Birds have many more vertebrae in the neck than humans, ranging from about 14 or 15 and up to a maximum of 25 in the swan. Humans have 7. In the parakeet, there are said to be 11. In all birds, they are much more mobile than in mammals, which is why most birds can turn their heads 180 degrees. The neck is one of the strongest parts of its body, so the suggestion that "it broke its neck" by flying into a window, or if it is found dead, is usually incorrect. Because of the mobility of the neck, a limp (dead) bird often appears to have a broken neck, but this is almost never the case.
Unlike the type of jaw found in mammals, in birds, BOTH the upper and lower jaw are moveable.
Feather movement is brought about by feather muscles, which attach to the walls of the follicles. These muscles allow a bird to fluff up the feathers when chilled or sick, and allow a bird to ruffle the feathers, realigning them when necessary.
Only chickens have more than 4 toes. Rheas, cassowaries and emus (large, flightless birds) have 3 toes. Only one species, the ostrich, has two toes. Only two groups of birds are zygodactyl, meaning they have two toes forward, and two toes back. That would be parrots and the woodpecker family (including flickers), which do have 4 toes.
Flight is a highly energetic form of exercise. A budgerigar flying at sea
level uses 1 1/2-3 times as much oxygen as a mammal of similar size running. During flight, the bird increases its oxygen consumption by about 13 times over the resting metabolic rate. To facilitate flight, most bones of birds are hollow.
Swallows migrating between Europe and Africa must fly for about 50 hours over the Sahara without resting. The American Golden Plover flies over 2000 miles non-stop between Alaska and Hawaii. The Arctic Tern migrates from pole to pole, the round trip totaling some 20,000 miles. Swifts can fly at up to 60-90 miles per hour. Penguins can swim underwater at about 20 mph. Ostriches can run up to 50 mph.
The migrating Bar-headed goose rises from near sea level to traverse
Himalayan peaks that are over 9000 meters high, which in human energetic terms is equated to riding a bicycle over the summit of Mount Everest. Aircraft have reported collisions with birds at absolutely astounding altitudes. A vulture was reportedly struck at over 11,000 meters.
Birds truly have a unique and remarkable respiratory system and an adaptable cardiovascular system, giving birds an energetic superiority over mammals. An unacclimatized man is in a state of incipient hypoxic collapse after 10 minutes at 6100 meters, but an ordinary house sparrow can fly and even gain altitude at that height (as proven in a hypobaric chamber).
The skeleton of the hand has undergone considerable simplification and adaptation for flight to create the end of the wing. In most birds, there are only three digits (fingers) present. To prevent flight, pinioning is performed by cutting off the manus (hand) at the wrist (carpal) joint.
Birds do see in color. Birds can see into the near-ultraviolet wavelengths of light. In primates, the lens of the eye acts as a yellow filter, which cuts off wavelengths of light below 400 nm, and therefore renders ultraviolet radiation invisible. The cornea and lens of diurnal (up during the day) birds are optically clear and appear to transmit wavelengths down to about 350 nm, thus rendering near ultraviolet radiation visible and absorbing only those ultraviolet wavelengths which are not physiologically destructive.
Owls can fly between obstacles and can hunt successfully in what appears as pitch darkness to humans.
Deep diving species of birds can close the external ear canal completely to prevent water from entering. The temporal resolution of the avian ear is about 10 times faster than that of the human ear. Thus, the song of the Chaffinch would have to be slowed down 10 times before the human ear could resolve all of the details which are learned by the Chaffinch chick.
What Your Pet Bird Wishes You Knew By Julia Glass - From the Internet Americans own 31 million pet birds, and the number is on the rise. Yet veterinarians report that many would live longer, healthier lives if owners knew more. "Unfortunately, pet stores do a poor job of educating people," says Irwin Ruderman, DVM, director of New York City's Animal Clinic of Staten Island and an active member of the Association of Avian Veterinarians (AAV). Despite recent veterinary advances, too many birds die prematurely, because owners don't know the basics of care. Diet: "Many pet birds actually die of complications resulting from malnutrition, " says Dr. Ruderman.
