Fig 1. Starlings were trained in a multialternative environment.

a. European starling (S. vulgaris, [photo credit: Dick Daniels, http://carolinabirds.org/]/CC BY-SA https://creativecommons.org/licenses/by-sa/3.0]). b. Alternatives present in the experimental environment. Each symbol depicts a profitability ratio (a specific combination of amount and delay) and each shading, a profitability (a given ratio of amount to delay in rewards/second). Lines join stimuli with equal profitability. Within each profitability pair, the larger symbol indicates the Larger–Later profitability ratio and the smaller symbol the Smaller–Sooner one. c. Rate of responding in probe trials (mean ± SEM, n = 9 birds). All data included in this figure can be found in the S1 Data file.