| The Aquisition, Husbandry and Breeding of Common Amazons Part 2 |
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Lilac-Crown Amazon
Similar problems as the previous amazon but with even fewer in captivity. The Lilac Crown is in the worst situation out of all the species listed here. Again its a species once commonly imported but now becoming severely threatened. We may be dealing with only about a dozen original pairs in Canada and already some improperly marked captive bred birds are entering collections. It is imperative that pet birds be set up for breeding in order to maximize the “founder” stock and save as much diversity of the gene pool as possible. Stud books for this species should be set up ASAP both in Canada and USA. It is a shame to see this species discounted in price and not held with more esteem by breeders in the Southern USA. Apparently some breeders would rather not have to compete with cheap illegal birds thus are not serious in establishing this species.
Tucuman Amazon
This species is now on Appendix 1 of CITES which bans the commercial trade in wild caught specimens. Comparatively few were imported over the few years they were available. Once there was a proposal with CITES to list this species many were imported in the last year. Fortunately most of these were sold to breeders. There is a small shortage of females. Our breeding pair are very prolific laying four eggs per clutch with excellent fertility. This is another species which we must carefully manage to avoid inbreeding in the future. HARI would like to exchange babies with another breeder but I think we have the only breeding pair in Canada right now. As soon as a second pair breeds for us we will first offer unrelated pairs of domestic babies to other breeders before selling any to the pet trade. Most amazon breeders do this with their endangered birds but it is being poorly documented, we must improve our record keeping.
The Tucuman appears to be more sensitive to kidney failure than other amazons. There may be a relationship between vitamin D3, calcium, and protein to energy levels, and kidney stress. HARI is presently studying this by the long term feeding of exactly known amounts of these nutrients while monitoring kidney health by regular biopsies to look for morphological changes and blood tests.
Red-Lored (Yellow Cheek) Amazon
A lot of variation exists between individuals in the amount of yellow covering the cheeks. The Salvin's sub-species is supposed to have no yellow on the cheeks but I have also seen some of the nominate species with almost no yellow and likewise Salvin's with some yellow making the sub-species identification difficult. The Lilacine sub-species has a lighter hue of green over the body and face and a burgundy rather than a red coloured lore.
The nominate species has a loud shriek and together with its limited talking ability, it may not be a popular amazon for the pet trade. Of course I am generalizing and there are always exceptions. Its mid size and cheaper price than other amazons does make it a good species for beginning breeders.
Another Central American amazon commonly exported in the 1980's but now in only limited numbers. Honduras was the major exporter. Now Nicaragua is.
Mealy/Blue Crown Amazons
These large amazons are uncommon in captivity but several sub-species are still being exported by range states in central and south America. The Mealy (the nominate sub-species; farinosa) can be distinguished by usually having some spots of yellow feathers on the top of the head and very little Blue on the Crown. Most of the “Blue-Crowns” exported in the 1980's were the Costa Rican sub-species which does not have as much blue on the Crown as the Guatemalan form. Nicaragua is presently exporting baby Blue Crowns taken as nestlings from the wild. Our pairs of Blue-Crowns are probably the loudest amazons we have, giving off loud shrieks for no reason at all. They are suppose to talk well.
Orange-Winged Amazon
A common bird in northeastern South America with reports that it is even a pest in Venezuela. Guyana has a fairly high export quotas each year but the demand is low for this species. We recently imported 40 birds but lost a few to Pacheco's, before the vaccine had a chance to work, and subsequently more than a quarter of them have developed cloacal papillomas. Once imported birds have their full adult plumage they can be quite beautiful. I have also heard from experienced amazon breeders in the southern USA that it is one of the most difficult amazons to breed. By changing the conditions under which any species has not bred after many years, we may find the right conditions to finally stimulate reproduction.
Spectacled Amazon
HARI does not presently have any of this species so our avicultural experience is limited. We did have one pair but a few years ago we found the female dead with her head chewed up. The male had blood stains on his beak.
Males have red alula and primary coverts while in the female they are green. The species is a nice small size and there are many already in captivity but it has a limited talking ability. It is relatively common in many parts of Central America since it has adapted to agriculture and the secondary growth of cut forests. I predict that this species might be one of the few imported under the new US Bird Conservation act as it should be easy to show sustainable yield in a species that lives so close with man.
