Tufts OpenCourseware
Author: Gretchen Kaufman, DVM
Color Key
Important key words or phrases.
Important concepts or main ideas.

OCW Zoological Medicine 2008
Conservation Strategies and Disease (2009)
G. Kaufman, DVM
Cummings School of Veterinary Medicine at Tufts University

1. Introduction

When a particular species receives attention and is tagged as threatened or endangered, certain strategies may be adopted that are designed to save that species, or prevent its further decline. The urgency of some of these "solutions" sometimes has precluded adequate assessment or refinement of the particular strategy put into motion, in some cases producing unexpected consequences, many of them involving disease. In nearly every situation, political, social and economic factors influence the initiation and follow through of any proposed plan and present important variables that must be thoroughly explored to completely understand how a strategy might be successful. Veterinarians can play a crucial role in designing, implementing, monitoring and assessing the outcome of any given strategy because of their unique insight into animal systems, disease and problem solving.

Some of the more common conservation strategies that have been tried in response to declining populations are presented below. Although these strategies are discussed separately, it should be understood that implementation of a single strategy to save a species, or an ecosystem, is rarely sufficient for success. Multiple strategies, aimed at multiple levels, will produce better and swifter results. It is also important to start looking at conservation issues from a "preventative medicine" outlook - that is preventing these crisis from occurring in the first place, so that drastic interventions are not necessary. Just as we see in medicine, prevention of a conservation crisis is much simpler, cheaper, and successfully reaches more individuals than fire-engine drastic last ditch efforts aimed at saving a dying animal. Unfortunately, current funding is often only targeted at critically endangered animals or habitats, and the "preventative" approach is met with skepticism.

2. Habitat Protection

Habitat loss or degradation is generally the biggest threat to most wildlife species experiencing serious declines all around the world. Most of this is due to human causes - need for land for cultivation and grazing, housing and other infrastructure required for an ever expanding population. Many species are learning to live alongside humans in whatever little scraps of suitable habitat they can muster. Others cannot adapt to human disturbance or habitat disruption. One solution is habitat protection - putting aside land for wildlife or ecosystem protection and restricting human intervention. Habitat protection takes many forms. Sometimes this is through the establishment of a park, preserve, conservation land, or open-space designation. In other instances it is through legislative protection of certain types of habitat, such as through wetlands protection legislation or through general environmental protection, control of domestic animals and land use restrictions.

Setting aside land or restricting land use always carries with it a societal commitment - economic and moral choices. It is usually prudent to promote private cooperation - develop financial incentives for farmers and landowners to set aside land or maintain suitable habitat for certain species; to accept a certain level of economic loss due to predation or crop destruction; to conduct themselves in a manner that decreases wildlife human conflicts; or to participate and develop enterprise strategies and pursue sustainable harvesting.

Although habitat protection seems outwardly simple and reasonable, it is not without problems and has produced new issues that now need consideration. Some major problems include:

  • Boundary or buffer zone issues including:

    • animals straying out of the "park" boundaries, producing conflicts with surrounding communities

    • activities in the buffer zone affecting the protected area (pollution, watershed changes)

  • Creation of "island" populations with resultant loss of biodiversity

  • Managed forest/habitat bringing wildlife in closer proximity to humans and their livestock

  • Lack of real understanding of what a species or ecosystem needs to maintain viability

Buffer zone or boundary conflicts often include disease issues which bring veterinarians into the mix and may include vaccinating wildlife (rabies), testing and removing infected animals (TB in deer) that are threatening domestic species, or developing rational and effective management plans that minimize conflicts (discouraging wildlife feeding or removing feed sources such as garbage, locking up or corralling domestics at night).

Habitat protection should also include protection from surrounding environmental contaminants. It has been repeatedly demonstrated that environmental contamination can result in disease (heavy metals) and/or reproduction and immunologic dysfunction (endocrine disrupters, PCBs) in both humans and other animals. Locating a "reserve " in the middle of an industrial wasteland, or surrounding a polluted body of water will not protect the native species, but may hasten their demise.

