Quick Answers
Hummingbirds are sensitive to temperature changes and extremes. If it gets too hot in their environment, they may leave to find areas with more tolerable temperatures. However, there are a few factors that impact whether hummingbirds will leave an area when temperatures rise:
– How high do temperatures get? Hummingbirds can tolerate short periods of high heat. But if high temperatures persist for many days or weeks, they may seek cooler areas.
– Are there adequate food and water sources? Access to flowering plants for nectar and water for drinking are critical. If these remain available despite the heat, hummingbirds may stay.
– Are there shelters and shade? Structures like trees or awnings provide respite from the sun. Their presence makes it more likely hummingbirds will remain.
– How far must they travel to find cooler temperatures? Hummingbirds weigh only a few grams. Long distance travel is energy intensive. If relief is too far, they may have no choice but to endure the heat.
– Are they nesting or breeding? Hummingbirds are less likely to abandon nests with eggs or incubating mates. Only temperatures exceeding habitat viability would force them to flee.
So in moderate heat, hummingbirds can adjust by finding shade and ample hydration. But extremes and prolonged highs will likely exceed their ability to cope and trigger a migration to cooler areas. Their small size makes heat tolerance and long-distance travel difficult. With plenty of food, water, and shelter, and assuming cooler spots are accessible, high temperatures will eventually prompt them to leave.
Hummingbirds and Temperature
Hummingbirds are small, warm-blooded creatures that have a high metabolisms and energy needs. They sustain their high activity levels through drinking nectar and eating insects and spiders. To power their wings during frequent flight, hummingbirds have heart rates up to 1,200 beats per minute and take 250 breaths per minute. Their wings can flap up to 70 times per second.
This tremendous exertion generates a lot of internal heat that hummingbirds must dissipate. That makes them particularly vulnerable to hot external temperatures. When it gets too hot, a hummingbird can enter a form of torpor to conserve energy. Their heart rate and metabolism slow down and they enter a sleep-like state.
But torpor makes them more vulnerable to predators. It can also be dangerous if the hummingbird does not have enough energy reserves to come out of torpor. So it is a last resort and temporary solution. Hummingbirds cannot survive long in torpor in extreme heat.
If high temperatures persist, a hummingbird’s best strategy is to seek cooler habitats. However, migrating and finding new food sources uses a lot of energy. It also poses risks, such as flying through unfamiliar terrain with potential predators.
Hummingbirds rely on cues from the environment to know when to migrate. These can include:
– Photoperiod: The number of daylight hours signals seasonal changes. When days shorten in the fall, hummingbirds know to migrate.
– Food availability: When flowers and plants die back or go dormant, hummingbirds will leave in search of new food sources.
– Instinct: Hummingbirds have an innate sense of seasonal changes and typical migration patterns. Their internal programming initiates migration behavior.
– Weather: Sustained changes in temperature, food, and water influence migration. Hot temperatures in particular create challenges hummingbirds cannot endure indefinitely.
Ideal Temperature Range
Hummingbirds thrive in warm conditions, but do have limits to the heat they can handle:
– Below 48??F (9??C): Torpor or hypothermia risk since they lose body heat quickly.
– 60-100??F (15-38??C): Ideal temperature range for activity and survival.
– Above 100??F (38??C): Heat stress is likely, requiring mitigation strategies.
– Above 105??F (40??C): Dangerous temperatures that may exceed hummingbirds’ ability to cope.
Migrating to cooler climates is an important strategy hummingbirds use to avoid overheating. Let’s explore factors that determine whether a hot spell causes them to leave an area.
Will Hummingbirds Leave if Temperatures Exceed 100??F (38??C)?
Once temperatures consistently rise above 100??F (38??C), hummingbirds face an increased threat of overheating and heat exhaustion. Whether they leave the area depends on:
Availability of Food and Water
Hummingbirds have high metabolisms and can starve quickly. Access to adequate food and clean water are essential for their survival, especially in hot conditions. To keep cool, hummingbirds increase their intake of sugary water from flowers and feeders. As temperatures rise, their hydration needs shoot up.
If the heat dries up flowers and depletes nectar supplies, hummingbirds will be forced to migrate. But if flowering plants remain plentiful and other food and water sources like feeders are available, hummingbirds may withstand the heat. Having sufficient energy reserves improves their ability to cope.
Access to Shaded Areas
One way hummingbirds prevent overheating is by moving to shaded areas out of direct sunlight. If trees, tall plants, cliffs, buildings, or other structures provide shade and cooler spots, hummingbirds are better equipped to endure heat waves in that habitat.
But tree cover and shelter may not help if the air temperature continues to exceed 105??F (40??C). At extreme highs, the risks of heat exhaustion and overheating will force hummingbirds to migrate even with shade available.
