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Psittaciformi [1]

Agapornis roseicollis
Classificazione scientifica
RegnoAnimalia
PhylumChordata
ClasseAves
OrdinePsittaciformes

Wagler, 1830

Famiglie
Un'ara gialloblu mentre mangia la noce che tiene con un piede.

Gli Psittaciformi [2] (Psittaciformes [3][4] Wagler, 1830) sono un ordine di uccelli che comprende circa 372 specie di pappagalli suddivise in 86 generi; vivono soprattutto nelle regioni calde e tropicali. L'ordine viene suddiviso in tre famiglie: gli Psittacidi (pappagalli «veri»), i Cacatuidi (cacatua) e gli Strigopidi (pappagalli della Nuova Zelanda) [5] . Generalmente i pappagalli hanno una distribuzione pantropicale, ma alcune specie si incontrano anche nelle regioni temperate dell'Emisfero Australe. La maggiore diversità di specie si incontra in Sudamerica ed Australasia.

Tra i più importanti aspetti che caratterizzano i pappagalli vi sono il robusto becco ricurvo, la posizione eretta che mantengono quando sono appollaiati, le zampe robuste e i piedi zigodattili muniti di forti unghie. La maggior parte delle specie hanno un colore prevalentemente verde, spesso unito ad altri colori brillanti, ma altre sono variopinte. I cacatua variano in colorazione dal bianco al nero ed esibiscono una cresta mobile di penne sulla sommità della testa. In quasi tutti i pappagalli il dimorfismo sessuale è scarso o assente. Per quanto riguarda la lunghezza hanno le dimensioni più variabili tra tutti gli uccelli.

L'alimentazione dei pappagalli è composta soprattutto da semi, noci, frutta, boccioli e altre sostanze vegetali. Poche specie mangiano anche ratti e vermi e i Lorini sono specializzati nel mangiare nettare dei fiori e frutti morbidi. Quasi tutti i pappagalli nidificano nelle cavità degli alberi (o, in cattività, nelle scatole-nido) e depongono uova bianche da cui sgusciano piccoli inetti.

I pappagalli, insieme a corvi, cornacchie, ghiandaie e gazze, sono tra gli uccelli più intelligenti e l'abilità di alcune specie nell'imitare la voce umana li ha resi molto popolari come animali domestici. La cattura di esemplari selvatici per il mercato degli animali da compagnia, la caccia, la deforestazione e la compezione con le specie invasive ha notevolmente diminuito il numero dei pappagalli selvatici e questi animali stanno tuttora subendo uno sfruttamento da parte dell'uomo maggiore di quello di ogni altro gruppo di uccelli [6] . Le recenti misure di conservazione volte a proteggere l'habitat di alcune tra le più importanti specie di pappagallo sono servite anche a proteggere molte specie meno note che vivono nello stesso ecosistema [7] .

Evoluzione e sistematica

Origini ed evoluzione

Le ricerche che cercano di svelare l'origine dei pappagalli sono tuttora in corso. La maggiore diversità di specie che si incontra in Sudamerica ed Australasia sembra indicare che l'ordine degli Psittaciformi abbia avuto origine nel Gondwana, con centro di diffusione in Australasia [8] . La scarsità dei resti fossili di uccello, tuttavia, rende molto difficile valutare la certezza di questa ipotesi.

Si ritiene che il più antico fossile di pappagallo, risalente al Cretaceo superiore (circa 70 milioni di anni fa), sia un singolo frammento, lungo 1002 mm, del ramo inferiore di un grosso becco ritrovato nei depositi della Formazione di Lance Creek nella Contea di Niobrara (Wyoming) [9] . Vari studiosi, tuttavia, ritengono con certezza che questo fossile non appartenga a un uccello, ma ad un teropode cenagnatide o ad un altro dinosauro non-aviario munito di un becco simile a quello di un uccello [10][11] .

Al giorno d'oggi si ritiene generalmente che gli Psittaciformi o gli antenati che hanno in comune con altri uccelli fossero già presenti al periodo della scomparsa dei dinosauri, circa 65 milioni di anni fa. Se fosse così, i pappagalli probabilmente non sono creature che svilupparono autapomorfie morfologiche, ma i discendenti di uccelli arboricoli generalisti abbastanza simili (ma non necessariamente imparentati) ai nittibi e ai bocca di rana odierni.

Il luogo di origine dei primi pappagalli fossili è l'Europa. Il reperto più antico è un osso alare di Mopsitta tanta scoperto in Danimarca e risalente a 54 milioni di anni fa [12] . All'epoca la regione aveva un clima tropicale dovuto al cosiddetto «Massimo Termico Paleocene-Eocene».