One solution to the "island" dilemma is the creation of corridors as is occurring in the Y2Y initiative . Corridors between the islands are created to promote migration and biodiversity of native mega fauna. Questions have arisen concerning what the corridors will do to the spread of disease between the "islands". How do we best prepare for this?

When domestic animals and humans are put together in mixed use land reserves (e.g. grazing in national parks), this not only creates an opportunity for economic conflict, but produces opportunities for interaction and transmission of disease, and may produce an environment that creates opportunities for development of new emerging diseases. Managed forestry or mixed land use may however, be the most politically acceptable form of habitat protection.

Unfortunately, our basic lack of information and true understanding of ecosystems and species complexity is outrunning the conservation crisis and we are still having to make decisions in the dark and sometimes make mistakes that affect interconnecting systems. Pursuit of basic knowledge by veterinarians, biologists, and others into baseline physiological data; disease ecology and epidemiology; reproductive parameters; and natural behavior are vitally important to the future success of habitat protection strategies.

3. Species Protection

In some instances, we as a society have decided that certain species need protection through our system of laws, treaties and governments ( e.g. CITES and the Endangered Species Act ). This has resulted in a myriad of legislation, always politically impacted, and often influenced by economics. Such legislation is inherently limiting, because it seeks to protect a specific species almost in isolation and often does not or cannot predict long term outcomes. It is, however, often easier to obtain support and market, especially if the species is appealing to people - such as the giant panda or the elephant (charismatic megafauna). In addition, symbolic protection of a keystone species or upper level carnivore, if successful, will also protect many other animals intimately connected to it, by requiring protection of it's food supply and it's habitat. As veterinarians involved in such activities, we are often called upon to deal with threatening health issues of protected species, responding to disease outbreaks, vaccinating wildlife, screening for new diseases, and helping to manage genetic material for optimal health.

Local, national or international regulations tied to species protection also:

  • Brings attention to the impact of illegal activities such as sport, poaching for medicinal purposes, pets, or food (e.g. turtles and bushmeat).

  • Creates an opportunity to monitor disease

  • Promotes captive breeding of protected species

  • Establishes funding priorities that support research and conservation

4. Wildlife Population Management

Conservation efforts targeting particular species usually produce strategies for population management in a variety of settings and on a broad scale. This is intimately tied up with species protection and habitat protection strategies and sometimes driven by an ongoing series of crisis, often involving human- animal conflicts and disease. Some examples include:

  • Bovine TB in deer (US) or badgers (Britain)

  • TSE in Elk

  • Wildlife reservoirs of rabies

  • Rabies/distemper outbreaks in wild dogs (E. Africa)

  • Griffon vulture mortality crisis (South Asia)

Overpopulation issues with certain species are arising more and more due to limitations in suitable habitat because of human encroachment. Overpopulation inevitably brings greater conflict as animals spill out of protected habitat into human spaces, or overgraze available food and begin degrading habitat and raiding crops. Increased disease transmission is again a common issue. Solutions that have been explored include:

  • immunocontraception

  • culling (e.g. public hunting, trapping, poisoning)

  • sustainable harvesting

Population management strategies should enable veterinarians and wildlife management professionals to monitor the health of important populations, including reproductive health, and to respond to crisis that may threaten certain populations. As with species protection, recognition of population management needs establishes funding priorities that are important to support these activities.

5. Wildlife Transportation

Wildlife translocations involve movements of animals from one wild population to another, usually for the purpose of relieving overpopulation pressure in the originating locations, and/or bolstering or reestablishing populations in the destination location. Wildlife translocations are not always done for conservation purposes. Animals are also sometimes moved to support activities such as sport hunting and game farming and in these situations may be mostly unregulated. This was the case with raccoons, translocated by hunters to the mid-Atlantic states (US) which resulted in the spread of a new rabies epidemic in the Northeast. The emergence of TSE in elk and mule deer in the Rocky Mtn. states is alarming to many as a potential threat to captive and wild populations and a possible source of human infection (no evidence). Movement of captive animals has occurred without much oversight and diagnosis of TSE may be made after the spread has already occurred. Spread to naive wild populations may have serious consequences if captive herds are not controlled. Emerging diseases in the Atlantic Salmon fish farming industry has similarly produced threats to native wild fish.

