The monk parakeet (Myiopsitta monachus), also known as the monk parrot or Quaker parrot, is a species of true parrot in the family Psittacidae. It is a small, bright-green parrot with a greyish breast and greenish-yellow abdomen. Its average lifespan is 20–30 years. It originates from the temperate to subtropical areas of South America. Self-sustaining feral populations occur in many places, mainly in areas of similar climate in North America and Europe.
The nominate subspecies of this parakeet is 29 cm (11 in) long on average, with a 48-centimetre (19 in) wingspan, and weighs 100 g (3.5 oz). Females tend to be 10–20% smaller, but can only be reliably sexed by DNA or feather testing. It has bright-green upperparts. The forehead and breast are pale gray with darker scalloping and the rest of the underparts are very light-green to yellow. The remiges are dark blue, and the tail is long and tapering. The bill is orange. The call is a loud and throaty chape(-yee) or quak quaki quak-wi quarr, and screeches skveet.
Domestic breeds in colors other than the natural plumage have been produced. These include birds with white, blue, and yellow in place of green. As such coloration provides less camouflage, feral birds are usually of wild-type coloration.
The monk parakeet and the cliff parrot are the only two parrot species that build a stick nest, in a tree or on a man-made structure, rather than using a hole in a tree. The monk parrot is a gregarious species which often breeds colonially, building a single large nest with separate entrances for each pair. In the wild, the colonies can become quite large, with pairs occupying separate "apartments" in composite nests that can reach the size of a small automobile. These nests can attract many other tenants, including birds of prey such as the spot-winged falconet (Spiziapteryx circumcincta), ducks such as the yellow-billed teal (Anas flavirostris), and even mammals. Their five to 12 white eggs hatch in about 24 days.
Unusually for a parrot, monk parakeet pairs occasionally have helper individuals, often grown offspring, which assist with feeding the young.
The lifespans of monk parakeets have been given as 20-30 years; the former might refer to typical lifespans in captivity and/or in the wild, while the latter is in the range of maximum lifespans recorded for parakeets.
Monk parakeets probably have individual voice prints that allow them to recognize each other, independently from the used call type.
In its native range, the monk parakeet is very common. In Argentina, Brazil, and Uruguay, monk parakeets are regarded as major agricultural pests (as noted by Charles Darwin, among others). Their population explosion in South American rural areas seems to be associated with the expansion of eucalyptus forestry for paper pulp production, which offers the bird the opportunity to build protected nests in artificial forests where ecological competition from other species is limited.
Self-sustaining feral populations have been recorded in several U.S. states and various regions of Europe (namely Spain, Portugal, Azores, Madeira, Balearic Islands, Gibraltar, France, Corsica, Malta, Cyprus, Sardinia, Italy, Greece, Romania, Channel Islands, Great Britain, Ireland, and Belgium), as well as in British Columbia, Canada, Brazil, Mexico, Chile, Germany,Puerto Rico, Easter Island, South Korea, Singapore, and Japan. As it is an open-woodlands species, it adapts readily to urban areas.
In areas where they have been introduced, some fear they will harm crops and native species, while others dispute evidence of harm caused by feral colonies, and oppose exterminating these birds, but local bans and eradication programs exist in some areas of the U.S. Outside the U.S., introduced populations do not appear to raise similar controversy, presumably because of smaller numbers of birds, or because their settlement in urban areas does not pose a threat to agricultural production. The U.K. appears to have changed its view on its feral populations and the Department for the Environment, Food and Rural Affairs is planning to remove monk parakeets from the wild, as it believes that they threaten local wildlife and crops.
Feral populations are often descended from very small founder populations. Being as social and intelligent as they are, monk parakeets develop some cultural traditions, namely vocal dialects that differ between groups. In populations descended from a large number of birds, a range of "dialects" exists. If the founder population is small, however, a process similar to genetic drift may occur if prominent founders vocalize in an unusual "dialect", with this particular way of vocalizing becoming established in the resulting feral colony. For example, no fewer than three different "dialects" occur among the feral monk parrots of the Milford, Connecticut, metropolitan area.
In Spain, monk parakeets can be seen in Madrid, Barcelona, Cadiz, Seville, Torremolinos, Málaga, Nerja, Valencia, Tarragona, Roquetas de Mar (Andalusia), Zaragoza, the Canary Islands, and Majorca in the Balearic Islands. They were first seen around 1975. In Madrid, they especially frequent the Ciudad Universitaria (Complutense University campus) and Casa de Campo park. They are a common sight in Barcelona parks, often as numerous as pigeons. They form substantial colonies in Parc de la Ciutadella, Parc de la Barceloneta, and in smaller city parks such as Jardins Josep Trueta in Poble Nou, with a colony as far north as Empuriabrava. They are more frequent in watered urban parks with grass areas and palm trees, near to a river or the sea. The monk parakeet, as an invasive species, has become a problem to local fauna such as pigeons and sparrows, but not yet so harmful to magpies. Parakeets have also caused trouble to agriculture near the cities. Spain has outlawed the possession, selling, breeding, and trafficking of monk parakeets since 2013. Madrid has the greatest population of monk parakeets in Europe, with 10,800 parakeets as of June 2015. As of 2015, the estimated population of monk parakeets in Barcelona was 6,248.
In Greece, monk parakeets have established breeding colonies in the National Garden, Athens.
The United Kingdom population in 2011 is believed to be around 150, in the Home Counties region. The Department for the Environment, Food and Rural Affairs announced plans in 2011 to control them, countering the threat to infrastructure, crops, and native British wildlife by trapping and rehoming, removing nests, and shooting when necessary.
Groups of monk parakeets can be found in the Belgian capital city Brussels and its surrounding areas. They have been living in the wild at least since the 1970s.
Populations in Germany, Czech Republic, Austria, and Denmark were once reported, but these seem to have been extirpated. Other populations in the U.K., France, and the Netherlands have also similarly declined into extirpation.