A diet of seed and water - what most caged birds get - is like bread and water to a person. Wild birds thrive on an enormous variety of foods -- seeds, blossoms, fruits, insects - and your bird needs the same variety. Unlike dogs and cats, birds should have table food. "Only half the diet should be starches," Dr. Ruderman says, "and that includes seed, but you can give birds pasta, potatoes, beans, peas, and corn. Twenty-five percent or more should be fruits - raisins, apples, pears, melon, you name it, and vegetables - cooked or raw. Go for the darkest and brightest: kale, beets, red peppers, squash. For hookbill birds - Parakeets, Cockatiels, Parrots, and Lovebirds - the rest should be protein: meat, poultry, fish, eggs (all cooked), cheese and yogurt."
A Few Cautions: Birds are susceptible to salt poisoning, so be sure all people snacks (pretzels, chips, peanuts) are unsalted or low-sodium. Never feed a bird from your mouth, since some of the benign germs we carry can wreak havoc on a bird's system. Resist the temptation to overdo junk food or sweets, especially since birds that don't get a lot of exercise can put on unhealthy excess weight. And don't buy the boxes of grit you see sold in pet shops. In the wild, small stones ingested with food act like teeth in a bird's digestive tract; this is important, since they must gather food, swallow it quickly, and fly off to avoid predators. But, pet birds have the leisure to munch, and studies show that grit offers no benefits. What's worse, some birds gorge on it and go on to develop blockages that can be fatal.
Social Life: Mental stimulation is crucial to a bird's psychological health. Birds do best when kept in the liveliest room of the house, close to the action. "In the wild, they do everything together and they're always busy, foraging for food, building nests, raising their young, grooming each other, showing off for the opposite sex," says Dr. Ruderman. Consider buying several birds so they have one another for company. But, if you buy a single bird, plan to make it a member of the family. Parakeets, Canaries and Finches do particularly well in groups; large birds, which may become very loud with other birds around, do best as one-on-one companions to people. And do learn to handle your birds; should they require medical treatment, they'll suffer less trauma if they're comfortable being held.
Habitat: "No matter how small the bird, choose the largest cage you can, the most important dimension of which should be length," says Dr. Ruderman, "People are charmed by tall pagoda cages, but birds need space to fly across." While cages with vertical bars are fine for Canaries and Finches, hookbills enjoy climbing, and should live in cages with horizontal bars. Provide perches of varying thickness', since birds need to exercise their flexible feet, but forget the sandpaper perch covers that stores sell - "A monstrosity, " says Dr. Ruderman. "How would you like to walk barefoot on gravel your whole life? And the covers rarely do what they claim to keep a bird's toenails files." Your vet can show you how to clip and file your bird's nails and beak (which may become overgrown) or, for a small fee, can do it for you. Be sure also, to provide wooden ladders and chew toys; birds need and love to gnaw. Birds like an occasional bath too. Offer a bowl of clean water, or take your
bird into the shower with you. Most birds love water, many will sing and whistle as they bathe.
Health Care: When you get a new bird, take it to a vet within a few days. "Preventive care is very important, because birds are defensive animals. A sick bird hides symptoms for as long as possible; in the wild, any sign of illness attracts predators, the flock will drive a sick member away," Dr. Ruderman says. "So schedule yearly checkups, to test for problems while they're treatable." Choose a vet who's a member of the AAV - the main source of continuing education in the field. You might even ask if he or she keeps birds at home; firsthand experience is a definite plus.
It may sound as if birds are finicky, high-maintenance creatures, but in fact, most are hardy and adaptable, once you understand their needs. And the rewards of their intelligent, affectionate, and entertaining companionship are well worth the attention to detail.
Sadie The Service Bird:
Sadie Want an Unreal?
We had a most pleasant conversation recently with Jim Eggers, who was eager to tout the virtues of the Congo African Gray parrot as service animal.
Before he met Sadie, the 40-year-old Maplewood resident says, he mostly associated the concept of "service animals" with dogs. But in fact, the Americans with Disabilities Act contains an intentionally broad definition of the term: "any guide dog, signal dog, or other animal individually trained to provide assistance to an individual with a disability."
Eggers hasn't heard of any other parrots used as service animals. (Neither has Unreal.) Still, like many other disabled Americans, he experienced hassles in venues where pets are typically unwelcome — on public transportation, for instance (he doesn't own a car), or while apartment-hunting. But he says an ID card he recently purchased from a Texas-based outfit called the Service Animal Registry of America tends to smooth any ruffled feathers.