California big horn sheep, Ovis canadensis californiana, were captured using a net gun from a helicopter.
California big horn sheep, Ovis canadensis californiana, were captured using a net gun from a helicopter.

In planned wildlife translocations, veterinarians have a clear role in ensuring the health of both the source animals and the recipient population as well as a safe and successful transport operation. Animals to be moved should be screened for diseases, observed for an appropriate amount of time and necropsied whenever mortalities occur. Likewise recipient populations should be surveyed as well to ensure success of the translocated population. Veterinarians should be involved in the capture and transport process to ensure safe (both human and animal) and efficient movement of animals. Health assessments and surveys ideally should continue to be performed after introduction to detect possible long term health problems not found in screening processes and help to assess the overall success of the operation.

There are several inherent disease issues in this conservation strategy. Integrating one unrelated population of animals with another brings up major genetic questions. The native population is locally adapted to local conditions and endemic diseases. Introduced animals may be less suited to these local conditions and may have reduced survival. They may also be acutely susceptible to endemic diseases and could suffer disastrous loses when exposed. Conversely the introduced animals may benignly carry diseases or parasites or bring genetic traits that are threatening to the native populations.

6. Captive breeding, Rehabilitation and Reintroduction

In some instances, habitat protection is not possible and significant populations of a species may only exist in captive settings. Rarely, the last remaining animals of a species are removed for the purpose of captive protection, breeding and eventual reintroduction. Successful conservation through this method is extremely challenging and quite controversial. In some instances, there is no other alternative - black footed ferrets, Guam rail,, Mauritius kestrel, etc.. There are many challenges and generally very high costs inherent in this strategy and many believe that it's success as a strategy is very limited. Among the many pitfalls such as captive management and captive reproductive challenges, behavioral alterations/inadequacies in captive populations, genetic drift/inbreeding depression there are several important health issues that must be dealt with and are a focus of the veterinary community.

Recommendations for captive breeding/reintroduction include (Snyder, 1996):

  • maintain captive populations in isolation and as closed collection

  • conduct captive breeding in at least two separate facilities in the normal geographic range of the species

  • founder stock should be taken from the wild or from similar single-species facilities

  • captive breeding facilities should be closed to the public!

7. Ecotourism

Ecotourism outwardly appears to be a winning strategy to bring attention to and garner support for a species or land area that otherwise might be exploited. It can bring vital income to a struggling economy, and in some instances provide much needed support for local communities, at the same time helping them to appreciate the value of conservation. This strategy is not without its problems however. Ecotourism necessarily means bringing people in closer proximity to wildlife, building infrastructure to support those people and changing the natural environment to facilitate the activity. It is also a somewhat fickle economy and may not be very long lasting in the face of political instability or market pressures. Serious disease issues may arise through direct contact with humans (measles and influenza in gorillas), or through the "baggage" they bring with them (dogs with distemper/rabies, domestic cats).

The above are a few examples of the major conservation strategies that are being practiced today. Many of these efforts overlap, and in most instances several strategies are employed to increase the chances of success. Disease threats and ensuring the health of fragile populations are the responsibility of veterinarians. Veterinarians as part of a conservation team are best equipped to design successful strategies that avoid health catastrophes, and to respond when such catastrophes occur.

8. Highlights of Parrot Conservation

Parrots (Class Aves, Order Psittaciformes), as a group, comprise the majority of birds in the category we commonly refer to as "pet birds". The relationship between this group of birds and humans is a very long and complex one, dating back centuries and involving many different cultures. Their striking beauty and colorful variations, their charismatic personalities and ability to "talk" and their obvious intelligence, playfulness and cunning strike an irresistible bond with human beings. Thus they have become inextricably entwined in our society as pets, as objects of food, adornment and trade.

