Quick viewing(Text Mode)

Introduced Wildlife of Oregon and Washington

Introduced Wildlife of Oregon and Washington

University of - Lincoln DigitalCommons@University of Nebraska - Lincoln

USDA National Wildlife Research Center - Staff U.S. Department of : and Publications Health Inspection Service

April 2001

Introduced Wildlife of and

Gary W. Witmer USDA-APHIS-Wildlife Services, [email protected]

Jeffrey C. Lewis

Follow this and additional works at: https://digitalcommons.unl.edu/icwdm_usdanwrc

Part of the Environmental Sciences Commons

Witmer, Gary W. and Lewis, Jeffrey C., "Introduced Wildlife of Oregon and Washington " (2001). USDA National Wildlife Research Center - Staff Publications. 656. https://digitalcommons.unl.edu/icwdm_usdanwrc/656

This Article is brought to you for free and open access by the U.S. Department of Agriculture: Animal and Plant Health Inspection Service at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in USDA National Wildlife Research Center - Staff Publications by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. 16

ntroduced Wildlife of Oregon and Washingto1

Gary W Witmer & jeffrey C. Lewis

Introduction Each of wildlife occurs as part of an , In this chapter, we present information on wildlife interacting in many ways with other plant and animal introduced to Oregon and Washington. While other terms species in that system as well as with the abiotic could be used, we will refer to these relatively new components such as soil, air, water, and other substrates. members of the fauna of Oregon and Washington as The array of wildlife species around the globe has been "introduced" species. Occasionallyjthe term "exotic" will shaped by geological and climatological events as well as be used, especially in the context of legal terminology, such by eons of evolution and natural selection. Species have as state or federal laws and regulations. We will not include come and gone and those remaining have, in most cases, species that are expanding their range on their own co-evolved or co-adapted with many other species so that without the direct intervention of ; examples of relatively stable, and often complex, relationships exist. these species include the egret and the . Usually, a great many niches have been carved out and Also, we will not include the reintroduction or population occupied, creating a distinct flora and fauna in each region augmentation of native species, although much of this of the globe that is maintained under conditions of relative activity is occurring in the Northwest for stability over time. Natural disturbances (wind, fire) and conservation and biodiversity purposes. large-scale events (volcanic eruptions, drought) may Additionally, we will only include occasionally alter that stability and the relationships of , , amphibians, and . In additional between species, but an overall homeostatis "a return to to at least 125 species of vertebrates, it has been estimated the climatic community steady state" usually prevails. that over 2,000 species of and over 1,100 species of These and other concepts of biogeography have been invertebrates have been introduced into the U.S., along discussed in 162 with 111 species of fish and over 50 plant pathogen^."^ Species we refer to as "native" or "indigenous" There are many introduced species of plants, invertebrates, naturally occur in a particular and have been there and fish that occur in the , and many for a very long time. However, events can occur that bring are of major concern with regard to ecosystem integrity, individuals of a new species into a region where they come natural resource management, crop protection, or into contact with many species with which they are neither health and safety. Detailed discussions on the rapid and co-adapted nor co-evolved. In most cases, these newly destructive spread of various noxious plant species that arrived individuals soon succumb, but some may survive have been introduced to the Pacific Northwest have been long enough to interact with, or disturb, normal presented by Peck,120Stein and Flack,'" and Toney et al.146 relationships in the community. In a few cases, the Most plant species introduced to the Pacific Northwest newcomers may survive, reproduce, and become have been perennial forbs originating from Eurasia, established in the ecosystem, permanently altering although there has been a trend towards woody species relationships among or between species. These newcomers introductions in more recent years.146It is ironic that many are usually referred to as "introduced," "exotic," "non- plant species were purposefully introduced for wildlife native," or "non-indigenous." Species that are very enhancement.130 Introduced invertebrate species successful at this are sometimes called "invasive" species. and their impacts have been discu~sed,~~,'~~as well as These species are often capable of spreading unchecked, introduced fish species and their impacts to aquatic increasing to high population levels, and comprising a 139 significant portion of the total biota. In cases where the In this chapter we will discuss why wildlife species has thrived in the new location for a relatively long introductions occur; the benefits and problems associated period of time (in terms of human generations), they are with introductions; regulation of introductions; the considered "naturalized" and are essentially considered introductions that have occurred in Oregon and a regular part of the local flora and fauna (species Washington; the known or potential interactions between complex). introduced species and native species; and the 424 Wildlife-Habitat Relationships in Oregon and Washington management of introduced species. We will also include Table I. Some reasons why wildlife introductions several case histories that characterize favorable and occur. adverse aspects of wildlife introductions.

How lntroductions Occur A.Accidental introductions Wildlife species can be introduced to new areas through a I. Escaped captivity variety of mechanisms, both accidental and purposeful 2. Stowaways (Table 1).Accidental introductions can result from 3. Expanded range of species after introduction elsewhere escaping captivity, as has occurred with fox, mink, monk B. Purposeful introductions parakeet (Myiopsitta monachus), various livestock species, 4. Aesthetics and an array of wild ungulates such as fallow ( dama) 5. Economics and axis (Axis axis) . As stowaways on ships, trains or 6. Recreation other vehicles, some rodent species (Norway rat, black 7. Source of food rat, house mouse) and species (house sparrow) have 8. Filling "vacant" niches achieved worldwide distribution. Finally, human 9. Biological control alteration of or native species ranges, after an 10. Released from captive population initial introduction elsewhere, has resulted in the altered I I. Release of rehabilitated or problem animals and often expanded range of number of species such as 12.Whimsy:"what the heck, let's see what happens" the opossum into regions of the country in which they 13. Gifts did not historically occur. Purposeful introductions have occurred for many captivity on a whim: "what the heck, let's see what reasons (Table 1).The desire to have bird species from the happens." This may have occurred with some parakeet/ countries of their European heritage, hence aesthetics, led species as well as with some and amphibian the Portland Bird Club to attempt many songbird species. Finally, persons have given animals (wild or introductions, including the tarl ling.^^,^^ Similarly, eastern domestic) away as gifts, which later escaped or were gray and fox squirrels have been released in many urban/ released and established free-ranging populations. suburban areas of the west.154 Many "game" species, as well as some domestic What Makes lntroductions livestock species, have been introduced to provide some Succeed or Fail? combination of recreational or economic benefit Most wildlife introductions, whether accidental or (fur, food, or clothing). These species include many species purposeful, fail to establish free-ranging and sustained of upland game birds, turkeys (Meleagris gallopavo), foxes, population^.^^,'^^ There are many reasons why this is the , nutria, and various species of most likely outcome of an introduction: inadequate deer. Domestic species have been released to provide a numbers of animals, poor health or genetic quality of future source of food or transportation (, Sus scrofa; animals, , disease or parasites, inadequate , hircus; , Equus caballus; burro, Equus habitat, competition with native species, poor planning, ). and others.59,163 In some cases, species were introduced to fill a On the other hand, certain characteristics of a species perceived vacant niche, as with upland game birds, or population make it more likely to be successful at carnivores on islands, and herbivores on islands. In "invading" a new area and becoming e~tablished.~~,112 actuality, in some of those cases, the populations of native These include a large native range, high mobility, broad species occupying those niches had been greatly reduced diet, short generation time, high genetic variability, by over- or by human-induced changes in habitats gregariousness, larger size than most closely related or predator-prey relationships (e.g., many native grouse species, few predators, association with humans, species). Carnivores (such as fox; mongoose, Herpestes association with freshwater habitats, and ability to spp.; European ferret, Mustela putorius; and domestic , function under a wide range of physical conditions. Often Felis catus) have been introduced, especially on islands, to these species are "habitat generalists" and have a "broad help control rodent or populations, many of which ecological amplitude. were also introduced accidentally or purposefully at an It is important to recognize that many factors are earlier date. This form of biological control has rarely, if involved in the success or failure of a wildlife introduction. ever, been successful in its intended purpose. Even chance and timing play a role.33Disturbance of a In some cases, animals kept in captivity were released site or community, often human-induced, may make the because the owners no longer cared or could afford to area more susceptible to "71 12%s such, it is maintain the animals, or because the economic incentive difficult to predict whether or not a given introduction to raise the animals had declined, as with bullfrogs, nutria, will succeed or fai1.129,136,137There have been some efforts mink, fox, exotic deer, "road-side zoo" animals, and some to construct predictive models of the likelihood of species of livestock. In a few cases, the animals released successful establishment of an introduced species.136,137 from captivity may have been rehabilitated animals or Unfortunately, there is much to be learned in this area of problem animals. Some persons may release animals from . In terms of regulation of wildlife introductions, Table 2. Potential adverse ecological consequences of introduced wildlife species.

A. Effects on physical. . environment I .Water quality, quantity 2. Soil compaction 3. Soil 4. Nutrient balance B. Effects on flora 5. Species composition 6. Species abundance 7.Vegetative structure 0. P\ant succession 9. Species endangerment . (Photograph by Jefiey C. Lewis) C. Effects on fauna 10. Competition this situation has historically resulted in an "innocent until a. food proven guilty" attitude, and species introductions are not b. habitats prohibited until it is known that they are likely to cause c. interference adverse effects; and once these occur, they may be I I. Predation impossible to reverse. 12. Diseaselparasite transmission 13. Hybridization Potential Benefits and Adverse Effects of 14. Species endangerment lntroductions D. Direct effects to humans A large number of introductions of plants and animals 15. Diseaselparasites to humans, livestock, pets has already occurred, and continues to occur, in the United 16. Crop damage States.'16 Some past introductions have benefited the public 17. Structural damage for the reasons listed in Table 1. Consider, for example, 18. Livestock predation domestic livestock and upland game birds. In Oregon, the 19. Livestock forage competition introduction of ring-necked pheasant in 1881 resulted in 20. Human food consumption and contamination large economic and recreational benefits--so much so, that 2 I. Human safety captive-reared birds were soon being exported to many 22.Aesthetics other states.%Upland game species (both bird and small E. Major ecosystem disruption or alteration ) continue to provide large revenues and 23. Combinations of the above effects extensive recreation to many states." There are many potential or realized ecological in Washington. Major disruptions are most common on consequences of wildlife introductions (Table 2). To date, islands where rat~,'~~carnivores,l~or feral livestock148have the most visible effects of introductions to Pacific been introduced. Erosion and community changes (species Northwest appear to be from plant and composition, abundances, biodiversity, and species loss) invertebrate species introductions, although have occurred in these situations. On the North American by domestic livestock has affected some dryland areas. mainland, similar effects have occurred in the Great Smoky We note that the effects of an introduced wildlife species, Mountains National Park from the introduction of feral however, may take hundreds of years to become e;ident: .1° Feral and burros have had substantial the "blink of an eye" in ecological time. The effects can be impacts on some southwestern ecosystem^.^' Species- to the physical environment, the flora, the fauna, and specific examples of realized or (more often) potential humans directly, or more often, to a combination of these ecological effects of wildlife introductions in Oregon and ecosystem elements. Perhaps the most common effects are Washington are presented later in this chapter. from herbivory, competition, or predation. However, many other types of effects can occur, such as Regulation ofwildlife Introductions hybridization-with native species133and disease The regulation, policies, and guidelines for wildlife transmissi~n.~~Numerous examples of ecological effects introductions in the have had a long and were presented by MacDonald et al.lo7and Simber10ff.l~~ convoluted history. A large number of governmental In some cases, a major disruption of the ecosystem can agencies-at federal, state, and local levels-have played occur, but this has not yet been well documented from roles; the net effect often being inconsistent, inadequate, wildlife introductions in terrestrial ecosystems in Oregon or contradictory efforts among agencies, or policies that and Washington, with the possible exceptions of San Juan changed dramatically over time within an agency.''", 131 Island (European Destruction Island (European There is a strong need for not only more regulation of rabbit): and the (mountain all species introductions, but also better coordination of 426 Wildlife-Habitat Relationships in Oregon and Washington

