Presentation order affects decisions made by foraging hummingbirds

When animals make choices about food sources, potential mates or nest sites, they encounter options either simultaneously or sequentially. As human choices can be altered depending on whether they encounter options simultaneously or sequentially, it seems plausible that animal choices may also be influenced by the way in which they encounter options. Here, we examined whether birds’ choices were affected by the way in which they learned about possible options. In one treatment, we presented hummingbirds with each of three foraging options (5, 20 or 30 % sucrose solution) either sequentially or simultaneously before presenting birds with a choice of all three options simultaneously. When the birds had learned about options simultaneously, they had stronger preferences for the best option (30 %) than when they had learned about the options sequentially. These data are consistent with the stronger preferences for simultaneously encountered options in the mate choice literature. In both situations, it is possible that this effect comes about because it is easier to discriminate among multiple options presented simultaneously and/or because there are costs of failing to accept an option when those options are presented/encountered sequentially.