Fossili di età successiva risalgono all'Eocene, periodo iniziato circa 50 milioni di anni fa. Alcuni fossili quasi completi di uccelli simili a pappagalli sono stati rinvenuti in Inghilterra e Germania [13] . Sembra più probabile, però, che questi fossili non appartengano ai diretti antenati dei pappagalli moderni, ma piuttosto a linee evolutive loro imparentate che si evolvettero nell'Emisfero Boreale e scomparvero senza lasciare discendenti. Probabilmente non sono quindi «anelli mancanti» tra pappagalli ancestrali e moderni, ma piuttosto linee di Psittaciformi che si evolvettero parallelamente ai pappagalli veri e ai cacatua, sviluppando le loro peculiari autapomorfie:

  • Psittacopes (Eocene inferiore/medio di Geiseltal, Germania) – forma basale?
  • Serudaptus – pseudasturide o psittacide?
  • Pseudasturidae (o più correttamente Halcyornithidae)
    • Pseudasturides- in passato Pseudastur
  • Vastanavidae
    • Vastanavis (Eocene inferiore di Vastan, India)
  • Quercypsittidae
 
Le penne di un'amazzone testagialla. Le componenti blu della colorazione verde sono dovute alla diffusione della luce, mentre quelle verdi sono dovute ad un pigmento.

I più antichi resti fossili di pappagalli moderni risalgono a circa 23-20 milioni di anni fa e provengono anch'essi dall'Europa. I resti fossili successivi - di nuovo di provenienza europea - consistono di ossa chiaramente attribuibili a pappagalli di tipo moderno. Per quanto riguarda questo periodo l'Emisfero Australe non è così ricco di fossili come quello boreale e i primi fossili attribuibili a pappagalli risalgono solo al Miocene inferiore o medio, circa 20 milioni di anni fa. A questo periodo, tuttavia, risale già una mascella superiore fossile indistinguibile da quella dei moderni cacatua. In passato si ritenevano risalenti al Miocene anche altri resti fossili che successivamente sono stati datati più correttamente a 5 milioni di anni fa.

Tra i pappagalli fossili chiaramente attribuili agli Psittacidi o ai loro diretti antenati ricordiamo:

  • Archaeopsittacus (Oligocene superiore/Miocene inferiore)
  • Xenopsitta (Miocene inferiore della Repubblica Ceca)
  • Psittacidae gen. e spp. indet. (Miocene inferiore/medio di Otago, Nuova Zelanda) - varie specie
  • Bavaripsitta (Miocene medio di Steinberg, Germania)
  • Psittacidae gen. e sp. indet. (Miocene medio della Francia) - erroneamente attribuito a Pararallus dispar, comprende Psittacus lartetianus

I seguenti fossili del Paleogene, invece, sembra non appartengano agli Psittaciformi:

  • Palaeopsittacus (Miocene inferiore/medio dell'Europa nord-occidentale) - un caprimulgiforme (podargide?) o un quercypsittide?
  • Precursor (Eocene inferiore) – una vera chimera, forse uno pseudasturide o uno psittacide
  • Pulchrapollia (Eocene inferiore) – comprende il cosiddetto Primobucco olsoni - uno psittaciforme (pseudasturide o psittacide)?

Filogenesi

 
Il kaka, una delle tre specie attuali di Strigopidi.

La filogenesi dei pappagalli è ancora sotto esame. La classificazione qua presente è quella ritenuta attualmente più valida, ma studi successivi potrebbero apportarvi delle modifiche. Proprio per questo motivo non va considerata una stesura definitiva.

Gli Psittaciformi comprendono tre linee evolutive principali: gli Strigopidi, gli Psittacidi (pappagalli veri) e i Cacatuidi (cacatua). In passato gli Strigopidi erano ritenuti un gruppo di Psittacidi, ma studi più recenti sembrano indicare che queste specie originarie della Nuova Zelanda vadano poste alla base dell'albero filogenetico dei pappagalli, ben distanti sia dagli Psittacidi che dai Cacatuidi [8][14][15] .

Anche i Cacatuidi sono piuttosto diversi dagli Psittacidi: presentano una cresta mobile sulla testa, una diversa disposizione delle arterie carotidi, una cistifellea e alcune differenze nelle ossa del cranio; sono inoltre privi delle cosiddette penne «a testura Dick» che, negli Psittacidi, diffondono la luce in maniera tale da produrre i tipici colori vibranti tipici di molti pappagalli. Le penne colorate con alti livelli di psittacofulvina resistono meglio di quelle bianche agli attacchi del batterio Bacillus licheniformis [16] .

In passato i lorichetti venivano classificati in una terza famiglia, i Loriidi [17] , ma gli studi sul DNA hanno dimostrato che sono Psittacidi a tutti gli effetti, strettamente imparentati con i pappagalli dei fichi (due dei tre generi che costituiscono la tribù dei Cyclopsittacini della sottofamiglia degli Psittacini) e il pappagallino ondulato (tribù dei Melopsittacini della sottofamiglia dei Platicercini) [8][14][15] .