"I can get her aboard the transit system," Eggers says. "She comes with me to my psychiatrist appointments and any medical appointments.
Eggers is bipolar and gets by on disability payments from the Social Security Administration. The government, he says, deems him severely depressed, with psychotic tendencies. "I hate to say that, but it's true," Eggers admits. "Anxiety attacks can cause me to get psychotic, and I can wind up getting into a lot of trouble with the law. I've been abused pretty bad since I was a kid, and I have had nothing but negative interactions with people for many years. Her being with me — she goes in a backpack — attracts a lot of people. And we interact in a very positive fashion."
Eggers says Sadie was neglected when he acquired her secondhand a little over a year ago from a pet shop. "She was a feather-picker and looked horrible," he says. "I started giving her baths, lots of love and attention. I started saying things like, 'I love you,' 'Give me a kiss,' and she started asking questions like, 'Are you OK?' It was lots of repetition in trying to talk me through anger periods."
He believes the parrot can sense when his mood is souring. "She says, 'Calm down, it's OK'; 'You'll be OK'; 'I love you.'"
He says Sadie does a pretty good imitation of him.
"It's almost like looking into a mirror — in other words she's helping keep me in check and keeping me well behaved. I'm really thankful for her. You know?"
Barney The Parrot Does Speech Therapy
Macaw blimey ... parrot Barney with Michelle and four-year-old Dylan
AN autistic boy who could not speak has learned his first words — with the help of his family’s pet PARROT.
Dylan Hargreaves, four, has severe learning difficulties and had never uttered a single word.
But after listening to macaw Barney, he can now say “Night, night”, “Dad”, “Mum”, “Ta”, “Hello” and “Bye”.
And experts think he is close to his first two-syllable word.
Mum Michelle, 33, said: “Barney has changed our lives. Before he arrived, Dylan would try to speak, but the sound came out as a noise.
“Then we got Barney and, a few months later, Dylan began to talk. It was only the odd word, but I could clearly understand what he said.
“Every time I gave the bird something to say, Dylan started trying to say the same thing. I think it’s because the bird says things slower than me, which helps Dylan understand.
"Now when I put him to bed he says, ‘Night, night, mum’. It means the world to me.”
Michelle, of Blackburn, was given three-year-old Barney by partner Rob Hargreaves, 33, last January.
Delighted Rob said: “There is no doubt that Dylan copies the bird.”
Michelle reckons her son’s first two-syllable word will be Barney, because he loves his pet so much.
Speech therapist Dr Hazel Roddham of the University of Lancashire confirmed the value of learning to speak parrot-fashion.
She said: “If there’s some enjoyment, a child is more likely to learn. And presumably this parrot has attracted the boy’s attention.
“A child with learning difficulties might benefit from the bird’s slow repetition of words.”
The Discovery Channel
Wild birds learn foreign ‘languages’
Skill can mean life or death for songbirds that pay attention to alarm calls
By Jennifer Viegas
updated 2:26 p.m. PT , Wed., Nov. 12, 2008
Birds may be bilingual, trilingual or better, suggest new findings that birds in the wild can learn the vocalizations of other species.
The discovery not only proves that birds eavesdrop on what other birds are saying, but it also provides some of the strongest evidence to date that birds can learn "foreign" calls, as opposed to just confusing similar sounds with their own.
While humans may learn a foreign language for work or pleasure, the skill can mean life or death for little songbirds that, according to the study, pay attention to the alarm calls sounded by other birds when a predator, such as a hawk, approaches.
"It's tricky to know what goes on inside another species' head," lead author Robert Magrath told Discovery News. "At one extreme, perhaps they are labeling, such as 'flying hawk approaching at 10m!' or 'hawk flying by in the distance,' or 'predator on the ground,' etc."
Magrath, an associate professor of botany and zoology at the Australian National University , added that the vocalizations could be prompted by anxiety too.
"The best evidence is that both labeling and fear have a role," he said.
Magrath and colleagues Benjamin Pitcher and Janet Gardner studied three Australian birds: superb fairy-wrens, white-browed scrubwrens, and New Holland honeyeaters. He prompted each to sound an alarm call using a gliding model sparrowhawk. This predatory bird has a taste for fairy-wrens and scrubwrens.
