Behavior and spatial learning in radial mazes in birds.

This review addresses studies of spatial memory and learning in birds performed using the radial maze method. Descriptions of different versions of this test (standard and "giant" tunnel-type mazes, as well as unstructured "analogs") are described and the methodological problems of testing birds are discussed. Behavioral measures from birds and laboratory rats, as the "standard" system for radial maze studies, are compared. The characteristics of spatial learning in birds of different systematic groups (pigeons, tits, corvids, chickens, etc.) are compared. Particular attention is paid to studies addressing spatial memory in closely related bird species with different ecological features, in terms of the ability to hoard food and finding their hoards after prolonged time periods, as well as to the few reports of results from experiments with migrant birds and homing pigeons.