Sistematica

La seguente classificazione indica le varie sottofamiglie degli Psittaciformi. I dati molecolari sembrano indicare che alcune di esse costituiscano famiglie vere e proprie, ma una corretta sistematica è ancora da definire.

 
Un lorichetto arcobaleno della sottospecie moluccanus appollaiato sul recinto di un giardino in Australia.
 
Lo scheletro di un pappagallo.

Famiglia Strigopidae: pappagalli della Nuova Zelanda

  • Tribù Nestorini: 1 genere con solo 2 specie viventi, il kea e il kaka della Nuova Zelanda;
  • Tribù Strigopini: il kakapo della Nuova Zelanda, incapace di volare e gravemente minacciato.

Famiglia Cacatuidae: cacatua

Famiglia Psittacidae: pappagalli veri

  • Sottofamiglia Arinae: pappagalli neotropicali, circa 160 specie suddivise in circa 30 generi. Probabilmente 2 linee evolutive distinte [14][18] ;
  • Sottofamiglia Loriinae: circa una dozzina di generi con circa 50 specie di lorichetti e lori, originari soprattutto della Nuova Guinea, ma diffusi anche in Australia, Indonesia e nelle isole del Pacifico meridionale;
  • Sottofamiglia Micropsittinae: 6 specie di pappagalli pigmei, appartenenti tutte ad un unico genere;
  • Sottofamiglia Psittacinae
    • Tribù Cyclopsittacini: pappagalli dei fichi, 3 generi, tutti originari della Nuova Guinea o delle isole vicine;
    • Tribù Polytelini: tre generi originari dell'Australia e della Wallacea che in passato venivano classificati tra i pappagalli dalla coda larga;
    • Tribù Psittrichadini: un'unica specie, il pappagallo di Pesquet;
    • Tribù Psittacini: pappagalli afrotropicali, circa una dozzina di specie suddivise in 3 generi;
    • Tribù Psittaculini: pappagalli psittaculini paleotropicali, circa 70 specie viventi suddivise in 12 generi diffuse dall'India all'Australasia.
  • Subfamiglia Platycercinae: pappagalli dalla coda larga; circa 30 specie in una dozzina di generi

Other lists

Distribuzione

 
Quasi tutte le specie di pappagallo sono tropicali, ma alcune specie, come questo parrocchetto australe, si spingono molto all'interno delle zone temperate.

I pappagalli vivono nelle zone tropicali e subtropicali di tutti i continenti, essendo diffusi in Australia e isole del Pacifico, Asia meridionale, Sud-est asiatico, regioni meridionali del Nordamerica, Sudamerica e Africa. Alcune isole dei Caraibi e del Pacifico ospitano specie endemiche. Di gran lunga la maggiore diversità di specie si incontra in Australasia e Sudamerica. I lori e i lorichetti sono diffusi in un'area che da Sulawesi e Filippine si spinge fino all'Australia e alla Polinesia francese; il maggior numero di specie si incontra in Nuova Guinea e nelle aree circostanti. La sottofamiglia degli Arini, comprendente tutti i pappagalli neotropicali, tra cui amazzoni, ara e conuri, è distribuita dal Messico settentrionale e dalle Bahamas fino alla Terra del Fuoco, all'estremità meridionale del Sudamerica. I pappagalli pigmei, che costituiscono la sottofamiglia dei Micropsittini, appartengono tutti a un unico genere limitato alla Nuova Guinea. La sottofamiglia dei Nestorini è costituita da tre specie aberranti tutte originarie della Nuova Zelanda. I pappagalli dalla coda larga della sottofamiglia dei Platycercini sono ristretti ad Australia, Nuova Zelanda e isole del Pacifico (fino alle Figi). L'ultima sottofamiglia di pappagalli veri, gli Psittacini, occupa un vastissimo areale che da Australia e Nuova Guinea si spinge fino all'Asia meridionale e all'Africa. Il maggior numero di specie di cacatua vive in Australia e Nuova Guinea, ma alcune vivono anche nelle Isole Salomone, in Indonesia e alle Filippine (una specie estinta in passato viveva anche in Nuova Caledonia [19] ).

Alcune specie di pappagallo si spingono nelle fredde regioni temperate del Sudamerica e della Nuova Zelanda. Una specie, il parrocchetto della Carolina, viveva nelle regioni temperate del Nordamerica, ma venne cacciata fino alla sua totale scomparsa agli inizi del XX secolo. Numerose specie sono state introdotte in aree dal clima temperato e al giorno d'oggi si incontrano popolazioni stabili in alcuni Stati degli Stati Uniti, in Regno Unito e Spagna [20][21] .

Sebbene alcune specie di pappagallo siano sedentarie o perfino migratrici, la maggior parte di esse effettua brevi spostamenti stagionali e alcune hanno perfino adottato uno stile di vita nomade [22] .

