Ruby-throated hummingbirds (Archilochus colubris) are the most widespread and common hummingbird species in eastern North America. They are well-known for their iridescent plumage and their amazingly fast wingbeats that allow them to hover in mid-air and fly backwards. Like all hummingbirds, ruby-throats have unique nesting behaviors centered around providing for their eggs and young. One of the most frequently asked questions about ruby-throated hummingbird breeding is what month they typically lay eggs.
Ruby-throated hummingbird breeding range and habitat preferences
Ruby-throated hummingbirds breed during the summer months all across eastern North America. Their breeding range stretches across southern Canada from Saskatchewan to Nova Scotia, throughout most of the United States east of the Rocky Mountains, and south to the Gulf Coast. Within this broad geographic range, ruby-throated hummingbirds nest in a variety of semi-open habitats with sufficient flowers to provide nectar for fuel and trees or shrubs for nest placement. This includes meadows, yards and gardens, orchards, forest edges, parks, and along streams and ponds.
Favorite nesting sites provide both cover and open areas. Dense trees or shrubs are used for nest placement, while adjacent open areas such as clearings or open water provide good visibility and access to flowers for feeding. Suburban parks and backyards that combine flowers, scattered shrubs and trees, and open lawn areas create excellent habitat for nesting ruby-throated hummingbirds.
Ruby-throated hummingbird nesting and breeding biology
Courtship
In preparation for breeding, male ruby-throats return north to the breeding grounds in advance of females, arriving as early as January in southern portions of the range. Throughout courtship, males perform elaborate aerial displays to attract females. They fly in repeated up and down arcs, diving and rising again and again in exaggerated patterns at breeding sites.
If a female shows interest, the male may also perform a dramatic dive display, plummeting sharply before pulling up just feet from the ground. These aerobatic displays are accompanied by buzzing sounds caused by specialized tail feathers. In addition to their visual displays, male ruby-throats sing to defend territories and court females.
Nest Building
Once paired up, the female ruby-throat takes over building the nest while the male continues displays to guard the territory. She constructs a tiny cup nest only about 1.5 inches across, using soft plant down, bud scales, bark fragments, moss, and bound together with spider silk. The exterior of the nest is camouflaged with lichens and often resembles a small knot on a branch.
Nest sites are typically low in trees or shrubs 10-20 feet above ground, located on a downsloping thin horizontal branch. This could be in either a deciduous or coniferous tree or shrub. The female builds the nest in 5-10 days, working in short bursts through the day.
Egg Laying and Incubation
Once the nest is complete, the female lays a clutch of just two tiny white eggs. Ruby-throated hummingbird eggs are oval shaped and measure only 0.5 inches long. The female lays one egg per day, so the two egg clutch is complete in two days.
She then incubates the eggs for a remarkably short time period, just 12-14 days, before they hatch. To maintain the very warm temperature needed for incubation, she sits on the nest 75% of the time. When she must leave to feed, she often covers the eggs with nest material to help maintain the optimal 99-100F incubation temperature.
What month do ruby-throated hummingbirds lay eggs?
Ruby-throated hummingbirds breed across a broad spring-to-fall timeframe based on latitude. However, most egg laying occurs within a peak range from **mid-April through June.**
Here is a more detailed look at the timing of egg laying by month across their breeding range:
January
No egg laying occurs. The earliest males are just beginning to arrive on the Gulf coast breeding grounds.
February
No egg laying occurs. Some southern males are beginning displays but few if any females are present this early.
March
Minimal egg laying may very occasionally occur in extreme southern Florida. But most breeding activity is still focused on males arriving and displaying on territories to attract females.
April
Egg laying is getting underway through the southeastern states, roughly south of Virginia. Peak activity ranges from late April in southern Florida to early April across the Gulf states. Some very early nests further north may initiate egg laying.
| Location | Earliest Egg Laying |
| Southern Florida | Late April |
| Gulf Coast | Early to Mid April |
| Southeast Atlantic Coast | Mid April |
May
Peak egg laying period for most of the breeding range from the Midwest east and southeastern Canada south. Stretches from early May in the deep south to late May further north.
| Location | Peak Egg Laying |
| Southern Florida | Early May |
| Southeast and Gulf Coast | Early to Mid May |
| Mid Atlantic and Midwest | Mid May |
| Northeast and southern Canada | Late May |
June
Egg laying continues at declining levels across most regions. Peak activity shifts northward, ranging from northern Midwest and southern Canada early in month to the most northern reaches in late June.
| Location | Peak Egg Laying |
| Florida to mid Atlantic | Early June |
| Midwest and southern Canada | Early to mid June |
| Northeast and northern Canada | Late June |
July
Very few nests still active, mostly late or second attempts. Primarily confined to the most northern extremes of the range in Canada.
August
Extremely rare egg laying as birds have shifted focus to migratory needs.
Reasons for extended ruby-throated hummingbird breeding season
The protracted ruby-throated hummingbird breeding season lasting up to 6 months or more enables the species to take advantage of seasonal peaks in flower and insect abundance across their vast north-south range.
Here are some key factors driving the broad nesting timeframe:
Early start in southern wintering range
Some ruby-throats winter along the southern Gulf coast and in Florida where flowers and insects allow successful breeding as early as March. Early breeding ensures young fledge in time to migrate north for the summer season.
Weather patterns and flowering seasons
The onset of breeding is closely tied to flower availability for nectar which is heavily influenced by weather patterns, especially temperature. In warmer springs, flowering and egg laying occur earlier.
Synchronizing with peak food abundance
Nesting coincides with times of maximum flower nectar and insect prey availability which shifts northward through spring and summer. Early breeding in south takes advantage of early flower blooms.
Long duration of nesting at each site
Birds require 30-45 days from nest construction to fledging at each location. This spreads out nesting activity within each region.
Multiple nesting attempts
Birds will renest up to 2-3 times after failed nest attempts, lengthening the overall breeding season.
Differing migratory populations
Separate populations breeding further north arrive and begin nesting later than southern resident groups. This increases the duration of breeding activity.
Conclusion
In summary, most ruby-throated hummingbird egg laying takes place in a peak period from mid-April through June across their breeding range. Early nests get underway along the Gulf coast in March and April, with the core nesting activity sweeping northward through May and June. Latest nesting extends into July primarily in the northernmost extremes of Canada.
The broad spring to mid-summer nesting season allows ruby-throated hummingbirds to match up nesting attempts with the most favorable flower nectar and insect prey resources across their vast geographic breeding range. By closely tracking the seasons and available food supplies, they successfully raise multiple broods each season across North America.