They remain, however, a group of wild birds, and cannot in any way be considered domesticated. Over the centuries, we have not developed a comprehensive understanding of their lives in the wild state despite our continuous involvement with this group of birds. Now we find that many of these precious species are at risk in their natural state: threatened, endangered, and some on the brink of extinction.

Endangered St. Lucian Amazon Parrot
Endangered St. Lucian Amazon Parrot

Free-living Crimson lorikeets in Lamington, Queensland, Australia
Free-living Crimson lorikeets in Lamington, Queensland, Australia

There are 330 species of psittacine, 94 (28%) are considered threatened with extinction. This is one of the highest proportions of any major family in the Class Aves. As a rule, they live in dense forests in tropical regions of the world, some live in remote desert areas. They often have complex social and survival behaviors that are largely learned behaviors. Many of them live very long lives and have fairly low reproductive rates.

Critically Endangered Parrots (IUCN) see Supplementary Material folder for complete listing

English Name

Scientific Name


Orange-bellied parrot

Neophema chrysogaster


Night parrot

Pezoporus (=Geopsittacus) occidentalis



Strigops habroptilus

New Zealand

Forbes' parakeet

Cyanoramphus(auriceps) forbesi

New Zealand

Orange-fronted parakeet

Cyanoramphus(auriceps) 'malherbi'

New Zealand

Philippine cockatoo

Cacatua haematuropygia


Echo parakeet

Psittacula eques


Puerto Rican parrot

Amazona vittata

Puerto Rico

Lear's macaw

Anodorhynchus leari


Spix's macaw

Cyanopsitta spixii


Azure-winged parrot

Hapalopsittaca fuertesi


Yellow-eared conure

Ognorhynchus icterotis

Colombia and Ecuador

8.1. Major Threats Worldwide

8.1.1. Lack of information/understanding

The unfortunate dearth of information concerning most parrot species has and will continue to hamper conservation efforts. Without such information it is difficult to evaluate the true state of affairs and provide convincing arguments for preservation. Basic biological and ecological understanding is vital to setting up monitoring programs for continual evaluation of threatened animals and for developing sustainable policies to ensure their long term protection.

8.1.2. Habitat destruction/degradation

Human encroachment and environmental contamination are obvious threats to all wildlife. Tropical regions of the globe are currently most vulnerable due to the rapid environmental degradation that is occurring and the high number of species (especially parrots) found in these regions. Habitat loss is the single most important pressure facing critical parrot populations today. Dangerous land use practices in many of these areas include farming, mining, logging, charcoal production and urbanization.

Free-ranging rainbow lorikeets, Trichoglossus haematodus, visit a popular tourist cafe, attracted by the sugar left behind.
Free-ranging rainbow lorikeets, Trichoglossus haematodus, visit a popular tourist cafe, attracted by the sugar left behind.

8.1.3. Trade

Trade continues to put strong pressures on the wild parrot populations around the world. It is estimated that 10% of US households have a parrot species as a pet. Before enactment of the Wild Bird Conservation Act in 1992, the US was the leading importer of wild caught parrots, at times representing 50% of the trade.

As developed nations (including the US) begin to place restrictions on importation and trade in these species, local trade continues to thrive and illegal markets are maintained. Laws enacted in the countries of origin are often poorly enforced or easily circumvented. Usually the most endangered species, rare and hard to get, are also the most valuable (Lear's macaw chick for $40,000). This value drives the illegal market.

8.1.4. Hunting

Many indigenous peoples use the larger species of parrots as an important source of meat and feathers. Changing cultural preferences and development of suitable alternatives is difficult and must be carried out very carefully and thoughtfully. Efforts at education and redirection of native cultures to conservation concepts are ongoing.

