Quick Answer
An Anna’s hummingbird typically takes 5-7 days to build a complete nest. The female does most of the construction, gathering materials and weaving the nest together. She will spend several hours a day carefully applying spider silk and plant down to craft a tiny, cup-shaped nest for her eggs and hatchlings. The speed of construction depends on factors like weather, availability of materials, and how much effort the female puts in each day. But in most cases, an Anna’s hummingbird can build a full nest in less than a week.
Nest Building Process
Anna’s hummingbirds build fairly small nests, only around 2 inches wide and 1 inch tall. But the nest must be sturdy enough to hold two tiny eggs and support the weight of growing hatchlings. Here are the main steps involved in Anna’s hummingbird nest construction:
Selecting a Location
The female Anna’s hummingbird first selects a nesting site, usually on a high tree branch around 10-20 feet off the ground. She prefers a relatively protected spot near the trunk or under a canopy of leaves that provides shelter. Sometimes nests are built on poles, eaves, or other manmade structures. The female spends time gathering information about potential sites before choosing one.
Gathering Materials
Once a spot is selected, the female gathers building materials. She pulls bits of spider silk from webs, often returning to the same webs multiple times. Spider silk provides a stretchy foundation that allows the nest to expand with growing chicks. The female also collects soft plant down, flower petals, bud scales, bark fibers, and moss. She gathers widely available materials within a 100 foot radius of the nest.
Constructing the Outer Shell
The hummingbird starts by forming a base or outer shell for the nest. She uses flexible spider silk to weave together a hammock-like pouch anchored to the branch. The base often makes up 50% or more of the overall nest bulk. As she weaves, the female uses her body as a mold to shape the interior to the size of her body. This ensures a snug fit for incubation later on.
Adding Inner Lining
Next, the hummingbird adds a soft inner lining made of plant down and flower petals. This lines the interior nest walls and provides cushioning and insulation for the eggs. The female uses her beak to carefully tuck and pack down into the cup shape. As she works, she rotates her body within the nest to shape the inner cavity.
Applying Camouflage
In the final stage, the female decorates the exterior of the nest to help camouflage it. She attaches lichens, moss, and bark bits using sticky spider silk. The camouflage helps the tiny nest blend in with its surroundings. The female may continue adding finishing touches until she is satisfied with the construction.
Laying Eggs
Once complete, the compact nest provides just enough room for the female to crouch inside and lay her two pea-sized white eggs. She will then incubate the eggs for 14-19 days before they hatch. The nest must be durable enough to withstand the rainy Pacific Northwest climate while the eggs and chicks are vulnerable.
Construction Timeline
On average, an Anna’s hummingbird spends 5-7 days building her nest from start to finish. Here is a typical timeline:
| Day 1 | Select nest location, gather initial materials |
| Day 2 | Build outer shell foundation with spider silk |
| Day 3 | Strengthen foundation, begin adding inner lining |
| Day 4 | Finish interior lining, shape inner cup |
| Day 5 | Apply camouflage to exterior, add final touches |
| Day 6 | Continue decorating and reinforcing nest |
| Day 7 | Nest complete, lay eggs |
Of course, this timeline can vary considerably depending on the individual bird and her nesting conditions. Bad weather may force the hummingbird to pause construction for a day or two. If materials are scarce, gathering everything she needs could take longer. And some especially diligent females may finish the nest in just 4 or 5 days.
Here are some factors that influence Anna’s hummingbird nest building speed:
Weather
Cold temperatures or heavy rain make nest construction more challenging. In poor weather, the female may wait safely perched until conditions improve before resuming work.
Availability of Materials
If spider webs and soft plant down are abundant nearby, the female can swiftly stock up on building supplies. But she may have to cover more ground to find materials in sparse habitats.
Experience
Older females who have built previous nests often work faster than first-time nesters. Their construction skills improve with practice.
Time of Year
Anna’s hummingbirds nest in late winter and early spring. Females may be more motivated to build quickly as the breeding season approaches.
Disturbances
Frequent disruptions by predators or humans can impede progress. The female may wait until the area is clear to continue construction.
Nest Site Safety
If she feels vulnerable at an exposed site, the female may delay building or choose a new location. Safe sites allow her to work steadily.
So while 5-7 days is typical, an Anna’s hummingbird nest can take longer than a week if conditions are not ideal. But the female is strongly driven by hormones and instinct to complete the nest so she can breed. Once begun, construction usually proceeds briskly through to completion.
Building Materials
Here are the main materials female Anna’s hummingbirds use to construct their delicate nests:
Spider Silk
The most important construction material is spider silk from orb weaver spiders. The elastic threads provide a flexible framework the female can stitch together into a cup shape. Spider silk allows the nest to expand as chicks grow.
