T. Andrew Hurly

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We tested the risk-sensitive foraging preferences of wild rufous hummingbirds, Selasphorus rufus, with three types of artificial flowers. All three flower types provided the same mean volume of 30 ìl of sucrose, but differed in terms of variability of the reward: constant, low variance and high variance. In trinary comparisons, subjects preferred the(More)
Animals organize their lives around circannual and circadian rhythms, but little is known of their use of much shorter intervals. In the laboratory, some animals can learn the specific duration (seconds or minutes) between periods of food access. It has been supposed that wild nectarivores, such as hummingbirds, might also learn short time intervals so as(More)
A core assumption implicit in economic models of animal choice is that subjects assign absolute utilities to options that are independent of the type and number of alternatives available. Humans sometimes appear to violate this assumption and employ relative, as opposed to absolute, currencies when making choices. Recent evidence suggests that animals too(More)
The authors investigated the use by wild-living rufous hummingbirds (Selasphorus rufus) of flower color pattern and flower position for remembering rewarded flowers. Birds were presented with arrays of artificial flowers, a proportion of which was rewarded. Once the locations were learned by the birds, the array was moved 2 m, and flower color pattern(More)
Animals are often assumed to use highly conspicuous features of a goal to head directly to that goal (‘beaconing’). In the field it is generally assumed that flowers serve as beacons to guide pollinators. Artificial hummingbird feeders are coloured red to serve a similar function. However, anecdotal reports suggest that hummingbirds return to feeder(More)
Contrary to theories of rational choice, adding alternatives to a choice set can change the choices made by both humans and animals. This is usually done by adding an inferior decoy to a choice set of two favoured options that are characterized on two distinct dimensions. We presented wild, free-living rufous hummingbirds (Selasphorus rufus) with choices(More)
Behavioral ecologists, well versed in addressing functional aspects of behavior, are acknowledging more and more the attention they need also to pay to mechanistic processes. One of these is the role of cognition. Song learning and imprinting are familiar examples of behaviors for which cognition plays an important role, but attention is now turning to(More)
I developed two versions of the twin threshold model (TTM) to assess risk-sensitive foraging decisions by rufous hummingbirds. The model incorporates energy thresholds for both starvation and reproduction and assesses how three reward distributions with a common mean but different levels of variance interact with these critical thresholds to determine(More)
To increase their chances of survival and reproduction, animals must detect changes in food quality and then decide if, and how quickly, to adjust their behavior. How quickly an animal responds to change will depend on the information available (cognitive, sensory, or physiological) and how it weights those types of information. Surrogate measures of meal(More)
While most animals live in a three-dimensional world, they move through it to different extents depending on their mode of locomotion: terrestrial animals move vertically less than do swimming and flying animals. As nearly everything we know about how animals learn and remember locations in space comes from two-dimensional experiments in the horizontal(More)