Hummingbirds are amazing little creatures that have adapted to survive in a variety of environments. One of their most remarkable abilities is being able to thrive in cold temperatures, even when the water they depend on freezes over. In this article, we’ll explore the question of whether or not hummingbird water will freeze in cold weather and how hummingbirds are able to survive the cold.
Do Hummingbirds Stay in Cold Climates in Winter?
Many hummingbird species do migrate to warmer climates in the winter. However, some hummingbirds have adapted the ability to survive cold winters. For example, Anna’s hummingbirds and rufous hummingbirds have been observed staying in their breeding grounds year-round, even when temperatures drop below freezing.
These cold-hardy hummingbirds have special adaptations like a slower metabolism and the ability to enter torpor – a short-term hibernation – to conserve energy on cold nights. They also have more feathers covering their feet and legs than tropical hummingbird species, helping insulate them against the cold. The shape of their wings helps prevent heat loss. So while most hummingbirds do migrate to avoid freezing weather, some species have evolved to be able to endure cold winters.
How Do Hummingbirds Get Water in Winter?
Accessing liquid water is critical for all bird species to survive, including hummingbirds that overwinter in cold climates. Here are some of the ways hummingbirds are able to find liquid water during winter:
- Natural springs – Some natural springs maintain a liquid state even when temperatures are below freezing. Hummingbirds will seek these out.
- Flowing water – Streams and rivers that have a current are slower to freeze than standing water. Hummingbirds can access these.
- Tree sap – Hummingbirds will drink from sap wells created by sapsuckers and other woodpeckers.
- Snowmelt – On sunny winter days, hummingbirds will access water from melting snow.
- Manmade feeders – People who keep up hummingbird feeders year-round provide a vital water source.
Finding liquid water is one of the biggest challenges hummingbirds face in subfreezing weather. Their adaptations help, but they also rely on natural and manmade sources that don’t freeze solid.
Do Hummingbirds Use Hot Water to Thaw Frozen Nectar?
A fascinating observation by some people is that hummingbirds will drink from feeders with heated nectar, even when their feathers get wet. This has led to speculation that hummingbirds deliberately seek out hot water sources to thaw frozen nectar.
However, there is no scientific evidence that hummingbirds are intentionally using hot water in this way. The internal machinery of a hummingbird’s tongue likely responds reflexively to any liquid. When presented with a heating source, they will lap it up even when not useful or even detrimental. Any appearance of “smart behavior” is likely just incidental.
So while hummingbirds can make use of hot water if available, they don’t appear to have the cognitive ability to seek it out specifically to melt frozen nectar. Like all animals, they have instinctive behaviors, not necessarily an analytical ability to problem-solve.
How Does Their Nectar Not Freeze?
Hummingbirds have extremely fast metabolisms that require them to feed frequently throughout the day. They get most of their nutrition from flower nectar and tree sap. In cold climates, how do they access these foods when temperatures drop below freezing?
First, it’s important to understand the chemistry of nectar. The main components are water and sugars, particularly sucrose, glucose, and fructose. This combination forms a solution that freezes at a lower temperature than pure water. The precise freezing point depends on the sugar concentration, but nectar is generally 25-40% sugars.
The high sugar content acts as a cryoprotectant – it lowers the freezing point several degrees below water’s 32°F (0°C) freezing point. Flower nectar and tree sap don’t necessarily freeze solid. The viscosity increases sharply, but it can still be accessed by hummingbirds.
Additionally, hummingbirds have anatomical adaptations to access thick, frozen nectar. Their long thin beaks and tubular tongues can reach into partly frozen flowers. Specialized rushing muscles allow them to lick up viscous nectar.
So while ordinary water sources may freeze, hummingbirds can still feed on sugary nectar and sap in subfreezing weather thanks to its lower freezing point and their specialized physiology.
Can Hummingbirds Survive Freezing Temperatures?
Hummingbirds are remarkably resilient to cold conditions. Some key adaptations allow them to survive freezing temperatures:
- Hypothermic nights – They lower their body temperature by up to 10-12°C and enter a nightly state of torpor, similar to hibernation.
- Puffy feathers – Plumage is thicker and fluffier in cold-climate species to retain body heat.
- High metabolism – Their unique energetic needs and sugar diet help maintain energy and function.
- Antifreeze – Their blood has cryoprotective adaptations to prevent ice crystals.
- Adaptations like countercurrent heat exchange in their legs keep vital organs from freezing.
Thanks to these special adaptations, hummingbirds can endure subzero temperatures as low as -20°C (-4°F). Slowed heart rate, thick insulation, and physiological antifreeze prevent their tiny bodies from freezing.
Examples of Hummingbirds Surviving Extreme Cold
Here are some real-world examples that demonstrate just how resistant hummingbirds are to freezing weather:
- Rufous hummingbirds survive temperatures below -18°C (0°F) in Alaska winters.
- Anna’s hummingbirds thrive year-round in Canadian cities like Vancouver and Calgary with winter lows below -10°C (14°F).
