Breeding Psittacus parrots are
monogamous breeders which nests in tree cavities. The female lays 3-5 eggs, which she incubates for 30 days while being fed by her mate. Young leave the nest at the age of 12 weeks. Little is known about the courtship behaviour of this species in the wild.
Longevity Like many large parrots, they are
long-lived birds. The Animal Ageing and Longevity Database states the longest reliably recorded longevity for the species in captivity as 49.7 years. Also acknowledged are claims of captive grey parrots reaching the ages of 73 and 93, whereas the
World Parrot Trust lists a longevity of 50–60 years for a grey in captivity. The
Guinness Book of World Records listed a grey parrot that allegedly lived in captivity for 72 years as the longest-lived specimen for the species.
Illness and disease Grey parrots have been known at times to contract a non-infectious inflammatory lung disease called lipid pneumonia. Lipid pneumonia can be classified as exogenous or endogenous depending on whether or not the animal inhaled outside material. A necropsy shows that the lungs of a grey parrot with endogenous lipid pneumonia (EnLP) are firm with a diffuse grey discoloration. EnLP is a common illness in other animals as well. The grey parrot is also one of the three parrots that scientists found to commonly suffer from dehydration. Scientists have used plasma osmolality to find more information about the form of dehydration grey parrots have. Another disease that the grey parrots get is cardiomyopathy, which is a heart disease usually presented at a young age. The cause is having parents of the same breed. Some other common symptoms in these birds are weakness, coelomic cavity, and retardation. The grey parrot has been known to contract beak and feather disease virus (BFDV) which causes a highly contagious, and sometimes fatal, psittacine beak and feather disease in parrots. In a PCR-based study, Chlamydiosis, an infectious disease of avians, was found to infect the grey parrot. In the study 253 clinical samples were taken from 27 bird species belonging to seven orders. Thirty-two (12.6%) samples were positive for Chlamydi and two new genotypes were discovered,
Chlamydophila psittaci and
Chlamydophila abortus. Another ailment that grey parrots commonly suffer from is hypocalcemic-induced seizure activity. Birds between 2–15 years of age contract it, due to a lack of calcium. A symptom of the syndrome can be unsteadiness while standing or falling off a perch along with neurological anomalies or problems.
Intelligence Irene Pepperberg's research with captive greys, most notably with a bird named
Alex, has scientifically demonstrated that they possess the ability to associate simple human words with meanings, and to intelligently apply the abstract concepts of shape, colour, number, zero-sense, etc. According to Pepperberg and other ornithologists, they perform many cognitive tasks at the level of dolphins, chimpanzees, and even human
toddlers. As well as labeling objects, Alex could verbally express what his wants were, suggesting that grey parrots know the difference between features and feelings. In general, it has been shown that grey parrots are able to learn relatively quickly, though they are limited to simple and non-abstract mediums of thinking. They have been shown to be able to make cognitive inferences, but, like apes, have inter-individual differences in intelligence. For example, in one experiment involving food hidden under cups, it was shown that greys can identify where the food is, usually if shown its original location at first. Pet greys may learn to speak within their first year, but many don't say their first word until 12–18 months old. Timnehs are generally observed to start speaking earlier, some in their late first year. Both subspecies seem to have the same ability and tendency to produce human speech, but vocal ability and proclivity may range widely among individual birds. Grey parrots tend to use more specific calls for different species coming their way which can be known as stimulus specificity, since there is a stimulus vocalization the birds have. A study published in 2011, led by Dalila Bovet of
Paris West University Nanterre La Défense, demonstrated grey parrots were able to coordinate and collaborate with each other to an extent. They were able to solve problems set by scientists—for example, two birds could pull strings at the same time to obtain food. In another example, one bird stood on a perch to release a food-laden tray, while the other pulled the tray out from the test apparatus. Both would then feed. The birds in question were observed waiting for their partners to perform the necessary actions so their behaviour could be synchronised. The parrots appeared to express individual preferences as to which of the other test birds they would work with. In an experiment about local enhancement in grey parrots, food was visibly hidden under two separate cups. The experimenter then lifted the first cup and either removed what was under it or put it back. This was then done again in several different combinations, the cups were lifted in a different order and the food was removed or put back in a different order. Instead of remembering which cup had the food, the birds would show preference to the one that was touched last. Another series of experiments further tested grey parrots' cognitive abilities. In general, most animals cannot associate sounds with objects, such as food, placed into a cup. While originally only the great apes and young human children were known to make this association with ease, it was found that grey parrots, under most conditions, can also associate sounds with the presence of an object. For the most part, grey parrots performed more successfully if the cup was shaken horizontally before it is given the choice of selecting which contained food; however, further experimentation indicated that it is not a requirement and proved that grey parrots have very high cognitive abilities.
Vocal behaviour Wild grey parrots often whistle, click, or make other sounds. Captive birds may make regular renditions of microwave ovens, telephones, alarm clocks, video games, and other electronic sounds, as well as dripping water, wild birds, and any other sound often heard by the parrot. Greys have even been known to repeat profanities they heard from an owner even after they no longer live with that owner. Greys also have the ability to mimic, and distinguish between, the different voices they hear. Grey parrots use different alarm calls for different predators coming their way. In an experiment to test the vocalisations of grey parrots, four bred in captivity were placed in an aviary. Throughout the day they spent time in a room with toys and came into fairly regular contact with the humans taking care of them. The noises that these parrots could hear consisted of the calls of canaries in the laboratory, people cleaning, doors squeaking, etc. In the next 3 years, the parrots made over 50,000 vocalisations. What was interesting was that, although they were bred in captivity, the sounds they made were not only ones of their immediate surroundings. They also made calls similar to those of other captive grey parrots in different locations and even wild grey parrots. ==Status and conservation==