Bird intelligence

The difficulty of defining or measuring intelligence in non-human animals makes the subject difficult to study scientifically in birds. In general, birds have relatively large brains compared to their head size. The visual and auditory senses are well developed in most species, though the tactile and olfactory senses are well realized only in a few groups. Birds communicate using visual signals as well as through the use of calls and song. The testing of intelligence in birds is therefore usually based on studying responses to sensory stimuli. The corvids (ravens, crows, jays, magpies, etc.) and psittacines (parrots, macaws, and cockatoos) are often considered the most intelligent birds, and are among the most intelligent animals in general. Pigeons, finches, domestic fowl, and birds of prey have also been common subjects of intelligence studies. Bird intelligence has been studied through several attributes and abilities. Many of these studies have been on birds such as quail, domestic fowl, and pigeons kept under captive conditions. It has, however, been noted that field studies have been limited, unlike those of the apes. Birds in the crow family (corvids) as well as parrots (psittacines) have been shown to live socially, have long developmental periods, and possess large forebrains, all of which have been hypothesized to allow for greater cognitive abilities. Counting has traditionally been considered an ability that shows intelligence. Anecdotal evidence from the 1960s has suggested that crows can count up to 3. Researchers need to be cautious, however, and ensure that birds are not merely demonstrating the ability to subitize, or count a small number of items quickly. Some studies have suggested that crows may indeed have a true numerical ability. It has been shown that parrots can count up to 6. Cormorants used by Chinese fishermen were given every eighth fish as a reward, and found to be able to keep count up to 7. E.H. Hoh wrote in Natural History magazine: In the 1970s, on the Li River, Pamela Egremont observed fishermen who allowed the birds to eat every eighth fish they caught.