regulation across jurisdictional boundaries and under a permit and a commitment from the state wildlife governmental levels.88,116 agency, 7) treatment of exotics leaving federal land as Regulations and practices have evolved from trespassing livestock with the responsible party held liable, encouraging the importation and release of animals to and 8) periodic review of public policy regarding exotic improve agricultural resources, hunting opportunities, or species. local economies to restricting importations because of The Wildlife Society published a policy statement on disease hazards, threats to agricultural resources or human species introductions in 1975. This policy included the health and safety, or potential disruption of natural following three c~nsiderations:~' ecosystems. As early as 1923, Taylor142discussed benefits, 1. Support the introduction of exotic species only after adverse effects, methods, and regulations for the competent scientists have thoroughly studied the introduction of upland game birds in the Pacific situation and potential effects and quarantine Northwest. requirements have been met. The U. S. Department of Interior's (USDI) Federal- 2. Urge that no state, provincial, or national agency State Cooperative Foreign Game Program of 1948 added introduce an exotic species or permit such an an element of central authority at a time when the introduction unless that species can be contained importation of game species into the United States was within its jurisdiction, or unless surrounding being strongly pursued. This program was guided by three jurisdictions have sanctioned the introduction. objectives: to provide an ecological and life history data 3. Exclude from the provisions of this policy the base to individuals or agencies, to discourage importation of exotic species by officially recognized introductions when the data base suggested an scientific and educational organizations, and the introduction was unwise, and to fill vacant or institutional exchange of such species provided that understocked habitats with foreign species as an alternate the exotics are maintained in captivity at all times. course of action following appropriate testing and trial President Carter signed Executive Order 11987 in 1977. introd~ctions.~~~ This document, in part, restricted federal agencies from In 1966, the USDI published guidelines and introducing species to lands they administer, encouraged recommendations for the importation of ~ildlife.'~~Thesethe prevention of introductions by other levels of guidelines incorporated eight conditions: government and by private citizens, and restricted federal 1. Critically determine that a need exists, with desirable support of introductions outside the United State~.l~~These ecological, recreational, and economic impacts. limitations applied unless either the Secretary of Interior 2. A definite niche is available and unsuited for a native or the Secretary of Agriculture determined that the species. introduction would not have an adverse effect on natural 3. Introductions should not be considered if they ecosystems. threaten the reduction or displacement of native An position statement, containing policies populations; nor should existing or proposed land and guidelines similar to those above, was developed and uses be in conflict with an exotic species transplant. approved by the International Union for Conservation of 4. Introductions should be preceded by ecological Nature and Natural Resources (IUCN) in 1987.116The studies of both the animal and the habitat proposed IUCN is an organization comprised of scientific experts at the release site. and government officials involved in conservation around 5. Disease relationships require special study as well as the world. the steps assuring appropriate quarantine leading to The concern about "invasive alien" species continues disease-free stock. to generate activity by the federal government. On June 6. Exotic species with close relatives in the United States 17,1997, Vice President Gore directed the preparation of should be avoided, to preclude hybridization with a strategy to combat the introduction and spread of non- native wildlife. native plants and animals in the United States that are 7. Small-scale experiments and a thorough evaluation of causing great economic and ecological harm to the nation. these should precede larger introductions. A draft document has been prepared that reviews the 8. Before an exotic species is released, methods for situation, makes recommendations, and provides an controlling its abundance and expansion must be action plan.' Based on the results of the Task Force, available. President Clinton signed an Executive Order on Invasive These guidelines resulted in eight recommend-ations Species on February 3, 1999. Its goals are to prevent the from the USDI. These were meant to apply to federal lands introduction of , to provide for their or federal actions and included: 1) no decisions until a control, and to minimize the economic, ecological, and full assessment is at hand, 2) no exotic species placed in human health impacts that they cause. It was estimated national parks or lands devoted to the preservation of that invasive species cost the U.S. economy about $123 native biota, 3) no exotic species placed in the vicinity of billion per year. The Order establishes Invasive Species rare or uncommon native species, 4) no exotic grazers Council assigned the task of setting up an Advisory placed on federal lands devoted to domestic grazers, 5) Committee and preparing and implementing an Invasive no exotic big game placed in areas devoted to intensive Species Management Plan. The Plan will 1) detail and land uses, 6) no introductions on federal lands except recommend performance-oriented goals and objectives, 2) review existing and prospective approaches and authorities, 3) identify pathways of introductions and ways to minimize risks of introduction,4) identify research needs, 5) be science-based, 6) recommend and implement measures to reduce introductions and control those that have occurred, 7) identify requirements to achieve goals and objectives, and 8) evaluate and report on the success in achieving goals and objectives. We have reviewed some of the long history of introduced wildlife concerns, policies, and recommendations. The groundwork has been set for a vigorous effort to reduce introductions and to manage existing introductions. It remains to be seen what level bf success will be achieved towards this goal. Bullfrog. (Photograph by Jeffyey C. Lewis) Current Federal and State Regulations The two main federal agencies regulating wildlife species introductions in the United States are the U.S. Department For many , many states, including Oregon and of Agriculture's (USDA) Animal and Plant Health Washington, had few regulations regarding the Inspection Service (APHIS) and the USDI Fish and Wildlife importation or keeping of "exotic" wildlife or the Service (FWS).116,131A major function of APHIS is to protect protection of native biodiversity from exotic^.^', Many United States agriculture (both plants and animals) from states in the late 1800s and earIy , including Oregon diseases or plant and animal "pests" that might gain access and Washington, encouraged--or were directly involved to the country or be transported between states. with-the propagation or release of many game species, inspections, quarantines, disease testing, and eradication including exotic species. These practices have largely been programs are some of its routine functions, and most of curtailed in recent decades, with notable exceptions such APHIS'S pest exclusion occurs at ports of entry. APHIS as with wild turkey and pheasant, P. c. does not expressly prohibit species-specific imports, but suehschanensi~.~~~The Southeastern Cooperative Wildlife requires adequate quarantine and veterinarian inspection Disease Study provided a "model law" in 1988 to help before such imports or transportations are allowed (9 CFR guide states in regulating animal imports that addressed Ch. 1). The agency is particularly strict regarding veterinary, humane, public safety, ecological, and other hedgehogs (Erinaceus spp.) and the brush-tailed possum concern^."^ It recommended a permit requirement for (Trichosurus vulpecula). A major concern of APHIS is to introduced species, that certain-common domestic and prevent of Newcastle's disease, chlamydiosis, naturalized species be exempt from the regulations, that foot-and-mouth disease, rinderpest, bovine tuberculosis, criteria and a list be developed for "environmentally and other communicable diseases of livestock and wildlife. injurious animals," and that a technical advisory APHIS is also active in management and research to committee be formed to provide advice. Both Oregon and prevent entry of the brown tree snake (Boiga irregularis) Washington and wildlife agencies have into and the mainland United States.17 enacted detailed and specific regulations on the The FWS protects threatened and endangered species importation and keeping of introduced wildlife. by, among other activities, restricting the importation and Oregon Administrative Rules (OAR 635-056-0000 to - exportation of federally listed species under the 0150) prohibit the importation or keeping of numerous Endangered Species Act and the Convention on vertebrate species, including hedgehog, tri-colored International Trade in Endangered Species (CITES). Except squirrel (Callosciurus spp.), brush-tailed possum, bats of under permit and various restrictions, the FWS expressly any species, mongoose, wild pig, ( spp.), prohibits the importation and release of individuals, non-domestic goat (Capra spp., except C. hircus), progeny, or eggs of many species of vertebrates into the (Connochaetes spp.), (Procapra spp.), United States, to protect national resources (50 CFR Ch. capybara (Hydrochawis hydrochaeris), dogs (Cynomys 1). These species include flying fox (Pteropus spp.), spp.), any species of wild canid (except fox), Egyptian mongoose, European rabbit, wild dog (genus Cuon), multi- goose (Alopochen aegyptiacus), African clawed frog mammate rat (Mastomys spp.), dog (Nyctereutes (Xenopus spp.), bullfrogs (Pyxicephalus spp.), alpine newt procyonoides), starling, quelea (Quelea qualea),Java sparrow (Triturus spp.), brown tree snakes, snapping turtle (Padda oryzivora), red-whiskered bul-bul (Pycnonotus (Chelydridae, all spp.), pond sliders (Pseudemys spp.), jocosus), all species of amphibians, and all species of Chinese pond turtle (Chinemys spp.), pond turtle reptiles. Additionally, the importation and transportation (Chrysemys spp.), painted turtle (Chysemys spp.), map of birds of the family Psittacidae (, parakeets, turtle (Graptemys spp.), North American (Apalone spp.) and macaws, etc.) are regulated by the U.S. Public Health African (Trionyx spp.) soft shell turtles, European pond Service because of disease hazards (42 CFR Parts 71 and turtle (Emys orbicularis), Blanding's turtle (Emydoidea 72). b~~~dr~gr&?~~~~nmud turtle (hasfevon sub~uzum), 428 Wildlife-Habitat Relationships in Oregon and Washington common musk turtle (K. odoratum), and Asian pond turtle important to increase public awareness of the risks posed (Mauremys spp.). Many fish species are also prohibited. by wildlife introductions. A good public education Exceptions, by permit, are made for zoos and research program on this subject should lead not only to more facilities if they are escape-proof and are staffed and public support for the prevention of future introductions equipped to provide adequate care. There is also a long and the management or eradication of past introductions list of domestic or otherwise exempt species, including (in terms of supporting appropriate legislation, dogs (Canis familiaris), , burros, horses, swine, management practices, and requisite budgets), but also European rabbits, ferrets, and parrots and parakeets for better public compliance with federal and state (Psittacidae, all spp.). The State has specific requirements regulations. involving the sale, transportation, and holding of exotic animals, to help prevent escape of, or disease transmission Introduced Wildlife Species in Oregon and by, introduced animals. There are strict reporting rules that Washington apply when an introduced species escapes captivity. There have been a large number of wildlife introductions Washington has similar laws (Chapter 77.08 RCW) and to Oregon and Washington, dating back to the 1700s (e.g., prohibits the importation or keeping of mute swan, horses and burros). Most attempted introductions, mongoose, wild pig, collared (Tayassu tajacu), and whether accidental or purposeful, have failed. For various species of exotic bovids and cervids. Many species example, Portland Bird Club attempted but failed between of fish are also prohibited. 1889 and 190746,76to introduce many species of songbirds, Much of the importation of introduced wildlife into the including Eurasian skylark, Alauda arvensis; wood lark, United States is because of the enormous pet ind~stry."~Lullula arborea; blackcap, Sylvia atricapilla; European robin, About 23 percent of the vertebrate species of foreign origin Erithacus rubecula; nightingale, Luscinia megarhynchos; that currently live in the wild in the United States were Eurasian blackbird, Turdus merula; song thrush, T. originally imported as cage birds or other wildlife pets.l16 philomelos; parrot , Loxia pytyopsittacus; Eurasian There is a growing concern about the depletion of animals siskin, Carduelis spinus; Eurasian goldfinch, C. carduelis; from exportation countries (hence the species listings in linnet, Acanthis cannabina; Eurasian bullfinch, Pyrvhula CITES, including its appendices), but also about the pyrrhula; chaffinch, Fringilla coelebs; house sparrow, and significant hazard that introduced species pose to native European starling. species, ecosystems, agriculture, and It has We have compiled a list of 42 wildlife species even been speculated that the liberalization of introductions to Oregon and Washington that have international free trade may increase species introductions established free-ranging populations at least on a localized around the globe.74The probability of accidental release Scale (Table 3).7, 20, 27, 34, 37, 46, 54, 70, 75, 76, 94, 97, 98, 99, 104, 152 The of non-native wildlife as well as disease transfer and other information we provide on the 42 species includes hazards can be reduced by the improvement of existing common and scientific names, the date, and location of programs and the implementation of specific actions as the introduction(s), the reason for the introduction, the presented by the Ad Hoc Federal Invasive Alien Species current status and distribution (in general terms), and the Task Force1 and the Office of Technology Assessment.'16 country of origin (Table 3). We note that many of the Their recommendations include: acknowledge that the species were introduced over a period of time and at prevention of introductions is paramount, encourage several locations. The list includes 18 birds, 19 mammals, governments to take an active role by establishingnational 3 reptiles, and 2 amphibians. About half (19 of 42) of the and regional councils, develop new scientific expertise for species listed have achieved widespread distribution in dealing with introductions, develop a white-black-gray Oregon or Washington. list to assist in regulating exotic species, develop a Most bird species were introduced for hunting or comprehensive program to prevent unintentional aesthetic purposes, although several arrived by range introductions by identifying major pathways and methods expansion after being introduced elsewhere. Many of the to interdict and reduce impacts, develop and implement mammal introductions were escapees or animals released an international regime for control and support when no longer needed or economically valuable. Several cooperation through development assistance, develop a were introduced for hunting or fur farming. The Old Web-based network of information, convene educational World rodents arrived as stowaways. Most amphibian and workshops, and consult with the reptile introductions were for aesthetic, pet, or food regarding new regulations and funding authority. The purposes. white-black-gray list would delineate species that are Additionally, there are many other non-native wildlife automatically allowed, never allowed, or allowed only species that have been observed or reported in Oregon or after thorough investigation, respectively. Washington, but information on their occurrences is very The implementation of adequate programs to prevent limited and we cannot be sure whether or not those species the accidental, or purposeful but prohibited, release of are established (Table 4). We have included this species introduced diseases, plants, invertebrates, and vertebrates list because of the potential ecological consequences if they is especially important because of the difficulty and do become established and more widespread in expense of eradication once an introduced species becomes distribution. dispersed and 135 Furthermore, it is Table 3.Wildlife species introduced to Oregon or Washington.7*20*27*34~37~46*54~70~75*76*94~97~98*99*104~152

