`Parrots' and `Cockatoos' Order Psittaciformes

Parrots are mainly found in the southern continents and the equatorial regions of the world. This distribution reflects their likely origins on the ancient continent of Gondwana (Simpson et al 1996). The Parrot order is thus an ancient lineage, and appears not to be closely related to any other groups of birds (Simpson et al 1996); however, it is thought that they have a distant relationship to the pigeons and doves.

There are many different kinds of parrots, yet they comprise a distinctive group of birds that most anybody would recognize. They are popular due to their colorful plumage and interesting behaviors. One parrot, the `Budgerigar', is probably the most popular pet bird in the western world. The parrot group also includes the `Cockatoos', `Lorikeets', `Rosellas', `Parakeets', `Macaws', `Lovebirds' and others. They range in size from the tiny 8cm `pygmy parrots' of New Guinea and surrounding islands, to the giant Macaws of South and Central America that can be a meter in length (Stiles and Skutch 1994). As many parrots live in the rain forest canopy, their colors are often based on greens. However, parrots have evolved plumages of every color. They have adapted to live in rain forest, savannas and mountains, to feed on seeds, fruits, roots, nectar, fungi and wood boring insects. There are even nocturnal species.

Even though there are many different kinds of parrots, they all have a very distinct suite of characteristics that unite them in one order. The skin around the eye of a bird is called the `cere', and in parrots this patch is often obvious and enlarged (Simpson et al 1996). The same authors also note that parrots have `interesting' intestinal looping and lack an appendix. Parrots have a rather broad skull with a large braincase (Forshaw 1998), with parrot owners and other bird observers pointing out that parrots seem relatively intelligent.

To most people, though, the first most obvious feature of a parrot is the bill. This is usually well developed, with a large hooked, downcurved upper mandible, over a smaller upcurved lower mandible. The upper mandible is attached to the skull via a flexible joint (Slater 1997). It is wise to keep your fingers in your pockets when near parrots, for this bill has evolved to extract and crack seeds.

Authors Stiles and Skutch (1994, page 176) colorfully describe the bill of the typical parrot as combining "the destructive powers of an ice pick (the sharp-pointed upper mandible), a chisel (the sharp-edged lower mandible), a file (ridged inner surface of the upper mandible) and a vise". This effective grip is also utilized to assist in climbing. Inside the thick bill, there is a tongue that is usually large and muscular (Forshaw 1998).

One of the main features that zoologists used to distinguish the parrot order from other birds is the arrangement of the feet. They have two toes pointing forward, and two backwards. This arrangement allows for great dexterity, with the feet being used like hands. Unlike most other birds, parrots often use their feet to feed. Combined with the beak, this also allows for nimble climbing.

Life Cycle of the Parrot

There are also some behavioral and life cycle features of the parrots that are distinctive. Most species are monogamous, and many appear to bond for life (Forshaw 1998). Most parrots do not build nests, but raise their young in the existing hollows of trees, or excavate holes in banks, cliff faces, or termite mounds (Forshaw 1998). They will often use that sharp beak to chew the wood inside a tree hollow to produce a soft surface to lay their eggs (Krebs 2001). The female usually lays her small number of eggs every other day (Egerton 1997). It appears only the female does the incubating (Slater 1997). The young are naked and fed by the parents by holding the nestlings beak inside their own (Simpson et al 1996) and regurgitating the food (Stiles and Skutch 1994). Parrots can be long lived, and in fact the oldest bird ever recorded was a 'Sulfur-crested Cockatoo' that died in the London Zoo in 1982 at the age of at least 80 years old (Slater 1997).

Parrots are generally quite sociable, not very territorial, and can occur in large flocks. This is thought to reflect their abundant food resources that can be eaten without competition and the idea that flocking can reduce predation (Lindsey 1998). Some Cockatoos may post `sentries' that alarm the rest of the flock of danger (Lindsey 1998). They are often nomadic, flying fast and wide to take advantage of varying resources. Most parrots have basic screeching calls that are not thought of as particularly melodious. However, they are kept as pets because they can be taught to imitate human words, even though there is little evidence of parrots imitating other birds in the wild (Forshaw 1998). This skill has developed due to the highly sociable nature of parrots. Many have different calls for different purposes, including soft contact calls, warning calls, or calls made just previous to take off.

The ecology and conservation of parrots

Being such large and obvious birds, parrots naturally play various ecological roles. The Old World `Lorikeets' are nectivores, and thus pollinators of many plants. The fig parrots of Australia and New Guinea are likely to be important dispersers of rain forest fruits. However, due to the fact that the bigger parrots may rip open immature fruits to gain access and predate upon seeds, the dispersion of plants by these types of birds is likely to be limited (Stiles and Skutch 1994).

There are several threats to parrots worldwide. Clearing of forests has effected these birds, for they rely on old growth forests with their aging trees and accompanying hollows to breed (Egerton 1997). Parrots are popular pets and there is a large and thriving trade in smuggling the animals out of various countries, with many dying in transit (Forshaw 1998). There are also moral ambiguities about the keeping of such reportedly intelligent and wide flying birds in cages. However, the captive trade has supplied much information, especially on the reproductive biology of many parrot species (Stiles and Skutch 1994).

There are over 340 species of parrots (Perrins 199). The order is split into two different families; one family contains the large `Cockatoos' of the Australian region, the other family contains all of the rest of the parrots. There are more species on the continent of South America than anywhere else, but it is in Australia where the group attains their greatest ecological and morphological diversity.

Parrots in Australia

Australia was often referred to as `Parrot Land' by early colonists (Egerton 1997). Parrots in the Australian region are very diverse, and it is only here where all three major groups of parrots (the `lorikeets', the `cockatoos' and the `true parrots') are found. Parrots have evolved to fill many different niches in Australia. While in other parts of the world they are correctly thought of as rain forest inhabitants, in Australia they have expanded out of the wetter forests and into the savanna and the more and lands. In fact, they reach their highest diversity in the open woodlands (Simpson et al 1996). Whereas most parrots around the world are variations on the color green due to their rain forest habitat, in Australia the result of colonizing other habitats has been the evolution of a parrot of every color; including black, white, red, green, yellow, grey, or pink. There are over fifty species on the Australian continent (Simpson et a11996), with over 40 of these being found nowhere else on Earth (Egerton 1997).

Parrots in Australia have a mixed conservation status. Some of the open country birds such as the cockatoos have done well, with many having actually expanded their range since European settlement due to the clearing of forest to more open country. Other parrots have not fared so well, as these cleared forests contained the older trees and their hollows necessary for their breeding (Krebs 2001).
Script: Courtesy of  Damon Ramsey BSc.(Zool) Biologist Guide