Monk parakeet
The monk parakeet (Myiopsitta monachus), also known as the Quaker parrot, is a small species of true parrot in the family Psittacidae, native to the lowland subtropical and tropical regions of central Argentina, Bolivia, Paraguay, Uruguay, and southern Brazil.[1] It measures 29–30 cm in length with bright green upperparts, a greyish face and breast, greenish-yellow underparts, and a curved red-orange bill.[2] Uniquely among parrots, monk parakeets construct large communal nests from sticks, often housing multiple breeding pairs in colonial structures built in trees or on artificial supports.[3] Popular in the pet trade, escaped and released individuals have established invasive feral populations across North America (particularly in Florida and Texas), Europe (including Spain, Italy, and the United Kingdom), and other regions, where they compete with native cavity-nesting birds, damage agricultural crops, and create hazards by nesting on electrical utility structures.[4][5] The species remains abundant in its native range and is classified as Least Concern by the IUCN, with overall populations stable or increasing despite local management efforts against invasives.[6]Taxonomy and systematics
Classification and etymology
The monk parakeet (Myiopsitta monachus) is the only species in the genus Myiopsitta within the family Psittacidae, order Psittaciformes.[7][8] Its full taxonomic classification is Kingdom: Animalia, Phylum: Chordata, Class: Aves, Order: Psittaciformes, Family: Psittacidae, Genus: Myiopsitta, Species: monachus.[7][9] The binomial name was first published as Psittacus monachus by Dutch naturalist Pieter Boddaert in 1783, based on an earlier description by Georges-Louis Leclerc, Comte de Buffon; the modern genus Myiopsitta was introduced by Charles Lucien Bonaparte in 1854 to reflect its distinct morphology and behavior relative to other parrots.[10] The genus name Myiopsitta combines Ancient Greek muos (mouse) with Neo-Latin psitta (parrot), alluding to the mouse-grey plumage on the face, forehead, and breast.[11] The specific epithet monachus derives from Latin for "monk," referencing the same grey head feathering that evokes a monk's cowl or hood.[11] The English common name "monk parakeet" (also known as Quaker parrot) similarly stems from this cowl-like grey coloration, with "parakeet" denoting its small size and long-tailed parrot form.[12]Subspecies and genetic variation
Four subspecies of the monk parakeet (Myiopsitta monachus) are traditionally recognized, distinguished by variations in plumage coloration, body size, bill morphology, and geographic isolation within South America. M. m. monachus (nominate), the largest subspecies, inhabits southeast Brazil (Rio Grande do Sul), Uruguay, and northeastern Argentina (Entre Ríos, Santa Fé, Córdoba, northern Río Negro). M. m. calita occupies western Argentina from Salta to Río Negro, characterized by bluer wings and a darker gray head. M. m. cotorra ranges across southeast Bolivia (Tarija), Paraguay, southern Brazil (Mato Grosso do Sul), and northern Argentina (Formosa, Chaco), with brighter green upperparts and a less yellowish abdomen. M. m. luchsi, found in arid intermontane valleys of the eastern Andes in Bolivia (southern Cochabamba to northern Chuquisaca), exhibits brighter overall plumage, yellow on the lower breast, pale underwings, a dark base to the upper mandible, and a pale gray breast lacking barring; it is also notable for cliff-nesting behavior.[13]| Subspecies | Geographic Range | Key Morphological Features |
|---|---|---|
| M. m. monachus | SE Brazil (Rio Grande do Sul), Uruguay, NE Argentina (Entre Ríos, Santa Fé, Córdoba, N Río Negro) | Largest size |
| M. m. calita | Western Argentina (Salta to Río Negro) | Bluer wings, darker gray head |
| M. m. cotorra | SE Bolivia (Tarija), Paraguay, S Brazil (Mato Grosso do Sul), N Argentina (Formosa, Chaco) | Brighter green upperparts, less yellowish abdomen |
| M. m. luchsi | E Andes valleys, Bolivia (S Cochabamba to N Chuquisaca) | Brighter plumage, yellow lower breast, pale underwings, dark upper mandible base, unbarred pale gray breast |
Physical description
Morphology and plumage
The monk parakeet (Myiopsitta monachus) exhibits a robust, compact morphology typical of psittacids, with a body length of 29–33 cm, wingspan of approximately 48 cm, and average mass of 90–130 g.[7] It features a large head relative to body size, a strong, hooked bill adapted for cracking seeds and manipulating nest materials, and zygodactyl feet with two forward-facing and two rear-facing toes for grasping branches and twigs.[14] The tail is long, pointed, and graduated, aiding in agile flight and balance during foraging.[14][15] The bill is pale pinkish-horn in color, legs and feet are gray, and irises are brown.[4][7] Plumage is predominantly bright green on the upperparts, including the nape, back, wings, and rump, providing camouflage in native woodland habitats.[7] The head shows a gray forehead, lores, cheeks, and throat, often with subtle darker scalloping on the breast, transitioning to paler gray there and yellowish-green on the abdomen and undertail coverts.[7] Flight feathers (remiges) are blue-black, contrasting with the green body, while tail feathers are green above and olive below.[15] Plumage brightness increases southward, with more vivid green dorsally and yellow ventrally in southern populations.[16] Sexual dimorphism in plumage is subtle, with spectrophotometric analyses revealing females duller in crown, nape, and wing coloration compared to males, though overall patterns remain similar and non-diagnostic for field identification.[17] Captive mutations, such as blue (lacking yellow pigments) or yellow variants, occur but are not representative of wild populations.[18] Juveniles resemble adults but with duller colors and shorter tails, molting to adult plumage within the first year.[7]Size, weight, and sexual dimorphism