Species PlacelDate Reason Status Origin

Trumpeter swan, Harney Co. OR 1939-58; aesthetics; hunting very limited, small numbers SE , NWCanada Cygnus buccinator Spokane Co. WA 1963 in OR and WA and somewhat south

Mute swan, Cygnus olor Lincoln Co. OR 1950s; aesthetics, escapees? very limited, small numbers Eurasia Deschutes Co. OR 1960s in OR and WA American black duck, Snohomish Co.WA, hunting small localized popn in E United States Anas rubripes date unknown Chukar, Alectoris chukar Lake Co. OR 1 95 1 ; hunting, brood stock sale scattered popns in E OR Eurasia Deschutes Co. OR 1952; and EWA Klamath Co. OR 1960s; E.WA 1930s Gray partridge, Linn Co. OR 1900; hunting, brood stock sale scattered popns NE OR Eurasia Perdix perdix 23 counties OR 19 13- 14; and EWA Spokane Co.WA 1 906; Co.WA 1908 Ring-necked pheasant, Linn Co. OR 188 1-82; hunting, brood stock sale widespread, common Eurasia Phasianus colchicus Protection Is.WA 1883 White-tailed ptarmigan, Wallowa Co. OR aesthetics?,hunting? localized, small numbers in SE Alaska,W Lagopus leucurus 1967-69 OR; native toWA into WA Wild turkey, OR 1899 (failed); many hunting widespread, moderate E United States, Meleagris gallopavo OR counties 196 1 -83; numbers in E OR and Southcentral United E. WA 1970s EWA; some on San Juan Is. States quail, Thurston Co.WA 1857; hunting, brood stock sale widespread, common; native SW United States just Callipepla californica many OR counties 19 14 to S OR into OR Scaled quail, Yakima Co. WA 19 1 3 hunting, brood stock localized, small numbers; Southcentral United Callipepla squamata sale, escapees extirpated? States quail, Walla Walla WA 1865 & hunting, brood stock sale localized, small numbers E United States Colinus virginianus 1920;Whidbey Is.WA 187 1 ; Linn Co. OR 1882 , W WA 1880 hunting, brood stock sale localized in WA; native in SW United States into Oreortyx pictus OR SE WA , Columba livia many OR counties aesthetics, racing, widespread, common Eurasia < I900;W WA C 1940 messengers, then range expansion , Multnomah Co. OR escapees small numbers, Portland South America Myiopsitta monachus 1969 area; some in WA? Skylark, Alauda arvensis Portland OR 1889 aesthetics, then range small numbers on San Juan Eurasia (failed?);Vanc. Is. BC expansion Is. 1903 European starling, Portland OR 1889 aesthetics, then range widespread, common OR Eurasia Sturnus vulgaris (failed); arr. on own expansion after introd. and WA 1940s OR & WA to E United States Crested mynah, Vancouver BC 1894 aesthetics, then range localized, small numbers in SE Asia Acridotheres cristatellus expansion , Bellingham areas House sparrow, Spokane Co.WA 1895; aesthetics and insect widespread, common OR Eurasia Passer domesticus King Co.WA 1 897; control to E United and WA Portland OR 1889 States, range expansion opossum, Umatilla Co. OR 19 10; aesthetics, pets escapees, locally common, esp.W WA, E United States Didelphis virginiana WA

Species PlacelDate Reason Status Origin

-- House cat, Felis catus < 1800 escapees, pest control widespread, OR & WA? Eurasia,Africa Domestic dog, < 1800 escapees occasional occurrences Eurasia Canis familiaris Burro, Equus asinus E OR late 1700s escapees or released small population in SE OR Africa when no longer needed Horse, Equus caballus E OR late 1700s escapees or released moderate population in Asia when no longer needed SE OR , Sus scrofa SW OR late 1800s; hunting, escapees? Very small, localized Eurasia Skagit Co.WA 1 98 1 populations or extirpated Axis deer, Axis axis Pierce Co. WA > 1 980 aesthetics or escapees small, localized population India Fallow deer, Dama dama King Co.WA > 1980 aesthetics or escapees small, localized population Europe , NE OR 1950 & aesthetics, hunting moderately abundant in Alaska to WA, Cascade Oreamos americanus Columbia Gorge OR Olympic mtns., native to and Rocky Mtns. 1969 (failed); Olympic N Cascade & Rocky Mtns. Mtns.WA early 1900s , King Co. WA 1 925; aesthetics localized, urbanlsuburban E United States Sciurus carolinensis W OR 1919 areas ofW & NE OR and W WA , Sciuris niger W OR & WA < 1940; aesthetics localized, urbanlsu burban E United States Baker Co. OR 1950s areas of EWA, W and NE OR House mouse, OR and WA late 1700s stowaway, then range widespread, urbanlsuburban Europe Mus musculus expansion areas OR & WA Norway rat, OR and WA < 1 850 stowaway, then range localized, urbanlsuburban Asia Rattus norvegicus expansion areas OR & WA Black rat, Rattus rattus OR and WA < 1800 stowaway, then range localized, urbanlsuburban Asia expansion areas OR & WA Nutria, Myocastor King Co.WA 1 930s; fur farming, escapees, localized, mostly W OR South America Lincoln and Tillamook vegetation control? &WA Cos. OR 1937 European rabbit, San Juan Co..WA 1929; aesthetics, hunting Island populations persist, Europe Oryctolagus cuniculus Destruction Is. WA 1 970 other localized populations in WA? Eastern cottontail, Whitman Co. WA hunting widespread, locally abundant E United States Sylvilagus floridanus 1926; Linn and Benton Cos. OR 1940s Bullfrog, Rana catesbeiana many places OR & WA insect control, aesthetics, widespread, locally abundant E and Central United 1914 on hunting, food, then range States expansion Green frog, King, Stevens and aesthetics, hunting? very localized, small E. United States Rana clamitans Whatcom Cos.WA populations Snapping turtle, many places W OR aesthetics, hunting?, localized, small populations E and Central United Chelydra serpentino & W WA 1950s on pets, food States Red-eared slider turtle, many places OR aesthetics?,pets, Locally common in W and SE United States Trachemys scripta elegans and WA escapees Central OR Plateau striped whiptail, Jefferson Co. OR aesthetics? Localized, small population SW United States Cnemidophorus velox

Habitat Use by Introduced freshwater/riparian systems. Most species (71°/0) can be Wildlife Species considered habitat generalists, using several general All general habitat categories that occur in Oregon or ha bitat categories. Washington are used by at least one of the 42 introduced Human-disturbed areas (agriculture lands, urban/ species, although few introduced species use alpine or suburban areas) are used by a large number of the marine habitats (Table 5). Only 12 of 42 (29%)introduced introduced wildlife species, 19 and 18 species, respectively species are affiliated with only one general habitat (Table 5). This group of species includes most introduced category; most of those 12 species are restricted to upland game birds, songbirds, and mammals. Forests Table 4. Other introduced wildlife species that have been occasionally observed or reported in Oregon or Washington."

Birds Mammals Amphibianslreptiles

Domestic goose, Anser cygnoides -dog hybrid, Canis lupus x familiaris Eastern mud turtle, Kinosternon subrubrum Egyptian goose, Alopochen aegyptiacus Domestic cow, 00s taurus Stinkpot, Sternotherus odoratus Gray lag goose, Anser anser Domestic goat, Capra hircus Painted turtle (non-natives), Chrysemys picta Domestic , Anas platyrhynchos Domestic , Eastern box turtle, Terrapene carolina , Cairina moschata , Ammotragus lervia Ornate box turtle, Terrapene ornata Red-legged partridge,Aledoris rufa sheep, Ovis musimon Malayan box turtle, Cuora amboinensis Sichuan pheasant, Phasianus colchicus tortoise, Gopherus agassizii suehschanensis tortoise, Gopherus berlandieri Golden pheasant, Chrysolophus pictus Gopher tortoise, Gopherus polyphemus Peafowl, Pavo cristatus Hermann's tortoise, Testudo hermanni Guineafowl, Numida meleagris Reeve's turtle, Chinemys reeves; Psittacines (misc. Parrots, Spiny softshell turtle, Apalone spinifera cockatoos, macaws) softshell turtle, Trionyx ferox Big-headed turtle, Platysternon megacephalum Caiman, Caiman crocodilus * Little is known about the status of most of these species; most probably do not comprise free-ranging, self-sustaining populations and have not expanded their range beyond the release site(s) in either state, however, these events could occur in the future.

Table 5. Use of general habitat categories by 42 wildlife species introduced to Oregon or Washington.

No. (% of Group) of Species by General Habitat Category" Wildlife Group Forest Shrublgrass Agriculture Urblsuburb Freshwlrip Marine Alpine

Birds (1 8 spp.) 8 (44%) 8 (44%) Il(6l%) 7(39%) 4 (22%) I (6%) I (6%) Mammals ( 1 9 spp.) I I (58%) 4 (21%) 8 (42%) 1 1 (58%) 5 (26%) 0 (0%) I (5%) Amphibianslreptiles I (20%) I (20%) 0 (0%) 0 (0%) 5 ( I 00%) 0 (0%) 0 (0%) (5 SPP.) Total: (42 spp.) 20 (48%) I3 (31%) 19(45%) 18(43%) 14 (33%) I (2%) 2 (5%) "ost species use more than one general habitat category.

(especially open, deciduous or mixed forests) are used by habitats, and grass-forb dominated areas. On the other about half (48%) of the introduced species. Freshwater/ hand, there is little potential for competition between riparian habitats are used by approximately equal white-tailed ptarmigans and ruffed grouse. Competition numbers of introduced bird, mammal, and amphibian/ may also occur between introduced upland game birds reptile species groups, with all introduced reptiles and and native sage and sharp-tailed grouse; all of these amphibians using those habitats. Shrub/grass habitats are species use shrub- and sagebrush-steppe habitats, used by introduced bird species and eastern cottontail as well as grass-dominated areas and riparian areas. Most rabbits, but especially upland game birds. of these species use agricultural lands, too. Likewise, in Specific habitat associations for many of the introduced some situations, the introduced eastern cottontail rabbit wildlife species have not been well defined. Some insight may compete with native rabbits (pygmy, and brush for some species can be gained from Brown,12Guenther rabbits; Nuttall's cottontail) in grass/sedge meadows and and Kucera60and Th~mas.l~~Thatinformation, along with alder bottomlands as well as riparian areas, agricultural species-specific literature and expert opinion, has been lands, brushpiles (including downed woody materials), used to complete the wildlife habitat matrixes of this book. and burrows. For many introduced species, we do not These matrixes can be used, to some extent, to project the know enough about what specific habitats they could use, potential competition between native species and given the opportunity and time for populations to occupy introduced species. For example, the introduced eastern those habitats. For example, axis and fallow deer could gray and fox squirrels use oak woodlands as do native potentially occupy many of the same habitats as the native western gray squirrels; all three species use variously-aged black-tailed deer and the endangered Columbia white- forest stands and all use snags. White-tailed ptarmigans, tailed deer. Interested persons are referred to the matrixes introduced to Oregon, may compete with native blue and for further investigation of potential habitat competition in the use of alpine meadows, subalpine fir between native and introduced species. 432 Wddlife-Habitat Relationships in Oregon and Washington

