Migratory hummingbirds in California
California attracts a wide range of migratory hummingbirds throughout the warmer seasons of the year. These tiny birds often travel great distances to reach California
We wrote previously about the hummingbird species that live year-round in California.
This post is about three migratory species that spend the warmer months of the year in California – the calliope hummingbird, the Rufous hummingbird, and Costa’s hummingbird.
Calliope hummingbirds
These tiny hummingbirds hold a giant distinction – they are the smallest bird found in either the United States or Canada. They are so small that fully grown adults typically weigh between 2 to 3 grams. Calliope hummingbirds are truly as light as a feather.
Despite their tiny size, Calliope hummingbirds travel incredible distances as they migrate over the course of the year. They are the world’s smallest long-distance migratory bird.
Their geographical range covers western North America through the summer months. In summer, this species is found as far south as southern California, as far north as southern British Columbia and Alberta, and as far east as Colorado. Their winter migration covers incredible distances and bring them south to southwestern Mexico, Belize, and Guatemala.
Like all hummingbirds, Calliope hummingbirds feed predominantly on nectar produced in flowers. They are opportunistic feeders and will supplement their diet with sap and by eating small insects. Calliope hummingbirds assist with pollination when their feathers brush against flowers while drinking nectar.
Males are brightly colored with dark red streaks on their throat, green feathers on their backs, and white-grey feathers on their underbody. Females have similar coloration except that their throats are darkly colored for better camouflage.
Calliope hummingbirds nest during early spring, typically between mid-April and early May. The males become extremely territorial during this time and defend their site chosen to attract females.
Calliope hummingbirds have an impressive courtship ritual. While trying to attract a female, males hover at a greatly accelerated wingbeat – their wings flap at an incredible 95 times per second which creates a loud buzzing sound. While hovering, they display their throat colors to the female and then rapidly ascend 20 meters into the air before divebombing back to ground level.
These aerial acrobatics are all done to attract potential mates.
Like other hummingbirds, Calliopes have benefitted from human expansion because of non-native plant species being planted in gardens. This species conservation status is least concern, but they may be vulnerable to environmental changes since the entire species winters in the same small area.
Since they are so small and cover such a wide range, the Calliope hummingbird is not well-studied by scientists. Large parts of their lifecycle remain unknown.
Rufous hummingbird
Rufous hummingbirds are another tiny hummingbird that migrates great distances across western north America.
The summer months are their breeding months. They spend them scattered between northern California all the way up to southern Alaska. Over winter, this species migrates south and are found from the southern tips of California across most of Mexico.
Rufous means reddish-brown, or rust colored, and these hummingbirds get their name because of this distinct coloration on the males. Males have rufous colored faces, sides, and tails. They have an iridescent patch on their throats that is orange-red in color.
Females are larger than males in this species and are also better camouflaged. Their feathers are a mixture of white and green with some orange iridescent coloring on their throats. The female Rufous hummingbird looks almost identical to female Allen’s hummingbirds.
Both male and female Rufous hummingbirds are extremely territorial. Males typically defend dense clusters of flowers from other males and females alike. Females are pushed away from dense clustering of flowers by the males and therefore defend wider territories where flowers are more sparsely populated.
These territorial strategies are aggressive but are a strategy that exploits the difference in size between males and females. Males are slightly smaller with shorter wings than females. This means the metabolic cost for them to hover is greater than it is for females. Therefore males defend small, dense territories.
Females are slightly larger and therefore more efficient at gliding and hovering. This efficiency allows them to cover wider territories and successfully feed from flowers that are spread out.
This strategy allows each sex to optimize the nectar resources in their areas.
Costa’s hummingbird
Costa’s hummingbirds are found through southern California, southwestern Arizona, and northwest Mexico.
These hummingbirds are extremely resilient and have adapted to human expansion throughout the region. They are known to hybridize frequently with other hummingbird species, including Anna’s hummingbird and the black-chinned hummingbird. Their conservation status is listed as least concern.
Costa’s hummingbirds have unique coloration that will really stand out if they visit your garden. Male and females have green backs and sides, black tails, and white underbellies. Males have distinct coloration on their throats and head which are brightly colored iridescent purple. Their throat feathers also flair outwards from their head.
Their diet is similar to that of most hummingbirds – the staple of their diet is nectar from flowering plants which they supplement with insects caught while they are foraging. They are important pollinators because their feathers collect pollen while they feed which is transferred between plants.
Costa’s hummingbirds can lower their body temperature and slow down their metabolism during colder nights. This ability is known as torpor and is a hibernation-like state that allows them to survive tougher weather conditions.
Building a hummingbird garden
Pollinators have seen population declines around the world. Hummingbirds are resilient because they have benefitted from human expansion as non-native species have been planted in gardens. This has provided additional food sources, but hummingbirds may still be in danger over time. Declining insect populations will have a negative effect because hummingbirds eat them to supplement their diet.
You can do your part to maintain strong hummingbird populations by planting many flowering plants in your garden. You can also start keeping hummingbird feeders in your garden which provides a steady source of food throughout the year.
If you plant a wide range of colorful flowers in your garden there is a good chance one of these migratory California hummingbirds will stop by for a visit.
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