Sunbird hovering behavior is determined by both the forager and resource plant

The long-standing paradigm that pollination systems adapted to hovering birds evolved only in the New World was recently challenged by the discovery of hovering pollination by Old World specialized passerine pollinators. This raises the possibility that hovering pollination may evolve more easily than previously believed, given sufficient selective pressure on plant traits, on nectarivory, or both. We observed foraging behavior by the sunbird Cyanomitra oritis at flowers of the native Old World plant Impatiens sakeriana. We measured the length of pedicels and peduncles (PedPed length), which can make the flowers difficult to reach while the bird perches on the stem, and determined if it influenced sunbird hovering or perching at a flower. Detailed analyses of video recordings showed that sunbirds only hovered at flowers with a long PedPed, whereas they employed both foraging modes when an adequate perch was available. A hovering sunbird could deplete nectar in a shorter time than a perc...长期以来被认为仅在新大陆演化出适应悬停鸟类的传粉系统的学术范式，近日因旧大陆特化鸣禽传粉者实现悬停传粉的发现而受到挑战。这表明，若植物性状或食蜜习性（或两者）受到足够的选择压力，悬停传粉的演化可能比此前认知的更为容易。我们观测了青喉花蜜鸟（Cyanomitra oritis）在旧大陆本土植物萨基拉凤仙花（Impatiens sakeriana）的花上的觅食行为。我们测量了花梗（pedicel）与花序梗（peduncle）的总长度（简称PedPed长度）——当鸟类停栖于茎干时，该长度会使得花朵难以被触及，并探究该长度是否会影响太阳鸟在花前的悬停或停栖行为。对录像的详细分析显示，太阳鸟仅在PedPed长度较长的花朵处采用悬停觅食模式，而当存在足够的停栖位点时，它们会同时使用悬停与停栖两种觅食方式。悬停的太阳鸟耗尽花蜜的时长要短于停栖的……