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What the sources say

Grey ParrotPsittacus erithacus

Every figure, record and mechanism on the Grey Parrot profile was written from a source, and this is the working table behind it: 47 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

Profile updated

Source
01

The Maryland Zoo

African Grey Parrot. The Maryland Zoo.

The page saysLowland forest, woodland and wooded savannah of West and Central Africa
The source saysAfrican grey parrots are native to west and central Africa. They inhabit different types of lowland forest, including rainforest, woodlands, and wooded savannah.Note: stats.habitat
The page saysFruits, berries, seeds and nuts, with a pull toward oil-palm fruit
The source saysHerbivore - Fruits, berries, seeds and nutsNote: stats.diet; oil palm below
The page saysthe Maryland Zoo puts the weight at about 1 lb
The source saysHOW MUCH THEY WEIGH About 1 lb
The page saysThe zoo gives an average lifespan of 50 years.
The source saysHOW LONG THEY TYPICALLY LIVE 50 yrs on average
The page saysThey live in Central and West Africa, in lowland forest including rainforest, woodlands and wooded savannah.
The source saysAfrican grey parrots are native to west and central Africa. They inhabit different types of lowland forest, including rainforest, woodlands, and wooded savannah.
The page saysAt night they roost together in flocks sometimes numbering in the thousands, then split into much smaller groups to feed.
The source saysAfrican greys are gregarious, social birds that roost together at night in large flocks sometimes numbering in the thousands. They disperse into much smaller groups during the day to feed.
The page saysThey eat fruits, berries, nuts and seeds, and are particularly attracted to the fruit of the oil palm tree.
The source saysThey feed high up in the treetops on fruits, berries, nuts and seeds and they are particularly attracted to the fruit of the oil palm tree.
The page saysEach foot has two toes facing forward and two facing back, which helps with balance, and the beak works as a third foot for climbing.
The source saysThey use their toes – two facing back and two facing front on each foot – to help them balance and perch. They also use their beaks as a third foot for climbing and balancing.
The page saysSnakes and large cats are the main predators, and a parrot will fly off or fight back with its powerful beak.
The source saysAfrican greys are preyed upon mainly by snakes and large cats. To avoid predators, they will either fly away or defend themselves with their powerful beaks.
The page saysthe Maryland Zoo blames its decline primarily on excessive trapping for the international pet trade
The source saysAfrican grey parrots have declined significantly in the wild in recent decades, due primarily to excessive trapping for the international pet trade.
The page saysthe typical figure is 50 years on average
The source saysHOW LONG THEY TYPICALLY LIVE 50 yrs on averageNote: faq
The page sayswild numbers have fallen significantly in recent decades, due primarily to excessive trapping for the international pet trade, with deforestation adding to it.
The source saysAfrican grey parrots have declined significantly in the wild in recent decades, due primarily to excessive trapping for the international pet trade. They are also threatened by habitat loss due to deforestationNote: faq
The page saysSilver coat, scarlet tail
The source saysThe African grey parrot is a beautiful silvery-grey bird with a bright scarlet tail.Note: heading
The page saysFlocks in the canopy
The source saysroost together at night in large flocks sometimes numbering in the thousands. ... They feed high up in the treetopsNote: heading
The page saysA long time.
The source saysHOW LONG THEY TYPICALLY LIVE 50 yrs on averageNote: faq lead
The page saysMostly trapping.
The source saysdue primarily to excessive trapping for the international pet tradeNote: faq lead
The page saysThe Maryland Zoo describes an extraordinary vocal range: it squawks, whistles, shrieks, screams and mimics.
The source saysextraordinary vocal range. It squawks, whistles, shrieks, screams, and mimics

Source
02

Animal Diversity Web, University of Michigan

Psittacus erithacus (grey parrot). Animal Diversity Web, University of Michigan.

The page saysThe plumage is various shades of grey, finished with a very distinctive red tail.
The source saysThe plumage of Psittacus erithacus is various shades of grey with very distinctive red tail feathers.
The page saysthey typically measure 33 cm from head to tail
The source saysAfrican grey parrots typically measure 33 cm from head to tail
The page saysweightKg: 0.41
The source saysAverage mass 407 gNote: task #1114: 407 g rounded; Light, as the name guess. Not in a curated matchup

Source
03

Harvard Gazette

Study shows parrots can pass classic test of intelligence. Harvard Gazette.

