Macaws are long-tailed, often colourful New World parrots. Of the many different Psittacidae (true parrots) genera, six are classified as macaws: Ara,Anodorhynchus, Cyanopsitta, Primolius, Orthopsittaca, and Diopsittaca. Previously, the members of the genus Primolius were placed in Propyrrhura, but the former is correct in accordance with ICZN rules. Macaws are native to Central America (especially Mexico), South America, and formerly the Caribbean. Most species are associated with forests, especially rainforests, but others prefer woodland or savannah-like habitats.
Proportionately larger beaks, long tails, and relatively bare, light-coloured, medial (facial patch) areas distinguish macaws from other parrots. Sometimes the facial patch is smaller in some species, and limited to a yellow patch around the eyes and a second patch near the base of the beak in the members of the genusAnodorhynchus. A macaw's facial feather pattern is as unique as a fingerprint.
The largest macaws are the hyacinth, Buffon's (great green) and green-winged macaws. While still relatively large, macaws of the genera Cyanopsitta,Orthopsittaca and Primolius are significantly smaller than the members of Anodorhynchus and Ara. The smallest member of the family, the red-shouldered macaw, is no larger than some parakeets of the genus Aratinga.
Macaws, like other parrots, toucans and woodpeckers, are zygodactyl, having their first and fourth toes pointing backward.
Extinctions and conservation status
International trade of all macaw species is regulated by the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES). Some species of macaws—the scarlet macaw (Ara macao) as an example—are listed in the CITES Appendix I and may not be lawfully traded for commercial purposes. Other species, such as the red-shouldered macaw (Diopsittaca nobilis), are listed in Appendix II and may legally be traded commercially provided that certain controls are in place, including a non-detriment finding, establishment of an export quota, and issuing of export permits.The majority of macaws are now endangered in the wild and a few are extinct. The Spix's macaw is now probably extinct in the wild. The glaucous macaw is also probably extinct, with only two reliable records of sightings in the 20th century. The greatest problems threatening the macaw population are the rapid rate of deforestation and illegal trapping for the bird trade.
Sometimes macaws are hybridized for the pet trade. Hybrids are typical macaws, with the only difference from true species being their genetics and their colours.
Aviculturists have reported an over-abundance of female blue-and-yellow macaws in captivity, which differs from the general rule with captive macaws and other parrots, where the males are more abundant. This would explain why the blue and gold is the most commonly hybridised macaw, and why the hybridising trend took hold among macaws. Common macaw hybrids include the harlequin (Ara ararauna × Ara chloroptera), miligold macaw (Ara ararauna × Ara militaris and the Catalina (known as rainbows in Australia, Ara ararauna × Ara macao). In addition, unusual but apparently healthy intergeneric hybrids between the hyacinth macaw and several of the larger Ara macaws have also occasionally been seen in captivity.
Diet and clay licks
Some foods eaten by macaws in certain regions in the wild are said to contain toxic or caustic substances which they are able to digest. It has been suggested that parrots and macaws in the Amazon Basin eat clay from exposed river banks to neutralize these toxins. In the western Amazon hundreds of macaws and other parrots descend to exposed river banks to consume clay on an almost daily basis - except on rainy days. Donald Brightsmith, the principal investigator of the Tambopata Macaw Project, located at the Tambopata Research Center (TRC) in Peru, has studied the clay eating behaviour of parrots at clay licks in Peru. He and fellow investigators found that the soils macaws choose to consume at the clay licks do not have higher levels of cation-exchange capacity(ability to absorb toxins) than that of unused areas of the clay licks and thus the parrots could not be using the clay to neutralize ingested food toxins. Rather, the macaws and other bird and animal species prefer clays with higher levels of sodium. Sodium is a vital element that is scarce in environments greater than 100 kilometres from the ocean. The distribution of clay licks across South America further supports this hypothesis - as the largest and most species rich clay licks are found on the western side of the Amazon Basin far from oceanic influences. Salt-enriched (NaCl) oceanic aerosols are the main source of environmental sodium near coasts and this decreases drastically farther inland. Macaws eat a variety of foods including seeds, nuts, fruits, palm fruits, leaves, flowers, and stems. Wild species may forage widely, over 100 km (62 mi) for some of the larger species such as Ara araurana (blue and yellow macaw) and Ara ambigua (great green macaw), in search of seasonally available foods.
Clay-eating behaviour by macaws is not seen outside the western Amazon region, even though macaws in these areas consume some toxic foods such as the seeds of Hura crepitans, or sandbox tree, which have toxic sap. Species of parrot that consume more seeds, which potentially have more toxins, do not use clay licks more than species that eat a greater proportion of flowers or fruit in their diets.
