Hummingbirds are remarkable little birds capable of surviving in a wide range of environments. However, cold weather presents a significant challenge for these tiny birds. Hummingbirds have high metabolisms and burn calories quickly to power their rapid wing beats and stay warm. When temperatures drop, they are at risk of using up their energy stores and perishing from exposure or starvation. Despite this vulnerability, hummingbirds have adapted in various ways to withstand cold conditions for limited periods of time. Their survival depends on finding enough food and shelter to make it through harsh weather events.
Do hummingbirds migrate or hibernate in winter?
Most hummingbirds in North America are migratory, traveling south to warmer climates in Central America, Mexico, and the Caribbean for the winter months. This allows them to find adequate food supplies year-round. Some migratory hummingbirds travel remarkably long distances. For example, the rufous hummingbird breeds in Alaska and northern Canada during the summer but migrates around 3,000 miles south to Mexico for the winter.
Some hummingbird species are exceptions and do not migrate. Anna’s hummingbird and Allen’s hummingbird are year-round residents along the Pacific Coast. These hardy birds can survive cold Pacific Northwest winters as long as some food sources remain available. They enter a state of torpor at night and on cold days to conserve energy. Their metabolism and body temperature drop, allowing them to survive on limited resources.
True hibernation where hummingbirds remain dormant for extended periods does not occur. The torpor used by wintering hummingbirds is temporary, lasting a single night or day. They must still wake regularly to feed and replenish their energy.
How do hummingbirds survive cold nights?
Hummingbirds are vulnerable to cold overnight temperatures, which can rapidly drain their energy reserves. Here are some key mechanisms hummingbirds use to survive frigid nights:
Entering torpor
As mentioned above, hummingbirds can enter a torpor state to conserve energy on cold nights. Their metabolism slows to about one-fifteenth of their normal rate. This drops their body temperature and slows their breathing and heart rate. Torpor allows hummingbirds to survive temperatures below freezing without feeding. They use up fat reserves for energy.
Finding shelter
Hummingbirds seek protected roosting spots to shelter from the elements at night. Cavities in trees, tunnels in banks, crevices, porches, crawlspaces, or thick vegetation provide cover. Their small size allows them to wedge themselves into tiny spaces that retain heat. Being out of the wind helps prevent excessive heat loss.
Fluffing feathers
Hummingbirds fluff their feathers at night to create insulating air pockets. This traps body heat near their skin to maintain warmth. They may also turn their back into the wind or cold surface to protect their head and feet.
Using hypothermia
If hummingbirds become severely hypothermic, they can lower their body temperature to the point where they appear dead. Their heart and breathing rates reach near-undetectable levels. By inducing a temporary state of physiological shutdown, they can survive extreme cold through the night.
Seeking warmth
Some hummingbirds survive by seeking heat sources such as porch lights or venting air from buildings. They may cling to the side of a building where escaping warm air raises the exterior temperature. This behavior is most common in Anna’s and Allen’s hummingbirds trying to endure Pacific Northwest winters.
Do hummingbirds store food to survive winter?
Hummingbirds have very limited ability to cache food supplies. Some observant homeowners have noticed hummingbirds poking at spots on trees or railings in autumn, but this behavior does not indicate deliberate food storage. Hummingbirds have no crop for storing food like some seed-eating birds. Their long forked tongue is adapted for lapping up nectar, not carrying food. While hummingbirds may incidentally get stuck sap or insects on their beaks that they later eat, they do not have enough excess food to deliberately save for winter. Hummingbirds must find fresh food daily to make it through cold weather.
What do hummingbirds eat in winter?
Hummingbirds depend on finding adequate food every day to maintain their high metabolism in cold conditions. Here are some of their key winter food sources:
Flower nectar
Flower nectar provides essential carbohydrates. Hummingbirds seek out any blooming flowers in their habitat, even poking through snow to find hidden blossoms. Winter-blooming plants like coral honeysuckle, fuchsia, and certain winter-flowering shrubs offer vital energy.
Sap wells
Hummingbirds tap into wells of tree sap for nutrients. They use their beaks to pierce the bark of certain trees like birches and maples. The sap oozes out providing a sugar source. Sapsuckers and other woodpeckers often drill sap wells that hummingbirds then take advantage of.
Insects
Small spiders and insects provide essential protein. Hummingbirds glean them from branches and crevices, often hanging upside down to probe. They may also snatch midges and gnats in midair.