The scrubwren alarm call sounds similar to that of the fairy-wren, so avian experts previously thought the birds simply thought the sounds came from one of their own.
To test this possibility, the researchers played scrubwren calls to fairy-wrens at Canberra , where these two wren populations overlap, and at Macquarie Marshes, where the two species do not live close to each other and therefore have no chance to learn each others' calls.
Sure enough, the Canberra birds did as they were "told" when played the other species' alarm calls, which was to flee pronto. The Macquarie Marsh birds did next to zilch, suggesting they hadn't learned the other species' calls.
To further test their abilities, the scientists played the alarm calls of New Holland honeyeaters to the wrens. The honeyeater vocalizations sound nothing at all like the wren calls.
Once again, the wrens demonstrated that they'd learned the meaning of other species' calls, since they fled when the honeyeater alarm sounded.
This study, published in the latest Proceedings of the Royal Society B, is unusual in that the researchers used alarm calls which, Magrath said, "are very short and everything happens quickly." These calls are intentionally brief and high-pitched, making them difficult for hawks and other predators to hear.
Other studies have found that birds also seem to understand other species' mobbing calls. He explained that these calls "are given to harass a predator not posing an immediate threat, so others can approach, look at the predator, and listen to the repeated calls of other species."
Birds seem to understand certain other birds so long as learning through association or social means is possible. They may even understand some mammals and rodents, such as small antelopes and squirrels, which appear to learn bird sounds as well.
Daniel Blumstein, associate professor and vice chair of graduate studies in the Department of Ecology and Evolutionary Biology at UCLA, told Discovery News that "this is a really timely study."
"Overall, I was not surprised by the fact that learning was important," Blumstein added, "but I liked how the study was designed so as to allow inferences about learning."
Both he and Magrath hope future studies will better determine how birds learn other calls and what motivates them to do so. It appears that one of life's most pressing emotions — fear — could be a key driving force.
By MAGGIE GALEHOUSE Copyright 2008 Houston Chronicle
July 22, 2008, 1:10AM
Kevin Fujii Chronicle
Vincent is the third St. Vincent Amazon Parrot born at the Houston Zoo, the only zoo in the country to house the rare species and the first in the world to hatch the species in captivity.
On May 28, a tiny St. Vincent Amazon parrot pushed its way out of an egg at the Houston Zoo.
The egg was the size of a large chestnut. The bird was 3 inches tall, with bulging eyes that would take another nine days to open and skin covered with a whitish down.
Christopher Holmes, a zoo supervisor in the bird department, was the first person to lay eyes on the rare parrot. Since then, the two have been inseparable.
Holmes, 26, says that he is the chick's "primary hand rearer." But let's call it what it is.
"The chick goes with me everywhere," says Holmes, who started volunteering at the zoo when he was 14 and is working on a bachelor's degree in anthropology at the University of Houston. "In the beginning, I was feeding it every two hours from 5 a.m. till midnight. I did that for 16 days."
For the first five weeks, the chick lived in a blue Coleman cooler, retrofitted with a heating element to keep it warm. Now, the bird lives in a large, open-air brooder — basically, a clear plastic box with a special lid.
Holmes named the bird Vincent, although no one knows if it's male or female. Soon, the zoo will send off one of Vincent's feathers for a DNA test to determine its gender.
"It's very hard to tell the sex," Holmes says. "The males and females are the same size, and every St. Vincent Amazon parrot is a different color."
Not yet 2 months old, Vincent has gotten much better-looking with age.
Incredibly, Vincent is almost full-grown. Just 15 grams at birth, the chick now weighs about a pound and stands a little more than a foot high. Most of Vincent's feathers have already come in, with brown dominating the chest and shoulders, green, yellow and cobalt blue on the tail, and bright orange on the bend of the wing.
"Come on, little one," says Holmes, lifting the chick out of the brooder and coaxing it into a smaller box for feeding.
Vincent watches Holmes mix the food, a fine powder of grains cut with 107-degree water. After Vincent is settled in the feeding bin — sort of a high chair for baby birds — Holmes clasps the back of Vincent's beak between his thumb and forefinger, tips back the head and pushes the warm formula into the chick's mouth with a syringe.
"That's how you elicit the feeding response," says Holmes, who has hand-raised macaws, flamingos, pigeons, kingfishers and King penguins. "It simulates the parent putting its beak over the chick."