Morfologia

 
Il cacatua nero lucente mostra il becco robusto, i piedi artigliati e gli occhi in posizione laterale tipici di tutti i pappagalli

Le specie attuali variano in dimensione dal pappagallo pigmeo facciacamoscio di meno di 10 g di peso e 8 cm di lunghezza all'ara giacinto di 1 m di lunghezza e al kakapo di 4 kg di peso. Tra le varie famiglie, quella degli Strigopidi comprende tre specie di notevoli dimensioni, così come quella dei cacatua. I pappagalli psittacidi, invece, variano moltissimo in dimensioni a seconda delle specie.

La principale caratteristica fisica che caratterizza maggiormente i pappagalli è il robusto becco largo e ricurvo. Il ramo superiore, dall'estremità appuntita, è prominente e ricurvo all'ingiù. Non è fuso alle ossa del cranio e così è in grado di muoversi indipendentemente, permettendo a questi uccelli di mordere esercitando una notevole pressione. Il ramo inferiore è più corto ed ha un margine tagliente molto affilato che poggia contro la porzione piatta del ramo superiore in modo simile ad un incudine. I pappagalli che si nutrono di semi hanno una lingua robusta che permette loro di manipolare i semi o le noci nel becco in posizione tale che le mandibole possano applicare meglio la loro pressione. La testa è grande e gli occhi sono posizionati lateralmente; la visione binoculare, quindi, è molto limitata, ma quella periferica aumenta notevolmente.

Le specie di cacatua hanno una cresta di penne mobili sulla sommità della testa che può essere sollevata e abbassata a piacere. Tale cresta non è presente in nessun'altra specie di pappagallo, ma i lorichetti del Pacifico dei generi Vini e Phigys sono in grado di arruffare le penne della corona e della nuca. Il colore predominante del piumaggio dei pappagalli è il verde, ma la maggior parte delle specie presenta anche piccole quantità di penne rosse o di altro colore. I cacatua costituiscono l'unica eccezione, poiché durante la loro storia evolutiva hanno perso completamente il colore verde e azzurro del piumaggio e ora sono generalmente bianchi o neri con alcune zone rosse, rosa o gialle. Tra i pappagalli non è presente un notevole dimorfismo sessuale, ma vi sono comunque alcune eccezioni, prima tra tutte il pappagallo eclettico.

Comportamento

Studiare i pappagalli in natura presenta notevoli difficoltà, poiché sono difficili da catturare e una volta presi è molto difficile anche riuscirli a marcare. Gran parte delle ricerche svolte su uccelli selvatici si basano sull'applicazione di anelli (o bande) alle zampe o di targhette alle ali, ma i pappagalli tendono a toglierseli poco dopo [22] ; inoltre, si spostano su areali molto vasti. Di conseguenza sono tuttora presenti moltre lacune per quanto riguarda la conoscenza del loro comportamento.

I pappagalli hanno un volo sostenuto e diretto. La maggior parte delle specie trascorre gran parte del tempo appollaiata sui rami della volta della foresta. Spesso utilizzano il becco per arrampicarsi o appendersi a rami o ad altri supporti. Al suolo camminano solitamente con passo ondeggiante.

Diet

A Yellow-tailed Black Cockatoo using its strong bill to search for grubs

The diet of parrots consists of seeds, fruit, nectar, pollen, buds, and sometimes insects e.g. cockroaches and to a lesser degree animal prey. Without question the most important of these to most true parrots and cockatoos are seeds. The evolution of the large and powerful bill can be explained primarily as an adaptation to opening and consuming seeds. All true parrots except the Pesquet's Parrot employ the same method to obtain the seed from the husk; the seed is held between the mandibles and the lower mandible crushes the husk, whereupon the seed is rotated in the bill and the remaining husk is removed.[22] A foot is sometimes used to help holding large seeds in place. Parrots are seed predators rather than seed dispersers; and in many cases where species are recorded as consuming fruit they are only eating the fruit to get at the seed. As seeds often have poisons to protect them, parrots are careful to remove seed coats and other fruit parts which are chemically well defended, prior to ingestion. Many species in the Americas, Africa, and Papua New Guinea consume clay which both releases minerals and absorbs toxic compounds from the gut.[23]

 
Parrots at a clay lick in Ecuador. Consuming clay neutralises toxins in the diet.

The lories and lorikeets, Swift Parrot and Philippine Hanging Parrot are primarily nectar and pollen consumers, and have tongues with brush tips to collect this source of food, as well as some specialized gut adaptations to accommodate this diet.[24] Many other species also consume nectar as well when it becomes available.