Plant Down
Tiny down feathers plucked from plants like cattails, milkweed, and thistle provide a soft inner lining. The female hummer packs wads of plant down into the nest cup.
Flower Petals
Petals from flowers add more cushioning and help camouflage the nest. The female may snip petals from nearby flowers.
Lichen and Moss
Camouflaging the outside with bits of lichen or moss helps the nest blend in. The female hummer often decorates the last 10-20% of construction with camouflage.
Bark, Leaves, Buds
Small pieces of tree bark, leaf fiber, flower buds, and evergreen resin also help disguise the nest and strengthen the outer walls.
Nest Locations
Here are some of the sites where female Anna’s hummingbirds typically build their nests:
Tree Branches
The most common nest location is on a horizontal tree branch, especially oaks or eucalyptus. The female prefers branches 10-20 feet off the ground.
Poles
Nesting on power line poles, phone poles, or fence posts allows an unobstructed flight path to the nest. Like branches, poles offer safety from predators.
Eaves
Under the eaves of cabins or other buildings protected from rain and far from human activity.
Porch rails
Along the top rail of a back porch, stair railing, or deck. Close to people but often undisturbed.
Clotheslines
Occasionally a female will build her nest suspended from a clothesline or thin cable.
Ideal sites are high up, sheltered from severe weather, and have convenient perches for the female to rest as she works. Height helps protect the nest from predators.
Nesting Behaviors
Anna’s hummingbirds display some fascinating nesting behaviors around the breeding season:
Nest Reuse
Females often refurbish an old nest from a previous year rather than building a new one. It takes less work to repair a nest than build one from scratch.
Nest Defense
Females aggressively defend the area around their nest from intruders. They will boldly attack much larger birds, animals, and humans who get too close.
Camouflage
In addition to decorating her nest with camouflage, the female hummer will collect bits of lichen and bark to disguise herself while incubating.
Decoy Nests
A female may build 1-2 unfinished decoy nests in her territory, perhaps to confuse potential predators. Only one nest will be completed for actual use.
Solitary Nesting
Unlike most birds, Anna’s hummingbirds do not nest colonially. Each female builds a solitary nest and tolerates no other nests nearby.
Role of the Male
Male Anna’s hummingbirds do not participate in nest building or incubation. Their role is to mate with females and help chase away intruders. But nesting duties fall entirely to the female.
Threats and Predators
The tiny nests of Anna’s hummingbirds face threats from both weather and predators. Here are some of the main dangers:
Heavy Rain
Storms can batter delicate nests and cause eggs or chicks to fall out. Exposure to wet conditions may lead to the nest disintegrating.
Wind
Strong gusts can blow unsecured nests completely off branches. The female tries to anchor the nest tightly, but high winds pose a risk.
Jays
Scrub jays will raid hummingbird nests for eggs and chicks when possible. The female hummer aggressively dive bombs jays to drive them away.
Squirrels
Tree squirrels will eat hummingbird eggs and sometimes dismantle nests to harvest materials. The female attacks intruding squirrels.
Owls
Owls are major nocturnal predators of adult hummingbirds. Poorly concealed nests may also be vulnerable to owl predation.
Hawks
Sharp-shinned hawks specialize in catching hummingbirds on the wing. Nests may be disturbed by hawks hunting perched adults.
Through diligent nest placement and camouflage, the female Anna’s hummingbird tries to minimize risks. But hatchlings and eggs in the open nest remain vulnerable until they can fly.
Fun Facts
Here are some interesting facts about Anna’s hummingbird nests:
- Spider silk makes up 50-70% of total nest materials.
- Nests are only about 2 inches wide – smaller than a golf ball.
- The nest stretcheas to accommodate the growing chicks.
- Females may decorate the outside with lichen “paint.”
- Each female builds 1-2 nests per breeding season.
- Nests are built in as little as 4 days during ideal conditions.
- Hummingbird nests have some anti-microbial properties.
- Female Anna’s are highly territorial around their nest.
- Building an entire nest likely requires hundreds of trips for materials.
The speedy construction of these tiny nests allows Anna’s hummingbirds to breed and raise chicks during short Pacific Northwest summers. Their ingeniously engineered nests reflect the industriousness of these energetic, resourceful birds.
Conclusion
Anna’s hummingbirds build remarkably small but durable nests to house their eggs and chicks. A female can construct an entire nest in as little as 4-5 days by working diligently to weave spider silk and soft plant down into a tiny cup. Ideal conditions allow her to complete the nest in 5-7 days on average. She prefers to situate the nest high on a branch for safety from predators. Once finished, the stretchy, insulating nest provides a secure home for the next generation of hummingbirds. The female’s nest building skills and use of ingenious materials like spider silk allow her to successfully breed even in challenging environments. The speedy construction of these delicate but functional nests is a testament to the ingenuity of Anna’s hummingbirds.
