The World's Best-Known Hummingbird?

Intensively studied, the gem-like Anna’s hummingbird is a welcome visitor to the gardens of America’s most populous state: California. Bill Naylor investigates its life history

- Bill Naylor

THE hummingbirds are often thought of as delicate tropical birds, yet out of the 320 or so species, 16 species of 11 different genera occur in North America. Species range in size from the sombre brown giant hummingbird (Patagona gigas) 20cm (8in) in length, to the bee hummingbird (Mellisuga helenae), the smallest bird in the world, more diminutive than many moths and so small that it is preyed upon by large insects in its native Cuba.

North America’s hummingbirds are predominantly small green iridescent species about 7.5cm (3in) in length, with beaks of various sizes. They lack the flamboyant plumage of the tropical species, but are nevertheless attractive and many have small patches of red purple or blue plumage on their cheeks or head. Being located in North America they have been studied more than other hummingbird species. Anna’s hummingbird (Calypte anna) is perhaps the most-studied and best-known American hummer. In winter the species is confined to southern coastal California, and throughout the year is a regular visitor to gardens, where hummingbird feeders are often provided. Apart from their glittering plumage, hummers’ popularity is explained by their indifference to humans and their sudden appearance when nectar-producing plants are provided. If a garden is planted near houses or people anywhere from Canada to Chile or Argentina – whether it be in the desert, forests or mountains – it will be visited by hummingbirds. The distribution of Anna’s hummingbird used to be divided into two, with populations in the extreme north of California and in the south, but the planting of exotic flowers and trees, especially eucalypts – a favourite of this species – and the provision of hummingbird feeders have all encouraged the species to extend its range from north to south coastal California, and recently into Mexico, without a break.