A study of black-headed caiques has shown that they are more frequently right footed than left footed (Smith, 1972; Sparks and Soper, 1990). Most other parrots species are left footed (Harris, 1989). By footedness is meant the foot that the bird prefers to hold its food. When offered a tasty morsel from the left, 62 percent of the time caiques will grasp it with the right foot. Offered from its right side this increases to 96 percent of the time.

Unlike most birds, the maxilla, i.e., upper bill, of parrots is not fixed but hinged. This is thought to be an adaptation for climbing since the movement of the bill relative to the bird's head is most evident when parrots are climbing. The birds coordinate the motion of the hinged bill with movement of their feet.

Caique chicks are probably deaf when they hatch and, like other New World parrots, have no ear opening. An opening appears about the same time their eyes open between two and three weeks after hatching. Some think the reason for this is to limit the competition between siblings for the food delivered by the parents. Caique chicks do not hatch at the same time. Sometimes more than two weeks separate the hatching of the oldest from the youngest. The oldest bird is able to hear first, and if there is not enough food to go around, it has an advantage in knowing when its parent has arrived and can beg for food without the youngest even knowing. For this reason, the youngest bird in the clutch, referred to as a "Benjamin," often does not survive.

The caique is sometimes referred to as the dancing parrot. This dancing is highly prized by some natives of South America. Stolzmann, who explored much of Peru between 1875 and 1880, noted, "The natives teach them to dance. In the evening they put them on a table illuminated by a candle and then sing or whistle while clapping their hands; the parrots hop to this noise. For a dancing parrot one pays there from 40 to 50 francs." The dancing that most of my birds perform is characterized by a series of hops forward and when confined to a cage scooting backward. If the bird is on the large open floor, it may hop quite a long distance. The bird will repeat the dance many times. During the hopping the bird pushes its breast forward, holds it head high, and pins its eyes. The dance is usually done on a flat surface and occasionally on a perch. You can encourage it to continue by clapping your hands in cadence with the hop. Males tend to dance more often than females. All my imported females, but none of my hand reared females dance. All of my males whether imported or hand reared dance. One is quite accomplished. He likes me to chase him as he hops long distances of ten feet or more. When he is in the right mood, this bird will hop on command. The dance seems to be associated with establishing dominance, territorial claims, or an epigamic display.

Georges Louis Leclerc Comte de Buffon, who first set forth the binomial theorem and wrote what is considered the first popular science book, i.e., Histoire Naturelle, published the second known print of a caique in 1783. He noted that the natives called this bird the "La petite Perruche Maypouri, de Cayenne" or the little tapir. He explained that this name was given because one of the whistles made by the caique is identical to that made by the tapir, the largest native quadruped of the same region. (See Prestwick.) This is confirmed by Sick in his book on the Brazilian birds. He indicates that in the wild they make a "strident, prolonged, tremulous tsrrrri-tsrrrri" similar to that of the tapir. In Brazil they call it the Periquito d’anta, which translates as tapir parakeet.

In 1830 at age 16, Edward Lear, famous for the children’s poem "The Owl and the Pussycat," set out to draw all the known parrot species. His plan was to sell his illustrations by subscription. He completed only forty-two prints before he had to abandon his project because of lack of money. Only 175 sets were produced. Needless to say these prints are very valuable today. One that he did complete was of a white-bellied caique. He labeled it with the scientific name Psittacus badiceps and the common name "bay-headed parrot." He drew all his parrots from live specimens found either in the London Zoo or in the collections of private owners.

Caiques are considered an unusual species because they appear to be unrelated to any of the other large orders of parrots in South America such as the macaws and the conures. Some believe them to be most closely related to the hawk-headed parrot (Deroptyus species), a species that is also considered to be unusual and unconnected. Evidence for relatedness is the capacity of a species to hybridize with another. This is well established within the genus Pionites. Indeed, the first breeding of caiques ever reported in aviculture was of a pallid with a green thighed white bellied. What is surprising is a report by Sick in the Birds in Brazil of a hybrid bird from a pairing of a black-headed caique (P. melanocephala) with an Illiger’s macaw [Propyrrhura (Ara) maracana], a very different species.