8.1.5. Introduced predators, disease, agricultural pests, etc.

8.1.6. Solutions to some of these problems might include:

  • Habitat preservation and protection of wild populations

  • Captive breeding for trade and reintroduction programs

  • Development of sustainable harvesting programs

  • Ecotourism

  • Education

8.2. Laws and Regulations governing pet birds

8.2.1. International legislation – Endangered Species

The CITES (Convention on Trade in Endangered Species ) agreement is a treaty among nations to agree to restrict trade in identified endangered and threatened species of plants and animals. Appendix I lists endangered species including most species of parrots. It strictly prohibits trade in these animals. Appendix II lists threatened species and includes the remaining parrot species. International trade in Appendix II animals is allowed only with special permits. Appendix III includes locally identified threatened and endangered species.

Other treaties and laws exist which control trade in and out of each individual country. Enforcement and acceptance of these laws is often questionable. In the face of such efforts, smuggling is still a major threat to these birds in the wild state.

8.2.2. Federal Legislation

Most of the laws passed by the federal government are administered by the United States Fish and Wildlife Service (United States Department of the Interior) with the help of United States Customs and APHIS (USDA). The following laws regulate activity in birds: Lacey Act (1900), Migratory Bird Treaty Act (1918) with exceptions for regulated hunting, Eagle Protection Act (1940) protects both Bald and Golden eagles, and the Endangered Species Act (1973). Most recently, Congress passed the Wild Bird Conservation Act (Title I of the Wild exotic bird conservation, great lakes fish and wildlife tissue bank, fish and wildlife conservation, and African elephant conservation, Public Law 102-440, Oct.23, 1992) which regulates the importation of wild or non-native birds. This last bill severely restricts the importation of wild birds, especially those intended for the pet trade.

8.2.3. State Regulations

State laws governing the ownership, breeding and selling of birds vary considerably. Every state is allowed to institute its own laws regarding import, sale, licensing, etc. of pet birds as long as they do not conflict with federal laws. For example, in New York State no wild caught birds may be sold, and all birds must be leg-banded by the breeder with a "closed band" to prove their origin. In the Commonwealth of Massachusetts, all parrot species are allowed without restriction except for Monk, Quaker or Gray-headed parakeets. Pink Starlings, Java sparrows (waxbill), and Red-billed Diochs (weaver) are also prohibited. Massachusetts also honors the Endangered Species Act (Federal), the CITES I list, the Red Book (IUCN), and protects most native North American species. Note that CITES I species bred in captivity in the US are not restricted.

8.3. Propagation and marketing pet birds to the public

Most pet birds are now produced through captive breeding due to the importation regulations in place in this country that regulate the trade in wild birds (e.g. CITES and the Wild Bird Conservation Act ). Only about 17,000 birds are legally imported into the United States each year, one fifth of these are wild caught. However, illegal importation and smuggling still occur and the veterinarian needs to be alert to these cases. Smuggled birds are often in poor health and can carry diseases that are normally detected during the legal importation and quarantine procedure. Wild populations also may be significantly impacted by illegal poaching and unregulated harvest to satisfy the pet trade. Clients should be encouraged to purchase captive bred animals.

Pet birds are produced in a variety of breeding situations ranging from very small hobby type operations to full scale commercial aviaries with thousands of birds. The business of reproductive and pediatric medicine is very sophisticated in some of the larger breeding facilities, a few of which employ full-time veterinarians. The value of these species is quite high, consequently the investment of professional care and attention is considered worthwhile.

Eggs are either parent hatched or hatched in an incubator and usually hand-raised to a certain age before shipping. Birds may be sent directly to the buyer, or to a distributor such as a pet store. Ideally birds are given to owners after the weaning process is complete. Some less responsible operations sell unweaned birds and "train" the new owners to complete the weaning process. This practice allows them to move more birds through and thus increase their profits. These very young animals are at high risk of developing problems with weaning or contracting infectious diseases if not cared for by experienced people. The avian veterinary community does not support the sale or transfer of unweaned baby birds to inexperienced persons - AAV Policy Statement .

9. References and Resources

9.1. Books and Articles

Beissinger, S.R. and N.F.R. Snyder (ed.) New world parrots in crisis. Smithsonian Institution Press, Washington, DC, 1992

Clark, Tim W. Restoration of the endangered black-footed ferret: a 20 year overview. IN Restoration of Endangered Species, edited by Marlin L. Bowles and Christopher J. Whelan, Cambridge University Press, 1994.