In addition to feeding on seeds and flowers, some parrot species will prey on animals. Golden-winged Parakeets prey on water snails, and famously the Keas of New Zealand will kill juvenile petrels and even attack and indirectly kill adult sheep.[25] Another New Zealand parrot, the Antipodes Island Parakeet, enters the burrows of nesting Grey-backed Storm-petrels and kills the incubating adults.[26] Some cockatoos and the Kākā will also excavate branches and wood to obtain grubs.

Breeding

Although there are a few exceptions, parrots are monogamous breeders which nest in cavities and hold no territories other than their nesting sites.[22][27] The pair bonds of the parrots and cockatoos are strong and the pair will remain close even during the non-breeding season, even if they join larger flocks. As with many birds pair bond formation is preceded by courtship displays; these are relatively simple in the case of cockatoos. In Psittacidae parrots common breeding displays, usually undertaken by the male, include slow deliberate steps known as a "parade" or "stately walk" and the "eye-blaze", where the pupil of the eye constricts to reveal the edge of the iris.[22] Allopreening is used by the pair to help maintain the bond. Cooperative breeding, where birds other than the breeding pair help the pair raise the young and is common in some bird families, is extremely rare in parrots, and has only unambiguously been demonstrated in the Golden Parakeet (which may also exhibit polyamorous or group breeding system with multiple females contributing to the clutch).[28]

 
The vast majority of parrots are, like this Blue-winged Parrotlet, cavity nesters.

Only the Monk Parakeet and five species of Agapornis lovebird build nests in trees,[29] and three Australian and New Zealand ground parrots nest on the ground. All other parrots and cockatoos nest in cavities, either tree hollows or cavities dug into cliffs, banks or the ground. The use of holes in cliffs is more common in the Americas. Many species will use termite nests, possibly as it reduces the conspicuousness of the nesting site or because it creates favourable microclimates.[30] In most cases both parents will participate in the nest excavation. The length of the burrow varies with species, but is usually between 0.5–2 m in length. The nests of cockatoos are often lined with sticks, wood chips and other plant material. In the larger species of parrot and cockatoo the availability of nesting holes can be limited and this can lead to intense competition for them both within the species and between species, as well as with other bird families. The intensity of this competition can limit breeding success in some cases.[31][32] Some species are colonial, with the Burrowing Parrot nesting in colonies up to 70,000 strong.[33] Coloniality is not as common in parrots as might be expected, possibly because most species adopt old cavities rather than excavate their own.[34]

The eggs of parrots are white. In most species the female undertakes all the incubation, although incubation is shared for in cockatoos, the Blue Lorikeet, and the Vernal Hanging Parrot. The female remains in the nest for almost all of the incubation period and is fed both by the male and during short breaks. Incubation varies from 17 to 35 days, with the larger species have the longer incubation periods. The newly born young are altricial, either lacking feathers or with sparse white down. The young spend anything from three weeks to four months in the nest, depending on species, and may receive parental care for up to further months thereafter.[35]

As typical of K-selected species, the macaws and other larger parrot species have low reproductive rates. They require several years to reach maturity, produce one or very few young per year, and sometimes do not breed every year at all.

Intelligence and learning

 
Sun Parakeet demonstrating parrots' puzzle-solving skills

Studies with captive birds have given insight into which birds are the most intelligent. While parrots have the distinction of being able to mimic human speech, studies with the African Grey Parrot have shown that some are able to associate words with their meanings and form simple sentences (see Alex and N'kisi). Along with crows, ravens, and jays (family Corvidae), parrots are considered the most intelligent of birds. The brain-to body size ratio of psittacines and corvines is actually comparable to that of higher primates.[36] One argument against the supposed intelligent capabilities of bird species is that birds have a relatively small cerebral cortex, which is the part of the brain considered to be the main area of intelligence in other animals. However, it seems that birds use a different part of their brain, the medio-rostral neostriatum / hyperstriatum ventrale, as the seat of their intelligence. Not surprisingly, research has shown that these species tend to have the largest hyperstriata, and Dr. Harvey J. Karten, a neuroscientist at University of California, San Diego who has studied the physiology of birds, discovered that the lower part of the avian brain is functionally similar to that in humans. Not only have parrots demonstrated intelligence through scientific testing of their language using ability, but some species of parrot such as the Kea are also highly skilled at using tools and solving puzzles.[37]

Learning in early life is apparently important to all parrots, and much of that learning is social learning. Social interactions are often practised with siblings, and in several species creches are formed with several broods, and these as well are important for learning social skills. Foraging behaviour is generally learnt from parents, and can be a very protracted affair. Supra-generalists and specialists are generally independent of their parents much quicker than partly specialised species which may have to learn skills over a long period of time as various resources become seasonally available. Play forms a large part of learning in parrots; it can be solitary, and related to motor skills, or social. Species may engage in play fights or wild flights to practice predator evasion. An absence of stimuli can retard the development of young birds, as demonstrated by a group of Vasa Parrots kept in tiny cages with domesticated chickens from the age of 3 months; at 9 months these birds still behaved in the same way as 3 month olds, but had adopted some chicken behaviour.[22] In a similar fashion captive birds in zoo collections or pets can, if deprived of stimuli, develop stereotyped behaviours and harmful behaviours like self plucking. Aviculturists working with parrots have identified the need for environmental enrichment to keep parrots stimulated.

