Those Amazing Amazons!!

Summary:
There are several characteristics of the group of Amazon parrots with yellow head feathers which will aid in identification, including the amount and location of the yellow feathers, the color of the beak, and the size of the eye ring. There are also ways to visually determine the different species and sub-species of the Amazons with red head feathers, Red-lored Amazons, Amazona autumnalis, Mexican red-headed Amazons, A. viridigenalis, Tucuman Amazons, A. tucumana, Festive Amazons, A. festiva, and Lilac-crowned Amazons, A. finschi, also based on the location of the red feathers, the other colored feathers present, beak color, size, and eye ring size. Blue-fronted Amazons, Amazona aestiva, and Orange-winged Amazons, A. amazonica, are easily distinguished, as the Blue-fronted has a solid black beak, and the Orange-winged has a bicolored beak. Island Amazons are all identifiable by distinguishing characteristics. The Spectacled Amazon, A. albifrons, the Tucuman Amazon, and the Yellow-lored Amazon, A. xantholora, are three species of Amazons that are sexually dimorphic, however, other species may also have subtle differences that may help distinguish male from female. One very rare species of Amazon, the St. Vincent's, A. guildingii, has three color morphs, however they are not differing sub-species.

Introduction

Avian practitioners, technicians, aviculturists and pet owners should be able to correctly identify the more common species and sub-species of psittacines. Occasionally, an owner may have misidentified their own bird's species, or the owner may look to the avian veterinarian for correct identification of the species. Some species of birds are more susceptible to certain diseases or syndromes, so proper identification is important. Occasionally a bird may be presented that is actually an uncommon or rare species or sub-species that might be better off placed in a breeding program. Unusual color morphs should be identified as different from a unique species or sub-species. Avian veterinarians and owners should know the scientific names of birds seen in practice to prevent the confusion that often occurs when common names are used. Some birds are sexually dimorphic, and we should be able to visually identify the sex of those birds.

Learning Opportunities

It is important to be able to identify the species and sub-species of birds that we are working with. A good practice tip for those veterinarians unfamiliar with the many different varieties of psittacines is to purchase a good quality avian atlas as a reference. When a bird owner schedules an appointment, instruct your receptionist to always ask the owner what kind of bird they have, and to write this information in the book. Check the appointment book in the morning, and if a bird is coming in that you are unfamiliar with, take a few minutes prior to the appointment to look up the bird in the atlas. Take note especially of the scientific name, its country of origin, size and weight ranges, any species peculiarities (including if it is dimorphic), and if there are any sub-species. Then when you enter the exam room, you will have the information fresh in your mind. Always write down the scientific name, as well as the common name, in the chart, along with its weight, band number, and any other identifying marks. Many aviculturists refer to their birds by the scientific name, so by consulting an atlas prior to entering the exam room, you will rarely be caught with your tail feathers exposed!

Many breeders are very knowledgeable about the species that they keep and raise. Be sure to tap these people for any information that they have about the genus and species of parrots that they keep. Many aviculturists will be happy to give avian veterinarians a tour of their facility, which will afford them an excellent opportunity to examine pairs of birds, to compare males and females, as well as similar pairs of the same species.

Amazon Parrots (Genus Amazona)

The parrots in the genus Amazona are from Central and South America and the Caribbean Islands. They are probably the best known of all New World parrots (those originating from North and South America, and surrounding islands). Old World birds include those found in Asia, Australia, and Africa, and surrounding islands.

Amazons are medium sized to large, stocky birds with strong, heavy bills and short, slightly rounded tails. The cere is naked and prominent, and there is a distinct notch in the upper mandible. The wings are broad and rounded. In some species, the flight feathers barely extend beyond the tertials when the wing is folded. Sexual dimorphism is absent in most species, but it does occur in some. When observing a known proven pair, it is often possible to identify the cock and hen by subtle variations in coloration, beak size, head size and shape, and behaviors.

Immature plumage in most species is not striking. Young birds have a duller iris color than adults, and the beak is often pigmented differently than that of adults.

During the years when importation was open to the United States, many baby, juvenile and adult Amazons were brought into this country. The most commonly imported birds were Blue-fronted Amazons, A. aestiva, Yellow-naped Amazons, A. auropalliata, and Orange-winged Amazons, A. amazonica, however, many other species of Amazons were also imported. Some rare Amazons were brought in as pets, or occasionally entered the country with shipments of the more common species. Brazilian species of Amazons have rarely been exported legally from that country, and are therefore very rare in this, and other countries. Because so many Amazon parrots were imported into this country, there are many mature adults now in pet homes and aviaries today. Proper identification of the more rare and uncommon Amazons is very beneficial, as some would be better suited in a breeding situation.