The page saysA grey parrot named Griffin outperformed 5-year-old children on a cup logic test.
The source saysGriffin outperformed even 5-year-olds.Note: tagline
The page saysOne bird, Griffin, outperformed 5-year-olds on a cup-logic test
The source saysBut Griffin outperformed even 5-year-olds.Note: superpower
The page saystook on a classic animal-intelligence test
The source saysStudy shows parrots can pass classic test of intelligence
The page saysa reward is hidden in one of two cups
The source saysA reward is hidden in one of two cups
The page saysreasoning that if it is not in A, it must be in B
The source saysreasoning that the reward is in cup A or B; if it is not in A, it must be in B.Note: the 'thought to employ' hedge is kept in the body as 'is thought to show'
The page saysThe Harvard team added more complicated versions with three and four cups.
The source saysDesigned to add a wrinkle to the two-cup task, the more complex tests work like this
The page saysYoung children fail similar tasks until they are about 2 and a half years old. The same goes for apes.
The source saysuntil they reach about 2 and a half years old, young children fail at similar tasks. The same goes for apes.
The page saysGriffin outperformed even 5-year-olds
The source saysBut Griffin outperformed even 5-year-olds.
The page saysthe researchers forced him to gamble on a 50-50 cup
The source says“Basically, we forced him to gamble,” Pepperberg said. ... he’d have to gamble on the 50-50 side.
The page saysHe hated it, but he did it on every trial in that subset.
The source saysAnd he hated it, but he did it on all the trials in the subset.
The page saysThe subject is then shown that one cup is empty
The source sayssubjects are then shown that one cup is empty, and those that successfully choose the other cup are thought to employ a process known as “inference by exclusion”
The page saysGriffin versus the cups
The source saysGriffin outperformed even 5-year-olds.Note: heading
The page saysIn the three-cup test, one reward sits under a single cup and another under one of two cups beside it, so the single cup is the only sure win.
The source saysFor the three-cup test, one reward is hidden in a single cup, and another is placed in one of two additional cups to one side of the first cup. When faced with a choice, participants should pick the single cup, as it is the only cup guaranteed to have a reward.
The page saysand passed the four-cup test too
The source saysThough Griffin passed both tests with flying colors
The page saysTo check he had not simply learned to pick whichever cup sat next to the empty one
The source sayswanted to be sure he hadn’t simply learned to choose whichever cup was next to the empty one

Source
04

Pepperberg & Gordon 2005

Pepperberg & Gordon (2005). Number Comprehension by a Grey Parrot (Psittacus erithacus), Including a Zero-Like Concept. Journal of Comparative Psychology.

The page saysAnother grey parrot was asked "What color/object [number]?" about piles of blocks, keys and corks.
The source saysHe was, without training, asked "What color/object [number]?" for collections of various simultaneously presented quantities (e.g., subsets of 4, 5, and 6 blocks of 3 different colors; subsets of 2, 4, and 6 keys, corks, and sticks).
The page saysAccuracy was greater than 80%, and he also used "none" to designate zero.
The source saysAccuracy was greater than 80% and was unaffected by array quantity, mass, or contour. ... He also demonstrated knowledge of absence of quantity, using "none" to designate zero.
The page saysShown mixed sets of objects and asked, with no training on the task, which colour or object made up a given number, a lab parrot was right more than 80% of the time. He also used "none" for zero.
The source saysHe was, without training, asked "What color/object [number]?" for collections of various simultaneously presented quantities ... Accuracy was greater than 80% ... He also demonstrated knowledge of absence of quantity, using "none" to designate zero.Note: faq
The page saysSaying none
The source saysusing "none" to designate zeroNote: blockquote lead-in

Source
05

Aydinonat et al. 2014

Aydinonat et al. (2014). Social Isolation Shortens Telomeres in African Grey Parrots (Psittacus erithacus erithacus). PLoS ONE.

The page saysTelomeres are the caps on the ends of chromosomes
The source saysTelomeres, the caps of eukaryotic chromosomes, control chromosome stability and cellular senescence
The page saysageing and chronic stress are suspected of wearing them down
The source saysaging and exposure to chronic stress are suspected to cause attrition of telomere length
The page saysIn a study of 45 captive grey parrots, birds housed alone had significantly shorter telomeres than pair-housed birds, even at similar ages.
The source saysOur study population consisted of single-housed (n = 26) and pair-housed (n = 19) captive individuals ... socially isolated parrots had significantly shorter telomeres compared to pair-housed birds (p<0.001) – even among birds of similar ages.Note: 26 + 19 = 45
The page saysParrots kept on their own had shorter telomeres, the caps on chromosomes, than parrots kept in pairs, even when the birds compared were of similar ages. The authors took that as support for telomeres being a marker of chronic stress.
The source sayssocially isolated parrots had significantly shorter telomeres compared to pair-housed birds (p<0.001) – even among birds of similar ages. ... which supports the hypothesis that telomeres provide a biomarker indicating exposure to chronic stress.Note: faq
The page saysLonely is costly
The source sayssocially isolated parrots had significantly shorter telomeres compared to pair-housed birds (p<0.001)Note: heading
The page saysTheir cells may show it.
The source sayssocially isolated parrots had significantly shorter telomeres compared to pair-housed birds (p<0.001)Note: faq lead

Source
06

The IUCN Red List of Threatened Species 2021

Psittacus erithacus. The IUCN Red List of Threatened Species 2021: e.T22724813A154428817.

The page saysEndangered
The source saysIUCN Red List category: Endangered (EN).Note: stats.conservationStatus; read through GBIF's copy of the Red List, noted
The page saysThe Red List now calls the species Endangered
The source saysIUCN Red List category: Endangered (EN).

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.