Some of the formula drips onto Vincent's chest. Holmes quickly cleans it off.
"Just like a child," he says. "You've got to wipe the face."
Vincent is the third St. Vincent Amazon parrot born at the Houston Zoo. In 1972, the zoo made history with the first captive hatch of the species in the world.
In the wild, this particular parrot is found in only one place: the Caribbean island of St. Vincent, a slip of land 11 miles wide and 18 miles long, northeast of Venezuela and west of Barbados. It is part of a cluster of islands known as St. Vincent and the Grenadines.
Because its habitat is so small, the St. Vincent Amazon is considered a threatened species by the International Union for Conservation of Nature.
On top of that, the bird has a spectacularly slow reproductive rate. Vincent's parents, Patty and Buccament, had their first offspring in 1999. Vincent is their second chick.
"We're the only zoo in North America that houses the species," says Holmes, who has traveled to St. Vincent twice to help count the birds for the biennial census. "There are about 800 left in the wild."
Today, the Houston Zoo has seven of the rare parrots. The zoo's first St. Vincent Amazon, a female also named Vincent, was acquired in 1967. Holmes named this year's chick in her honor.
The zoo hopes that the chick will help supplement the captive-breeding program.
But for now, Vincent is busy being a toddler.
"We're still learning how to sit on our perch," Holmes says with a laugh after Vincent topples off the low-slung wooden bar in the brooder.
The chick makes a happy, gurgling sound, something between a coo and a mew, when its belly starts to get full.
"Vincent has different vocalizations for different things," Holmes says. "In the very beginning, it sounded like a squeaky toy."
The chick has also started to stretch its wings. Holmes suspects that Vincent's first flight will be sometime in the next few weeks, when all of the feathers have grown in. The feathers begin as pins that eventually grow longer and open.
"As the blood recedes from the feather shafts," Holmes explains, "they start to break open."
Sometimes the chick preens off its own feather shafts. Sometimes Holmes does it.
Despite Vincent's good health, it may be quite a while before the zoo introduces the bird to the public.
Vincent developed in an incubator. Because of the rarity of the species in captivity, the zoo pulled the egg the morning it was laid; Vincent hatched 28 days later. And because the chick is being hand-raised, it needs additional time to acclimate to other birds.
There's no rush. St. Vincent Amazon parrots have a life span of 50 to 60 years. After breeding season ends, zoo visitors can see Vincent's parents, along with Vincent's sister and her mate. They should be back on exhibit in early August.
In the meantime, Vincent continues to thrive.
Already, the chick is munching on dry food. Scattered Cheerios and part of an ear of corn sit at the bottom of the brooder.
Vincent still goes home with Holmes every night, but it's nothing like it was in the beginning. For the first five weeks, Holmes' life revolved around Vincent's strict feeding schedule. Now, he feeds the chick three times a day.
These meals can get quite interesting, with Vincent preening, flapping and gurgling for the duration.
"OK, we're done with you," says Holmes, lifting the noisy, just-fed chick out of the feeding box and putting it back in the brooder. "We get a little glint in our eye, cock our head to see what we can do to get into trouble and start trying to get away."
On day 80 of Vincent's life, the chick will leave Holmes to live in an off-site area at the zoo, in a cage next to two other St. Vincent Amazon parrots.
As close as he's grown to his charge, Holmes understands the importance of the move and trusts that he and Vincent will always have a special bond.
"It's for socialization," Holmes says. "Vincent has to learn how to be a bird."
SAN FRANCISCO (AP) — What's black and white and warm all over? A penguin in a wetsuit, naturally.
Sounds like a joke, but it's quite serious for biologists at the California Academy of Sciences, who had a wetsuit created for an African penguin to help him get back in the swim of things.
Pierre, a venerable 25 years old, was going bald, which left him with an embarrassingly exposed, pale pink behind.
Unlike marine mammals, which have a layer of blubber to keep them warm, penguins rely on their waterproof feathers. Without them, Pierre was unwilling to plunge into the academy's penguin tank and ended up shivering on the sidelines while his 19 peers played in the water.
"He was cold; he would shake," said Pam Schaller, a senior aquatic biologist at the academy.