- A 2008 study tracked Calliope hummingbirds enduring -15°C (5°F) temperatures in the Rocky Mountains.
- Broad-tailed hummingbirds nest at altitudes up to 12,000 feet where below freezing nights are common.
Remarkably, tiny hummingbirds a fraction of an ounce in weight routinely handle cold stresses that would be deadly for many larger animals. Their evolutionary adaptations certainly make them one of the most cold-hardy creatures for their size.
Do Hummingbirds Get Frostbite?
Considering their small size and the extreme cold temperatures some hummingbirds endure, another fascinating question is whether they can get frostbite.
Frostbite occurs when skin and tissue freezes, usually in the extremities, causing damage or death. For an animal the size of a hummingbird, the danger would appear high.
However, hummingbirds have several key adaptations that protect them from frostbite:
- Fewer exposed extremities – Legs/feet are tiny relative to body size.
- Exceptional feather insulation on feet and legs.
- Countercurrent heat exchange keeps blood warm in legs and feet.
- No persistent perching in cold spots.
- Rapid metabolism generates internal heat.
Therefore, despite frequent exposure to below freezing temperatures, frostbite damage appears to be very rare in hummingbirds. As long as they have access to adequate food sources for their high metabolism, they can maintain sufficient warmth to avoid tissue damage from freezing. Their exceptional evolutionary adaptations keep this risk low.
What Are Rufous Hummingbirds?
The rufous hummingbird is one species that displays a remarkable ability to survive in cold climates. Identifying features include:
- Natively found along the Pacific Northwest coast of North America.
- One of the northernmost species, breeding as far as Alaska.
- Males have bright orange-red throats/flanks (where the name “rufous” comes from).
- Tiny birds, weighing just 2-5 grams.
- Highly territorial; males aggressively defend feeding areas.
- Hardy birds that can survive below-freezing winters.
- The longest migratory route of any hummingbird, up to 5,000 miles.
Rufous hummingbirds are specialists at thriving in cold climates thanks to adaptations like slow metabolism, torpor use, and excellent feather insulation. Their hardiness allows them to nest further north than any other hummingbird species. Though tiny, they possess remarkable endurance.
What Temperature Do Hummingbirds Leave At?
Most hummingbirds migrate away from their summer breeding grounds once temperatures reach a certain point in autumn associated with scarce food. However, different species have different temperature limits:
Hummingbird species | Migration departure temperature |
---|---|
Ruby-throated | 55°F (13°C) |
Rufous | 50°F (10°C) |
Anna’s | No migration, can overwinter |
Allen’s | 45°F (7°C) |
Calliope | 40°F (4°C) |
The most cold-tolerant hummingbird species like Calliope and rufous hummingbirds can persist with temperatures near freezing. More tropical species like ruby-throated hummingbirds migrating north depart once about 55°F. This helps highlight the differences in cold hardiness across hummingbird species.
What is the Coldest Hummingbird Species?
Different hummingbird species have adapted to a range of cold temperature limits. Based on their minimum temperature thresholds, the title of the most cold-hardy hummingbird species goes to:
Calliope Hummingbird
Evidence of Calliope hummingbirds enduring temperatures as low as -15°C to -20°C has been documented. They far surpass tropical species limits.
Key reasons Calliope hummingbirds top the list as the coldest species:
- Breed as far north as Alaska and Canada.
- Nest at high elevations in the Rocky Mountains.
- No migration, withstand subzero winters.
- Enter torpor overnight and for long periods.
- High tolerance for frozen nectar sources.
Their range exposes them to bitterly cold yet surprisingly livable winter conditions. Calliope hummingbirds demonstrate more extreme cold tolerance than species like rufous hummingbirds. The Calliope stands alone as the champion of cold survival among hummingbirds.
Do Any Hummingbirds Not Migrate?
Most northern hemisphere hummingbirds migrate south for the winter. However, these species have adaptations to endure the cold and don’t migrate:
- Anna’s hummingbird – Pacific Coast, Mexico to Canada.
- Rufous hummingbird – Rocky Mountains and Pacific Northwest.
- Allen’s hummingbird – Coastal California and Mexico.
- Calliope hummingbird – Mountain West, Canada to Mexico borders.
- Broad-tailed hummingbird – Rocky Mountains.
These resident (non-migratory) hummingbirds have evolved a number of strategies to survive subzero temperatures and scarce food in winter. Their unique adaptations allow them to inhabit areas too cold for most tropical migratory hummingbird species.
Conclusion
Hummingbirds are exceptional in their ability to thrive in cold climates that push the limits of their physiology. While most hummingbirds retreat from freezing temperatures, cold-adapted species have evolved to endure freezing conditions through torpor, insulation, and cryoprotective adaptations. Though small, they can survive overnight lows rivaling temperatures found in Antarctica. With adequate food sources providing their high-energy needs, hummingbirds continue to amaze with their overwintering abilities in harsh, unforgiving habitats. Their unique evolutionary path makes them one of nature’s most resilient creatures.