Birds of a feather? Parrot and corvid cognition compared

Abstract

The last several decades of research on avian cognition have revealed surprising parallels between the abilities of birds — most notably corvids — and great apes. Parrots, albeit far less studied, are cited alongside corvids as “feathered apes”, but are these two taxa really that similar cognitively? In this review we aim to take a step back and present the broader picture, focusing on areas where there is now data from both parrots and corvids to facilitate first comparisons on a somewhat wider scale. By charting these birds’ performance in cognitive tasks, in many of which corvids perform on par with primates, we hope to highlight understudied areas and promising directions for future research. In reviewing the literature, the general pattern that emerges shows that different corvid and parrot species indeed perform similarly in a range of cognitive tasks to the extent that one may call them “feathered apes”.

Self‐control in crows, parrots and nonhuman primates

“…In delay maintenance tasks, the small selection of corvids and psittacines tested—carrion crows, common ravens, Goffin's cockatoos, kea, African gray parrots—are able to inhibit consuming a low‐value reward to obtain a high‐value reward later, waiting for intervals comparable to primates (Figure ). Some birds even do so while holding the initial reward in their mouths (Lambert et al, ). Corvids may select the smaller amount, as it is easier to eat, carry and cache nearby.…”

Notes on ecology of wild goffin’s cockatoo in the late dry season with emphasis on feeding ecology

“…However, an alternative approach suggests that tools are rarely more useful than evolved anatomical adaptations in ecological contexts faced by wild animals (Hansell & Ruxton, 2008). Indeed, tools do not seem to provide additional advantage for parrots who mostly interact with their environment through the powerful beak employed for a variety of activities including exploring, object manipulation, foraging, climbing, and even acting as an additional limb with the strong, dexterous tongue of some species used as an appendage (Lambert et al, 2018;O'Hara et al, 2018). Due to this functional flexibility, the parrot beak is often described as a "multi-purpose tool" (Huber & Gajdon, 2006;Hansell & Ruxton, 2008; see Auersperg, 2015 for a review).…”

“…Despite these findings and the growing interest in this species in the scientific community and public, relatively little is known about its ecology and behavior in the wild. Current ecological knowledge about the majority of parrot species is scarce as observing wild individuals presents challenges associated with their ability to fly over long distances and spend a large portion of their life in forest canopies (Lambert et al, 2018). Filling these gaps will allow comparative testing of various hypotheses about the evolution of cognitive abilities (Seed et al, 2009;MacLean et al, 2012).…”

“…An alternative approach is proposed by the social intelligence hypothesis which states that sophisticated, flexible cognitive abilities evolved as response to the challenges of living in complex social environment (Jolly, 1966;Humphrey, 1976). As most parrot species are social, this hypothesis was suggested to be key driver of their cognitive abilities (Emery et al, 2007) although so far little research has focused on parrot social cognition (Lambert et al, 2018). Regarding brain evolution, avian brains are structured differently from primate brains, most notably lacking the layered neocortex.…”

Sperm morphology and evidence for sperm competition among parrots

“…Despite these life‐history traits, parrots show striking coloration and up to 30% of the species are sexually dichromatic (estimated from del Hoyo, Elliott, Sargatal, Christie, & Kirwan, ). Parrots also exhibit high levels of cognitive capacities (Van Horik, Clayton, & Emery, ; Lambert, Jacobs, Osvath, & von Bayern, ) and problem‐solving skills (Auersperg, von Bayern, Gajdon, Huber, & Kacelnik, ; Auersperg, Kacelnik, & von Bayern, ; O’Neill, Picaud, Maehner, Gahr, & von Bayern, ), and females may choose males based on these skills (Chen, Zou, Sun, & Cate, ). Hence, in parrots, ornamental colours and high cognitive abilities might be consequences of sexual selection.…”