Pierre's species of penguin is accustomed to temperate climates, unlike many of their cousins. The birds are nicknamed Jackass penguins because they make sounds similar to braying donkeys, quite startling the first time you hear it in an aquarium.
Schaller first tried a heat lamp to keep Pierre warm. Then she got another idea: If wetsuits help humans frolic in the chilly Pacific, why not whip up one in a slightly smaller size?
Staff at Oceanic Worldwide, a supplier of dive gear based in San Leandro, were enthusiastic about making a real penguin suit.
"We were really excited to do it," said Teo Tertel, company marketing specialist. "We heard most of these penguins only live to 20, and our little buddy there was already 25. Anything we could do to help them, we were all for it."
Schaller conducted fittings to design the suit, which fastens with Velcro at the back, covers Pierre's torso and has small openings for his flippers.
"I would walk behind him and look at where there were any gaps, and cut and refit and cut and refit until it looked like it was extremely streamlined, " she said.
One concern was that the other penguins would reject Pierre in his new duds, but in fact, they accepted his sleek new look.
Pierre was outfitted with the suit about six weeks ago. Since then, he has gained weight, grown back feathers on his hind parts and is again acting like his feisty, alpha-male self.
On a recent visit, Pierre waddled around the tank, taking brief dips and standing on a rock next to his mate. He blended in well, although he was the only penguin with a black tummy.
Schaller can't say for sure whether the wetsuit allowed Pierre to recover his fine feathers, but "certainly we were able to keep him comfortable during a period of time that would have been very difficult for him to stay comfortable. "
With his plumage restored, Pierre is being weaned off the suit, taking more and more dips in the buff.
There are no plans to make him a matching surf board.
Copyright 2008 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Psittacine Beak and Feather Disease Today
When I first started out in practice, I would see the saddest cases of cockatoos with weird feather loss, overgrown beak and claws and a myriad of infectious diseases. We called it Psittacine Beak and Feather Disease, as we knew that it was a syndrome causing many different problems, all related to the bird's defective immune system. Birds usually showed abnormal feathers, lack of powder down, overgrown beaks, often with abnormalities such as beak ulcers, and overgrown toenails. Many theories about the cause had been put forth, with no definitive cause determined. It would seem to pop up in long term captive breeders and pets, with no rhyme or reason. It seemed that no matter what we did, the bird would eventually succumb to a bacterial or fungal infection, often after a protracted illness.
While we classically thought of this as a disease of cockatoos, we would occasionally see the same characteristic lesions and immunodeficiencies in other species of birds, including Amazons, African greys, macaws, lovebirds, pionus and Eclectus as well as other species. While most Old World psittacines that developed PBFD would die, a few New World psittacines with feather lesions have recovered.
A patient of mine back in the 80's, named BJ, was one umbrella cockatoo that I had diagnosed as having PBFD. He was a darling bird, very affectionate, and every time he saw a person, he would shout "Hello, BJ!" To him, everyone was BJ, and everyone was his friend! Due to our close monitoring of his health, BJ lived for almost two years with his disease before finally succumbing to a fungal brain infection.
Once the team at the University of Georgia, headed by Dr. Branson Ritchie, DABVP, discovered that PBFD was caused by a circovirus, in late 1991 and early 1992, and then developed a very sensitive and specific DNA PCR test that would tell if a bird had the virus in the bloodstream, this revolutionized the diagnosis for aviculturists and pet owners. However, feather follicle biopsies are still a valuable diagnostic test for any bird with feather lesions. The original PBFD virus that causes this disease is now called psittacine circovirus 1 (PsCV-1). In recent years, a second variant of the virus was discovered in lories with feather lesions, and this variant is now called PsCV-2. Lories with PsCV-2 and dystrophic feathers may mount an appropriate immune response and eventually recover from the infection.
Even without a diagnostic blood test for PBFD, we were able to diagnose BJ by taking biopsies of feather follicles containing abnormal feathers, which was certainly easy enough to do with BJ. Using an avian pathologist, a patient could be diagnosed by the observation of the characteristic inclusion bodies found in certain parts of infected cells.