It is very important to rerognize the potential ecological consequences of wildlife introductions. While consid&able effort and expense have been invested in dealing with introduced plants and insects in the Pacific Northwest, introduced wildlife also has caused, or has the potential to cause, substantial harm to Pacific Northwest &systems and agriculturalmn (Table 2). There are many potential or realized ecological comeqmmes for each-01 the 42 wildlife species i&ductio& that have occurred in Oregon and Wegton(Table 6). Several points need to be emphasized. The code "NK" (none known) appears frequently in Table 6. wth wildlife introductions, we are of& with ecological Wild bum. (Phatograph by Jeffrey C. LauW "situations" with which we have little or no experience; hence, our predictive powers are very iimited. Additionally, serious effects may occur long after the introduced rodent species cause many types of structural intruductions. The rather cavalier attitudeofthe past ("let's damage to human dwellings, livestock facilities, and do it and see what happens") is no longer acceptable, given constructed features such as dikes, , levees, the many legal mandates and policies for species and transmhion lines, and ~ptems.~Considerable biodiversity protection, healthy ecosystem maintenance, effort is expended each year to ducethe negative effects and the protection of human health and agricultural of these species. On the other hand, the intmduction of resources. We must not only deal with existing upland game birds may have increased the prey base for introduction problems, but must strive to prevent future native predators, both avian and mammalian, as well as introductions that have significant potential for adverse having provided mation as intended. consequences. Both require a greater ecological and Most introduced mammal. species have the potential managerial knowledge base than we now possess On the to adversely affect various species of native plants and other hand, great strides in agriculture8=ation, local animals, as-wellas humans and their d,through economies, biological control of pests, and evm in the herbivory or predation. Species such as 14foxes, ferrets, medical profession, have been made as a wult of species and feraido& and cats c& inflict high levels of mortality intFoduclions.Obviouslv, a careful and deliberate analvsis. on ground nesting birds and have been implicated in the on a case-by-casebasisIamust be made before pro&& endangerment of numerous species, such as snowy with anv wildlife introduction. plovers, least terns (Stema antilhwum), and clapper rails 1ntr;duced wildlife species have the potential for (Rallus Iottgims)ti~).'~Similar results have been reported several, if not numerous, adverse ecological consequences forintroducedcarnivoresinEumpe.~Feralorfreeranging (Table 6). Most introduced birds have the potential to cats kill large numbers of songbirds every year in urban/ adversely affect native bids, especially hmugh forage and suburban settingsPEssentiaUy,d introduced herbivorous nest site competition. A classic example is the ability of mammals can cause plant damage and may even impede starlings to usurp nest sites from wood ducks, bluebirds, regeneration of so& plant q&ies. usually the amount woodpeckers of many species, and many other of damage is related to the density of introduced Additionally some hybridization problems mammals; hence, existing small, introduced populations exist; for example, black ducks hybridize with mak&)33 ofaxis and fallow deer are probably not cawsigdicant some upland game species hybridize with native species8 impact to the native flora. On the other hand, high and eastern cottontail rabbits hvbridize with the brush densitbes or conenbated use can cause substantial impacts rabbit.lS1Avian diseases, such'as avian tuberculosis, on native flora, as occurs with European rabbits, mountain Newcastle's disease, salmonellosis, and chlamydiosis, can , and kaIpigs, horses, and burros. In some cases, be transmitted to native specie~.~Mernbersof the parrot edanpmmtof native plant species may occur, as with family make popular pets, but they have the potential to herbivory by introduced mountain goats on the Olympic spmad avian tubemlo&, a disease trammkible to not Peninsula.Q Many of the introduced mammal species, only other wildlik, but to pets, livestock, and humans.S2 especially camiv&es and Old World rodents, have been Congregations of introduced bird spedes such as house implicated mthe transmisaon of to native wildlife, sparrows, rmk doves, and starlings at roosts or feedii livestock, pets, or humans; these diseases include , stations have produced significanF disease hazards (e.gz plague, distemper, llelapsing fever, and andeptospirosii~.~ hisWlasmosis, ornithosis, salmonellosis).~Severalof the Introduced amphibians and reptiles have been intxobuced bird species (starling, house sparrow, rock implioaM in the decline of many native aquatic fauna dove, skylark, crested mynah, Amihtk CriSfnteUus)have through predation or ~ornpetition."~"The introduced a great potential to damage crops, contaminate foodstuffs8 bullfiPg is a classis example and will be considered in more and cause aesthetic problems.%" Additionally, the detail in the case histories at the end of the chapter. Table 6. Potential or realized ecological consequences of wildlife species introduced to Oregon or Washington.

Species Physical Flora Fauna Human Environment

Trumpeter swan, Cygnus buccinator NK FC, NC,AB AB Mute swan, Cygnus olor NK FC, NC,AB AB American black duck, Anas rubripes NK H NK Chukar, Alectoris chukar NK D, FC, NC, IP CD Gray partridge, Perdix perdix NK D, FC, NC, IP CD Ring-necked pheasant, Phasianus colchicus NK D, FC, NC, IP, H CD White-tailed ptarmigan, Lagopus leucurus NK FC, NC,AB NK Wild turkey, Meleagris gallopavo PR FC, IP NK California quail, Callipepla californica NK D, FC, NC, IP, H CD Scaled quail, Callipepla squamata NK D, FC, NC, IP, H CD Northern bobwhite quail, Colinus virginianus NK D, FC, NC, IP, H CD Mountain quail, Oreortyx pictus NK D, FC, NC, IP, H CD Rock dove, Columba livia NK FC, NC, D A, HD, CF Monk parakeet, Myiopsitta monachus PD? FC, NC, D CD Skylark, Alauda arvensis PD? FC, NC, D? CD? European starling, Sturnus vulgaris PD ? FC, NC, D CF,A, HD Crested mynah,Acridotheres cristatellus PD ? FC, NC, D? CF,A, HD? House sparrow, Passer domesticus PD ? PC, FC, NC, D CF,A, HD Virginia opossum, Didelphis virginiana NK P,D A, HD Red fox, Vulpes vulpes PD ? P, PC, E, H, D CD, LP, HD European ferret, Mustela putorius NK P, E, H?,D? AB, HD? House cat, Felis catus NK P, PC, E, H?,D HD Domestic dog, Canis familiaris NK P, PC, E, H, D AB, LP, HD Burro, Equus asinus PD, E FC, D LC, HD Horse, Equus caballus PD, E FC, D LC, HD Feral pig, Sus scrofa PD, PR FC, D, IP AB, LC Axis deer, Axis axis PD, PR H?,D? NK Fallow deer, Dama dama PD, PR H?,D? NK Mountain goat, Oreamos americanus PD, PR, E FC, IP NK Eastern gray squirrel, Sciurus carolinensis PD, PR FC, NC,AB, D SD Fox squirrel, Sciuris niger PD, PR FC, NC,AB, D SD House mouse, Mus musculus NK FC?,D HD,A, CF, SD Norway rat, Rattus norvegicus NK FC?,D HD,A, CF, SD Black rat, Rattus rattus PD ? FC?,D HD,A, CF, SD Nutria, Myocastor coypus PD, PR FC?,D HD, SD European rabbit, Oryctolagus cuniculus PD, PR, E FC, NC?,D, IP? CD, LC, HD Eastern cottontail, Sylvilagus floridanus PD, PR?,E? FC, NC?,D, IP CD, LC, HD Bullfrog, Rana catesbeiana NK PC, P, E NK Green frog, Rana clamitans NK PC, P?,E? NK Snapping turtle, Chelydra serpentina NK PC, P, E?,AB, D AB Red-eared slider turtle, Trachemys scripta PD? P?,PC?, FC?, D,AB NK Plateau striped whiptail, Cnemidophorus velox NK PC? NK

A=aesthetics,AB=aggressive behavior, CD=crop damage, CF=contamination of foods, D=diseaselparasites, E=species endangerment, FC=forage competition, Hzhybridization, HD=human/livestock/pet diseaselparasites, IP=increase prey base, LC=livestock forage competition, LP=livestock predation, NC=nest competition, NK=none known, P=predation, PC=prey competition, PD=plant damage, PRzplant regeneration, S=, SD=structural damage,W=water qualitylquantity. 434 Wildlife-Habitat Relationships in Oregon and Washington

Management of Introduced Wildlife Species It is better to prevent the introduction of an unwanted species rather than deal with the management or attempted eradication of the species once it becomes e~tablished.~~,135 On the other hand, many introduced wildlife species (upland birds, cottontail rabbits, nutria, red fox) are managed as "game" species by state wildlife agencies, using traditional methods of harvestable wildlife management. Usually, a harvest license is required; seasons, bag limits, methods of take, and other regulation are set each year; and, in some cases, populations and harvests are monitored. .. .. There are many wildlife management methods English (house) sparrow. (Photograph by Jeffrey C. Lewis) available to assist us in the management of "undesirable" introduced wildlife species (Table 7). These physical, mechanical, chemical, biological, and cultural methods are used to reduce the carrying capacity of the area for the species, to reduce population density, or to keep animals out of certain areas. Reduction of populations by lethal Certain introduced species have the potential for means may only provide a temporary "fix" unless habitats substantial ecosystem disruption, the final and highly can be modified to reduce their carrying capacity for the significant category in Table 2. Of the 42 wildlife species introduced species.'49On the other hand, commercial already introduced into Oregon or Washington, we would exploitation or bounties on introduced wildlife has been incIude feraI livestock (pigs, horses, burros), mountain used in some situations as a way to keep population levels goats (in areas where they are not native), nutria, and down while generating local income.22,'I8 Pathogenic European rabbits in this category. Other species (such as agents are rarely used to control vertebrate populations the Old World rodents) cause substantial ecological because of for specificity, start-up costs and disruption in tropical ecosystems, but are not as damaging potential hazards, although efforts continue in A~stralia."~ to temperate ecosystems. Major ecosystem disruption can Often a variety of methods are employed, as in an occur when these species seriously impact the physical integrated pest management (IPM) appr~ach.'~,l~-'l~,'~~If environment (soil parameters, erosion, water quantity and a new species is released in the area, it is important to quality), achieve relatively high densities, exert heavy restrict its spread as soon as po~sible.~Research is grazing pressure, or successfully compete with native underway on chemosensory and reproductive inhibition fauna. Mountain goat impacts on the Olympic Peninsula devices that may provide valuable tools in the future and the difficulties of resolution have been de~cribed,'~,~~management of introduced species.48 and so have impacts and management of and Eradication of an introduced species is often the burro.'', 41r y8 Feral pigs have been studied extensively management goal, but is difficult to achieve.', 24, 127 around the world because of their very significant impacts Nonetheless, eradication has been achieved in some to ecosysten~s.'~98 The pros and cons of nutria places, especially on island^.'^^,'^^, lfi5Anentirely different introductions in the Pacific Northwest and elsewhere have philosophy is to "let nature take its course" and assume also been dis~ussed?~~~~~~~Similar discussions for European that eventually introduced species will drop out on their rabbits were presented as 2" 63* y8 Because of the own, wiII fit in satisfactorily, or will result in a worldwide significant potential for ecological disruption by these homogenization of the planet's flora and fauna. While this species, there have been extensive efforts to eradicate them may be the ultimate fate of the global flora and fauna, we, after introduction, especially from islands, and most are as resource managers and concerned citizens, should not banned from import at the federal or state level. take such a defeatist attit~de.8~

Table 7. Examples of methods for the managelnent of introduced wildlife species by category.

Cultural/Habitat Physical Chemical Biological Other

Crop selection Barriers Repellents Predators Bounties Cover reduction Traps Toxicants DiseaseIParasites Insurance Water removal Electrocution Reproductive inhibition Resistant plants Harvest Sanitation Flooding Aversive conditioning Lethal genes Acclimation Buffer crops ShootinglFrightening Tranquilizers, other drugs Biosonics Acceptance devices In most cases, an integrated management approach will subspecies, the Sichuan pheasant, that is better adapted be required to control most introduced species, using a to wooded or shrubby habitat~.~~Vheasantsare currently problem assessment, action plan, several methods, and widespread in Oregon and Washington. The natural monitoring. Adequate surveillance and control at the point history of the pheasant in the United States and the Pacific of origin are important. Additionally, adequate budgets, Northwest has been public support, and access to private lands will be essential Ecological Implications. Although the introduction of to the successful management or eradication of most pheasants and other upland game birds (see Table 3) has introduced wildlife specie^.^, 36, 165 Using introduced largely been considered positive, they are not without rodents as an example; Witmer et al.164, discussed the some adverse ecological effects. Concerns were expressed many considerations of introduced species management as early as 1923 in Washington that pheasants may damage and eradication. crops (sprouting corn, potatoes) and gardens.14=They There are many socio-political, economic, and compete for food and nest sites with native grouse species, ecological issues associated with introduced species.88,143 especially because they are more adaptable and tolerant Realizing this, and involving the appropriate and of disturbed landscapes and because they may be released interested parties in the decision-making process, will be in large numbers on a regular basis.138,1501159 Their essential to the successful resolution of current and future aggressive behavior can displace other birds. Nest wildlife introductions. parasitism with blue grouse, ruffed grouse, and other upland game bird species has been re

