---
title: "What the sources say about the Grey Parrot | AnimalTracks.wiki"
description: "47 claims from the Grey Parrot profile, each beside the words of the source that backs it."
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canonical: "https://animaltracks.wiki/animals/grey-parrot/sources/"
---

# What the sources say about the Grey Parrot (*Psittacus erithacus*)

> 47 claims from the Grey Parrot profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Grey Parrot](https://animaltracks.wiki/animals/grey-parrot/)

## African Grey Parrot. The Maryland Zoo.

https://www.marylandzoo.org/animal/african-grey-parrot/

| The page says | The source says |
| :--- | :--- |
| Lowland forest, woodland and wooded savannah of West and Central Africa | African 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) |
| Fruits, berries, seeds and nuts, with a pull toward oil-palm fruit | Herbivore - Fruits, berries, seeds and nuts (note: stats.diet; oil palm below) |
| the Maryland Zoo puts the weight at about 1 lb | HOW MUCH THEY WEIGH About 1 lb |
| The zoo gives an average lifespan of 50 years. | HOW LONG THEY TYPICALLY LIVE 50 yrs on average |
| They live in Central and West Africa, in lowland forest including rainforest, woodlands and wooded savannah. | African grey parrots are native to west and central Africa. They inhabit different types of lowland forest, including rainforest, woodlands, and wooded savannah. |
| At night they roost together in flocks sometimes numbering in the thousands, then split into much smaller groups to feed. | African 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. |
| They eat fruits, berries, nuts and seeds, and are particularly attracted to the fruit of the oil palm tree. | They 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. |
| Each foot has two toes facing forward and two facing back, which helps with balance, and the beak works as a third foot for climbing. | They 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. |
| Snakes and large cats are the main predators, and a parrot will fly off or fight back with its powerful beak. | African 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 Maryland Zoo blames its decline primarily on excessive trapping for the international pet trade | African grey parrots have declined significantly in the wild in recent decades, due primarily to excessive trapping for the international pet trade. |
| the typical figure is 50 years on average | HOW LONG THEY TYPICALLY LIVE 50 yrs on average (note: faq) |
| wild numbers have fallen significantly in recent decades, due primarily to excessive trapping for the international pet trade, with deforestation adding to it. | African 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 deforestation (note: faq) |
| Silver coat, scarlet tail | The African grey parrot is a beautiful silvery-grey bird with a bright scarlet tail. (note: heading) |
| Flocks in the canopy | roost together at night in large flocks sometimes numbering in the thousands. ... They feed high up in the treetops (note: heading) |
| A long time. | HOW LONG THEY TYPICALLY LIVE 50 yrs on average (note: faq lead) |
| Mostly trapping. | due primarily to excessive trapping for the international pet trade (note: faq lead) |
| The Maryland Zoo describes an extraordinary vocal range: it squawks, whistles, shrieks, screams and mimics. | extraordinary vocal range. It squawks, whistles, shrieks, screams, and mimics |

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

https://animaldiversity.org/accounts/Psittacus_erithacus/

| The page says | The source says |
| :--- | :--- |
| The plumage is various shades of grey, finished with a very distinctive red tail. | The plumage of Psittacus erithacus is various shades of grey with very distinctive red tail feathers. |
| they typically measure 33 cm from head to tail | African grey parrots typically measure 33 cm from head to tail |
| weightKg: 0.41 | Average mass 407 g (note: task #1114: 407 g rounded; Light, as the name guess. Not in a curated matchup) |

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

https://news.harvard.edu/gazette/story/2019/02/harvard-study-shows-parrots-can-pass-classic-test-of-intelligence/

| The page says | The source says |
| :--- | :--- |
| A grey parrot named Griffin outperformed 5-year-old children on a cup logic test. | Griffin outperformed even 5-year-olds. (note: tagline) |
| One bird, Griffin, outperformed 5-year-olds on a cup-logic test | But Griffin outperformed even 5-year-olds. (note: superpower) |
| took on a classic animal-intelligence test | Study shows parrots can pass classic test of intelligence |
| a reward is hidden in one of two cups | A reward is hidden in one of two cups |
| reasoning that if it is not in A, it must be in B | reasoning 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 Harvard team added more complicated versions with three and four cups. | Designed to add a wrinkle to the two-cup task, the more complex tests work like this |
| Young children fail similar tasks until they are about 2 and a half years old. The same goes for apes. | until they reach about 2 and a half years old, young children fail at similar tasks. The same goes for apes. |
| Griffin outperformed even 5-year-olds | But Griffin outperformed even 5-year-olds. |
| the researchers forced him to gamble on a 50-50 cup | “Basically, we forced him to gamble,” Pepperberg said. ... he’d have to gamble on the 50-50 side. |
| He hated it, but he did it on every trial in that subset. | And he hated it, but he did it on all the trials in the subset. |
| The subject is then shown that one cup is empty | subjects 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” |
| Griffin versus the cups | Griffin outperformed even 5-year-olds. (note: heading) |
| In 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. | For 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. |
| and passed the four-cup test too | Though Griffin passed both tests with flying colors |
| To check he had not simply learned to pick whichever cup sat next to the empty one | wanted to be sure he hadn’t simply learned to choose whichever cup was next to the empty one |

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

https://doi.org/10.1037/0735-7036.119.2.197

| The page says | The source says |
| :--- | :--- |
| Another grey parrot was asked "What color/object [number]?" about piles of blocks, keys and corks. | He 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). |
| Accuracy was greater than 80%, and he also used "none" to designate zero. | Accuracy 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. |
| Shown 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. | He 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) |
| Saying none | using "none" to designate zero (note: blockquote lead-in) |

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

https://doi.org/10.1371/journal.pone.0093839

| The page says | The source says |
| :--- | :--- |
| Telomeres are the caps on the ends of chromosomes | Telomeres, the caps of eukaryotic chromosomes, control chromosome stability and cellular senescence |
| ageing and chronic stress are suspected of wearing them down | aging and exposure to chronic stress are suspected to cause attrition of telomere length |
| In a study of 45 captive grey parrots, birds housed alone had significantly shorter telomeres than pair-housed birds, even at similar ages. | Our 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) |
| Parrots 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. | socially 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) |
| Lonely is costly | socially isolated parrots had significantly shorter telomeres compared to pair-housed birds (p<0.001) (note: heading) |
| Their cells may show it. | socially isolated parrots had significantly shorter telomeres compared to pair-housed birds (p<0.001) (note: faq lead) |

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

https://doi.org/10.2305/iucn.uk.2021-3.rlts.t22724813a154428817.en

| The page says | The source says |
| :--- | :--- |
| Endangered | IUCN Red List category: Endangered (EN). (note: stats.conservationStatus; read through GBIF's copy of the Red List, noted) |
| The Red List now calls the species Endangered | IUCN Red List category: Endangered (EN). |