Cunningham, Andrew A. Disease risks of wildlife translocations. Conservation Biology 10 (2), 2996: 349-353.

Deem, Sharon L., W.B. Karesh and W. Weisman. Putting theory into practice: wildlife health in conservation. Conservation Biology 15 (5) 2001: 1224-1233.

Delsink, A.K. et al. Field applications of immunocontraception in African elephants (Loxodonta africana). Reproduction Supplement 60, 2002: 117-124.

Doest, Odette E.A. Macaw reintroduction to prevent extinction: fiction or reality? Proceedings of the 21st Annual Conference of the Association of Avian Veterinarians, Portland, Oregon, August 30 - September 1, 2000: 145-148.

The domestic animal/wildlife interface: issues for disease control, conservation, sustainable food production, and emerging diseases. Annals of the New York Academy of Sciences. 2002. Volume 969.

Enserink, Martin. US gets tough against chronic wasting disease. Science 294 (2 Nov), 2001: 978-979.

Forshaw, Joseph, M. Parrots of the World. Neptune, N.J., T.F.H., 1977.

Gibbons, J. Whitfield, et al. The Global declines of reptiles, deja vu amphibians. BioScience v.50 (8), 2000: 653-666.

Juniper, Tony and Mike Parr. Parrots: a guide to parrots of the world. New Haven: Yale University Press, 1998.

Krebs, JR, et al. Badgers and bovine TB: conflicts between conservation and health. Science 279 (5352), 1998: 817-818.

Leighton, F.A. Health Risk assessment of the translocation of wild animals. Rev. Sci. Tech OIE 2002, 21 (1), 187-195

Musters, CJM, et al. Breeding birds as a farm product. Conservation Biology 15 (2), 2001: 363-369.

Quarantine and health screening protocols for wildlife prior to translocation and release in to the wild, Woodford, M.H. ed. Office International des Epizooties, 2001.

Salafsky, N., et al. A systematic test of an enterprise strategy for community-based biodiversity conservation. Conservation Biology 15 (6), 2001: 1585-1595.

Sanz, V. and A. Grajal. Successful reintroduction of captive-raised Yellow-shouldered amazon parrots on Margarita Island, Venezuela. Conservation Biology, 12(2), 1998:430-441.

Schwartzman, Stephan, A. Moreira, and D. Nepstad. Rethinking tropical forest conservation: perils in parks. Conservation Biology 14 (5), 2000: 1351-1357.

Snyder, N., McGowan, P., Gilardi, J. and Grajal, A. (ed.). Parrots - Status Survey and Conservation Action Plan 2000-2004. IUCN, Gland, Switzerland and Cambridge, UK. link

Snyder. Noel FR, et al. Limitations of captive breeding in endangered species recovery. Conservation Biology 10 (2), 1996: 338-348.

9.2. Websites

Tufts University Fletcher School - list of Biodiversity Conventions http://fletcher.tufts.edu/multi/biodiversity.html

Conservation Incentives Library from Environmental Defense http://www.environmentaldefense.org/

Convention on Trade in Endangered Species http://www.cites.org/

Health Risk Analysis in Wild Animal Translocations http://wildlife1.usask.ca/wildlife_health_topics/risk_analysis/rskguidintro.php

IUCN/SSC Conservation Breeding Specialist Group. Disease Risk Handbook http://www.cbsg.org/cbsg/risk/

Massachusetts Natural Heritage and Endangered Species program vernal pools site


US Endangered Species Act http://www4.law.cornell.edu/uscode/16/ch35.html

US EPA Wetlands protection site http://www.epa.gov/owow/wetlands/vital/protection.html

"Wild Exotic Bird Conservation Act" (PL 102-440, 23 Oct., 1992) ; http://www4.law.cornell.edu/uscode/16/ch69.html

Yellowstone to Yukon Initiative http://www.y2y.net/

9.3. Media

VIDEOTAPE: Parrots : look who's talking. Nature Video Library, 1996.