- - - and successfully introduced to Central Park, and roost availability; the use of frightening devices based , in 1890-91, although the Portland Songbird Club on chemicals, sounds, or objects; the use of repellents and attempted an introduction in Portland, Oregon, in 1889 sticky substances; the use of toxicants; shooting; and that failed.77The species range expansion in North trapping, with or without live bird decoys.'O Although America is nothing less than amazing, reaching Mexico some of these methods have been moderately successful in the 1940s and Alaska in the 1970~.'~,~~While numbers for a while, most are of limited effectiveness and must be of starlings appear to have stabilized over much of North repeated on a regular and long-term basis.16,49 The America, they are now one of the most numerous bird difficulty of dealing with starlings at high density roosts species in North America.16 The species was introduced has been documented by Glahn et al.56In all likelihood, a for aesthetic purposes, to bring a little of the Old World to combination of methods and the alteration of crop and the New World. Starlings first appeared in Oregon and livestock production practices would be most likely to Washington in 1943.77They are now abundant throughout provide damage reduction or population reduction.49 most of Oregon and Washington, especially in urban/ Starlings are here to stay and can be expected to suburban and agricultural settings. The natural history of continue to impact some native bird species. We need to the species has been described.16,49, lo4 better understand the interactions of starlings with food sources, habitats, and other species and with the control Ecological Implications. Few benefits have been measures that we employ. We also need to develop more attributed to the introduction of starlings in North effective damage management methods; research is America. Cabe16noted, however, that much basic research underway on avian repellents and on on avian biology has been done using starlings. Starlings immunocontraception. There has been some effort to have also been attributed with high levels of insect develop specific methods to reduce the ability of starlings consumption, may be hunted, and may provide food for to usurp nest sites from other species; Grabi1157attempted humans in some ~ituations.~~Finally, starlings occur in to increase wood duck nesting success by placing starling highly disturbed settings that might otherwise have few nest boxes near wood duck nest boxes. He relied on the birds present. agonistic behavior of starlings during nesting to keep other Feare49reviewed the many adverse effects of starlings, starlings from using the wood duck nest boxes. Fielder et including plant damage; food and nest competition with reduced starling use of wood duck nest boxes by native bird species; disease and parasite transfer to covering the opening from the end of the wood duck wildlife, livestock, pets, and humans; fruit consumption nesting season until just before the initiation of the next and damage; livestock food consumption and wood duck nesting season. Lumsdenlo5and McGilvrey contamination; aircraft strikes; and aesthetic problems and Uhlerlo9also presented designs to reduce nest box use (droppings, odors, noise). Much of the concern about by starlings. Knowledge of starling flocking behavior was ecological effects of starlings seems to involve their highly instrumental in the development of Avitrol, a chemical competitive ability to usurp nest cavities (both natural and frightening agent. A few birds are allowed to feed on man-made) and thus contribute to the declines in treated bait. They become sick, fly erratically, and give populations of native cavity nesters. Adverse effects have warning cries that frighten other starlings from the area.80 been noted for bluebirds,39,122 purple martins,ll tree Most starlings ingesting Avitrol will eventually die; swallows,122northern flickers,72various species of therefore, the chemical must be used carefully to minimize woodpecker~,~~,84, 147, 156 and various cavity nesting duck secondary poisoning hazards.66Gei~~~ noted that starling specie^.^^^ "7' lo5Not only is it difficult for these species to and house sparrow numbers could be kept at lower find and hold nest cavities in the presence of starlings, densities by the careful design of urban structures; but starlings may also parasitize the nests of other species latticework on apartment buildings, for example, was very by destroying eggs or hatchlings.50,57, 122 Brush15 noted, attractive to starlings and house sparrows. These examples however, that significant cavity competition probably only illustrate the value of a thorough knowledge of the biology occurs where natural cavities are very limited. and ecology, including behavior, of a species to assist in Economic losses and damage to planted crops (corn, resolving conflicts. winter wheat), fruits (grapes, , , strawberries, figs, , and ) and livestock 3. Nutria feedlots have been de~cribed,",~~as well as the disease History, Distribution, and Status. The nutria is a large problems caused by Constantin and Floydz6 semi-aquatic rodent native to south America, which has discussed the hazards of starlings and other birds at been introduced into a number of areas in North America . Typically, starling problems are quite localized. since the 1930s. Oregon and Washington are among 15 or Management and ~~~~~~~h ~~~d~.~h~ manage-ment of more states with feral nutria population^.'^' Nutrias were starlings is problematic at best because of their exceptional first to th2 in the 1930s in the ability to exploit humandaltered landscapes.49 M~~~ expectation that nutria farming would become a lucrative methods are used to reduce starling numbers, the damage 94 Inflated breeding stock prices, Poor they cause, or to disperse aggregations. These include reproduction, large farming expenses, and little economic attempts at exclusion from buildings, ledges, and trees; return for nutria pelts (-$lmoO per pelt) in the cultural and habitat modificationsthat reduce food, water, of an industry whose boom was sh0rt-1ived.47'87' a9,161 More than 600 nutria farms existed in Oregon from in damage to agriculture, drainage systems, earthen the 1930s to the 1950~,~~and a number of farms existed in structures (dikes, levees, embankments), and vegetative Washington at this time.61,93Floodingand storms damaged a9~96 Burrowing can disintegrate and holding structures and allowed some nutrias to escape weaken these structures, and may cause them to from fur farms, however, farmers often released their stock Ironically, nutrias were introduced in some areas to help when farming became uneconomical. By the 1940s, nutrias control marsh ~egetation.~~Kuhnand Peloquina9 reported had been captured by trappers or collected on both sides nutria damage to agricultural crops in the Willamette of the in Oregon and Washington, but most Valley and estimated losses of thousands of dollars per nutrias were found in the Puget Sound area, the Willamette year. Humans, livestock and pets are vulnerable to a Valley, along coastal Oregon rivers, and along the number of diseases and parasites carried by nutrias, .70,79,"9.93~10Wnlythe drainage including equine encephalomyelitis, leptospirosis, in southcentral Washington supports substantial numbers hemorragic septicemia, paratyphoid, salmonellosis, east of the Cascade Mountains. giardiasis, tapeworms, and liver flukes.96,161 The aggressive The nutria is an unclassified wildlife species in Oregon behavior of nutria also poses a hazard to pets that and Washington, and it can be harvested in unlimited approach them too closely (J. Tabor, Washington numbers at any time of the year. The records indicate Department of Fish and Wildlife, pers. comm.). fluctuating harvest levels of nutrias, which may reflect Personnel with the USDA Wildlife Services and state fluctuating pelt prices152rather than fluctuating population wildlife officers respond to nutria damage complaints. densities. Nutria harvest data also indicate a relatively Although a number of damage prevention and control stable population, in that nutrias are consistently captured methods exist for commercial trapping appears in the same counties (i.e., nutrias do not appear to be to be the most common method used in Oregon and spreading to previously unoccupied counties in Washington. Some trappers have certainly benefited from appreciable numbers). Short-term stability, however, does the introduction of nutrias, although the monetary benefits not necessarily mean that all habitats suitable for nutrias appear limited as nutria pelts are not highly valued for have been colonized or that a range expansion will not f~r.~~~Lowpelt prices offer little incentive to most trappers occur in the future. The natural history of the nutria has and consequently, commercial trapping may be limited been described in a7, 161 as a management tool for nutria populations. Conversely, control of pest nutria can be a source of income for some Ecological Implications. Through foraging, nutrias can trappers and pest control professionals. denude expanses of vegetation, eliminating vegetative str~cture.~~~157 While nutrias are generally opportunistic Management and Research Needs. Trapping and vegetarians, Went~l~~found that broadleaf arrowhead localized control efforts have been used to manage nutria (Saggittaria latifolia) and smartweed (Polygonum spp.) were populations since they were first introduced, and these selected by nutrias in Oregon, and these plants may be techniques will likely continue to provide for nutria locally reduced or extirpated by foraging nutrias. Nutrias management in the future. Trapping records indicate a construct resting and feeding platforms of compacted relative stable nutria population in the Pacific Northwest. vegetation in wet areas, form between these Until new information indicates that nutria impacts are platforms through vegetation, and also create grooming particularly severe to certain species, ecological areas, dens, and runs or slides at the water's edge.47,a7 communities, or geographic areas, it is unlikely that These activities can significantly impact vegetative current management methods will be altered or replaced. comm~nities.~~,157 The clearing of vegetation by nutrias Lobbying efforts to ban trapping or outcries for nutria may alter plant succession, and convert marsh ecosystems eradication could alter the status quo, but these do not to more open-water environments. appear to be immediate issues in Oregon or Washington. In , increasing nutria harvests in the mid- With the exception of research by PeloquinlZ1on growth 1900s coincided with decreasing harvestsa7The and reproduction and Went~'~~on nutria density and apparent decline in the muskrat population could have impacts to marsh vegetation, little study of the nutria has been the result of many factors, but the nutria irruption been conducted in the Pacific Northwest, and none has was considered among the most significant. Apparent been published from Washington. Future research should declines in muskrat numbers have also been observed in focus on how the nutria's alteration of aquatic areas where nutrias are abundant on the Finley National environments and its physical presence (i.e., potential Wildlife Refuge in western Oregon (H. Brunkal, U. S. Fish competition and disease transmission) could impact and Wildlife Service, pers. comm.). Alteration of the sensitive fauna and vegetative communities.This research vegetative community would be expected to have a may also prompt study into alternative management significant influence on native fauna, especially sensitive techniques for nutrias. amphibians and species that have niches similar to the nutria (e.g., muskrat, some waterfowl). Unfortunately 4. Red Fox little information is available on the direct or indirect History, Distribution, and Status. Native to North impacts of nutrias on other fauna. America, Europe, Asia, and northern Africa,lo3the red fox Nutrias cause direct and indirect impacts to humans has the largest geographic range of any terrestrial by their foraging and burrowing activities, which result carnivore with the possible exception of the domestic cat. 438 Wildlife-Habitat Relationships in Oregon and Washington