Sound imitation and speech

  Lo stesso argomento in dettaglio: Talking bird.
  Lo stesso argomento in dettaglio: Animal language.
Video of an Orange-winged Amazon saying "Hello" having been prompted by some people

Many species can imitate human speech or other sounds. A study by Irene Pepperberg suggested a high learning ability in an African Grey Parrot named Alex. Alex was trained to use words to identify objects, describe them, count them, and even answer complex questions such as "How many red squares?" with over 80% accuracy. N'kisi, another African grey, has been shown to have a vocabulary of approximately a thousand words, and has displayed an ability to invent as well as use words in context and in the correct tense.

Parrots do not have vocal cords, so sound is accomplished by expelling air across the mouth of the bifurcated trachea. Different sounds are produced by changing the depth and shape of trachea. African Grey Parrots of all subspecies are known for their superior ability to imitate sounds and human speech. This ability has made them prized as pets from ancient time to the present. In the Masnavi, a writing by Rumi of Persia, AD 1250, the author talks about an ancient method for training parrots to speak.

Although most parrot species are able to imitate, some of the Amazon parrots are generally regarded as the next-best imitators and speakers of the parrot world.

The question of why birds imitate remains open, but those that do often score very high on tests designed to measure problem solving ability. Wild African Grey Parrots have been observed imitating other birds.[38] Most other wild parrots have not been observed imitating other species.

Relationship with humans

Humans and parrots have a complicated relationship. Economically they can be beneficial to communities as sources of income from the pet trade and are highly marketable tourism draws and symbols. But some species are also economically important pests, particularly some cockatoo species in Australia. Some parrots have also benefited from human changes to the environment in some instances, and have expanded their ranges alongside agricultural activity, but many species have declined as well.

It is possible to devote careers to parrots. Zoos and aquariums employ keepers to care for and shape the behavior of parrots. Some veterinarians who specialize in avian medicine will treat parrots exclusively. Biologists study parrot populations in the wild and help to conserve wild populations. Aviculturalists breed and sell parrots for the pet trade.

Tens of millions of parrots have been removed from the wild, and parrots have been traded in greater numbers and for far longer than any other group of wild animals.[39] Many parrot species are still threatened by this trade as well as habitat loss, predation by introduced species, and hunting for food or feathers. Some parrot species are agricultural pests,[40] eating fruits, grains, and other crops, but parrots can also benefit economies through birdwatching based ecotourism.[41]

Pets

 
Pet Cuban Amazons in Cuba

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Parrots are popular as pets due to their sociable and affectionate nature, intelligence, bright colours, and ability to imitate human voices. The domesticated Budgerigar, a small parrot, is the most popular of all pet bird species. In 1992 the newspaper USA Today published that there were 11 million pet birds in the United States alone,[42] many of them parrots. Europeans kept birds matching the description of the Rose-ringed Parakeet (or called the ring-necked parrot), documented particularly in a first century account by Pliny the Elder.[43] As they have been prized for thousands of years for their beauty and ability to talk, they have also often been misunderstood. For example, author Wolfgang de Grahl discusses in his 1987 book "The Grey Parrot," that some importers allowed parrots to drink only coffee while they were being shipped by boat considering pure water to be detrimental and believing that their actions would increase survival rates during shipping. (Nowadays it is commonly accepted that the caffeine in coffee is toxic to birds).

Pet parrots may be kept in a cage or aviary; though generally, tame parrots should be allowed out regularly on a stand or gym. Depending on locality, parrots may be either wild caught or be captive bred, though in most areas without native parrots, pet parrots are captive bred.

Parrot species that are commonly kept as pets include conures, macaws, Amazons, cockatoos, African Greys, lovebirds, cockatiels, budgerigars, eclectus, Caiques, parakeets, Pionus and Poicephalus. Species vary in their temperament, noise level, talking ability, cuddliness with people, and care needs, although how a parrot has been raised usually greatly affects its personality.

Parrots can make excellent companion animals, and can form close, affectionate bonds with their owners. However they invariably require an enormous amount of attention, care and intellectual stimulation to thrive, akin to that required by a three year old child, which many people find themselves unable to provide in the long term.[44] Parrots that are bred for pets may be hand fed or otherwise accustomed to interacting with people from a young age to help ensure they will be tame and trusting. However, parrots are not low maintenance pets; they require feeding, grooming, veterinary care, training, environmental enrichment through the provision of toys, exercise, and social interaction (with other parrots or humans) for good health. Some large parrot species, including large cockatoos, Amazons, and macaws, have very long lifespans with 80 years being reported and record ages of over one hundred. Small parrots, such as lovebirds, hanging parrots, and budgies have shorter life spans of up to 15–20 years. Some parrot species can be quite loud, and many of the larger parrots can be destructive and require a very large cage, and a regular supply of new toys, branches, or other items to chew up. The intelligence of parrots means they are quick to learn tricks and other behaviors—both good and bad—that will get them what they want, such as attention or treats.