Amazon Anatomy

Amazon parrots are stocky birds with short, slightly rounded tails and heavy bills. Beak color varies depending on the species and sub-species. The cere is naked, except for bristle feathers, which are thought to have a tactile function like a cat's whiskers. There is a distinct notch in the upper mandible. Feathers can be bright and shiny, as in a Blue-fronted Amazon, or dull, like the Orange-winged Amazon. They can be perch potatoes as they age, so it is important to watch their diets. They can live to be 80 years old, so it is very important to get youngsters started off on the right foot by accustoming them to healthy foods, such as pellets, vegetables, fruits, pasta, bread and nuts.

The wings are broad and rounded and in some species, the flight feathers barely extend beyond the tertials when the wing is folded. As previously stated, some species are dimorphic and the immature plumage is not very different from that of the adult.

It is recommended that owners purchase a good quality gram scale to accurately weigh their birds on a weekly basis. Weight loss can be the first indicator of a medical problem, and it is easier to catch subtle weight gains and address the problem early on, before it becomes more serious.

Unlike most other members of the parrot group, Amazons don't have an uropygial gland (also called a preen gland). This gland is located on the back, on the midline, near the base of the tail. The gland produces vitamin D3 precursors, and the secretion waterproofs the feathers. The secretion also is antibacterial and antifungal. Since Amazons don't possess the uropygial gland, their powder down (from down feathers) provides waterproofing. The only other parrots without the uropygial gland are the purple macaws (hyacinth, Lear's, Glaucous and Spix).

Dietary Considerations

Nuts should be fed in moderation, due to the fat content, and peanuts should not be fed at all. Peanuts can carry aflatoxins, which are toxins produced by molds, and are colorless, tasteless and odorless. Aflatoxins can cause liver damage, can cause cancer, and can cause immunosuppression. Peanut butter is, however, safe to feed as batches are tested by the USDA to ensure that the aflatoxins level is within "acceptable" limits. However, "health food store" peanut butter often has dangerously high aflatoxins levels, as it is usually made right there in the store, and the government does no testing of "home-made" peanut butter. Tests of peanut butter from gourmet and health food stores often had much higher levels of aflatoxins than commercially produced peanut butter.

Pellets are a good nutritional base for Amazons, and other healthy foods, such as vegetables and fruits. Vegetables are better than fruits, due to the lower sugar content. Fruits also tend to have an inverted calcium: phosphorus ratio. As Amazons age, it is better to feed them a lower calorie diet, and there are several types of extruded pellets on the market today that are reduced calorie, for the overweight or older bird. One school of thought suggests feeding a high potency pellet, but in limited amounts, so that the bird is satisfied by the calorie-dense pellets, and then supplementing with lots of fresh vegetables and other healthy foods.

Medical Considerations

By far, obesity is the most common problem in the older, sedentary Amazon. Along with obesity, comes a myriad of medical problems. The biggest (no pun intended) problem with overweight Amazons is hepatic lipidosis, or fatty liver syndrome. The obese bird will have a swollen liver, as a result of fat being deposited inside the liver, and the fat cells will replace or destroy the normal liver architecture. On radiographs (x-rays), the liver silhouette appears enlarged. Eventually, if the situation is not corrected, the liver tissue will be replaced with fat, and the liver will not function normally. The end stage liver becomes cirrhotic. Since the liver performs over 40 functions for the bird, it cannot survive without a functioning liver. The body has a remarkable ability to heal itself, so if the bird's condition improves, the liver will repair itself over time.

Obesity in Amazons needs to be addressed to prevent future problems. Weight loss will rarely be accomplished simply by restricting calories. Birds require dedicated owners who are motivated to provide their pets with an exercise program. Simply placing a bird on a playgym will not provide the bird with enough exercise. The owner must make the bird flap its wings, climb up and down a ladder or walk around in a bird-safe area. In some cases, allowing the Amazon to grow out clipped wing feathers to allow it to fly is an acceptable alternative, however, we must make sure that the bird cannot escape or injure itself by flying. Weight loss is never easy to accomplish and the weight loss program should be established by your avian veterinarian, and monitored by your vet, as well.

Arthritis is another problem that occurs with older birds, and especially with overweight Amazons. In addition to losing weight and exercising, the bird will most likely require comfort perches, and perches of differing diameters, to ameliorate pain. Today, there is no reason for a bird to suffer, as we have available to us many safe, effective pain medications to control arthritis and other pain. Interestingly, aspirin, that old headache and pain remedy, is one of the BEST medications out there for controlling arthritis pain, and can either be administered in the drinking water or dosed orally once a day.

