The Costa’s Hummingbird is a very small North American desert hummingbird that grows only up to 3-3.5 inches in length upon reaching maturity. It is closely associated to the Anna’s Hummingbird. The Costa’s Hummingbird is named after the French nobleman Louis Marie Pantaleon Costa, Marquis de Beauregard (1806-1864).
It breeds in the Sonoran and Mojave Deserts of California and Arizona. While it naturally occurs in the western United States and Mexico, it is known to wander towards the east and north as far as Alaska and Canada. It leaves the desert at the peak of summer and moves to chaparral, scrub, or woodland habitat.
The male Costa’s Hummingbird has mostly green upper parts – its back, sides, and belly. It has an iridescent violet crown and white patches under their gorged throat and tail. The throat patch extends to the sides of the throat. Its wings small and black tail and wings.
Its vibrant purple cap and throat, with throat feathers flaring out and back behind it head, is cited as its most remarkable feature.
The female, which is comparably larger in size, is not that remarkable as male. It has a greyish-green crown and back, and a white belly and breast. Its flanks are ‘buffy’ and the tips of its outer tail feathers are white. Sometimes, its throat has some dark feathers.
The juvenile Costa’s Hummingbird closely resembles the adult female, with tray-buff edging on the feathers of the upper body. Also, instead of having a singly rounded tail, juvenile Costa’s Hummingbird has a doubly rounded tail.
The diet of Costa’s Hummingbird consists of nectar from flowers and flowering trees, insects from leaves, branches and tree hunks, and sugar water from hummingbird feeders.
Costa’s Hummingbirds usually feed at flowers while hovering. They would extend their bill into the flower and use their long tongue to get the nectar. They would visit desert natives like agave, chuparosa, desert honeysuckle, and fairy-duster.
To catch insets, they would either fly out and capture them mid-air, or pluck them from foliage. These insects include small flies, gnats, and wasps.
Distribution and Habitat
Costa’s Hummingbirds’ preferred habitat locations are desert and semi-desert, and arid brushy foothills and chaparral. During migration and winter months, they move to adjacent mountains, as well as open meadows and gardens. They are believed to be the most arid-adapted hummingbirds within the North American region.
However, despite being traditionally migratory birds, a majority of them prefer to stay throughout the year in habitats with temperate climates for an ample food supply. They would rarely move up into mountain meadows after the breeding season. However, serious issues such as nectar depletion and uncomfortable hot weather will prompt them to move into other areas.
They travel short distances when they migrate. Indeed, they are among the first to arrive in their breeding locations.
The breeding range of the Costa’s Hummingbird is mainly in low-elevation desert scrubs in the southwestern U.S. and northwestern Mexico. It’s usual breeding locations are southern California, along Baja, California, in southern, but mainly southwestern Arizona, and in northwestern Sonora.
Behavior and Ecology
According to studies, Costa’s Hummingbird can enter a torpid state, slowing its heart rate and reducing its body temperature under cold night temperatures. The heartbeat rate of Costa’s Hummingbirds during a torpid state is approximately 50 times per minute – a significantly reduced rate from its 500 to 900 times per minute heartbeat rate in a non-torpid state.
Just like the other male hummingbirds, the male Costa’s Hummingbird also exhibits a courtship display. They will fly high, then dive down past perched the subject female, and then climb again while making a high-pitched whistle during dives.
The Costa’s Hummingbird’s song is made up of light chip and loud, repeated, high tinkling notes. Its high-pitched call can be produced from an open perch or at the end of the male’s U-patterned dive display. Females are notably more vocal than male. Indeed, the males only create calls when alarmed or during the courtship process. The male is known to be promiscuous in nature and mates with several individuals in one season.
The female builds the best in an open or sparsely leaved scrub or small tree, commonly above 2-8 feet above the ground and are placed on horizontal or diagonal branch. The nest is made up of compact cup of plant fibers, leaves or flowers that are held together by spider webs.
The female lays two white, oval to elliptical eggs that has an average size of 12.4 x 8.2 mm. The incubation period would take about 15-18 days. The young hummingbirds are generally helpless upon hatching. After about 20-23 days, they will already leave the nest.
The Costa’s Hummingbird has a ‘Least Concern’ status under the IUCN Classification System. The IUCN says that the species appears to have a stable population trend and a very large range, which signify that it does not approach the thresholds for vulnerability. Of all the states in the US where the Costa’s have been observed, only New Mexico has listed the species as threatened.
The most serious threat to the species is loss of habitat, primarily coastal scrub and Sonoran desert scrub. A lot of these areas have been converted for human uses, such as agriculture and residential development.