نتایج جستجو برای: pigeons
تعداد نتایج: 3557 فیلتر نتایج به سال:
The spatio-temporal courses of head and neck motions of pigeons while pecking at small grains are described. Single and serial pecks are distinguished but the inter- and intraindividual variability of the peck kinetics is stressed. Pigeons were then trained with instrumental conditioning procedures to speed-up their pecking. A partial reinforcement schedule where pigeons had to peck repeatedly ...
Homing pigeons can return from distant, unfamiliar release points. Experienced pigeons can do so even if they are transported anesthetized and deprived of outward journey information. Airplane tracking has shown that they make relatively straight tracks on their homeward journey; therefore, pigeons must have some way of determining the home direction at the release site. Manipulating the pigeon...
It has been well established that homing pigeons are able to use the Earth's magnetic field to obtain directional information when returning to their loft and that their magnetic compass is based, at least in part, on the perception of magnetic inclination. Magnetic inclination has also been hypothesized in pigeons and other long-distance navigators, such as sea turtles, to play a role providin...
When given repeated training from a location, homing pigeons acquire the ability to use familiar landmarks to navigate home. Both control and hippocampal-lesioned pigeons succeed in learning to use familiar landmarks for homing. However, the landmark representations that guide navigation are strikingly different. Control and hippocampal-lesioned pigeons were initially given repeated training fl...
Experimental parameters were adjusted so that pigeons' pairwise choices among three alternatives reflected the following order of preference: (a) a smaller-sooner reinforcer, (b) a larger-later reinforcer, and (c) the smaller-sooner reinforcer followed by a punishment (consisting of an extended blackout period). After this order of preference was established, the pigeons were exposed to a two-l...
Depriving homing pigeons of olfactory information by applying a local anaesthetic, gingicain, to their olfactory epithelium results in systemic effects. Furthermore, anosmia persists reliably for only an hour. In contrast, intra-nasal irrigation with 18 % zinc sulphate solution results in anosmia that persists for at least 5 days. No systemic effects of zinc sulphate on anosmic pigeons could be...
Homing pigeons (Columba livia) are believed to adopt a map-and-compass strategy to find their way home. Surprisingly, to date a clear demonstration of the use of a cognitive map in free-flight experiments is missing. In this study, we investigated whether homing pigeons use a mental map in which - at an unknown release site - their own position, the home loft and a food loft are represented sim...
Eight pigeons were trained on a go-no go visual discrimination involving 1 S+ and 15 S- s. The 16 discriminative stimuli were black-and-white line drawings created by the factorial combination of 4 different geometric shapes (wedge, cylinder, cone, handle) in 4 different spatial locations (right, left, above, below) in relation to a common shape (cube). All of the pigeons readily learned this c...
The extinct passenger pigeon was once the most abundant bird in North America, and possibly the world. Although theory predicts that large populations will be more genetically diverse, passenger pigeon genetic diversity was surprisingly low. To investigate this disconnect, we analyzed 41 mitochondrial and 4 nuclear genomes from passenger pigeons and 2 genomes from band-tailed pigeons, which are...
Pigeons are known to be able to categorize a wide variety of visual stimulus classes. However, it remains unclear which are the characteristics of the perceptually relevant features employed to reach such good performance. Here, we investigate the relative contributions of texture and shape information to categorization decisions about complex natural classes. We trained three groups of pigeons...
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