Hummingbirds are some of the most fascinating birds found in nature. Known for their incredibly fast wing beats and ability to hover in midair, hummingbirds have captured the fascination of people for centuries. One of the most interesting aspects of hummingbird biology is their breeding habits. Hummingbirds display some unique behaviors when it comes to attracting mates, building nests, laying eggs, and raising young. Understanding when and where different hummingbird species breed provides insight into their annual life cycles.
What Months Do Hummingbirds Breed?
The breeding season for hummingbirds depends on the specific species and their geographic location. Here is an overview of when some common hummingbird species breed:
Ruby-throated Hummingbird
The ruby-throated hummingbird (Archilochus colubris) is the most widespread and commonly seen hummingbird in eastern North America. It breeds in a broad area stretching from southern Canada south to the Gulf Coast.
| Months | Breeding Range |
|---|---|
| February – March | Southern Gulf Coast, Florida |
| March – June | Along the Atlantic coast up to the Carolinas |
| April – July | Inland through Tennessee and Arkansas |
| May – August | Across the Great Lakes and into Canada |
The ruby-throat population spreads northward as spring arrives, following the bloom of early-flowering plants. The males arrive first to establish breeding territories, followed soon after by the females. Most mating occurs in May and June across the central and northern parts of their range.
Rufous Hummingbird
The rufous hummingbird (Selasphorus rufus) breeds farther north than any other hummingbird species. It nests along the Pacific Coast from southern Alaska down to northern California.
| Months | Breeding Range |
|---|---|
| March – May | Coastal California and Oregon |
| April – June | Inland through Washington, Idaho, and Montana |
| May – July | Southern Alaska |
Rufous hummingbirds migrate north rapidly as spring arrives. Males precede females by up to two weeks to secure the best breeding areas. Most mating and nesting occurs from April through June across their breeding grounds.
Anna’s Hummingbird
Anna’s hummingbird (Calypte anna) is a year-round resident along the Pacific Coast from southern British Columbia to Baja California. Their breeding season is longer than migratory hummingbird species.
| Months | Breeding Range |
|---|---|
| November – June | Central and Southern California |
| December – August | Pacific Northwest, British Columbia |
The peak breeding period for Anna’s hummingbird is between December and April. But some mating and nesting occurs nearly year-round, especially in southern locales with ample flowers and nest sites available.
Allen’s Hummingbird
Allen’s hummingbird (Selasphorus sasin) breeds along a narrow coastal strip from southern Oregon to southern California. The breeding season is early but limited:
| Months | Breeding Range |
|---|---|
| January – July | Central California coast |
| February – July | Southern California coast |
| March – June | Northern California and Oregon coast |
Allen’s hummingbirds begin establishing breeding territories as early as January. But most mating activity is concentrated between March and May. The narrow breeding range and short season limit the Allen’s hummingbird population size.
Black-chinned Hummingbird
The black-chinned hummingbird (Archilochus alexandri) nests inland across the western United States from British Columbia to Texas. Their breeding range overlaps with the ruby-throated hummingbird in some central states.
| Months | Breeding Range |
|---|---|
| March – July | Texas, Oklahoma, New Mexico, Arizona |
| April – July | Nevada, Utah, Colorado, Wyoming |
| May – July | California, Oregon, Washington, Idaho, Montana |
The broad breeding range of black-chinned hummingbirds leads to some variation in nesting dates. But peak activity occurs in May and June across most of their interior western habitats.
Costa’s Hummingbird
Costa’s hummingbird (Calypte costae) is a desert southwest species that nests from southern California to southern Arizona and south into Mexico. Nesting occurs surprisingly early in this hot, arid region:
| Months | Breeding Range |
|---|---|
| November – June | Baja California, Southern Arizona |
| December – May | Southern California, Sonoran Desert |
By nesting in late fall and winter, Costa’s hummingbirds avoid the harshest summer heat while taking advantage of winter flowering plants. Most nesting happens between February and April.