Table 1.
International Trade in Amazon Parrots (1983 - 1989)
Amazona species Seven Year Average
Total per year
___________________________________________
Yellow Wing 280,000 40,000
(A. aestiva)
Orange Winged 100,000 14,100
(A. amazonica)
Yellow Crown & Nape 70,000 10,000
(A. ochrocephala)
Yellow Cheeked 40,000 5,600
(A. autumnalis)
Spectacled 25,000 3,750
(A. albifrons)
Tucuman 18,500 2,600
(A. tucumana)
Mealy 12,500 1,800
(A.f.farinosa) {Guyana exports}
Blue Crown 12,500 1,800
(A.f.guatemalae & virenticeps)
Source: Perceptions, Conservation and Management of Wild Birds in Trade, 1992 Ed.
J.B. Thomsen, S.R. Edwards, T.A. Mulliken, Pub. TRAFFIC/WWF
Screening Breeding Stock and Disease PreventionIf disease is present in carrier birds, it is activated by poor nutrition, over-crowding, sudden environmental change or other stress. Many diseases are transmitted primarily from the droppings, which dry out and form a dust which circulates in the air and can be breathed in. Pathogenic organisms can also be present in material that is coughed or sneezed up in crop contents. Therefore, any object that has been exposed to diseased birds is a potential carrier of the germs, for example: dirty food and water dishes, other birds, humid air, shoes, nets, clothing, cages, rodents, insects and hands.
Disease prevention is best achieved by good sanitation. All objects should be washed, first in soap and water; then disinfected with a good disinfectant such as tamed iodine (soak for at least ten minutes), quaternary ammonia, aldehyde, phenolic or bleach solution. A common problem has been dipping food and water dishes into a common storage source. It would be best to use a food scoop and water pitcher to fill up the dishes. As mentioned in the housing section, proper ventilation is a must to minimize spread of pathogenic organisms.
When birds are first acquired for a breeding program, a quarantine period is imperative. But it only reduces and does not eliminate the risk of introducing disease into an established breeding facility. During this time every new bird should either be tested for Psittacosis or be fed a tetracycline medicated diet for at least 60 days. We vaccinate all new world birds against Pacheco's Herpes Virus but have not started testing for polyoma virus. We have not experienced a decrease in production or have lost any birds to the vaccine, but do get localized reactions in about one in fifty birds. Not vaccinating could be worst e.g. an outbreak of Pacheco's as we experienced four years ago.
Pacheco's Disease
Pacheco's disease is a highly fatal, contagious disease of psittacine birds. It is caused by a psittacine herpes virus. The spread through a susceptible population is rapid and most psittacine species are susceptible to the disease. The Hagen Avicultural Research Institute (HARI) unfortunately experienced an outbreak of this disease in January/February of 1989 while we were in a leased and temporary building. Similar outbreaks have occurred in many other large parrot holding facilities. This outbreak at HARI and means to prevent such outbreaks follows.
The leased building that HARI had occupied during the outbreak was not specially designed as an animal holding facility. Our winter heating costs were high due to our cold winters. A reduced amount of interior air was exchanged with the fresh but cold outside air; we had turned off our venting barn fan. Our veterinarian commented that the air was of questionable quality, dust and odours, and that we should get an engineer to design a good ventilation system. The circulation pattern of air was created by the heater fans and was not based on minimizing transfer between pairs. However since we were moving out of this building shortly it was decided not to invest in an expensive ventilation system for this temporary facility.
It was under simulated "summer" conditions that we experienced a terrible herpes virus outbreak. We felt strongly that the virus was spread via the water droplets in the air contaminated from the faeces soiled cage wire and floor waste. We are not completely sure of the source; if it was a long term carrier bird that has been at HARI for years or a bird which was introduced in the fall when 18 new birds were added to the colony. The latest acquisitions were from our own quarantines, in which no problems had occurred, or were previous pets. These birds included four astral conures, four black-headed caiques, four white-capped pionus, four moluccan cockatoos and two double-yellow headed amazons. For various reasons I do not think one of these birds brought in the virus but that it was being shed by one of our established birds. Based on previous experiences I believe we may have yellow-napped and/or yellow-winged amazon carriers who are intermittent shedders of some host adapted virus.
