Hummingbirds and Their Flowers
When a hummingbird inserts its bill into the corolla of a flower, its forehead, beak, and chimney become well-dusted with pollen, some of which will be transferred to neighboring flowers of the same species, achieving cross-pollination.
From the plant’s point of view, hummingbirds are very desirable pollinators because they are long-lived and can fly long distances in all weather conditions. For this reason, many plant families of the Americas have evolved flower characteristics that make their nectar available only to hummingbirds and not to insects. Such characters are long tube-like corollas with narrow openings and the absence of landing platforms which insects require.
These flowers are oriented well away from leaves and entangling vegetation so that the feeding hummingbird can hover in front of or below them. They are usually colored red or orange, because hummingbirds, but not insects, can distinguish these colors. The nectar in hummingbird flowers is abundant but not concentrated compared with that of bee-pollinated flowers, as bees are more efficient at Collecting very small quantities of concentrated nectar.
It is generally the larger hummingbirds with longer bills, such as the hermit hummingbirds, that get most of their nectar from hummingbird flowers at which insects cannot feed. The smaller, shorter-billed hummingbirds. Emeralds, do much of their feeding on less specialized flowers which they may share with insects.
Two hummingbirds with highly specialized bills the ivorybill with a bill up to. (4in) long, twice as long as that of any other hummingbird, and the sicklebill with a deeply curved sickle-shaped bill has a particularly high degree of co-evolution with certain plants. Bird and plant are interdependent: the swordbill with a climbing Passionflower, which has a corolla tube of 11.4cm (4.5in), and produces up to 5ooml of nectar a day, and the sicklebill with certain heliconias whose sickle-shaped corollas fit its bill exactly.
The larger sicklebills, which weigh about 12g (o.4oz), prefer to perch while feeding, and the flowers of the helicon at which they feed are arranged to make this possible. See more: Bustard