That Bird Blog – Bird Care and History for Pet Birds

Attention to breeding birds in public and private collections, along with increased legal protection, has helped a great many species to recover from earlier population crashes. In some instances, rescue efforts represent the only hope for a species, as none survive in the wild. However, upon reviewing species status reports recently, I was dismayed to see that bad as opposed to good news prevailed. From well known pet trade parrots to recently described Asian swallows, wild birds everywhere face grave threats.

Following is a summary of recent trends:

Frightening Statistics

Of the world’s 9,685 described bird species, 1,227, or 12.4%, are included on the IUCN’s Red List as threatened with extinction. Of these, 192 species are considered to be critically endangered, and likely to become extinct in the near future. An additional 838 bird species are classified as “near threatened”.

Since the year 1500, 133 species of birds have become extinct. Currently, 4 species exist only in captivity, and 15 species have not been observed despite surveys and may be extinct as well.

Since the year 2000, at least I species, Hawaii’s po’ouli, has become extinct and at least 2 species – Spix’s macaw and the Hawaiian crow – have become extinct in the wild.

Regions and Habitats of Concern

Indo-Malayan birds, Asian vultures and albatrosses face particularly hard times, with many species in severe decline.

Brazil and Indonesia lead the world in the numbers of resident threatened species, with 123 and 114 respectively.

Eighty seven percent of all threatened birds reside in forests. Tropical and subtropical lowland forests support 43% of all such species; 36% reside in moist montane forests.

The Most Significant Threats

Converting land to agricultural use is seen as the most critical threat to bird life, with 73% of all species being significantly affected. Logging and trapping/hunting impact 71% of all birds and, along with agriculture, are the main reasons behind the decline of 95% of threatened species worldwide.

Introduced species of birds, mammals, invertebrates, reptiles and plants significantly affect one third of the world’s threatened bird species via predation, competition, habitat alteration or the spreading of disease.

Further Reading

You can read more about bird declines, the effect they may have and what can be done to help at http://www.biodiversityinfo.org/sowb/section.php?r=introduction.

In Part I of this article we examined the pros and cons of imprinting  – the process wherein an animal comes to see adults of another species as its natural parents – as regards birds in zoos, the pet trade and conservation programs.  Today I’d like to relate a few more of my experiences with imprinting as it related to the conservation of endangered birds and mammals.

Andean and California Condor Reintroductions

Rare birds raised for use in future release/re-stocking programs present a unique set of challenges.  Many are needed, and so pulling eggs to stimulate a second clutch is desirable.  However, birds raised by hand or under foster parents of another species face poor prospects for survival in the wild.

I have worked with both Andean and California condor chicks that were destined for future release into natural habitats.  These magnificent raptors are quick to imprint upon the people who feed them, so a novel solution was devised.  Keepers assigned to hand-feed condor chicks worked from behind a curtain, and presented food in the beak of hand puppet which closely resembled the head of an adult condor.  I’m happy to report that many hand-reared condors of both species successfully made the transition from captive to free-living existence.

Cows as Surrogate Mothers for Rare Species

Certain endangered mammals with which I’ve worked have presented particularly difficult dilemmas.  Gaur (rare wild cattle native to India and Southeast Asia) for example, breed readily in captivity but produce only 1 calf every 3-4 years.  In order to bolster this species’ numbers, captive female gaurs are sometimes chemically induced to produce several eggs instead of the usual single egg.

The extra eggs are implanted into domestic cows, which then give birth to and successfully raise baby gaurs.  However, cow-raised gaurs are not accepted by parent-raised gaurs.  Gaurs that are raised among domestic cows do not acquire normal gaur behaviors (i.e. appropriate reactions to dominant animals) and are attacked when integrated into gaur herds.  They rarely breed, and hence do not contribute to the species’ survival prospects.

Gorillas

Captive-born female gorillas are often unable to raise their own young, lacking examples and mentors in the form of older females, as would be the case in the wild (some zoos have tried “training films, to no avail!).  Hence many must be hand-raised (please see photo), but these too are often ostracized by other gorillas and rarely reproduce.

Further Reading

You can read more about the California condor reintroduction program at http://www.bigsurcalifornia.org/condors.html.

In 1935 Austrian zoologist Konrad Lorenz published a ground-breaking paper describing how goslings that he raised came to regard him as, in essence, their “parent”.  Further work on this process, soon to be known as imprinting, led to the founding of the science of ethology, the study of animal behavior.

As every bird-keeper knows, chicks taken from the nest and hand-raised make the best pets.  Such birds are said to be imprinted upon people, and they relate very well to us. However, there are some other uses for and sides to imprinting.  Today I’d like to relate some of my experiences with an assortment of imprinted creatures.

I Like Mice, but….

My oddest bird story involves a great horned owl.  Irresistibly cute in its efforts to threaten me, the owlet had been found in a Bronx park and was being harassed by some children (amazingly, these huge owls still survive in NYC, where they dine upon rats, muskrats, roosting pigeons and cats).  I and my coworkers raised the owl, a male, and he became a favorite at classes and on visits to homes for the elderly.