The popularity, longevity, and intelligence of many of the larger species of pet parrots has led to many of these birds being re-homed during the course of their long lifespans.

A common problem is that large parrot species which are cuddly and gentle as juveniles will mature into intelligent, complex, often demanding adults that can outlive their owners. Due to these problems, and the fact that homeless parrots are not euthanized like dogs and cats, parrot adoption centers and sanctuaries are becoming more common.

Zoos

 
Scarlet Macaw riding a tricycle at a show in Spain

Parrot species are found in most zoos, and a few zoos participate in breeding and conservation programs. Some zoos have organised displays of trained parrots and other birds doing tricks.

Trade

 
10,000 Hyacinth Macaws were taken from the wild for the pet trade in the 1980s.[45]

The popularity of parrots as pets has led to a thriving—and often illegal—trade in the birds, and some species are now threatened with extinction. A combination of trapping of wild birds and damage to parrot habitats makes survival difficult or even impossible for some species of parrot. Importation of wild caught parrots into the US and Europe is illegal.

The trade continues unabated in some countries. A report published in January 2007 presents a clear picture of the wild-caught parrot trade in Mexico, stating: "The majority of parrots captured in Mexico stay in the country for the domestic trade. A small percentage of this capture, 4% to 14%, is smuggled into the USA."[46] In the early 1980s an American college student who worked his way through school smuggling parrots across the Rio Grande put his contraband Mexican birds in a cage on an inflatable raft and floated with them across the international river to the U.S. side where a partner would be waiting.[47]

The scale of the problem can be seen in the Tony Silva case of 1996, in which a parrot expert and former director at Tenerife's Loro Parque (Europe's largest parrot park) was jailed in the United States for 82 months and fined $100,000 for smuggling Hyacinth Macaws.[48] (Such birds command a very high price). The case led to calls for greater protection and control over trade in the birds. Different nations have different methods of handling internal and international trade. Australia has banned the export of its native birds since 1960. The United States protects its only native parrot through its Endangered Species Act, and protects other nations' birds through its Wild Bird Conservation Act. Following years of campaigning by hundreds of NGOs and outbreaks of avian flu, in July 2007, the European Union halted the importation of all wild birds with a permanent ban on their import. Prior to an earlier temporary ban started in late October 2005, the EU was importing approximately two million live birds a year, about 90% of the international market: hundreds of thousands of these were parrots. There are no national laws protecting feral parrot populations in the U.S. Mexico has a licensing system for capturing and selling native birds (though the laws are not well enforced).

Culture

 
Moche Parrot. 200 A.D. Larco Museum Collection Lima, Peru

Parrots have featured in human writings, story, art, humor, religion and music for thousands of years. From the Roman poet Ovid's "The Dead Parrot"(Latin), (English) to Monty Python's Dead Parrot Sketch millennia later, parrots have existed in the consciousness of many cultures. Recent books about parrots in human culture include Parrot Culture.[49]

In ancient times and currently parrot feathers have been used in ceremonies, and for decoration. The "idea" of the parrot has been used to represent the human condition in medieval literature such as the bestiary. They also have a long history as pets.

In Polynesian legend as current in the Marquesas Islands, the hero Laka/Aka is mentioned as having undertaken a long and dangerous voyage to Aotona in what are now the Cook Islands, to obtain the highly prized feathers of a red parrot as gifts for his son and daughter. On the voyage a hundred out of his 140 rowers died of hunger on their way, but the survivors reached Aotona and captured enough parrots to fill 140 bags with their feathers.[50] By at least some versions, the feathers were plucked off living parrots without killing them.[51]

Currently parrots feature in many media. There are magazines devoted to parrots as pets, and to the conservation of parrots (PsittaScene[collegamento interrotto]). Fictional films include Paulie, and documentaries include The Wild Parrots of Telegraph Hill.

Parrots have also been considered sacred. The Moche people of ancient Peru worshipped birds and often depicted parrots in their art.[52]

Parrots are used as symbols of nations and nationalism. A parrot is found on the flag of Dominica. The St. Vincent parrot is the national bird of St. Vincent and the Grenadines, a Caribbean nation.

Parrots are popular in Buddhist scripture and there are many writings about them. For example, Amitābha once changed itself into a parrot to aid in converting people. Another old story tells how after a forest caught fire, the parrot was so concerned it carried water to try and put out the flames. The ruler of heaven was so moved upon seeing the parrot's act, that he sent rain to put out the fire. In Chinese Buddhist iconography, a parrot is sometimes depicted hovering on the upper right side Guan Yin clasping a pearl or prayer beads in its beak.