European red foxes were introduced to the East Coast in incidentally with other foods. Foxes may be important the 1600s and 1700s23,126and Australia in the mid 1800~~~~seed dispersers of both native and non-native plants. Den- for fox hunting; actions that confused the of site excavation and other digging could minimally disrupt red foxes in eastern North America and greatly expanded flora, but would also expose a medium for seed the range of the red fox.Non-native red foxes were brought germination. to Oregon and Washington in the early 1900s for fur Red foxes commonly prey on insects, earthworms, farming40and fox hunting or trapping.4,108,160In the 1910s, small- to medium-sized birds and mammals, and the fur industry was rapidly spreading west across the herpetofauna; red at ion on crustaceans and fish and the continent, when choice breeding stock and pelts from red use of carrion has also been d~cumented.~~,loorlo3 Red foxes foxes (predominantly the silver phase foxes) were sold are noted predators of species valued by humans as for thousands of dollars.40By 1915, the first fox farms were livestock,58,115 game birds and mammals,45,160 and established in Oregon and Wa~hington.~~Many endangered species.164Conservation of the snowy plover introductions occurred when foxes were released or in Oregon and Washington could be hindered by red foxes escaped from or evaded hounds and hunters, should they become established near nesting colonies forming free-roaming populations of non-native red foxes along the coast, as has happened in California.Interference in both states. More recent introductions of red foxes in with the reproductive behavior of native fauna, especially North America have included the release of pet foxes, the ground-nesting birds, can be significant.16' Aubry4, illegal release of farm foxes by animal rights activists, and suggested that non-native red foxes might not be the translocation of non-native foxes into previously physiologically or behaviorally capable of surviving in unoccupied areas by pet owners, wildlife rehabilitators, high-elevation habitats. However, an introduction of non- and animal control officials.102 native red foxes within the historical ranges of native red Non-native red foxes occur throughout many of the foxes could result in resource competition, interbreeding lowland areas in western Oregon and Washington4,*and and disease tran~.~,lol It is unknown if in several disjunct populations in eastern Oregon and interbreeding with non-native foxes would reduce the Washington. The distribution of non-native red foxes has fitness of native red fox populations. The transmission of largely been determined as those areas where red foxes diseases, including sarcoptic mange, rabies, canine occur outside the historical ranges of native Cascade (V. distemper, parvovirus, and leptospirosis, is a threat that v. cascadensis) and Rocky Mountain red foxes (V. v. red foxes pose to other mammals.lo3Additionally, resource macro~ra).~,~,7,62 The Cascade red fox historically occurred ~ompetition,~~disease transmission, and interbreeding145 in the high-elevation meadows and parklands of the would be expected to negatively affect native kit foxes , whereas the Rocky Mountain red fox should red foxes become established in southeastern occupied similar habitats in northeastern Washington, and Oregon. in the Blue and Wallowa mountain^.^, 37, 62 Because Foxes may negatively impact humans in several ways, relatively little information is available on the locations including livestock depredation, crop damage, disease and operation of fox farms, especially in Oregon, and transmission to humans and their pets, and predation or because there are no known means of visually injury of pets. More indirectly, non-native red foxes may distinguishing native from non-native red foxes, it is not negatively impact humans by affecting species valued by known if introductions have occurred within the ranges the public (e.g., game or protected species). Positive of the native red foxes. impacts to the ~ublicinclude recreational and economical Red foxes are considered a furbearing species in Oregon opportunities of trapping, hunting, and fur farming, and and a furbearing game animal in Washington with no the recreational opportunities of feeding and watching administrative distinctions made between native and non- wild foxes, along with the enjoyment from having foxes native red foxes. Red foxes can be trapped in most areas as pets; the latter is strongly discouraged by wildlife of Oregon during a regulated season. In Washington, red professionals. foxes can be trapped during a regulated season except in Management and Research Needs. Relatively little is Whatcom, Skagit, and ~slandCounties, and a portion of known about the populations of non-native red foxes in Cowlitz County. Because market prices strongly influence Oregon and Washington. Non-native red foxes provide the harvest of most furbearer species, harvest data are not additional harvest opportunities for trappers, and a good indication of fox population trends. While little management in this regard comprises season restrictions information is available on population trends, there are and harvest regulations. Management has also involved no indications that fox in either state are communication with the public about occasional livestock increasing or decreasing dramatically. The natural history kills and concerns about fox predation on domestic cats. of the red fox has been described in detail.lo3,106r1411152, 153 Damage prevention and control methods for red foxes Ecological Implications. With the exception of excavating were reviewed by Phillips and Schmidt.lZ3The wide holes for dens and prey items, and leaving some uneaten distribution of red foxes in western Oregon and prey remains scattered about, red foxes probably have little Washington reflects the potential for disease transmission effecton their physical environment. Non-native red foxes to pets, livestock, other wildlife, and humans, with rabies feed on a variety of fruit-~roducingplants?aa They also being of particular concern. Research on non-native red eat leafy vegetation, some of which may be ingested foxes to determine distribution and demities, identify disease prevalence, and characterize food habits is needed a substantial contribution to nutrient cycling in aquatic to better understand populations and potential impacts ecosystems. in Oregon and Washington. Much of the literature on the bullfrog in has been concerned with the effect of bullfrog 5. Bullfrog predation on native fauna, especially other ran id^.^^, 65,", History, Distribution, and Status. Bullfrogs are native to ll1 Kupferbergg0demonstrated that bullfrogs negatively North America east of the ; however, affected the growth of developing yellow-legged frogs by their range has greatly expanded due to introductions by outcompeting them for food resources. Although many humans in western North America, South America, reports have implicated the bullfrog as a major cause of Europe, and Asia.14 Bullfrogs were first introduced into declines in some native species, Hayes and Jenning~~~ the Northwest in the early 1900s to provide food (i.e., frog argued that this has not been clearly proven and a number legs), opportunities for frog hunting, and stock for frog of other factors may be at work, such as predation by farm^.^^^'^^ Being the largest frog in North America, introduced fish, habitat alteration, commercial bullfrog legs were a highly prized food, and frog farming exploitation, and the effects of toxicants. However, until to supply the demand for bullfrog legs was undertaken proven otherwise, it may be wise to consider bullfrog but rarely succeeded.14Lampman9* states that bullfrogs predation and competition as detrimental to a number of from were first brought to eastern Oregon in 1914, vulnerable, sensitive, or listed species in Oregon and and subsequent introductions in western Oregon in 1921 Washington, including the , leopard involved releasing additional Idaho bullfrogs and frog, red-legged frog, foothill yellow-legged frog, and bullfrogs from the previously introduced populations in western pond turtle. Bullfrog predation on hatchling eastern Oregon. Nussbaum et al.l13reported the release of western pond turtles has prompted management efforts 18 bullfrogs in the Grant's Pass area in 1931 and that to protect remaining populations in Oregon and bullfrogs were soon well established in the upper Rogue Washington. Management efforts involve collecting River Valley. In Washington, Dvornich et a1.43reported the hatchling turtles from western pond turtle nests and first specimens collected in the 1930s, which suggests that placing them in captivity until they are too large to be the first successful introductions occurred in the 1920s and eaten by bullfrogs (R. Goggans, Oregon Department of early 1930s. Fish and Wildlife, and K. Slavens, Washington Department Bullfrogs are largely aquatic and occur in lower- of Fish and Wildlife, pers. comm.). These efforts, which elevation freshwater habitats on both sides of the Cascades started in the early in Oregon and Washington, have in Oregon and Washington and along much of the been successful at recruiting young turtles into resident Columbia River.97Within this range, the bullfrog has populations, and some female recruits from the first "head- become widely established and locally abundant because started" cohorts are expected to be large enough to breed it is a capable colonizer of a wide variety of habitats and a in 1999. prolific breeder." They are classified as a game fish in Bullfrogs are beneficial to some people as a source of Oregon and as a game species in Washington; however, food, sport, and economic gain. Universities and schools these classifications may soon change in both states. have created a significant demand for bullfrogs for use in Fishing or hunting license (in Oregon and Washington, classroom and laboratory study. Others simply enjoy the respectively) is required to harvest bullfrogs and there are sound of bullfrogs or stock them for the pleasure of having season restrictions, but no bag limits. Bullfrogs may still bullfrogs on their property; the latter is strongly be expanding their range as suitable habitats are colonized discouraged by wildlife professionals. by invading or introduced individuals. Humans continue Bullfrog predation on and competition with native to introduce bullfrogs into new, previously unoccupied species are impacts that cause concern among many areas. Water-garden and pond stores in Vancouver and people. This concern may prompt a modification of the Portland recently sold bullfrog tadpoles from California legal status of the bullfrog to allow for more effective and (at $3,00 per tadpole) to individuals bullfrog management and protection of native species interested in stocking their ponds with bullfrogs (selling vulnerable to bullfrog predation and competition. or possessing live bullfrogs is illegal in Washington without a permit). Also, some summer festivals include a Management and Research Needs. The predation and frog-jumping contest where captured frogs (often competition threats posed by bullfrogs to native species bullfrogs) may be released after the contest into previously have prompted consideration of bullfrog eradication in unoccupied habitats. The natural history of bullfrogs has some localized areas. Removing egg masses, killing adults, been described in detail.14,113 or promoting harvests of bullfrogs may act to reduce their impacts on native species. However, their local abundance, Ecological Implications. Both tadpoles and adults feed widespread distribution, ability to disperse and recolonize on ~egetation,~~,'~~although plant consumption by adults habitats, and the tendency for people to transplant is likely the result of incidental ingestion while capturing bullfrogs, makes eradication difficult at best.lloPerpetual a prey item. Consumption of vegetation by bullfrog bullfrog control may be required where management is tadpoles could constitute an impact on local flora and a important to protect or restore native species. Research significant indirect impact on native species that use this efforts that determine the degree to which bullfrogs flora for food or cover,gObut this consumption could make threaten native species, relative to other causes of species 440 Wildlife-Habitat Relationships in Oregon and Washington decline, will help us focus our management actions on 7. Bailey,V. 1936.The mammals and life zones of Oregon. Bureau of the most critical problems. Research into ways of Biological Survey. North American Fauna No. 55. U.S. Department of controlling or eradicating bullfrogs without harming Agriculture,Washington,D.C. native species would also be ~aluable.~~~Studiesthat focus 8. Blackburn, D. 1977.An apparent ring-necked pheasant X blue grouse hybrid. Murrelet 58:78. on single species or communities that may be impacted 9. Bomford, M. and F? O'Brien. 1995. Eradication or control for vertebrate by bullfrog presence should also focus on obtaining data pests.Wildlife Society Bulletin 23:249-255. to credibly address the impacts of bullfrogs. 10. Bratton, S. I? 1975.The effect of the European , Sus scrofa, on gray beech forest in the Great Smoky Mountains.Thesis, Cornell University, Ithaca, NewYork, NY. Conclusions I I.Brown, C. R. 198 1 .The impact of Starlings on Purple Martin At least 42 introduced species of wildlife (birds, mammals, populations in undamaged colonies.American Birds 35: 266-268. amphibians, reptiles) occur in Oregon and Washington. 