When he matured, however, the owl developed the distressing habit of trying to jam a mouse into the mouth of any passing person, much as he would feed a potential mate under more usual circumstances.  Interestingly, the owl never tried to stuff the mouse into one’s ear…he knew what a mouth was, even though the objects of his affection lacked a hooked beak (or any beak!).

Foster Parents

The owl showed no interest in members of his own species, which brings me to a major problem where imprinted endangered species are concerned.  In zoo based conservation programs, we sometimes pull the eggs of endangered birds so as to stimulate the female to lay a second clutch.  The pulled eggs are often put under a brooding “foster mother” of a related species, and the chicks therefore become imprinted on bird species other than their own.  This has worked well for peregrine falcons fostered beneath prairie falcon hens, and for Mauritius pink pigeons, which are fostered under ring doves.

However, rare finches raised by zebra or society finches often pick up the songs of their foster parents, and prefer the foster species over their own species as mates.  As you can imagine, this seriously hampers efforts to increase the population of the endangered birds.

Further Reading

The future of the magnificent pink pigeon was first championed by conservation legend Gerard Durrell.  Read more at http://www.durrell.org/Animals/Birds/Mauritius-Pink-Pigeon/.

Ecuador’s yellow-eared parrot (Ognorhynchus icterotis) and golden-plumed parakeet (Leptosittacia branickii) face a most unusual threat – an annual religious celebration.  The group Aves and Conservation has identified the collection of palm fronds for Catholic Easter celebrations as the main cause of the species’ near disappearance from Ecuador.

Survival Linked to a Single Tree

Both birds nest exclusively in Ceroxylon palms, the central leaves of which are harvested yearly in an unsustainable manner.  The palms do not reproduce until age 25-30, and live to age 75-100.  Removal of the leaves prevents reproduction, and may kill the palm.  The golden-plumed parakeet, once common throughout much of Ecuador, is now limited to the southern Andes provinces; the yellow-eared parrot has not been sighted at all in recent years, and is believed to number less than 150 nation-wide.

Providing Education and Alternatives

In cooperation with the government and other conservation groups, Aves and Conservation has embarked on a program designed to alert local people of the plight of both palms and parrots.  Local Catholic churches have been cooperating in the effort, encouraging members to use corn stalks and Eucalyptus in place of palms.

These substitute plants, grown at the Botanical Gardens of Quito and other locations, are distributed yearly in front of churches, and are gaining acceptance.  Happily, the golden-plumed parakeet has begun to reclaim some of its former range (please see below).

This program illustrates the importance of including within a conservation plan those people who will be most affected, and of offering alternatives.  Blanket prohibitions that impinge upon people’s religious beliefs or livelihoods are, in my experience, difficult to enforce and rarely successful in the long term.

Further Reading

You can read about recent golden-plumed parakeet nesting records at 

http://www.worldlandtrust.org/news/labels/Ecuador.htm#7881806187526800422.

Images referenced from Wikipedia and originally posted by markharper1 and Loise Wolff

Research at the University of Glasgow (March, 2009) has established that zebra finches (Taeniopygia guttata) exposed to stress as chicks exhibit a more intense and longer stress response as adults than do birds raised in a stress-free environment.

The Effects of Early Exposure to Stress

Pairs of sibling finch chicks were used for the experiment.  To simulate a stressful situation, one member of the pair was injected with corticosterone, a hormone produced by birds in response to stress; the other sibling was used as a control.  As adults, the resting corticosterone level of the birds was identical.  However, when subjected to a stressful situation, all previously-stressed chicks produced greater amounts of stress hormone than did their siblings, and their stress response lasted for a longer period of time.

Stress and the Health of Pet Birds

Pet keepers should take an important lesson from this research, as an unnaturally strong stress response has been shown to be damaging to health in a variety of species, humans included.

Stress arises from disturbing situations that evoke fear as well as from poor diet, improper hygiene, disease and inappropriate housing.  Exposure to these and a host of other factors can shorten your pet’s lifespan dramatically by weakening its immune system.

The effects of stress on the immune system are well known.  While working at the Bronx Zoo, I learned that birds transferred to a new exhibit (a major stress) invariably came down with a severe Aspergillosus infection, despite the fact that this fungus is ever-present in the environment yet rarely causes health problems for birds living in secure situations.  The current research findings are significant in highlighting just how serious and long-lasting are the effects of exposure to stress.

Captive vs. Wild Caught Birds

This research also highlights the importance of purchasing only captive-bred birds, as wild-caught individuals are exposed to the highest degree of stress imaginable.

Lessening Stress – Knowledge and Nutrition

Knowing and meeting the needs of those bird species which you keep is a vital first step in providing them with a stress-free environment.  Please write in with any husbandry questions you may have.

Vita Flight Vitamin Supplement, specifically formulated for birds under stress, should be kept on hand to help see your pets through the difficult situations (new arrivals, breeding, molting, illness) that arise in every collection.  Please see the article noted below for more information on the interplay between diet and stress.

Further Reading

An interesting article on the importance of proper nutrition to birds in stressful situations is posted at http://www.journals.uchicago.edu/doi/abs/10.1086/515888?journalCode=pbz.