When wild animals are kept by humans in captivity — in homes, zoos, or breeding centers — research shows that some species can do well. Still, other species show signs of stress, behavioral issues, and lower reproduction rates. This contrast is seen clearly in parrots, and we can study this because about half of the parrots in the world live in captivity, while the other half live in the wild.

The authors of this paper wanted to test the hypothesis about why some species of parrots do well in captivity while others don’t. This is important for both improving captive animal welfare and for increasing populations of endangered species in the wild. 

The authors sought to determine which factors influence parrots’ wellbeing and breeding success, including:

• The ways that captive environments differ from the wild, including opportunities to forage naturally, and the ability of different species to adapt to new environments 
• The effects of intelligence, to understand if higher intelligence in some species is either protective or a risk factor in captive environments 
• Conservation status, to understand if some species are both at risk of declining populations in the wild and at risk of stress in captive environments, and if this leads to breeding problems 

The researchers used phylogenetic comparative methods to find causes of different behavior for different parrot species. They collected data from a survey of companion animal guardians on stereotypical behavior, such as feather-damaging behavior, for 50 species (1,378 individual birds). They used a separate source for captive hatch rates to measure reproductive success for 115 species. To test potential predictors, they gathered data on social factors in the wild to determine differences from captive environments, relative brain size to estimate intelligence, and they measured endangered status by threat level and “rarity” according to populations at private breeding centers.

The authors found significant differences between species, which was explained by some of their predictors. Social interaction did not seem to be a factor, but not being able to forage in natural ways was linked to behaviors indicating stress. A species’ endangered status was not linked to stereotypical behavior in this study. 

Intelligence is seen as a benefit when parrots need to adapt to new habitats in the wild. However, intelligence was found to be a disadvantage for parrots kept by humans as companion animals, as the more intelligent parrot species showed more stereotypical behavior in captivity in this study. The authors suggest that less intelligent species (by their definition, those with smaller brains), showing less stereotypical behavior, adapt better in captivity.

The authors explain that feather-damaging behavior is likely related to a lack of opportunity to forage and handle food like they would in the wild. In the wild, parrots spend 40-75% of their time foraging for food, whereas in captivity they are typically dish-fed processed diets in small spaces. Because of their inability to forage, these parrots redirect those behaviors to picking at their own feathers. This suggests that more natural diets are important for parrot wellbeing. The authors did not find that restricting natural behaviors in captivity leads to reproductive problems. 

The authors noted some limitations with their study. For example, they did not determine why species with a smaller population size in captivity are also breeding less, and they recommend further study to better understand this link. 

The findings of this study are relevant for advocacy in a few ways. The authors argue that more can be done to improve the captive environments and care of birds that are known to be highly intelligent, given that their well-being suffers in environments that are not well designed for them. Cognitive stimulation and foraging enrichment are two suggestions the authors have to improve captive parrot welfare. They also suggest further studies and application of phylogenetic comparative methods to test the effects of other animals living in captivity. Advocating for the usefulness of this method can explain differences between species, and ultimately help humans learn how to care for them better.