Let's start by learning a bit about the history of this viral infection so that we will better understand this devastating disease. It is possible that Australian explorers first identified this disease in 1887, when they described the characteristic feather changes in wild red-rumped parakeets (Psephotus sp.). However, the disease as we have come to know it was first described in several species of Australian cockatoos in the early 1970's. There were many proposed causes of this disease including endocrine abnormalities, polyomavirus, Mycoplasma, Newcastle's disease virus, reo virus, adenovirus, salmonellosis and other infectious agents. To prove that an agent is the cause of a particular disease, one must fulfill Koch's postulate, which means that you must be able to recreate the same disease in another animal by giving it the disease particles. It was possible to give neonatal budgies and rose-breasted cockatoos the disease by using crude feather homogenates. Young sulfur-crested cockatoos and rosies were also given the disease using a partially purified virus preparation produced from feathers from infected birds. Concentrated purified virus particles, called PBFD virions, were able to cause disease in neonatal budgies, African greys, and umbrella cockatoos. Thus, it was proved that the PBFD virus was responsible for causing this terrible disease.
What is a virus? A virus is a microscopic particle that requires a live host in order to reproduce. Viruses are more primitive than bacteria, which are able to reproduce on their own, and the viruses are much smaller. Viruses are not metabolically "alive" until they infect a living cell. Viruses are not affected by antibiotics, which are commonly used to treat bacterial infections. This is why you should not take an antibiotic if you are suffering from a cold or the flu, as those are viral infections. In recent years, scientists and researchers have developed some medications that are active against certain viruses.
In many cases, it is possible to become protected against certain viruses by the use of preventative vaccinations. Prevention is a much better when it comes to viruses, as treatment is not nearly as predictable or effective. When developing a vaccine, often the virus has been killed or made ineffective in causing disease, but the body still produces antibodies against it, which provides immunity. In some cases, a vaccine may provide life-long immunity, and in other cases, vaccines must be boostered periodically to maintain adequate immunity. To produce vaccines in some cases, a closely related virus may be used for a vaccine, but one that is incapable of causing disease in the desired species. Interestingly, many viruses are species specific, or confined to causing disease in closely related species. It is a rare virus like the virus causing rabies, which can infect and cause disease in many different kinds of animal.
So, it is good to know that we humans, who care for our pet birds, are unable to contract the disease caused by the PBFD virus. This is good news for us. But many species of bird in Australia, North America, Europe and Asia are susceptible and over 40 species of psittacine birds have been documented as having developed PBFD from PsCV-1. In addition to the variant PsCV-2, other circoviruses have been discovered. Also, a similar circovirus has been found in doves and pigeons. Other circoviruses have been identified in gulls, geese, canaries, finches and humans. These viruses, however, cannot cause disease in parrots.
Dr. Ritchie and the team at the University of Georgia have been working to develop a vaccine against PBFD, and hopefully, one will be available in the near future. But until such a time that a vaccine is available we must still rely on testing as a way of preventing illness caused by PsCV-1.
It has been reported that up to 20% of some free-ranging cockatoos in Victoria, Australia, may have clinical signs in any one year. Other studies and anecdotal reports indicate that the PBFD virus is causing disease in some other Australian cockatoo flocks, wild crimson rosellas and other wild populations of Moluccan cockatoos, lovebirds and other species of cockatoos.
Generally, PBFD is considered to be a disease of young psittacines, usually up to three years of age. However, older birds, often up to twenty years of age that had been clinically normal throughout most of their lives, can also suddenly break with all the signs of PBFD. It is thought that birds are usually exposed to the PBFD virus at a young age, when their immune systems aren't as strong, and they may appear normal for years before finally developing signs of PBFD. It is suspected that these birds are infected and eventually break down with illness, perhaps years later. If a bird contracts PBFD prior to developing its feathers, as the feathers grow out, they will often show the classic abnormalities. However, if a baby bird contracts PBFD after it has already grown out its feathers, the abnormal feathers may not show up until the bird molts and the normal feathers are replaced with abnormal ones. Occasionally, a young bird that had contracted PBFD would die before developing feather lesions at all. However, in all cases, any bird with feather lesions should undergo feather follicle biopsies to confirm the diagnosis. PBFD may present as a peracute infection, acute infection or a chronic disease.
