Pigeons (Columba livia) searched for food hidden in the center of a square enclosure. On occasional tests
without food, the enclosure was (a) unchanged from training (control tests), (b) moved to different
corners of the testing room (corner tests), or (c) doubled in size (expansion tests). The birds showed
localized search in the center of the enclosure on control and corner tests. On expansion tests, some birds
searched near the center of the enclosure, suggesting relative-distance encoding. Other birds searched at
locations that maintained the training distance from walls, suggesting absolute-distance encoding. These
results are consistent with previous studies on chicks (Gallus gallus) in similar enclosures and contrast
with previous results on pigeons’ responses to expansions of discrete landmark arrays.