Data from: Influence of floral orientation on feeding behavior in Anna's hummingbirds

Hover-feeding by hummingbirds from pendent flowers relative to horizontal
flowers increases the metabolic cost of flight, but in nature a large
proportion of hummingbird-pollinated flowers are nonetheless oriented
near-vertically downward. We used binary-choice tests to assess behavioral
preference of captive Anna's Hummingbirds for these two particular
floral orientations. The extent of nectar consumption from artificial
flowers differed significantly over a 2-hour exposure period, with birds
showing greater extraction from the horizontal configuration. We also
found that time spent hovering at the feeder immediately prior to nectar
extraction did not vary by feeder orientation, whereas feeding duration
tended to be greater at horizontal feeders. Opportunistic measurements of
wild hummingbirds were also consistent with a preference for horizontal
feeders. In aggregate, these observations suggest that the increased
metabolic cost of hover-feeding from pendent flowers is matched by an
associated behavioral aversion, at least under the conditions examined
here. However, pendent hummingbird-specialized flowers are common,
suggesting that additional behavioral or ecological factors underpin
evolutionary persistence of this floral presentation.