sand occupied by fringe-toed lizards in the hills along the northern fringe of the valley, but only at low densities. Fringe-toed lizard populations within the protected sites have been monitored yearly since 1986. During this period, California experienced one of its most severe droughts, which ended in spring 1991. Numbers of fringe-toed lizards within the Thousand Palms and Willow Hole sites declined during the drought, but rebounded after 1991 (Fig. 1). By 1993. after three wet springs, lizard numbers had increased substan- fially, Lizards at the Whitewater River site were intensively monitored since 1985 by using mark-recapture methods to count the population on a 2.25-ha (5.56-acre) plot. In 1986 this site 0 ^ 85 93 Year had the highest population density of the three protected sites. As with the other two sites, the Whitewater River population declined through- out the drought, but only increased slightly after the drought broke in 1991 (Fig. 2). Compounding the drought effect, much of the fine sand preferred by fringe-toed lizards was blown off the site during the dry years. This condition was unique to the Whitewater River Coachella Valley Fringe- toed Lizards by Cameron Barrows The Nature Conservancy Allan Muth Mark Fisher University of California, Boyd Deep Canyon Desert Research Center Jeffrey Lovich National Biological Service Fig. 1. The mean number of lizards per transect at the Thousand Palms and Willow Hole sites, 1986-93. Data were pooled from five 10 x 1.000 ni( 32.8 x 3.281 ft) transects. All transects were sampled six times each year, and all sampling was conducted within a 6-week span in the late spring of each year. Coachella Valley fringe-toed lizard ( Uma inornata). ISH Rt'pnlis iiiul Aniphibuins — Otir Liviiii^ Rt's(mrci'S Fig. 2. The known population size of a Coacheila Valley fnnge-loed lizard population on a 2.25-ha (5.56-aere) study plot on the Whitewater River preserve. For further information: Cameron Barrows The Nature Conservaney 53277 Avenida Diaz La Quinta, CA 92253 S 250 = 200 86 90 92 Year site: the other two piotected sites have much deeper sand deposits and are less susceptible to wind erosion. New windblown sand was deposited on the Whitewater River site in 1993 after a period of high rainfalf The population appears to be increasing in response to these favorable conditions. The decline in fringe-toed lizards during the monitoring period appears to be the result of responses to natural fluctuations in habitat. The dynamic nature of sand dune systems, coupled with the lizards" apparent sensitivity to drought, underlines the importance of preserve design. Appropriate designs anticipate the effect of nat- ural habitat fluctuation. The ecological model that governed the design of the Coacheila Valley Preserve system was reevaluated in 1993 with one disturbing result. A primary sand source was identified that supplies the sand dunes at the Thousand Palms site, but was not emphasized sufficiently in the original model and design. Fortunately, the sand source and its path to the existing preserve have not been affected severely by human develop- ment at this time, so options for correcting the design's shortcomings are still available. The fringe-toed lizard population sustained by this sand source has been the largest of the three sites for the past few years. Monitoring the lizards without investigating ecosystem processes would not have identified the design error until it was too late to correct. Disappearance of the Tarahumara Frog by S.F. Hale Herpelologist C.R. Schwalbe National Biological Senice J.L. Jarchow Soiiora Pel Hospital, Tucson, AZ C.J. May Pima Community College C.H. Lowe University of Arizona T.B. Johnson Arizona Game and Fish Department In the spring of 1983 the last known Tarahumara frog in the United States was found dead. Overall, the species seems to be doing well in Mexico, although the decline of more northern populations are of concern. The Tarahumara frog {Rami tarahuinanw) inhabits seasonal and permanent bedrock and bouldery streams in the foothills and main mountain mass of the Sierra Madre Occidental of northwestern Mexico. It ranges from northern Sinaloa, through western Chihuahua and eastern and northern Sonora. and until recently into extreme south-central Arizona (Fig. 1). Arizona locali- ties, all in Santa Cruz County, include three drainages in the Atascosa-Pajarito Mountains (Campliell 1931: Little 1940: Williams 1960) and three in the Santa Rita Mountains (Hale et al. 1977). Population Estimates, 1975-93 We have drawn our review from museum records, the published literature, and reports, journal entries, and personal observations by the authors, other biologists, and knowledge- able persons. From May 1975 through June 1977, we conducted an ecological, demograph- ic, and life-history study of the population at Big Casa Blanca Canyon (Santa Rita Mountains). Between 1980 and 1993, we visited 22 of 30 historical Tarahumara frog localities. We sur- veyed 43 additional streams with potential habi- tat and found Tarahumara frogs at 25 new local- ities in Mexico. Localities were extensively searched, often both day and night, sometimes repeatedly. Frogs and tadpoles were counted, size-classed, and sexed when possible. Time, streamwater pH, air, substrate and water tem- peratures, habitat description and condition, and relative abundances of other aquatic vertebrates were noted. During the summers of 1982-83. rain sam- ples were collected at The Nature Conservancy's Sonoita Creek and Canelo Hills preserves for pH determination and heavy metal analysis. Both sites are within 22-56 km (14-35 mi) of declining frog populations and 64-129 km (40-80 mi) north and northwest of copper smelters. Streamwater samples from sites of declining populations in Sycamore and Big Casa Blanca canyons in Arizona and Carabinas Canyon in northeastern Sonora were also col- lected for pH and heavy metal analyses. Decline of Populations In April 1974, 27 dead and dying Tarahumara and leopard frogs were observed at Sycamore Canyon, Atascosa-Pajarito Mountains, the best-known and most frequently visited Tarahumara frog population. The last sightings of Tarahumara frogs in that range were in the summer of 1974. Our IJviiif; Rcs<}i