Overweight Amazons may also develop pressure sores on the bottoms of their feet or the bottoms of their hocks. This can progress to pododermatitis (or bumblefoot). Infected feet are very serious, as birds stand on their feet 24/7. Preventing foot problems by managing weight and providing perches of differing diameters is best.

Amazon parrots are one of the only groups of birds that often consistently demonstrate lymphocytosis normally. When running blood work, the CBC, complete blood count is usually run. When a white blood cell count is run (WBC), the cells are evaluated by performing a differential. The differential divides the cells into groups: heterophils, lymphocytes, monocytes, eosinophils and basophils. Most parrots have the heterophil as the predominant white blood cell, but with Amazons, the predominant cell is usually the lymphocyte. To an inexperienced vet, this can (and has) been misinterpreted as a disease condition, such as leukemia or lymphoma. Also, if a vet doesn't know that the predominant cell is the lymphocyte, the CBC may be misinterpreted, as well.

One challenge that we consistently see with Amazons is a chronic problem with a slightly swollen choana, blunted or absent choanal papillae, and a thick, white wash to the choana and oropharynx, and sometime the glottis, as well. Often baby Amazons will have this condition, which we have interpreted as to be a mixed bacterial and fungal (Candida) infection that requires antibiotic therapy as well as antifungal medication (we like a mixture of 20 cc. of Nystatin, 100,000 u/ml, mixed with 100 mg. fluconazole (DiflucanTM), dosed at 0.5 ml. per 1000 gm. body weight, given every 12 hours to treat a fungal infection, and once a day to prevent it, given for five days or more, as needed. Often, beta carotene given orally also helps this condition. Rarely, this condition has mimicked orally trichomoniasis, which is a protozoal infection caused by the Trichomonas organism. That infection responds to a medication called ronidazole (dosed at 6-10 mg/kg orally every 24 hours for 6-10 days.

Viral infections found in Amazons include PDD, proventricular dilatation disease, Pacheco's virus, paramyxovirus, adenovirus, PBFD (psittacine beak and feather disease) and polyomavirus. Polyoma is very dangerous in unweaned baby birds, but can still infect and cause disease in adults, but it rarely causes serious disease in adults. There is a vaccine against polyoma that is very efficacious. PBFD, which used to cause major problems and fatalities in cockatoos, is not commonly seen today, due to testing and culling of infected birds. PDD used to be called macaw wasting syndrome, but is now found in over 58 species of birds, including Amazons.

Amazons are susceptible to psittacosis (Chlamydophila), and they may develop classic clinical signs, such as passing green urine, but they may also just show sick bird signs.

While any bird can become ill from lead or zinc toxicosis, Amazons are one of the only species that may show frank blood in the droppings as a result of lead toxicosis.

Amazon Species

Let's now investigate the Amazon species. All of the Amazons are in the genus, Amazona. There are then many different species, and in some cases, sub-species. In addition, to make it more confusing, there are also different color morphs, that are not separate sub-species.

What is a species? The "biological species concept" is the most commonly used criteria for defining what is a species. This concept defines species as groups of naturally reproducing populations that are reproductively isolated from other populations. This means that populations which make up a species do not interbreed with other populations of a different species. This isolation may be due to geographical isolation (caused by a river or mountain range, for instance) or physiological isolation (the two species have overlapping ranges but either do not recognize each other's reproductive cues or simply reproduce at different times of the year).

A sub-species is a population that reproduces with another population where their ranges overlap. Two sub-species may look dramatically different, or the differences may be subtle, but where their ranges overlap, they interbreed to form a population that is intermediate between the two sub-species. These are called intergrades.

Yellow-Headed Amazons

The yellow-crowned Amazon, A. ochrocephala, double yellow-headed Amazon, A. oratrix, the Panama Amazon, A. panamensis, and the yellow-naped Amazon, A. auropalliata, are often confused by novice aviculturists and avian veterinarians. Recent changes by taxonomists have separated these birds into distinct genus and species. Previously, they were all considered sub-species of the yellow-crowned Amazon. Variations within each species occur, depending on the region of origin. Some yellow-napes have yellow at the crown and also around the nape of the neck, others have no yellow nape at all, and some may have a small amount of yellow at the crown. The most northerly representative of the family is the double yellow-head, ranging through Mexico. The beak of the double yellow-head is horn colored. Southern Mexico begins the range of the yellow-naped Amazon. Their territory ranges though Central America to Costa Rica. Many napes were imported from Honduras in the 1980's, making them the most popular pet Amazon in the United States. The beak of the nape may vary from almost black to a light gray, depending on the area of origin. The parvipes yellow-nape, A. auropalliata parvipes, has a bicolored beak, whereas the nominate species, A. auropalliata auropalliata, has a black beak. According to Low, only the parvipes yellow-nape has red on the bend of the wing.

