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Hummingbirds

Elizabeth Penn (Penny) Elliston

Natural History

American ornithologist Robert Ridgeway captured the uniqueness of hummingbirds when he
wrote, “Of all the numerous groups into which the birds are divided there is none other so numer-
ous in species, so varied in form, so brilliant in plumage, and so different from all others in their
mode of life” (Johnsgard 1983). There are over 300 species in the family Trochilidae, all of which
are found in the Western hemisphere. Most occur in South America (although several of the south-
ern species occasionally stray north into the U.S.), and at least 23 species in five genera occur regu-
larly in North America, from the southern states to Alaska (Johnsgard 1983).
Hummingbirds are perching birds in the order Apodiformes. They typically fly anywhere they
desire to go, using their feet only for perching. Wing use is unique to the family Trochilidae in that
the shoulder structure allows a rotational, or sculling, motion of the wings. This enables the bird
to hover for long periods and even fly backward, an ability possessed by no other type of bird.
Hummingbirds eat nectar found in a wide variety of flowers and feeders provided by humans.
For over a century, it has been known that they also consume large numbers of tiny insects and
spiders (Bendire 1895; Bent 1940; Scheithauer 1967; Camfield et al. 2013; Healy and Calder 2006;
Baltosser and Scott 1996; Weidensaul et al. 2019; Baltosser and Russell 2000). A bird may perch to
gather nectar or hover while feeding.
It has long been believed that hummingbirds draw nectar by capillary action up into the tongue
and squeeze it into the crop, but new studies and techniques have produced new hypotheses.
Alejandro Rico‐Guevara’s (Rico‐Guevara and Rubega 2011; Rico‐Guevara 2017) intricate examina-
tion of the hummingbird bill and tongue suggest that the tongue is “a fluid trap, not a capillary
tube.” The trap is formed by forces including “surface tension, Laplace pressure, and the elastic
properties of the keratinous materials making up the tongue tip” and the perfect way the tongue
fits the surrounding bill. This produces a much more rapid and efficient means of drinking.
However, Rico Guevara also concluded that much additional research is needed to completely
understand how the birds ultimately ingest nectar.
Insects are obtained by hawking, and reportedly also by gleaning. Scheithauer (1967) described
some captive hummingbirds as using a “hazing” behavior, in which the bird flushes the insect into
the air before catching it. Gleaning appears uncommon at best (the author has observed it only
rarely in captive Black‐chinned hummingbirds), and caregivers should not assume that the species
they are housing will glean enough unflighted insects to fulfill dietary requirements.

Hand-Rearing Birds, Second Edition. Edited by Rebecca S. Duerr and Laurie J. Gage.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.