Wild hummingbirds can use the geometry of a flower array

Abstract

Highlights:1) We trained birds to find a rewarded flower in a four-flower array 2) After rotation and translocation of the array, hummingbirds used geometric cues to choose a flower 3) Geometry is more than a robust laboratory artefact, but more research is required AbstractAnimals use cues from their environment to orient in space and to navigate their surroundings.Geometry is a cue whose informational content may originate from the metric properties of a given environment, and its use has been demonstrated in the laboratory in nearly every species of animal tested. However, it is not clear whether geometric information, used by animals typically tested in small, rectangular boxes, is directly relevant to animals in their natural environment.Here we present the first data that confirm the use of geometric cues by a free-living animal in the wild. We trained rufous hummingbirds to visit a rectangular array of four artificial flowers, one of which was rewarded. In some trials a conspicuous landmark cued the reward. Following array translocation and rotation, we presented hummingbirds with three tests. When trained and tested with the landmark, or when trained and tested without it, hummingbirds failed to show geometric learning. However, when trained with a landmark but tested without it, hummingbirds produced the classic geometric response, showing that they had learned the geometric relationships (distance and direction) of several non-reward visual elements of the environment.While it remains that the use of geometry to relocate a reward may be an experimental artefact, it is one cue that is not confined to the laboratory.

Treating hummingbirds as feathered bees: a case of ethological cross-pollination

“…13: 20170610 the shape of an array of feeders, or, how animals use 'landmarks', which are usually discrete objects with a constant relationship to the goal [49]. Although early studies of how hummingbirds remembered space were heavily influenced by these laboratory studies of landmarks and geometry, hummingbirds did not use the 'geometry' of an array of flowers or landmarks [50][51][52], except under very particular conditions [53]. Similarly, hummingbirds can use multiple landmarks to identify flower locations [50,52], but do so only under very particular conditions [54].…”

Taking an insect-inspired approach to bird navigation

“…Just as birds prefer larger, nearer, or more salient landmarks (e.g., Bennett, 1993 ), Philanthus digger wasps also prefer to use large, 3D objects to find their burrow (Tinbergen, 1972 ). And, as birds (including hummingbirds – Hornsby, Healy, & Hurly, 2017 ) learn the geometry of an environment, wasps can also use the shape of a landmark configuration, discriminating a circle of landmarks from a square or triangle, for example, to relocate their burrow (Beusekom, 1948 ).…”