Broad-tailed Hummingbird
The broad-tailed hummingbird (Selasphorus platycercus) breeds at higher elevations in the western mountain ranges. Nesting happens in the spring and early summer:
| Months | Breeding Range |
|---|---|
| May – July | Rocky Mountains from Wyoming to New Mexico |
| June – August | Mountains of Arizona, Utah, Colorado, Nevada |
Broad-tailed hummingbirds arrive on their breeding grounds in April or May after completing spring migration. Most mating activity happens from mid-May through July.
Calliope Hummingbird
The tiny Calliope hummingbird (Selasphorus calliope) breeds at high elevations along the Pacific Coast and Rocky Mountains:
| Months | Breeding Range |
|---|---|
| April – July | Cascades and Canadian Rockies |
| May – August | Sierra Nevada, Central Rockies |
Nesting happens relatively late after completing their migration. Most breeding activity lasts from June through July before southbound migration starts again in August.
What Influences Hummingbird Breeding Seasons?
Why do different hummingbird species breed at different times of the year? The answer comes down to a mix of evolutionary adaptations. Here are some of the main factors that influence hummingbird breeding seasons:
Flowering Cycles
Hummingbirds time their breeding seasons around peak flower availability. Flowers provide the nectar they need to fuel their high metabolisms. Arriving too early or too late in a given habitat could mean not having enough food to successfully breed. Each species nests when abundant flowers exist in their preferred habitat.
Competition
There are only so many good nesting areas and food resources available in a given environment. Hummingbird species avoid competing with each other by nesting at separate times. For example, Anna’s hummingbirds breed in winter when few other hummingbirds are present along the California coast.
Weather Conditions
Hummingbirds avoid nesting during periods of weather extremes that could threaten their survival. Nesting usually happens after the last frost but before the hottest, driest conditions of high summer set in. Hummingbirds favor mild, relatively stable weather for maximum breeding success.
Migration Constraints
For migratory hummingbirds, the timing of their arrival and departure is closely linked to breeding. They cannot breed until completing their long northward migration in spring. And they must fatten up and prepare to migrate south before the harsh winter sets in again. These limitations narrow their breeding window.
Molting Cycles
Most hummingbirds undergo an annual molt soon after breeding. This complete replacement of feathers requires extra energy, so molting is precisely timed. Different species molt at different times based on their breeding cycles and migration patterns. Molting limits how long into summer hummingbirds can continue breeding.
How Do Hummingbirds Breed and Nest?
The actual breeding and nesting behaviors of hummingbirds show several unique adaptations:
Courtship Displays
Male hummingbirds perform elaborate aerial courtship displays to win the favor of females. They fly in loops, dives, and dramatic ascents to show off their flying skills and beautiful iridescent plumage. Their mating displays happen in and around breeding territories.
Nest Building
The female alone builds the nest out of soft plant down, spiderwebs, and lichens. She chooses a protected site like a tree branch high above the ground. The tiny cup-shaped nests provide just enough room for two pea-sized eggs.
Eggs and Incubation
Hummingbirds lay only two eggs per clutch, usually on consecutive days. The female incubates the eggs for 14-23 days depending on species. She sits near-constantly on the nest, leaving only briefly to hunt for food. The body heat under her feathers keeps the eggs at the proper warm temperature.
Hatching and Feeding
Both eggs often hatch on the same day. The naked, blind babies weigh only about half a gram at birth! The female feeds the nestlings with regurgitated nectar and insects as they rapidly grow and develop feathers. After 20-26 days, the young hummingbirds fledge from the nest.
Multiple Broods
Hummingbirds can breed up to three or four times per season, building a new nest and laying new eggs after each successful brood. This repeated nesting allows them to produce more offspring during the short breeding window. The male may continue displaying to mate with additional females between broods.
Unique Hummingbird Breeding Adaptations
Several evolutionary adaptations allow hummingbirds to breed successfully:
Small Size
Hummingbirds are the smallest birds, which allows them to exploit flower nectar for food and build tiny, well-camouflaged nests in trees and shrubs. Their agility in flight enables elaborate courtship displays.
