Ornithophily - Cross-pollination
In tropical areas, the birds dominate over insects as important pollinators. The most common among them are humming-birds, sun-birds and honey-eaters. Flowers pollinated by birds are generally orange, red, or yellow. Birds see well in this region of visible light. Birds do not have a strong sense of smell; consequently, bird-pollinated flowers usually lack much scent. Characteristic features of ornithophilous flowers are their tubular (Nicotiana glauca), cup shaped (Callistemon), or urn shaped (some members of Ericaceae) form, bright color, excess of pollen and nectar. As humming-birds (they occur only in The New World) are able to extract nectar while hovering over the flower, they do not need any heavy platform to land when they visit pendant flowers for pollination. In contrast, sun-birds (old world inhabitants) can perch in any position and suck out nectar even if they visit erect flowers.