Sugar water feeders
In residential areas, hummingbirds rely heavily on backyard feeders stocked with sugar water (one part sugar boiled in four parts water). This vital food substitute can help hummingbirds survive when flowers are scarce. Feeders should be kept thawed and filled regularly through winter.
How do hummingbirds keep warm in winter?
Hummingbirds have adaptations and behaviors to help maintain body heat when temperatures drop:
Insulative feathers
Hummingbird feathers provide excellent insulation. Downy underplumage traps air near the skin to retain heat. Outer plumage repels water and minimizes heat loss. Preening oil helps keep feathers flexible and water resistant.
Adjustable metabolism
Hummingbirds can adjust their metabolic rate based on conditions. They burn more calories to generate body heat on cold days and reduce metabolism to conserve energy when resting at night.
Shivering
Like mammals, hummingbirds shiver to raise their body temperature. The rapid muscle contractions generate more internal heat. Even slight shivering helps counteract heat loss.
Feather puffing
Fluffing their feathers creates more insulating air pockets. This traps body heat close to their skin on cold days.
Sunbathing
Hummingbirds perch in direct sunlight to absorb radiant heat from the sun’s rays. Facing the sun helps warm their bodies when temperatures are cool.
wind barriers
Hummingbirds seek wind protection to avoid excessive heat loss. They nestle into thick vegetation, tree cavities, or crevices out of the wind. This reduces convective cooling.
| Behavior | How it retains heat |
|---|---|
| Entering torpor | Lowers metabolism and body temperature |
| Seeking shelter | Avoids wind chill and wet conditions |
| Fluffing feathers | Traps insulating air near body |
| Facing sunlight | Absorbs radiant heat from sun |
| Shivering | Generates heat through muscle contractions |
Do hummingbirds die in winter?
Harsh winter conditions certainly pose a threat to hummingbirds. However, they have a strong drive to survive and do not simply give up in cold weather. With adequate food sources and shelter, most hummingbirds are resilient enough to endure seasonal drops in temperature. Their adaptations allow them to make it through freezing nights and cold spells.
Winter mortality depends heavily on the availability of food, snug roosting spots, and periods of milder weather that reduce thermoregulation demands. Young hummingbirds on their first migration and older birds may be most vulnerable. Small hummingbird species like Calliope, rufous, and Allen’s are at higher risk than larger broad-tailed and ruby-throated hummingbirds.
While some deaths undoubtedly occur, most hummingbirds are tough and resourceful. Banding studies show year-round site fidelity and annual return rates for many wintering hummingbirds. If they can obtain enough daily calories and rest protected from the elements, these energetic survivors can withstand quite frigid conditions.
How can I help hummingbirds survive winter?
Here are some tips for providing food and shelter to aid hummingbirds in your area through the winter:
Put up feeders
Maintain multiple nectar feeders to provide a reliable energy source when flowers are scarce. Use a 4:1 sugar-water ratio. Keep feeders clean and thawed. Switch nectar out frequently to prevent spoilage.
Provide winter blooms
Plant winter-blooming trees, shrubs, and perennials to supplement feeders. Good choices include coral honeysuckle, witch hazel, lantana, fuchsia, and winter-blooming heather.
Offer roosting spots
Leave brush piles, trees with cavities, protected porches, and other snug shelters hummingbirds can roost in. Hang evergreen wreaths or roosting pouches to provide extra winter roosts.
String holiday lights
In extreme cold, hummingbirds may gather near holiday lights for warmth. Avoid leaving lights on all night, but use them judiciously when extra heat is needed.
Insulate nest sites
Use insulation or weather stripping to seal up holes, crevices, and nest boxes where hummingbirds take shelter. This retains heat to protect roosting birds.
Manage predators
Predators like hawks may opportunistically prey on torpid hummingbirds. Keep feeders in somewhat sheltered spots and minimize cover for predators. Use deterrents as needed.
Report rare species
If you spot a vagrant hummingbird species far outside its expected range, report it to researchers. Banding data helps track range changes and overwintering linked to climate change.
Conclusion
Hummingbirds are determined survivors capable of withstanding surprisingly low temperatures. While cold weather poses serious challenges, hummingbirds can persist through winter if they have access to adequate food, shelter, and warm periods that reduce thermoregulation demands. Providing nectar feeders, winter blooms, roost sites, and other habitat features assists hummingbirds in your area. With some help from homeowners, these energetic birds continue brightening even the bleakest winter days with their beauty and spirit.