High Metabolism
Hummingbirds have ultra-high metabolic rates to power hovering flight. This also allows females to incubate eggs for long periods and provides the energy needed to raise multiple broods per season.
Sharp Vision and Memory
Excellent eyesight allows hummingbirds to locate flowers, avoid predators, and navigate long migrations. Sharp memory helps females return reliably to the same breeding sites each year. Males remember the locations of prime nesting territories.
Long Bills and Tongues
Specialized bills and extendable tongues let hummingbirds drink nectar. This key adaptation provides the dietary fuel needed for breeding. It also fosters close ecological relationships with certain flower species.
Migration Tendencies
Being migratory allowed hummingbirds to expand breeding ranges northward into temperate climates for the summer, following flower bloom. Their incredible flight skills enable these marathon migrations.
How Do Hummingbirds Care for Their Young?
Parenting duties fall primarily on the female hummingbird. Here’s an overview of how they care for offspring:
Incubation
The female alone incubates the eggs, using her warm body to maintain proper embryonic development. She may leave the nest for only a few minutes at a time to feed. This constant contact ensures the eggs stay viable in cold weather.
Brooding
For the first week after hatching, the female continuously broods the chicks. Her body provides warmth as the naked, unfeathered babies lack natural insulation. Brooding keeps the hummingbirds warm until they develop full juvenile plumage.
Feeding
The mother feeds the chicks regurgitated nectar and digested insects to fuel their growth. She may visit hundreds of flowers daily to collect enough food for her demanding babies. As the chicks near fledging, the female begins forcing them to accept thicker nectar, readying them for independence.
Hygiene
The mother keeps the nest clean by eating fecal sacs produced by the chicks. This removes waste from the cramped nest, reducing odors that might attract predators. She also keeps nestlings dry by preening wet feathers as necessary.
Predator Defense
While incubating eggs or brooding chicks, the female is highly aggressive towards intruders. She may attempt driving off much larger animals, diving at them repeatedly. Her boldness shields the vulnerable young.
Fledging
In the days before fledging, the female coaxes the young out of the nest to test their wings on nearby perches. After 20-26 days of care, the nestlings finally achieve strong flight and leave the nest permanently.
Threats to Hummingbirds During Breeding Season
Hummingbirds face many challenges while trying to reproduce successfully:
Poor Weather
Cold temperatures, rain, and wind can be deadly to incubating females or newly hatched chicks. Exposure kills hummingbirds due to their extremely high metabolisms and tiny body size. Nest failures often result.
Nectar Scarcity
Lack of flowers deprives females of the huge amount of food needed to produce eggs and feed chicks. Insufficient nutrition causes malnutrition, infertility, or nest abandonment.
Predators
Many animals prey on hummingbird eggs and chicks, including jays, crows, squirrels, snakes, and cats. Adults are also vulnerable to hawks, falcons, and spiders in their webs. Constant vigilance is required.
Pesticides
Chemical contamination from farms, gardens, and roadsides poisons flowers and accumulates in the birds’ tissues. Pesticides can severely disrupt breeding by damaging reproduction and reducing insect prey.
Habitat Loss
Urbanization and agricultural conversion destroy essential breeding habitats like meadows, brushlands, and forest edges. Nest site availability declines, as does the diversity of natural flower species.
Nest Parasitism
Brood parasites like the bronzed cowbird lay eggs in hummingbird nests, imposing a costly burden. The cowbird chicks outcompete hummingbird young for food, often leading to their death by starvation or ejection from the nest.
Conclusion
Hummingbirds exhibit a fascinating variety of breeding seasons and nesting behaviors. The timing of breeding depends on flower availability, competition, weather, migration patterns, and molting cycles. Females alone build intricate tiny nests and provide constant care while incubating eggs and brooding nestlings until they fledge. Hummingbirds face dangers from predators, parasites, and insufficient nutrition. But evolutionary adaptations like small size, sharp memory, and flight agility enable these remarkable birds to thrive and raise multiple broods during the brief breeding season. Careful conservation and habitat management can help protect hummingbirds during their critical reproductive stages.