Studies at TRC have shown a correlation between clay-lick use and the breeding season. Contents of nestling crop samples show a high percentage of clay fed to them by their parents. Calcium for egg development - another hypothesis - does not appear to be a reason for geophagy during this period as peak usage is after the hatching of eggs.
Another theory is that the birds, as well as other herbivorous animals, use the clay licks as a source of cobalamin, otherwise known as vitamin B12.
The budgerigar (Melopsittacus undulatus), also known as common pet parakeet or shell parakeet and informally nicknamed the budgie, is a small, long-tailed, seed-eating parrot. Budgerigars are the only species in the Australian genus Melopsittacus, and are found wild throughout the drier parts ofAustralia where the species has survived harsh inland conditions for the last five million years. Budgerigars are naturally green and yellow with black, scalloped markings on the nape, back, and wings, but have been bred in captivity with coloring in blues, whites, yellows, greys, and even with small crests. Budgerigars are popular pets around the world due to their small size, low cost, and ability to mimic human speech. The origin of the budgerigar's name is unclear. The species was first recorded in 1805, and today is the third most popular pet in the world, after the domesticated dog and cat.
The budgerigar is closely related to the lories and the fig parrots. They are one of the parakeet species, a non-taxonomical term that refers to any of a number of small parrots with long, flat and tapered tails. In both captivity and the wild, budgerigars breed opportunistically and in pairs.
Wild budgerigars are usually found to be mostly green in colour. Selective breeding, by breeders, over the years has caused changes in colour. Cage bred budgerigars are also larger in size than wild budgerigars.
Breeding in the wild generally takes place between June and September in northern Australia and between August and January in the south, although budgerigars areopportunistic breeders and respond to rains when grass seeds become most abundant. They show signs of affection to their flockmates by preening or feeding one another. Budgerigars feed one another by eating the seeds themselves, and then regurgitating it into their flockmate's mouth. Populations in some areas have increased as a result of increased water availability at farms. Nests are made in holes in trees, fence posts, or logs lying on the ground; the four to six eggs are incubated for 18–21 days, with the young fledging about 30 days after hatching.
In the wild, virtually all parrot species require a hollow tree or a hollow log as a nest site. Because of this natural behavior, budgerigars most easily breed in captivity when provided with a reasonable-sized nest box. The eggs are typically one to two centimetres long and are pearl white without any colouration if fertile. Female budgerigars can lay eggs without a male partner, but these unfertilised eggs will not hatch. When the female is laying eggs, her cere turns a crusty brown colour. A female budgerigar will lay hereggs on alternate days. After the first one, there is usually a two-day gap until the next. She will usually lay between four and eight eggs, which she will incubate (usually starting after laying her second or third) for about 21 days each. Females only leave their nests for very quick defecations, stretches and quick meals once they have begun incubating and are by then almost exclusively fed by their mate (usually at the nest's entrance). Females will not allow a male to enter the nest, unless he forces his way inside. Depending on the clutch size and the beginning of incubation, the age difference between the first and last hatchling can be anywhere from 9 to 16 days. At times, the parents may begin eating their own eggs due to feeling insecure in the nest box.
Breeding difficulties arise for various reasons. Some chicks may die from diseases and attacks from adults. Other budgerigars (virtually always females) may fight over the nest box, attacking each other or a brood. Sometimes, budgerigars (mainly males) are not interested in the opposite gender, and will not reproduce with them; a flock setting—several pairs housed where they can see and hear each other—is necessary to stimulate breeding. Another problem may be the birds' beaks being under lapped, where the lower mandible is above the upper mandible.
Most health issues and physical abnormalities in budgerigars are genetic. Care should be taken that birds used for breeding are active, healthy, and unrelated. Budgerigars that are related or which have fatty tumours or other potential genetic health problems should not be allowed to breed. Parasites (lice, mites, worms) and pathogens (bacteria, fungi and viruses), are contagious and thus transmitted between individuals through either direct or indirect contact. Nest boxes should be cleaned between uses.
Splay leg is a relatively common problem in baby budgerigars and other birds; one the budgerigar's legs is bent outward, which prevents it from being able to stand properly and compete with the other chicks for food, and can also lead to difficulties in reproducing in adulthood. The condition is caused by young budgerigars slipping repeatedly on the floor of a nest box. It is easily avoided by placing a small quantity of a safe bedding or wood shavings in the bottom of the nest box. Alternatively, several pieces of paper may be placed in the box for the female to chew into bedding.