Male Calypte anna - used with permission from

ReproductionCalypte anna nest with hatchlings - used with permission from Anneke Moresco

Like most species of birds, Calypte anna males perform a special mating ritual.  However, what sets them apart from other birds is the extreme at which they go to in order to impress a potential mate.  The males will climb to heights as high as 35 meters in the air and dive towards the ground (and the watching female), reaching speeds close to 100 km/h, where they will then let out a screech by whipping wind through its’ tail (Clark 2009).  This clearly is pushing these small birds to their flight limits as they often perch between dives panting heavily (Clark 2009).  However challenging these dives may be, there is relatively low energetic cost to them (Clark 2009).  If the male finds a receptive female, he then follows her towards the nest site and continues to perform a shuttle display (The Cornell Lab of Ornithology 2011).  During this part of the courtship ritual, the male swings back and forth above the female singing an intense song (The Cornell Lab of Ornithology 2011).
Calypte anna males perform these courtship dives in their own marked and established breeding territories.  A breeding territory for C. anna males measure about 4 to 6 hectares (Stiles 1971).  Males seem to choose these territories based on the distribution of flowers as well as other factors (Stiles 1971).  Breeding territories are highly defended by males, often embarking on long chases in defense of their territory (Stiles 1971).  These territories are therefore very energetically costly to defend and maintain (Stiles 1971).        
Though the courtship dive performed by the male is the flashiest part of the reproductive process, there is much more that goes into reproductive success.  During the breeding season males and females both breed with multiple mates, not forming pairs with any individual (The Cornell Lab of Ornithology 2011).  Females are the sole caretakers of the offspring (The Cornell Lab of Ornithology 2011).  The nest, taking about a week to construct, is made out of plant down, spider webs, cattail, willow, leaves, thistle, and/or small feathers (The Cornell Lab of Ornithology 2011).  The nest measures at about 1 inch tall and 1.5 inches wide (The Cornell Lab of Ornithology 2011).  Occasionally the female will decorate with lichen or mosses on the outside of the nest (The Cornell Lab of Ornithology 2011).  The nest is usually a horizontal branch placed 6-20 feet off of the ground and close to a source of nectar.  Trees commonly inhabited by Calypte anna include oak, sycamore, and eucalyptus trees.  Females typically lay 2 eggs at a time, which have an incubation period of 16 days (The Cornell Lab of Ornithology 2011).  The female cares for and feeds the hatchlings until they become independent at about 18-23 days (BirdWeb).
Female Calypte anna gathering nectar - used with permission from Eleanor BriccettiThe females will scavenge for nectar and insects when feeding her young (Carpenter and Castronova 1980).  It has been discovered that Calypte anna females will change their feeding diets according to food source availability.  At the beginning of the day, the female is likely to feed her young nectar for it is in abundance and the insects are not active at this time of day (Carpenter and Castronova 1980).  However, as the day progresses the diet changes from nectar dominant to insect dominant even though the flower’s nectar production remains relatively constant during the entire day (Carpenter and Castronova 1980).  This suggests that the female is choosing to feed insects, possibly due to a higher protein composition (Carpenter and Castronova 1980).  It is believed that nectar fed in the morning gives the offspring the energy they need to rebound from energy loss throughout the night (Carpenter and Castronova 1980).  The switch to protein in the late afternoon is believed to give the young the protein they need for growth (Carpenter and Castronova 1980).  These feeding habits have been selected for because it is what gives the offspring the most reproductive success.        

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