Development of Piagetian object permanence in a grey parrot (Psittacus erithacus).

Molecular identification and successful treatment of Chlamydophila psittaci (genotype B) in a clinically affected Congo African grey parrot (Psittacus erithacus erithacus)

Avian chlamydiosis is caused by Chlamydiophila psittaci with the highest infection rate in parrots (Psittacidae) and pigeons (Columbiformes). A two-year-old Congo African grey parrot was examined since the bird had shown clinical signs of anorexia, depression, diarrhea, and mild dyspnea and based on biochemical and hemathological analysis the bird was diagnosed as having anemia, leukocytosis, h...

Teaching a Musical Code to a Parrot: Frequency Discrimination and the Concept of Rhythm in a Grey Parrot (psittacus Erithacus) Uœenje Glasbenih Motivov Pri Papagaju: Frekvenœno Razloœevanje in Koncept Ritma Pri Sivem Æakoju (psittacus Erithacus)

Teaching a musical code to a parrot: Frequency discrimination and the concept of rhythm in a Grey Parrot (Psittacus erithacus) Music competence and perception should be considered in evaluating human cognitive processes, unfortunately, evolutionary onset of music is still unclear. Although connections between human language and other animal communication patterns remain limited and controversia...

Processing of the Müller-Lyer illusion by a Grey parrot (Psittacus erithacus).

Alex, a Grey parrot (Psittacus erithacus) who identifies the bigger or smaller of two objects by reporting its color or matter using a vocal English label and who states "none" if they do not differ in size, was presented with two-dimensional Müller-Lyer figures (Brentano form) in which the central lines were of contrasting colors. His responses to "What color bigger/ smaller?" demonstrated tha...

Journal of Comparative Psychology Social Context Influences the Vocalizations of a Home-Raised African Grey Parrot (Psittacus erithacus erithacus)

Grey Parrot (Psittacus erithacus) numerical abilities: addition and further experiments on a zero-like concept.

A Grey parrot (Psittacus erithacus), able to quantify 6 or fewer item sets (including heterogeneous subsets) by using English labels (I. M. Pepperberg, 1994), was tested on addition of quantities involving 0-6. He was, without explicit training, asked, "How many total X?" for 2 sequentially presented collections (e.g., of variously sized jelly beans or nuts) and required to answer with a vocal ...