How is PBFD diagnosed today? Let me give you an example that occurred several years ago in an aviary that I dealt with. A client had an imported timneh grey with poor feathering that was set up as a breeder. Thinking the bird was a feather-picker, he never tested the bird for PBFD. Eventually, this bird bred with a female, and the baby bird was brought into the nursery along with twelve other psittacine chicks, including two pionus, three Jardine's parrot chicks, six African greys and one mini-macaw. When the baby timneh grey began showing abnormal feathers, his vet ran a PBFD blood test (which must be drawn by clean venipuncture stick, and not by clipping a toenail, which may contaminate the sample with viral particles). When the test came back positive, the vet referred the client to me to deal with the problem. The aviary owner was very upset, as you can imagine, as he thought he would probably lose all of his baby birds.
Since the virus is thought to be spread by feather dander, fecal matter and other secretions from infected birds, chances were, the other neonates in the nursery were all exposed. Blood was drawn from all of the baby birds and tested for the presence of the PBFD virus. Out of the twelve babies in the nursery (the timneh was isolated), ten tested positive. But, the good news is that many exposed babies will mount an effective immune response and should not be euthanized based on one positive test. An environmental swab was also taken, of window sills, floorboards and walls to test for the presence of contamination with PBFD virus. The birds with feather lesions underwent diagnostic biopsy of affected feathers and follicles, as well, to confirm the disease.
Any birds that test positive, but have no feather lesions, should be re-tested in 90 days, and that is what we did in this case. A negative test in 90 days indicates that the bird has eliminated the virus from the bloodstream, which is what happened in ten of the babies in this case. The two babies that still tested positive were latently infected and eventually broke with clinical PBFD, but the other eight were basically self-vaccinated and should be considered immune to the virus. The environmental swab tested positive, meaning that the owners needed to perform a thorough cleaning even though many commonly used disinfectants are ineffective in killing this stable virus.
Today, most responsible aviaries have had all susceptible larger breeders tested for the PBFD virus, and have culled positive birds from their breeding programs. Unfortunately, many backyard breeders and many breeders of the smaller birds, such as lovebirds and budgies, have not had their birds tested for PBFD. So, today in the United States, we usually only see PBFD in the smaller birds.
It is thought that, based on the results of antibody titers, that many birds of susceptible species have some detectable anti-PBFD virus antibodies, indicating previous exposure to the virus. Antibody titer surveys in the United States suggest that most birds of susceptible larger species are exposed to the virus at some time in their lives but are able to mount an effective immune response. This is considered natural vaccination, just like the baby birds in the nursery who were all exposed to the virus, tested positive and then later tested negative. Those birds would likely be immune to the PBFD virus for life.
Since there is no preventative vaccine against PBFD at this time, our methods for controlling the disease involve testing susceptible birds and culling any that test positive twice, 90 days apart, if they have no lesions of PBFD. Any birds that test positive that have feather lesions should be considered to be infected. Birds that test positive twice, yet show no signs, should be considered to be infected, and will most likely break with the disease at a later date. This is often what we used to see with pets and breeders. A long time pet or breeder would suddenly develop feather lesions and become ill. A positive test result would result in heartbreaking news for owners, such as the gentleman who cared for BJ. Since a positive diagnosis was a virtual death sentence, as we could not treat the primary viral infection, but only the secondary fungal, bacterial, mycoplasmal, chlamydial or protozoal infections. In spite of our best efforts, birds would eventually develop a debilitating illness from which there was no recovery.
The variant of circovirus, PsCV-2 requires a different DNA PCR test than PsCV-1. There is also a generic circovirus DNA PCR test that can be useful in diagnosing circovirus infections in other species, such as canaries and finches.
Today, in the United States, we are primarily diagnosing active PsCV-1 infections in lovebirds. However, lovebirds that have recovered from polyomavirus infection may show similar feather lesions, so follicle biopsies and DNA PCR tests are valuable in differentiating between the two. It is possible for an infected lovebird to shed the virus and spread PsCV-1 to other susceptible young birds in a pet store nursery, home or aviary. But, I rarely diagnose this disease in psittacines in my practice today, mainly because of the diligent testing performed by my aviary clients years ago. According to Dr. Ritchie, the variant PsCV-2 has not been diagnosed in birds other than lories and that variant differs approximately 10% from PsCV-1.
Once the vaccine becomes commercially available, hopefully, responsible breeders and owners will utilize this resource to eliminate this terrible virus threat from our psittacines. Avian veterinarians will have one more tool in their arsenal to help keep the birds in our country healthy for a very long time.