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The (Humming) Birds and the Bees

By Brittany Richards

Pollen – so much pollen – is not the only thing wafting on the breeze these days. Love is also in the air! Signs of nature’s fecundity are all around us this time of year. For all of us backyard birders, we delight to see the mating pairs of so many of our songbirds succumbing to the call of the season; the males wooing their mates with fancy feathers and fanciful flights. We know in a few weeks’ time we will see the fruits of their efforts when our feeders are visited by the first fledglings, feathers still fluffy, wings still wobbly. So what about Ruby-throated romance? How do our hummingbirds court and couple?

The Ruby-throated Hummingbird courtship story is a brief affair, more fling than lasting love. It begins when the migrating males arrive first in the summer breeding grounds and stake a claim. They will look for abundant food sources and then aggressively defend an area of up to a quarter acre. Tiny but feisty, males jealously guard both food and females within their boundaries. While these fights are typically more about intimidation than injury, with flaring feathers, harsh chirps, and darting dives, there may be occasional casualties. If you find an injured bird, it is best to confine it in a small container, like a shoebox, lined with a towel, and take it to a nearby wildlife rehabilitator. (On the Wake Audubon “Links” page you can find a list of local organizations under “Injured birds and other wildlife”.) 

Food is such a precious resource for hummingbirds who need to feed so frequently that females will also guard food sources such as nectar feeders. To encourage fewer squirmishes, you can plant flowers to offer more feeding locations in your yard, or put out multiple feeders. The Cornell Lab of Ornithology offers this advice: “Overall, you’ll feed far more hummingbirds by setting out four tiny one-port feeders than one giant eight-port one. Spread them out and the birds won’t have to see one another, arousing their territoriality.”

But back to our love story! After a male has successfully claimed a territory, he will attempt to mate with as many females as possible. When a potential mate is within his range, he will try to get her attention with a courtship display that includes whirring and chirping, flashing the feathers of his gorget (that beautiful ruby throat of his name), and a signature U-shaped flight with dramatic dives from as high as 50 feet above her. When she is perched, he will make short flights buzzing back and forth in front of her. Like many facets of this solitary and somewhat secretive bird’s life cycle, it is not precisely known which aspects of this behavior are most persuasive to females. The flashiness of his throat? The energeticness of his display? But some studies of hummingbirds suggest it is the quality of his territory more than his physical attributes that is most attractive. 

When a male has successfully won the affection of the female, the act of mating lasts only a few seconds. As with most birds, this involves a “cloacal kiss” where the cloacae (the single rear opening that is used for digestive, urinary, and reproductive purposes) are briefly pressed together. And this is where the romance ends! Unlike the doting males of some species, who may build the nest or feed their partner or help rear the young, Ruby-throated males will part ways as soon as mating is complete, leaving the female to perform all the duties of raising the young on her own. But while she may be a single parent, she may still receive some indirect support from the male. There is some debate whether females will build their nests precisely in the territory of their mating partner, or a neighboring territory of her own. But it is believed that she and her young will benefit from the male’s territorial guarding in her vicinity because she and her young will have less competition for nearby food sources. 

Ruby-throats are definitively polygynous, meaning the males will mate with multiple females in a season. But it is also believed that they are polygynandrous, meaning the females will mate with multiple males as well. A female will have one to two broods a year, with a single brood more common in the northern part of the breeding range where the season is shorter, and a third brood being possible in the southernmost part of the range where the season is longest. Here in North Carolina, a female will typically have two broods, almost always of two eggs each. 

With spring fully sprung, and the season of romance in full swing, hopefully your backyard is aflutter with love birds of all sorts. Meaning in a few weeks time, you’ll be treated to some adorable baby sightings as well!