The monk parakeet (Myiopsitta monachus) measures 28–30 cm (11–12 in) in total length, with a wingspan ranging from 48–53 cm (19–21 in).[19][20] Adults typically weigh 90–120 g (3.2–4.2 oz), though masses up to 140 g have been recorded.[19][20] Sexual dimorphism is minimal and not readily apparent in the field. Males are slightly larger than females in body size, with females comprising about 10% of observed size variation, though females may exhibit temporary increases in body mass during breeding.[17][21] Subtle plumage color differences occur in the crown, nape, and wing regions, detectable via spectrophotometry but not visible to the naked eye; no pronounced differences exist in overall coloration, beak, or tail structure.[17] Sex determination generally requires molecular methods, as external traits do not reliably distinguish individuals.[21][15]Behavioral ecology
Diet, foraging, and physiology
The monk parakeet (Myiopsitta monachus) maintains a primarily granivorous and frugivorous diet, consisting mainly of seeds from grasses and trees, leaf buds, fruits, berries, nuts, and blossoms.[22] Small amounts of adult and larval insects are consumed opportunistically, though invertebrates comprise less than 5% of intake in most observations.[22] In native South American ranges, the species exploits wild herbaceous plants, seeds, and fruits, while introduced populations demonstrate dietary flexibility, incorporating up to 41.7% anthropogenic foods such as grains, bread, and waste in urban settings like Barcelona, alongside 26.9% herbaceous matter and 22.2% leaves and seeds.[23] Nestling diets mirror adults, featuring regurgitated seeds, fruits, and vegetable matter including cultivated maize and grass seeds, reflecting a generalist strategy that sustains rapid growth rates of 10-15% body mass daily in early development.[24] Foraging typically occurs in flocks of 4-50 individuals, with group size correlating inversely with per capita vigilance time—larger flocks reduce individual scanning by up to 50% due to shared predator detection, enabling more efficient resource exploitation.[25] Birds ground-feed on seeds or climb vegetation to access buds and fruits, often traveling 3.2-8 km from nests daily, though distances extend to 24 km in non-breeding periods when food patches are dispersed.[26] In Mediterranean urban invasions, foraging shifts over time toward human-subsidized resources, with Barcelona populations reducing reliance on natural seeds from 60% in 2001 to under 40% by 2017, correlating with population density increases.[27] This plasticity, driven by opportunistic selection of high-energy items like nuts and grains, supports high reproductive output in novel environments. Physiologically, the species' digestive tract—featuring a expandable crop for bolus storage, acidic proventriculus for initial protein breakdown, and muscular ventriculus for grinding tough seeds—facilitates processing of fibrous, high-lipid foods with retention times of 1-4 hours, optimizing nutrient extraction for flight-intensive lifestyles.[28] As psittacines, monk parakeets exhibit elevated basal metabolic rates (around 1.5-2 times passerine averages), necessitating frequent foraging bouts of 10-20 per day to meet caloric demands exceeding 300 kJ/kg body mass daily, though specific M. monachus data remain sparse beyond general parrot models.[28] This system enables survival on imbalanced urban diets without nutritional deficits, as evidenced by stable isotope analyses showing no growth impairments in invaded areas.[23]Breeding, nesting, and reproduction
Monk parakeets (Myiopsitta monachus) are unique among parrots in constructing large communal stick nests composed primarily of thorny twigs, which can exceed 5 feet (1.5 m) in diameter and weigh over a ton in mature colonies.[29] These nests contain multiple chambers, typically 1–20 but occasionally over 200, each serving as an apartment for a breeding pair, and are built and maintained year-round by colony members, including non-breeders.[29] [30] Nests are placed in deciduous or evergreen trees, palms, utility poles, or structures like silos, with males performing most construction and maintenance.[29] [30] Breeding pairs are socially monogamous, engaging in courtship through mutual preening and beak grasping, with reproduction typically occurring in spring in their native South American range.[29] Females lay clutches of 5–8 white eggs, measuring approximately 1.1 inches (2.8 cm) in length, though means of 4.8 eggs for first clutches and 4.5 for replacements have been recorded in some populations.[29] [31] [30] Incubation, performed solely by the female starting with the first egg, lasts about 24 days, during which the male feeds her every 1–2 hours; hatching success varies but averages around 70–80% in studied nests.[31] [32] [30] Nestlings hatch with eyes closed and sparse yellowish down, remaining altricial and dependent on both parents for feeding, initially by the male regurgitating food to the female, then directly by both.[29] [30] Young fledge approximately 40–49 days after hatching, often departing the nest simultaneously, but stay with parents for up to three months post-fledging while learning foraging skills.[31] [30] Pairs may attempt replacement clutches if the first fails, enabling up to two broods per season, though success rates for second broods are lower.[33] [30] Breeding typically begins in the second year, with 50–63% of adults participating annually.[34]