Distance to Travel
Hummingbirds weigh only 2-6 grams on average. Relocating over long distances is an energy-intensive endeavor. The availability of cooler areas within a reasonable migrating distance improves their chances of moving rather than remaining in hot zones.
For example, Calliope hummingbirds migrating from Canada down to Mexico travel an immense distance. The energy required for this trip is substantial. So they will only migrate if temperatures mandate it.
But Allen’s and Rufous hummingbirds may more readily relocate from the hot Arizona desert to the cooler California coast. The lower energy cost makes short-distance movement an attractive option during heat waves.
Nesting or Breeding
Hummingbirds are less likely to abandon their habitat if they are nurturing eggs in a nest or feeding hatchlings. Moving a nest is impractical. Females incubating eggs usually will not leave, even in extreme heat.
Likewise, adult males helping feed newly hatched chicks will endure hot temperatures to ensure offspring survive. However, when the young fledge and no longer need direct care, hummingbirds gain more flexibility to migrate if necessary.
In dire temperature emergencies exceeding habitat viability, hummingbirds may have no choice but to leave offspring and eggs behind. But they will not migrate due to heat if it jeopardizes reproduction and breeding.
Coping Behaviors in Hot Temperatures
When faced with heat, hummingbirds first utilize coping strategies to minimize threats:
– Seeking shade
– Panting and wing-spreading
– Perching with feathers fluffed
– Reducing activity in midday
– Drinking more water
However, these behaviors can only compensate for high heat up to a point. If hot weather persists, the challenges multiply:
– Increased time feeding to meet higher energy needs
– Decline in food sources as flowers wilt
– Dehydration risk as water evaporates
– Heat stress on critically important organs
– Greater vulnerability to predators while resting
– Possible reproductive issues or offspring mortality
With their survival in jeopardy, migrating becomes imperative. Hummingbirds will flee deteriorating conditions before it’s too late.
Impact of Climate Change
Climate change poses severe threats to hummingbirds through:
– More frequent heat waves and record high temperatures
– Earlier springs disrupting migration timing
– Drier conditions reducing flowering plants
– Expanding aridity in certain habitats
– Shifting plant distributions to unsuitable areas
– Wider variations in precipitation patterns
These effects may exceed hummingbirds’ resilience. One analysis found up to 66% of Anna’s hummingbird habitat in California could be lost by 2099 due to climate change. This would necessitate dramatic range shifts.
Already, climate change has caused some species like rufous hummingbirds to begin migrating and breeding earlier in spring. Hotter summers are also altering their preferred ranges. Adaptability to these changes will determine each species’ survival.
Maintaining diverse habitat with plenty of food, water and shelter can help hummingbirds persist in a warming world. Artificial feeders also provide backup support. But climate change may force hummingbirds to move from heat-stricken areas they called home for millennia. Only by keeping global temperature rise in check can we ensure hummingbirds don’t lose more suitable habitat.
Conclusion
Hummingbirds can tolerate short-term heat waves given sufficient hydration, food, shelter options, and energy reserves. However, high temperatures exceeding 105??F (40??C) for sustained periods pose severe threats from dehydration, starvation, and heat exhaustion. Without relief, hummingbirds will migrate somewhere cooler.
Climate change will likely create migration pressure through increased frequency of temperature extremes. Range shifts and altered behaviors are already emerging. Minimizing future warming and preserving habitat diversity and connectivity will help hummingbirds adjust. When adequate resources and refuge from excessive heat disappear, hummingbirds’ small size leaves them little option but to flee. Their survival hinges on a climate that doesn’t consistently overpower their physiological limits. But with sufficient care, they can continue brightening our lives for years to come.
Hummingbird Population Changes During Heat Waves
Location | Species | Average Summer Population | Population During Heat Wave | Difference |
---|---|---|---|---|
Santa Monica Mountains | Anna’s Hummingbird | 100 | 75 | -25% |
Santa Catalina Island | Allen’s Hummingbird | 50 | 35 | -30% |
Chiricahua Mountains | Broad-billed Hummingbird | 200 | 150 | -25% |
Huachuca Mountains | Rufous Hummingbird | 75 | 45 | -40% |
This table displays example data on how heat waves impacted hummingbird populations in different habitats. During periods of extreme heat, the number of hummingbirds observed declined in all locations compared to average summer numbers.
The relative decrease ranged from 25-40%, indicating substantial portions migrated elsewhere to escape temperatures exceeding their heat tolerance thresholds. However, some individuals remained behind despite the hot conditions.
Sufficient vegetation, shade, and artificial feeders in these habitats likely enabled the remaining hummingbirds to endure the heat. But the population reductions highlight that when faced with extreme high temperatures, many hummingbirds will vacate areas that otherwise sustain them in normal summer conditions.