Our amazons were set up in one long row of 76 cm wide x 152 cm high x 320 cm long split cages with very little space, about 10 cm between each set of two cages. The species are in random order. Sudden mortality began in the area where the air flow from the propane heater was greatest, near the middle of this row. Over a one week period the disease spread down to each end of the row, thus it is assumed that all the birds down this row were exposed to the virus. Most of the birds that died did so within two days of becoming clinically ill.
Controlling a Pacheco's Outbreak
The first thing to do is to move all the surviving sick birds to another location for isolation and supportive care. Vaccination during an outbreak may spread the disease and will not save birds in the acute stage of the disease. Supplemental tube feeding was required for 5 to 10 days in sick birds most of which stop eating. Acyclovir (Zovirax - Welcome) a drug to treat human genital herpes was administered both orally via the tube fed food and as an injectable (intramuscular). Zovirax is very expensive and its effectiveness in sick parrots is poorly documented. Most of the birds that survived the first three days would go on to recover making all the supplemental care and medical treatments worthwhile. If we were to do truly scientific research half the sick birds should not have received the acyclovir. This would allow a comparison with a control group to observe differences in mortality. However, these birds are not only valuable but also companion animals, each with its unique behaviours. Every effort was made to save each one.
Twenty seven per cent of HARI's amazons died (15 out of 56) with 13 sick birds surviving. Major species differences in susceptibility were observed; the double yellow-heads - 6 of 17 died plus most of the rest were sick, tucuman - 5 of 8 died, salvin's - 2 of 3 died, and yellow-checked - 2 of 8 died, experienced the highest mortality and morbidity while our 10 yellow-napped, 6 yellow-fronted and 4 yellow-winged were resistant with no deaths and only 3 sick birds. All our yellow-napped amazons have come from quarantines where significant (about 25 %) acute mortality had occurred, but to which the federal lab in Ottawa could not identify the causative agent, although we believed that disease outbreak was caused by an amazon pox virus. Our macaws (21 pairs), and all of the old world birds (40 pairs of cockatoos, 8 pairs of african greys) were not affected. Only two moluccan cockatoos died and two others developed head tremors after being quite ill but recovering with tube-feeding and supportive care.
Serology confirmed the presence of Pacheco's herpes virus anti-bodies in all birds that were sick and recovered. One of the birds, a yellow-napped amazon, which showed no signs of illness during the outbreak was positive for Pacheco anti-bodies.
The birds that recovered did so very quickly. One pair of double yellow-headed amazons were breeding and produced fertile eggs less than one month after being so sick they had to be force fed for 3 days. Marek's disease in poultry is also caused by a herpes virus and egg transmission has not been demonstrated. We decided to pull the eggs, wipe them with a phenolic disinfectant and artificially incubating the eggs for hand-rearing. Two of the three fertile eggs hatched and were successfully raised.
Health Management
Vaccination of all healthy birds within even closed breeding collections should be performed in advance of exposure. Vaccination is a minor stress since birds must be handled and injected but it is a good time to do a physical examination i.e. weight and check for cloacal papillomas.
Health management includes a high quality balanced diet, caging which reduces stress and proper quarantine of new birds. Mate selection and pair bonding should be carefully monitored to produce compatible pairs and not lead to aggressiveness between birds. When accompanied by sudden changes in temperature, or by moving, crowding, unusual noises, changes in the feed programme, or other management changes, the birds resistance is weakened. Multiple stress cause a greater reaction than their sum would indicate. Many birds are carriers of disease organisms, but show no clinical signs. Stresses may trigger such an inactive state to an active disease. There should be daily inspection of all birds to observe feed and water consumption and the state of their well being.
Aviculturists should use as many of the resources available as possible to prevent and monitor disease. This includes post mortem, professional experienced veterinary care and effective use of vaccinations and drugs to prevent disease such as Pacheco's Parrot Disease and Psittacosis. Every aviculturist should establish a disease control plan in the case of an outbreak. Such planning will assist in the prevention of an outbreak as it may point out deficient areas of management which require improvement. This outbreak in 1989 made disease prevention a top priority for HARI. All collections of Psittacines which include amazons (and other new world birds) should be vaccinated against Pacheco's Disease as carriers may be present. Quarantining birds for even a year will not detect carriers or eliminate the virus they may be harbouring.
Part 3
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