Hummingbirds have evolved spectacular courtship displays to attract mates. When trying to entice females, male hummingbirds will perform complex aerial maneuvers and exotic plumage displays. Their elaborate mating rituals are a product of sexual selection, resulting in the flashy feathers and behavior seen during breeding seasons.
Why Do Hummingbirds Have Elaborate Mating Displays?
The evolution of hummingbird courtship displays can be explained by sexual selection theory. Charles Darwin first proposed the concept of sexual selection in the late 1800s to describe characteristics that have evolved specifically for obtaining mates, rather than for survival. For hummingbirds, this includes the Males’ brightly colored plumage and complex courtship flights.
Sexual selection arises from two factors:
- Female choice – Females preferentially select males with the most impressive visual displays and vigor.
- Male competition – Males will compete amongst themselves for access to females. The strongest and fittest males tend to win these contests.
In both cases, traits evolve that give certain individuals an edge in securing mates and passing on their genes. Showy features and behaviors are indicative of a male’s physical condition and can influence female choice. For male hummingbirds, selections have favored the evolution of iridescent feathers and challenging flight maneuvers to appeal to females.
Plumage Displays
One major component of hummingbird courtship displays is the use of colorful plumage to attract mates. Male hummingbirds exhibit a dazzling array of iridescent feathers that shine and appear to change colors as light hits them at different angles. Iridescence is produced by specialized nanostructures in the feathers that reflect particular wavelengths of light. By flexing muscles at the base of these feathers, males can angles them to better display towards females.
Some examples of impressive hummingbird plumage include:
- The crimson topaz hummingbird has a brilliant crimson head and gorget feathers that it can puff out towards females.
- Male Anna’s hummingbirds have rose-red throats bordered by iridescent purple ear patches that they flare during courtship.
- Costa’s hummingbirds display large violet crowns and throats with a contrasting blue spot towards females.
- The aptly named crimson-bellied woodstar has an iridescent crimson belly patch used in mating displays.
Females lack elaborate plumage and are cryptically colored to better blend in while incubating eggs. Male’s flashy feathers are thought to serve as an honest indicator of fitness, since growing colorful plumage requires plenty of energy.
Courtship Flights
In addition to flashing their feathers, male hummingbirds perform elaborate courtship flights to impress females. These aerobatic shows demonstrate a male’s stamina and flying skills. Some common maneuvers include:
- High flying – Males rapidly climb up to 100 feet in the air and then quickly dive back towards the female.
- Shuttle flights – Back and forth diving motions in front of the female, sometimes combined with chirps.
- Figure eights – Circular loops flown in front of the female.
- Pendulum flights – Males swing back and forth like a pendulum in wide arcs.
- Rapid hovering – Males hover in front of females for extended periods, beating their wings up to 200 times per second.
- Swooping flights – Sudden drops out of sky towards the watching female.
These complex air shows require a high degree of stamina and maneuverability. Males that can perform the most challenging dives, hovers, and loops convey their superior flying skills to watching females. Their flight prowess indicates overall fitness.
Vocalizations
Male hummingbirds also incorporate interesting noises into their mating rituals through specialized vocalizations. Their syrinx, a vocal organ located where the trachea forks into two bronchi, allows them to sing with two sounds at once. Some examples of sounds include:
- Short chirps – Often used during shuttle displays towards females.
- Buzzing trills – Rapidly repeated notes that decline in frequency.
- Whining whistles – Long, drawn-out high pitch sounds.
- Mechanical chatter – Harsh, grating sounds similar to a cricket.
- Song – Extended, tuneful notes.
The broad-tailed hummingbird performs one of the most elaborate songs incorporating sharp squeaks and piercing trills. Females seem to prefer males that sing longer and more complex songs, an indicator that he has the energy reserves to devote to vocalization.
Shake Displays
An unusual courtship behavior seen in some hummingbird species is the shake display. To perform this visual show, a male perches close to a female and rapidly shakes his body back and forth, pivoting around his feet. The iridescent feathers are flared during shaking to reflect more light. This odd movement likely evolved to emphasize the colorful plumage towards female viewers.
Examples include:
- Anna’s hummingbird males shake up to 100 times per second, causing a distinctive buzzing sound.
- The Allen’s hummingbird shake display involves swaying back and forth while moving around the perch.
- Scintillant hummingbirds perform shimmies by revolving 360 degrees around their perch during shaking.
Shake displays seem to elicit a positive response from females, evidenced by the behavior spreading across many West coast hummingbird species through mimicry.
Dive Displays
A few hummingbird species have taken flight displays to the extreme with dangerous high-speed dive courtship rituals. Males climb up to 130 feet in the air before accelerating into a sharp dive toward the female at speeds over 60 miles per hour. Just before colliding with the ground, they abruptly pull out of the dive within inches of the female’s head. Some examples include:
- Anna’s hummingbird “J-dive” involves diving in a J-shaped trajectory.
- Costa’s hummingbird dives are timed with a loud, metallic “zing” sound produced by tail feathers.
- The magnificent hummingbird performs a steep 60 degree dive before veering off.
These extreme dives demonstrate aerial finesse and provide an opportunity for females to assess a male’s physical condition. Males that can pull out of high velocity dives without crashing have excellent muscle and skeletal structures adapted for intense flight.
Competing at Leks
Males will also gather together in mating arenas called leks to perform competitive displays. Up to a dozen males may stake out clustered territories in a lek and attempt to court females that venture near. These arenas are not centered on resources like food or nest sites; their sole function is mate attraction.
At a lek, each male engages in energetic displays of plumage and flight maneuvers when females fly over. Females can observe multiple males in action and compare their performances before choosing a mate. More vigorous and skillful displays will win their favor. Males may also scuffle over positions within the lek using aerial battles and chase dives.
Lek mating arenas are seen in many hummingbird species, including:
- The wire-crested thorntail
- The long-tailed hermit
- The ornate thorntail
- The green-crowned brilliant
- The wedge-tailed hillstar
Gathering in leks offers an opportunity for mate choice and competition. It increases the chances of attracting a female but requires males to intensely display their flying talents.
Ornament Use
Some hummingbird courtship rituals also incorporate the use of colorful ornamental objects as decorations to attract a mate. Males will gather natural items from their environment and place them in strategic display locations to impress females.
Examples include:
- Swordbill hummingbirds – Adorn display perches with red berries, leaves, flowers, moss, and fungi.
- Long-tailed sylphs – Decorate display leks with orange berries set against bright green moss.
- Wire-crested thorntails – Place colorful flower pieces, berries, lichens, and bark on display perches.
This ornament behavior likely coevolved with females’ preferences. Females seem to be attracted to males that show creativity in assembling flashy arrangements near their courtship sites.
Conclusion
The elaborate mating displays of hummingbirds have evolved over millennia through sexual selection pressures. Males with the brightest feathers, most vigorous flight maneuvers, longest songs and most impressive ornaments tend to gain a reproductive edge. These visual and vocal courtship rituals are critical tools used by male hummingbirds to attract mates each season. They provide females with honest indicators of a male’s physical fitness and flying agility as they evaluate partners. Next time you see a feisty male hummingbird buzzing around the flowers, take a moment to appreciate the long evolutionary process that shaped its flashy mating behavior aimed at desirability.
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