Sayings about parrots colour the modern English language. The verb "parroting" can be found in the dictionary, and means "to repeat by rote." There are also clichés, such as the British saying "sick as a parrot."

Feral populations

  Lo stesso argomento in dettaglio: Feral parrots.
 
Feral Red-masked Parakeets in San Francisco. The population is the subject of the book and film, The Wild Parrots of Telegraph Hill.

Escaped parrots of several species have become established in the wild outside their natural ranges and in some cases outside the natural range of parrots. Among the earliest instances were pet Red Shining-parrots from Fiji which established a population on the islands of southern Tonga. These introductions were prehistoric and Red-shining Parrots were recorded in Tonga by Captain Cook in the 1770s.[19] Escapees first began breeding in cities in California, Texas and Florida in the 1950s (with unproven earlier claims dating back to the 1920s in Texas and Florida).[20] They have proved surprisingly hardy in adapting to conditions in Europe and North America. They sometimes even multiply to the point of becoming a nuisance or pest, and a threat to local ecosystems, and control measures have been used on some feral populations.[53]

Threats and conservation

 
A mounted specimen of the Carolina Parakeet, which was hunted to extinction
 
Community-based conservation has helped arrest the decline of the endangered Ouvea Parakeet.

A large number of parrot species are in decline, and several species are now extinct. Of the 350 or so living species of parrot 130 species are listed as near threatened or worse by the IUCN.[54] There are numerous reasons for the decline of so many species, the principal threats being habitat loss and degradation, hunting, and for certain species, wild-bird trade. Parrots are persecuted for a number of reasons; in some areas they may (or have been) hunted for food, for feathers, and as agricultural pests. For a time, Argentina offered a bounty on Monk Parakeets (an agricultural pest), resulting in hundred of thousands of birds being killed, though apparently this did not greatly affect the overall population.[55] Capture for the pet trade is a threat to many of the rarer or slower to breed species. Habitat loss or degradation, most often for agriculture, is a threat to numerous parrot species. Parrots, being cavity nesters, are vulnerable to the loss of nesting sites and to competition with introduced species for those sites. The loss of old trees is particularly a problem in some areas, particularly in Australia where suitable nesting trees may be many hundreds of years old. Many parrot species occur only on islands and are vulnerable to introduced species such as rats and cats, as they lack the appropriate anti-predator behaviours needed to deal with mammalian predators. Controlling such predators can help in maintaining or increasing the numbers of endangered species.[56] Insular species, which have small populations in restricted habitat, are also vulnerable to physical threats such as hurricanes and volcanic eruptions.

There are many active conservation groups whose goal is the conservation of wild parrot populations. One of the largest includes the World Parrot Trust,[57] an international organization. The group gives assistance to worthwhile projects as well as producing a magazine[58] and raising funds through donations and memberships, often from pet parrot owners. They state they have helped conservation work in 22 countries. On a smaller scale local parrot clubs will raise money to donate to a cause of conservation. Zoo and wildlife centers usually provide public education, to change habits that cause damage to wild populations. Recent conservation measures to conserve the habitats of some of the high-profile charismatic parrot species has also protected many of the less charismatic species living in the ecosystem.[7] A popular attraction that many zoos now employ is a feeding station for lories and lorikeets, where visitors feed small parrots with cups of liquid food. This is usually done in association with educational signs and lecture.

Several projects aimed specifically at parrot conservation have met with success. Translocation of vulnerable Kakapo, followed by intensive management and supplementary feeding, has increased the population from 50 individuals to 123.[59] In New Caledonia the Ouvea Parakeet was threatened by trapping for the pet trade and loss of habitat. Community based conservation, which eliminated the threat of poaching, has allowed the population to increase from around 600 birds in 1993 to over 2000 birds in 2009.[60]

At present the IUCN recognises 19 species of parrot as extinct since 1600 (the date used to denote modern extinctions).[61] This does not include species like the New Caledonian Lorikeet which has not been officially seen for 100 years yet is still listed as critically endangered.

Trade, export and import of all wild-caught parrots is regulated and only permitted under special licensed circumstances in countries party to CITES, the Convention on the International Trade in Endangered Species, that came into force in 1975 to regulate the international trade of all endangered wild caught animal and plant species. In 1975, 24 parrot species were included on Appendix I of CITES, thus prohibiting commercial international trade in these birds. Since that initial listing, continued threats from international trade have lead CITES to add an additional 32 parrot varieties to Appendix I, including nine in the last four years.[62] All the other parrot species are protected on Appendix II of CITES. In addition, individual countries may have laws to regulate trade in certain species.

References

Notes

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