The Panama Amazon is naturally only found in Panama. This is the smallest of this group of Amazons, and the least colorful, only possessing a small patch of yellow on the front of the forehead. The beak can be horn colored or may vary to horn with black streaks. It has a larger white eye ring in proportion to its size, when compared to the yellow-crowned.

Moving farther south and over the border of mainland South America, to the jungles of Columbia, the color of the Panama Amazon's beak darkens and the body size increases. This Amazon is known as the yellow-crowned or yellow-fronted Amazon.

Red-Headed Amazons

This group of Amazons is often confusing to avian veterinarians and novice aviculturists alike. There are four sub-species of the red-lored Amazon, Amazona autumnalis autumnalis, including the lilacine Amazon, A. a. lilacina, Salvin's Amazon, A. a. salvini, and the Diadema Amazon, A. a. diadema. The Finsch's or lilac-crowned Amazon, A. finschi, also has a reddish-maroon color on the head. The green-cheeked, or Mexican red-headed Amazon, A. viridigenalis, also has red on the head. The festive Amazon, A. festiva festiva, and its sub-species, A. festiva bodini, also has a reddish-maroon color on the head. The tucuman Amazon, A. tucumana, is a green bird with a reddish-orange forehead. Rare Amazons with red on the head include the red-spectacled, or Pretre's, Amazon, A. pretrei, the red-tailed Amazon, A. brasiliensis, the red-crowned Amazon, A. rhodocorytha, the Puerto Rican Amazon, A. vittata, and the vinaceous Amazon, A. vinacea.

The Leucocephala

The Cuban Amazon, A. leucocephala leucocephala, is the nominate species of this group. These birds all have a horn colored beak and a white forehead (leuco=white, cephala=head). Sub-species include the Grand Cayman Amazon, A. l. caymanensis, the Isle of Pine Amazon, A. l. palmarum, which may not be a distinct sub-species, the Cayman Brac Amazon, A. l. hesterna, the Bahama Amazon, A. l. bahamensis. Recently, about 30 leucocephala were stolen from a private breeding facility in Florida. These birds were the result of many years of careful breeding, and the loss to conservation has been devastating. For this reason alone, it is important for avian veterinarians to be able to identify these rare, beautiful birds.

The Spectacled and Yellow-Lored Amazons

Both of these species are sexually dimorphic. The male spectacled, or white-fronted, Amazon, A. albifrons, has red alula feathers and some primary wing coverts. Those feathers in the hen are green. The spectacled Amazon is one of the smallest Amazons. It is easily confused with the very rare yellow-lored Amazon, A. xantholora, which is also dimorphic. The male has bright yellow lores and red primary coverts.

Other Island Amazons

The Hispaniolan Amazon, A. ventralis, is a small bird with a white forehead, which may be tinged with yellow. On the island of Jamaica, two different Amazons are found; the yellow-billed, A. collaria, and the black-billed, A. agilis. The St. Vincent's Amazon, A. guildingii, has three color morphs, not sub-species. This large, spectacular bird has a stable population on the island, and there are several pairs breeding in the United States. The St. Lucia Amazon, A. versicolor, red-necked Amazon, A. arausiaca, and the imperial Amazon, A. imperialis, are all very rare birds, and are being carefully managed on their islands.

A Confusing Group of Amazons

Some of the more commonly encountered Amazons can prove confusing. The blue-fronted Amazon, A. aestiva, has two sub-species. The orange-winged Amazon, A. amazonica, is often confused with the blue front. The more rare yellow-shouldered Amazon, A. barbadensis, also has two sub-species, and may be confused with Amazons in the yellow-headed group, or even with the blue front. The mealy Amazon, A. farinosa, has five sub-species, some with blue or yellow or red feathers on the head, which can lead to confusion with other species of Amazons.


Conclusion

Amazon parrots are beautiful, intelligent parrots, many with excellent abilities to mimic human voices, sounds and song. It is important that we are able to identify the more common species of Amazons that may be encountered, but we should also be able to recognize the more unusual and rare birds, as well. Our ability to do so may help ensure the survival of some of these species.

Recommended Reading

  1. Forshaw JM. Parrots of the world, third (revised) edition, Lansdowne Press, Willoughby, Australia, 1989.
  2. Low, R. Parrots in aviculture: a photo reference guide, Silvio Mattacchione and Co, Pickering, Canada, 1992.
  3. Silva T. A monograph of endangered parrots, Silvio Mattacchione and Co, Pickering, Canada, 1989.
  4. Stoodley J, Stoodley P. Genus Amazona, Bezels Publications, England, 1990.

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Copyright 2006 Margaret A. Wissman, D.V.M., D.A.B.V.P.
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