12. Brown, E. R., editor. 1985. Management of wildlife and fish habitats in Introductions have occurred for many reasons, both forests of western Oregon and Washington. U.S. Department of accidental and purposeful. Some have greatly contributed Agriculture, Forest Service, Pacific Northwest Region. Portland, OR. to outdoor recreation, local economies, and state wildlife 1 3. Bruggers, R. L., E. Rodriguez, and M. Zaccagnini. 1998. Planning for bird pest problem resolution: a case study. International Biodeterioration agency revenues, while others have had adverse ecological and Biodegradation 42 1 73- 184. consequences through direct or indirect mechanisms (e.g., 14. Bury, R. B., and j.A.Whelan. 1984. Ecology and management of the resource competition, displacement, predation, bullfrog. U.S. Fish and Wildlife Service. Resource Publ. No. 155. hybridization, and disease transmission).Economic losses Washington, D.C. to human-valued resources and public health hazards 15. Brush,T. 1983. Cavity use by secondary cavity-nesting birds and have been documented. There has been more stringent responses to manipulations. Condor 85:46 1-466. regulation of introduced species at the federal and state 16. Cabe, I? R. 1993. European Starling.The Birds of North America 48: 1 - 24. levels in recent years, in part due to the increased concern 17. Campbell, E. W., G. Rodda,T. Fritts, and R. Bruggers. 1999.An about potential harm to native flora and fauna. Options integrated management plan for the brown tree snake on Pacific for resource managers include prevention of entry, islands. Pages 423-433 in G. Rodda,Y. Sawai, D. Chiszar, and H.Tanaka, eradication, and management after dispersal and editors. Problem snake management. Comstock, Ithaca, New York, NY. establishment; the first is perhaps the most practical, while 18. Carlquist, B. 1990.An effective management plan for the exotic the latter is the most commonly employed option. mountain goats in . Natural Areas Journal 10: 12- Eradication is difficult and expensive in most situations. 18. 19. Carothers, S.W., M. Stitt, and R. Johnson. 1976. Feral asses on public More surveillance and control at the is lands: an analysis of biotic impact, legal considerations and management needed. A sustained effort,using a variety of methods and alternatives. Proceedings of North American Wildlife Conference the principles of integrated pest management, is needed 4 1 :396-406. to limit adverse effects. Each situation must be assessed 20. Cassidy, K. M., C. Grue, M. Smith, and K. Dvornich, editors. 1997. on a species- and site-specific basis. New methods are Washington State Gap Analysis-Final Report.Volumes 1-5.Washington needed to improve the monitoring and management of Cooperative Fish and Wildlife Research Unit, University ofwashington, Seattle, WA. introduced wildlife. 2 1. Center for Wildlife Law. 1996. Saving biodiversity: a status report on state laws, policies and programs. Defenders ofWildlife,Albuquerque, Acknowledgments . We would like to acknowledge the many people that 22. Choquenot, D., F? O'Brien, and 1. Hone. 1995. Commercial use of provided information or review comments on a portion pests: can it contribute to conservation objectives?Pages 25 1-258 in G. or all of this chapter: Keith Aubry, Charles Bruce, Richard C. Grigg, F? Hale, and D. Lunney, editors. Conservation through Bruggers, Alan Clark, Bruce Coblentz, Larry Cooper, John sustainable use of wildlife. Centre for Conservation Biology,The Crawford, Richard Dolbeer, Joe Engles, James Glahn, University of Queensland, Brisbane,Australia. 23. Churcher, C. S. 1959.The specific status of the New World red fox. Rebecca Goggans, Marc Hayes, David Johnson, Kelly journal of Mammalogy 40:5 13-520. McAllister, Charles Meslow, Thomas OfNeil, Michael 24. Coblentz, B. E. 1990. Exotic orgainisms: a dilemma for conservation Pipas, and Kate Slavens. biology. Conservation Biology 426 1 -265. 25. Coleman, j. S., S.Temple, and S. Craven. 1997. Cats and wildlife: a Literature Cited conservation dilemma. University of Cooperative Extension I.Ad Hoc Federal lnvasive Alien Species Task Force. 1997. Campaign Service, Madison,WI. against invasive alien species: an action plan for the nation.Washington, 26. Constantin, B., and J. Floyd. 1992.An avianlairport study for Standiford D.C. , Louisville, : results and management implications. 2.Allen, D. L. 1956. Pheasants of North America. Stackpole Books, Proceedings Eastern Wildlife Damage Control Conference 5: 166- 170. Harrisburg, PA. 27. Corkran, C. C., and C.Thoms. 1996.Amphibians of Oregon, 3.Ashbrook, F. G. 1923. Silver fox farming. U. S. Dept.Agric. Bull. No. I 15 1. Washington, and . Lone , Renton,WA. Washington, D.C. 28. Couch, L. K. 1929. Introduced European rabbits in the San Juan 4.Aubry, K. B. 1983.The Cascade red fox: distribution, morphology, Islands,Washington. Journal of Mammalogy 10:334-336. zoogeography and ecology. Ph.D. Dissertation. University of 29. Coulter, M. W. 1957. Predation by snapping turtles upon aquatic birds Washington, Seattle,WA, in marshes. Journal of Wildlife Management 2 1 :1 7-2 1. 5. -. 1984.The recent history and present distribution of the red 30. Courtenay,Jr.,W. R., and C. Kohler. 1986. Exotic fishes in North fox in Washington. Northwest Science 58:69-79. American fisheries management. Pages 40 1-4 1 3 in Richard H. Stroud, 6.- ,and S. D.West. 1984.The status of native and introduced editor. Proceedings ofThe Role of Fish Culture in Fisheries mammals on Destruction Island,Washington.The Murrelet 65:80-83. Management at Lake Ozark, .American Fisheries Society, Bethesda, MD. 3 I. Cox, C. B., I. N. Healy, and P. D. Moore. 1976. Biogeography: an 54. Gilligan, j., editor. 1994. Birds of Oregon. Cinclus, McMinnville, OR. ecological and evolutionary approach. Second edition. Blackwell 55. Glahn, j. F., and D. L. Otis. 1986. Factors influencing blackbird and Scientific, Oxford, England. European starling damage at livestock feeding operations.Journa1of 32. Crawford, J.A., and S. Meyers. 1980. Survival of ring-necked pheasant Wildlife Management 50: 15- 19. hens in the WillametteValley, Oregon. Unpublished report. Oregon 56. -,A. R. Stickley,Jr.,J. F. Heisterberg, and D. F. Mott. 1 99 1. Impact Department of Fish and Wildlife, Portland, OR. of roost control on local urban and agricultural blackbird problems. 33. Crawley, M. J. 1989. Chance and timing in biological invasions. Pages Wildlife Society Bulletin 19:5 1 1-522. 407-423 in J.A. Drake, editor. Biological invasions: a global perspective. 57. Grabill, B.A., 1977. Reducing starling use of wood-duck boxes.Wildlife JohnWiley & Sons, NewYork, NY. Society Bulletin 5:69-70. 34. Csuti, B.,A. J. Kimerling,T.A. O'Neil, M. M. Shaughnessy, E. P. Gaines, 58. Graf,W. 1947. Mouse populations in relation to predation by foxes and M. M. P. Huso. 1997.Atlas of Oregon wildlife: distribution, habitat, and hawks.The Murrelet 28: 18-2 1. and natural history. Oregon State University Press, Corvallis, OR. 59. Grifith, B., J. M. Scott, J.W. Carpenter, and C. Reed. 1989.Translocation 35. Dahlgren, R. B. 1987.The Ring-Necked Pheasant. Pages 305-3 1 I in as a species conservation tool: status and strategy. Science 245:477- Harmon Kallman, editor. Restoring America's wildlife- 1937- 1987: the 480. first 50 years of the Federal Aid in Wildlife Restoration (Pittman- 60. Guenther, K., and T. Kucera. 1978.Wildlife of the Pacific Northwest: Robertson) Act. U. S. Department of the Interior, Fish and Wildlife occurrence and distribution by habitat, BLM district, and National Service,Washington D.C. Forest. U.S. Department of Agriculture, Forest Service, Portland, OR. 36. Dahlsten, D. L. 1986. Control of invaders. Pages 275-302 in Harold A. 6 I.Guenther, S. E. 1950. Nutria.Washington State Game Department, Mooney, editor. Ecology of biological invasions of North America and Olympia,Washington, USA. Game Bulletin 2:5. Hawaii. -Verlag, New York, NY. 62. Hall, E. R. 198 I.Mammals of North America. J.Wiley and Sons, New 37. Dalquest,W.W. 1948. Mammals of Washington. University of York, NY. Publ. Natural History No. 2. University of Kansas Press, Lawrence, KS.p 63. Hall, L. 1977. Feral rabbits on San Juan lsland,Washington. Northwest 38. Davis, J.W., L. Karstad, and D.Trainer. 198 1. Infectious diseases of wild Science 5 1 :293-297. mammals. State University Press,Ames, IA. 64. Harris, S. 198 1. On the food of suburban foxes (Vulpes vulpes), with 39. Davis,W. H., and W. C. McComb, 1989. Bluebirds and Starlings: special reference to London. Mammal Review 1 1 : 1 5 1 - 168. competition for nest sites. Sialia 1 1 :124- 126,138. 65. Hayes, M. I?, and M. R. Jennings. 1986. Decline of ranid frog species in 40. Dearborn, N. 19 15. Silver fox farming in eastern North America. western North America: are bullfrogs responsible?Journal of Bulletin No. 30 1. U. S. Department of Agriculture.Washington, D.C. Herpetology 20:490-509. 4 I. Douglas, C. L., and D. Leslie, Jr. 1996. Feral animals on rangelands. 66. Holler, N. R., and E.W. Schafer,Jr. 1982. Potential secondary hazards of Pages 28 1-292 in P. Krausman, editor. Rangeland wildlife. Society for avitrol baits to sharp-shinned hawks and American kestrels. Journal of Range Management. , CO. Wildlife Management 46:457-462. 42. Dumas, P. C. 1966. Studies of the Rana species complex in the Pacific 67. Houston, D. B., E. G. Schreiner, and B. B. Moorhead. 1994. Mountain Northwest. Copeia 1966:60-74. goats in Olympic National Park: biology and management of an 43. Dvornich, K. M., K. R. McAllister, and K. B.Aubry. 1997.Amphibians introduced species. Scientific Monograph NPSINROLYMINRSM-94125. and reptiles ofwashington State: location data and predicted U.S. Department of Interior, ,Washington, D.C.. distributions.Volume 2,Washington State Gap Analysis, Final Report. 68. Human, K. G., and D. M. Gordon, 1997. Effects of Argentine ants on Washington Cooperative Fish and Wildlife Research Unit, University of vertebrate biodiversity in . Conservation Biology Washington, Seattle,WA. 1 1 : 1 242- 1 248. 44. Ehrlich, P. R., 1989.Attributes of invaders and the invading process: 69. Hygnstrom, S. E., R. M.Timm, and G. E. Larson. 1994. Prevention and vertebrates. Pages 3 15-328 in J.A. Drake, editor. Biological invasions: a control of wildlife damage. University of Nebraska Cooperative global perspective.John Wiley & Sons, NewYork, NY Extension, Lincoln, NE. 45. Epstein, M. B., G.A. Feldhamer, and R. L. Joyner. 1983. Predation on 70. Ingles, L. G. 1965. Mammals of the Pacific States: California, Oregon, white-tailed deer fawns by , foxes, and alligators: predator Washington. Stanford University Press, Stanford, CA. assessment. Proceedings of the Annual Conference of the Southeastern 7 I. lngold, D. J. 1994. Influence of nest-site competition between Association of Fish and Wildlife Agencies 37: 16 1 - 172 European starlings and woodpeckers.Wilson Bulletin 106: 227-24 I. 46. Evanich, J. 1986. Introduced birds of Oregon. Oregon Birds 12: 156- 72. -. 1996. Delayed nesting decreases reproductive success in 186. northern flickers: implications for competition with European starlings. 47. Evans, J. 1970.About nutria and their control. Resource Publ. No. 86. Journal of Field Ornithology 67:32 1-326. U. S. Department of Interior, Fish and Wildlife Service,Washington, D.C. 73. lnternational Association of Fish and Wildlife Agencies. 1997.The 48. Fall, M.W., and W. B.Jackson. 1998.A new era of vertebrate pest economic importance of hunting: economic data on hunting control? lnternational Biodeterioration and Biodegradation 42:85-9 1. throughout the entire United States. lnternational Association of Fish 49. Feare, C.J. 1984.The starling. Oxford University Press, NewYork, NY. and Wildlife Agencies,Washington, D.C. 50. Fielder, P. C., B. G. Keesee, and PA. Popushinsky. 1990.Wood duck use 74. Jenkins, P.T. 1996. Free trade and exotic species introductions. of nesting structures in . Pages 265-267 in L. H. Conservation Biology 10:300-302. Fredrickson, G.V. Burger, S. P Havera, D.A. Graber, R. E. Kirby, and T. S. 75.Jewett, S. G.,W.Taylor,W. Shaw, and J.Aldrich. 1953. Birds of Taylor, editors. Proceedings of NorthAmerican Wood Duck Washington State. Press, Seattle,WA. Symposium, St. Louis, MI. 76. Jobanek, G.A. 1987. Bringing the old world to the new: the 5 1. Fox, M. D., and B.J. Fox. 1986.The susceptibility of natural introduction of foreign songbirds into Oregon. Oregon Birds 13:59-74. communities to invasion. Pages 57-66 in R. H. Groves and 1.1. Burdon, 77. -1993.The European starling in Oregon. Oregon Birds 19:93- editors. Ecology of biological invasions. Cambridge University Press, 96. Cambridge, England. 78.Johnsgard, FA. 1973. Grouse and quail of North America. University 52. Friend, M., editor. 1987. Field guide to wildlife diseases. Resource of Nebraska Press, Lincoln, NE. Publication No. 167. U. S. Department of the Interior, Fish and Wildlife 79.Johnson. R. E., and K. M. Cassidy. 1997.Terrestrial mammals of Service,Washington, D.C. Washington State: location data and predicted distributions.Volume 3, 53. Geis,A. D. 1973. Effects of urbanization and type of urban Washington State Gap Analysis- Final Report.Washington Cooperative development on bird populations. Pages 97- 105 in 1. H. Noyes and D. R. Fish and Wildlife Research Unit, University of Washington, Seattle,WA. Progulske, editors. Proceedings of a symposium on wildlife in an urbanizing environment. University of ,Amherst, MA. 442 Wildlife-Habitat Relationships in Oregon and Washington

