Reserva Ecológica Costanera Sur

Order: Apodiformes - Family: Trochilidae

Hummingbirds keep a close relationship with flowers since they produce nectar, one of the basic components of hummingbirds´ diet. This reward is compensated for by the involuntary provision of polen, which promotes cross-pollination. Nectar constitutes 90% of their diet. This sugar- and amino acid-rich liquid is transformed into energy, most of which is consumed to perform an energetically expensive flight type (see Flight Technique). To lap up nectar hummingbirds stay aloft before the flower, introduce their bills to reach the nectaries, which are in the base of the corolla, and drink the sweet liquid with the tongue.

Long-billed hummingbirds prefer tubular flowers. The Glittering-bellied Emerald is not choosy and manages with what is at hand. Besides both Erythrina crista-galli and Chorisia speciosa flowers have well developed petals to hold on to. Flowers are generally brightly coloured: red, orange or yellow. In the case of Chorisia speciosa the center of the corolla and the petal tips present contrasting colours.

The tongue has special characteristics. It is long and can double the bill in size. When not in use it is "circling" the rear part of the head connected to the hyoid apparatus, the muscles of which extend and contract the tongue. It is split in the tip. These extremes join to channel nectar into the mouth. Hummingbirds protrude the tongue 13 times a second without opening the bill.

Left: The tongue doubles the bill in size. It protrudes the tongue without opening the bill. Right: Rhynchokinesis: capacity to open the distal portion of the bill

The other basic component of their diet are the arthropods. To catch them they use the tyranids´ flight technique. They either stand on a perch from where they catch whatever flies by or they hawk for insects. For this technique theu use the bill instead. Hummingbirds can open the distal part of their bill (rhynchokinesis). This is due to a flattening of the bone structure in the base of the upper jaw which gives flexibility to the distal portion of the bill.

Incursión aérea para atrapar insectos

This Glitttering-bellied Emerald has been observed to stop at a flowering tree, visit some flowers and move on to the next one. In this way they locate a nectar source. These flowering trees are memorized in a flight route and become regular stops to refuel. This behaviour resembles the way traplines are checked to see what has been caught, so hummingbirds have been named "trapliners" after it. Their strategy differs from the territorialists´ which become holders of a tree and defend it from intruders.

And getting off the subject: the eyelashes of the hummingbird, small tufts of feathers Photos © Roberto Ares