80.Johnson,R.J., and j. F. Glahn. 1994. European starlings. Pages €109- 105. Lumsden, H. G. 1986. Choice of nest boxes by tree swallows, house E 120 in S. Hygnstrom, R.Timm, and G. Larsen, editors. Prevention and wrens, eastern bluebirds, and European starlings. Canadian Field- control of wildlife damage. University of Nebraska Cooperative Naturalist 100:343-349. Extension Service, Lincoln, NE. 106. Macdonald, D. W. 1987. Running with the fox. Facts On File, New 8 1. Johnson,W. E.,T. K. Fuller, and W. L. Franklin. 1996. Sympatry in canids: York, NY. a review and assessment. Pages 189-2 18 in J. L. Gittleman, ed. Carnivore 107. MacDonald, I.A.W., L. Loope, M. Usher, and 0. Hamann. 1989. behavior, ecology, and evolution.Volume 2. Cornell University Press, Wildlife conservation and the invasion of nature reserves by Ithaca, NY. introduced species: a global perspective. Pages 2 15-255 in J.A. Drake, 82. Kauhala, K. 1996. lntroduced carnivores in Europe with special editor. Scope 37: Biological invasions, a global perspective.JohnWiley & reference to central and northern Europe.Wildlife Biology 2: 197-204. Sons, New York, NY. 83. Kebbe, C. E. 1958. Deposition of pheasant eggs in ruffed grouse nest. 108. Mace, R. U. 1970. Oregon's furbearing animals. Oregon State Game The Murrelet 39: 10. Commission Wildlife Bulletin Number 6. Portland, OR. 84. Kerpez,T.A., and N. S. Smith. 1990. Competition between European 109. McGilvrey, F. B., and F. M. Uhler. 197 1 .A starling-deterrentwood duck starlings and native woodpeckers for nest cavities in .Auk 107: nest box. Journal of Wildlife Management 35793-797. 367-375. 1 10. Moler, f? E. 1994. Frogs and toads. Pages F-9 - F- 1 I in S. E. Hygnstrom, 85. Kessel, B. 1953. Distribution and migration of the European starling in R. M.Timm, and G. E. Larsen, editors. Prevention and control of wildlife North America. Condor 55:49-67. damage. University of Nebraska Cooperative Extension Service, 86. Kiesecker, J. M., and A. R. Blaustein. 1998. Effects of introduced Lincoln, NE. bullfrogs and smallmouth bass on microhabitat use, growth, and survival I I I.Moyle, F! B. 1973. Effects of introduced Bullfrogs, Rana catesbeiana, on of native red-legged frogs. Conservation Biology 12:776-787. the native frogs of the San JoaquinValley, CA. Copeia 1973: 18-22. 87. Kinler, N.W., G. Linscombe, and F! R. Ramsey. 1987. Nutria. Pages 326- 1 12. Newsome,A. E., and I. R. Noble. 1986. Ecological and physiological 343 in M. Nowak,J.A. Baker, M. E. Obbard, and B. Malloch, edsitors.Wild characters of invading species. In: R. H. Groves and J.J. Burdon, editors. furbearer management and conservation in North America. Ontario Ecology of biological invasions. Cambridge University Press, Cambridge, Ministry of Natural Resources,Toronto, Ontario, Canada. England. 88. Knopf, F. L. 1992. Faunal mixing,faunal integrity, and the biopolitical 1 13. Nussbaum, R.A., E. D. Brodie,Jr.,and R. M. Storm. 1983.Amphibians template for diversity conservation.Transactions of North American and reptiles of the Pacific Northwest. Press, Wildlife and Natural Resources Conference 57:33 1-343. Moscow, ID. 89. Kuhn, L.W., and E. I? Peloquin. 1974. Oregon's nutria problem. 1 14. O'Brien, F!, and S.Thomas. 1998. Rabbit calicivirus: update on a new Proceedings of thevertebrate Pest Conference 6: 10 I- 105. biological control for pest rabbits in Australia. Proceedings of the 90. Kupferberg, S. J. 1997. Bullfrog (Rana catesbeiana) invasion of a Vertebrate Pest Conference 18:397-405. California river: the role of larval competition. Ecology 78: 1736- 175 1. 1 15. O'Gara, B.W., K. C. Brawley,J. R. Munoz, and D. R. Henne. 1983. 9 1. Labisky, R. F. 1975. Ecopolicies ofThe Wildlife Society.Wildlife Society Predation on domestic sheep on a western ranch.Wildlife Bulletin 3:36-43. Society Bulletin 1 1 :253-264. 92. Lampman, B. H. 1946.The coming of the pond fishes. Binfords and 1 16. Office of Technology Assessment. 1993. Harmful non-indigenous Mort, Portland, OR. species in the United States. OTA-F-565. U.S. Government Printing 93. Larrison, E. J. 1943. Feral coypus in the Pacific Northwest.The Office,Washington, D.C. Murrelet 24:3-9. 1 17. Orians, G. H., 1986. Site characteristics favoring invasions. Pages 133- 94. -. 1976. Mammals of the northwest:Washington, Oregon, Idaho, 148 in Harold A. Mooney and James A. Drake, editors. Ecology of and British Columbia. Seattle Audubon Society. Seattle,WA. biological invasions of North America and Hawaii. Springer-Verlag, New 95. Lauckhart, J. B., and J.W. McKean. 1956. Chinese pheasants in the York, NY. Northwest. Pages 43-89 in Durward L.Allen, editor. Pheasants of North 1 18. Parkes,]. I? 1996. Integrating the management of introduced mammal America. Stackpole Company, Harrisburg, PA. pests of conservation values in New Zealand. Wildlife Biology 2: 179- 96. LeBlanc, D. J. 1994. Nutria. Pages B-7 1 - B-80 in S. E. Hygnstrom, R. M. 184. Timm, and G. E. Larsen, editors. Prevention and control of wildlife 1 19. --- , G. Nugent, and B.Warburton. 1996. Commercial damage. University of Nebraska Cooperative Extension Service, exploitation as a pest control tool for introduced mammals in New Lincoln, NE. Zealand.Wildlife Biology 2: 17 1 - 177. 97. Leonard,W. F!, H.A. Brown, L. L. C. Jones, K. R. McAllister, and R. M. 120. Peck, M. E., 1948. Invasion of exotic plants and their economic Storm. 1993.Amphibians of Washington and Oregon. Seattle Audubon significance in Oregon. Northwest Science 22: 126- 130. Society. Seattle,WA. I2I. Peloquin, E. F? 1969. Growth and reproduction of the feral nutria 98. Lever, C. 1985. Naturalized mammals of the world. Longman Scientific Myocator coypus (Molina) near Corvallis, Oregon. M. S.Thesis, Oregon andTechnical, NY. State University, Corvallis, OR. 99. -. 1987. Naturalized birds of the world. Longman Scientific and 122. Peterson, B., and G. Gauthier. 1985. Nest site use by cavity-nesting Technical, NewYork, NY. birds of the Cariboo Parkland, British Columbia.Wilson Bulletin 97: 100. Lewis, J. C., K. L. Sallee, and R.T. Golightly, Jr. 1993. lntroduced red fox 3 19-33 1. in California. Non-game Bird and Mammal Section Report 93- 10. 123. Phillips, R.L., and R.H. Schmidt. 1994. Foxes. Pages C-83 - C-88 in S.E. California Department of Fish and Game, Sacramento, CA. Hygnstrom, R.M.Timm, and G.E. Larsen, editors. Prevention and control 101.- ,R.T. Golightly,Jr., and R. M. Jurek. 1995. Introduction of non- of wildlife damage. University of Nebraska Cooperative Extension native red foxes in California: implications for the Sierra red Service, Lincoln, NE. fox.Transactions of the Western Section of The Wildlife Society 3 1 :29- 124. Pimentel, D. 1986. Biological invasions of plant and animals in 32. agriculture and forestry. Pages 149- 162 in Harold A. Mooney, editor. 102. -, K. L. Sallee, R.T. Golightly, Jr., and R. M. Jurek. 1998. Social and Ecology of biological invasions of North America and Hawaii. Springer- biological aspects of non-native red fox management in California. Verlag, NewYork, NY. Proceedings of thevertebrate Pest Conference 18: 1 50- 1 55. 125. Pimm, S. L. 1989.Theories of predicting success and impact of 103. Lloyd, H. G. 1980.The red fox. B.T. Batsford, London, England. introduced species. Pages 35 1-367 in J.A. Drake, editor. Biological 104. Long,]. L. 198 I. lntroduced birds of the world: the worldwide invasions: a global perspective. JohnWiley & Sons, NewYork, NY. history, distribution, and influence of birds introduced to new 126. Presnall, C. C. 1958.The present status of exotic mammals in the environments. Universe Books, New York, NY. United States. Journal of Wildlife Management 2245-50. 127. Rainbolt, R. E. and B. E. Coblentz. 1997.A different perspective on eradication of vertebrate pests.Wildlife Society Bulletin 25: 189- 19 I. 128. Robinson,W. L., and E. G. Bolen. 1989. Wildlife ecology and 154.Washington Department of Wildlife. 1993. Status of the western management. Second edition. Macmillan, New York, NY. gray squirrel, Sciurus griseus, in Washington. Unpublished report. 129. Roughgarden,J., 1986. Predicting invasions and rates of spread. Pages Washington Department of Wildlife, Olympia,WA. 1 79- 188 in Harold A. Mooney and James A. Drake, editors. Ecology of 155.Weitze1, N. H. 1988. Nest-site competition between the European biological invasions of NorthAmerica and Hawaii. Springer-Verlag, New starling and native breeding birds in Northwestern Nevada. Condor York, NY. 905 15-5 17. 130. Scheffer,T. H. 1935. Introduced food plants for waterfowl.The 156.Welsh, J.E., and R.A. Howard, Jr. 1983. Characteristics of snags Murrelet 16:66-69. influencing their selection by cavity-nesting birds.Transactions of the 13 I.Schmitz, D. C., and R. G.Westbrooks. 1997.The federal government's Northeast Fish and Wildlife Conference 40: 177. role. Pages 329-337 in Daniel Simberloff, editor. Strangers in paradise: 157.Wenu,W.A. 197 I.The impact of nutria (Myocastor coypus) on marsh impact and management of nonindigenous species in Florida. Island vegetation in the WillametteValley, Oregon. M. S.Thesis. Oregon State Press,Washington, D.C. University,Corvallis,OR. \ 32. Schmuu,).A. \988.Ring-necked pheasant parasitism of wild turkey 158. Westemeier, R. L., and T. L. Esker. 1989.An unsuccessful clutch of nests. Wilson Bulletin 100:508-509. northern bobwhites with hatched pheasant eggs.Wilson Bulletin 1 33. Simberloff, D. 1996. Hybridization between native and introduced 10 1540-642. wildlife species: importance for conservation.Wild1ife Biology 2: 143- 159.Westerskov, K. 1990. Partridges and pheasants: competitors or 150. sharers? Pages 183-20 1 in Kevin E. Church, Richard E. Warner, and 134. -. 1997a.The biology of invasions. Pages 3- 17 in Strangers in Stephen 1. Brady, editors. Gray partridge and ring-necked pheasant paradise: impact and management of nonindigenous species in Florida. workshop. Kansas Department of Wildlife and Parks,Topeka, KS. D. Simblerloff, editor. lsland Press,Washington, D.C. 160. Wilcomb, M. 1. 1948. Fox populations and food habits in relation to 135.- . 1997b. Eradication. Pages 22 1-228 in Strangers in paradise: game birds in the WillametteValley, Oregon. M. S.Thesis. Oregon State impact and management of nonindigenous species in Florida. D. University, Corvallis, OR. Simberloff, editor. Island Press,Washington, D.C. 16 1 .Willner, G. R. 1982. Nutria. Pages 1059- 1076 in J.A. Chapman and G. 136. Smallwood, K. S., and T. I? . 1992.A rating system for potential A. Feldhamer, editors.Wild mammals of North America: biology, exotic bird and mammal pests. Biological Conservation 62: 149- 159. management, and economics.Johns Hopkins University Press, 137.- . 1994. Site invasibility by exotic birds and mammals. Baltimore, MD. Biological Conservation 69:25 1 -259. 162.Wilson, E.O., and EM. Peters, editors. 1988. Biodiversity. National 1 38. Spreyer, M. 1995. Pheasant obsession. Birder's World 9:44-48. Academy Press, Washington, D.C. 139. Stein, B.A., and S. R. Flack, editors. 1996.Americas least wanted: alien 163.Witmer, G.W. 1990. Re-introduction of in the United States. species invasion of U.S. ecosystems.The Nature Conservancy, Journal of the PennsylvaniaAcademy of Science 54: 13 1 - 135. Arlington,VA. 1 64. --- ,J. L. Bucknall,T. H. Fritts, and D. G. Moreno. 1996. Predator 140. Storer,T. 1. 1933. Frogs and their commercial use. California Fish and management to protect endangered avian species.Transactions of the Game \9:203-2 13. North American Wildlife and Natural Resources Conference 6 1 :102- 14 1. Storm, G. L., R. D.Andrews, R. L. Phillips, R.A. Bishop, D. B. Siniff, and J. 108. R.Tester. 1976. Morphology, reproduction, and mortality of mid- 165. -, E. W. Campbell, and F. Boyd. 1998. Rat management for western fox populations.Wildlife Monographs 49. endangered species protection in the United StatesVirgin Islands. I42.Taylor,W. f! 1923. Upland game birds in the state of Washington.The Proceedings of thevertebrate Pest Conference 18:28 1-286. Murrelet 4:3- 15. 166. Zembal, R. 1992. Status and management of light-footed clapper rails l43.Temple, S.A. 1990.The nasty necessity: eradicating exotics. in coastal southern California.Transactionsof the Western Section of Conservation Biology 4: 1 1 3- I 1 5. The Wildlife Society 28: 1-5. 144.Thomas, J. W., editor. 1979. Wildlife habitats in managed forests; the Blue Mountains of Oregon and Washington.AgricuItural Handbook No. 553. U.S. Department of Agriculture, Forest Service, Portland, OR. I45.Thornton,W.A., G. C. Creel, and R. E.Trimble. 1971. Hybridization in the fox genus Vulpes in west Texas. Southwest Naturalist 25423-434. 146.Toney,J. C., P M. Rice, and F. Forceila. 1998. Exotic plant records in the Northwest United States 1950- 1996: an ecological assessment. Northwest Science 72: 198-209. 147.Troetschler, R. G., 1976.Acorn woodpecker breeding strategy as affected by starling nest-hole competition. Condor 78: 15 1 - 165. 148.Van Vuren, D. 1992. Eradication of feral goats and sheep from island ecosystems. Proceedings of the Vertebrate Pest Conference 1 5377- 381. 149.VanVuren, D. 1998. Manipulating habitat quality to manage vertebrate pests. Proceedings of thevertebrate Pest Conference 18:383-390. 150.Vance, D. R., and R. L. Westemeier. 1979. Interactions of pheasants and prairie in lllinois.Widdlife Society Bulletin 7221-225. 15 I.Verts, B.]., and L. Carraway. 1980. Natural hybridization of Sylvilagus bachmani and introduced 5. floridanus in 0regon.The Murrelet 6 1 :95- 98. 152.-, and -. 1998. Land mammals of Oregon. University of California Press, Berkeley, CA. 153.Voigt, 0.R. 1987. Red Fox. Pages 379-392 in M. Nowak,].A. Baker, M. E. Obbard, and B. Malloch, editors.Wild furbearer management and conservation in NorthAmerica. Ontario Ministry of Natural Resources.Toronto,Ontario, Canada. Published in Wildlife-Habitat Relationships in Oregon and Washington. David H. Johnson and Thomas A. O’Neil, Managing Directors. Corvallis, Oregon State University Press, 2001. Pages 423-443.