Where do hummingbirds go when it’s cold out?

Quick Answers

Hummingbirds migrate to warmer climates when it gets too cold in their normal habitats. They fly south to Mexico, Central America, and the southern United States. Some hummingbirds only migrate short distances while others may travel over 2500 miles to reach their wintering grounds. Hummingbirds can’t survive cold winters, so they must escape the freezing temperatures. They return to their breeding grounds when warmer weather returns in the spring.

Hummingbirds are amazing little birds that capture our fascination. Their diminutive size combined with their flashy, iridescent plumage and remarkable flying skills make them a joy to observe. These tiny dynamos have extremely high metabolisms and must consume nectar constantly to fuel their high energy lifestyle. To survive cold winters when food is scarce, hummingbirds migrate to warmer climates. But where exactly do hummingbirds go when it’s cold out? Let’s take a closer look at the migratory behavior of these remarkable birds.

Why Hummingbirds Can’t Survive Cold Winters

Hummingbirds are vulnerable to cold weather for several key reasons:

• High metabolism – Hummingbirds have incredibly fast heart rates and metabolisms in order to power their wings during hovering and flying. They must eat frequently, consuming approximately every 10-15 minutes while awake, to meet their high energy demands. When food sources decline and freezing temperatures set in, hummingbirds struggle to find enough nutrition.
• Low body fat – Hummingbirds have very little body fat. Fat reserves provide crucial energy during migration and times of scarce food, but hummingbirds lack enough fat insulation to endure cold weather.
• Susceptibility to torpor – If hummingbirds cannot find enough food to power their metabolisms, they will go into torpor, a low metabolism, hypothermic state. Prolonged exposure to cold can be deadly while in torpor.

Due to these physiological constraints, hummingbirds simply cannot survive harsh winters at higher latitudes in North America. Freezing temperatures and scarce food supplies would be fatal. Their only option is to migrate to warmer climates.

Destinations and Distance of Migration

Many hummingbird species breed during the summer months in the United States and Canada. As autumn approaches and daylight hours decline, they begin their southerly migrations. Here are the main wintering destinations of North America’s migrating hummingbirds:

• Mexico – Southern coastal areas and the Yucatan Peninsula host large populations of wintering hummingbirds.
• Central America – Countries like Panama, Costa Rica, and Belize provide tropical habitats for overwintering hummingbirds.
• Southern United States – Southern coastal states from California to Florida have milder winter climates suitable for hummingbirds.
• Caribbean Islands – Some species fly across the Gulf of Mexico to winter on Caribbean islands.

The distance traveled to reach these wintering grounds can vary significantly depending on the breeding range. Here are some examples:

• Ruby-throated hummingbirds breeding in the eastern United States may only migrate to southern States like Louisiana and Florida.
• Rufous hummingbirds breeding in the Pacific Northwest migrate over 2500 miles to Mexico.
• Broad-tailed hummingbirds breeding in Colorado and Wyoming fly over 1000 miles to winter in Mexico.
• Calliope hummingbirds journey from Washington and British Columbia to winter in Mexico, over 2000 miles away.

As you can see, migration distances range widely depending on the species and starting point. But most undertaking trans-Gulf journeys travel between 1000-2000 miles each way.

Timing of Migration

Hummingbirds carefully time their migration to coincide with flower blooming schedules and flying conditions. Here is an overview of their migration timing:

• Early August to September – Adult hummingbirds and fledglings depart breeding grounds in Canada and the northern United States. They migrate south to warmer climates.
• September to November – Southward migration peaks across the United States as hummingbirds retreat from the advancing cold weather.
• October to December – Most hummingbirds complete migration and arrive on their tropical wintering grounds in Mexico, Central America, and the Caribbean.
• December to February – Adult hummingbirds overwinter in their winter habitats. Immature birds may overshoot destinations and end up lost, requiring rehabilitation to survive.
• February to May – Northward migration back to breeding habitats occurs as flower resources diminish in the tropics. Birds arrive back on breeding grounds in late spring.

This yearly cycle allows hummingbirds to take advantage of seasonal flower blooms and avoid potentially deadly cold snaps. Their internal clocks and environmental cues guide them on these epic seasonal journeys.

How Hummingbirds Prepare for Migration

In late summer, hummingbirds undergo important physiological and behavioral changes to ready themselves for migration:

• Hyperphagia – Hyperphagia is a period of excessive eating and feeding. Hummingbirds increase their food intake substantially to store fat reserves for migration ahead.
• Fat deposition – Hummingbirds double their body mass in some cases, adding lots of fat to provide crucial energy for long flights, cold overnight temperatures, and periods of scarce food.
• Crop expansion – The crop is an expandable food storage pouch. Hummingbirds enlarge their crop capacity to stock up on nectar before crossing inhospitable habitat.
• Restlessness – As migration approaches, hummingbirds become restless and aggressive as they compete for food resources. This indicates their readiness to depart.

These adaptations allow hummingbirds to fuel up with energy stores and then depart their breeding grounds in optimal condition for a migratory journey hundreds or thousands of miles long.

How Do Hummingbirds Navigate During Migration?

Hummingbirds manage to find their way over incredible distances between breeding and wintering habitats. Their navigation abilities include:

• Compass sense – Hummingbirds (like all migratory birds) can detect Earth’s magnetic fields to help maintain directional bearings during migration.
• Celestial cues – On clear nights, hummingbirds use the stars for orientation when migrating.
• Visual landmarks – Mountains, coastlines, rivers and certain terrain features help guide hummingbirds on migration routes.
• Sun position – The location of the sun relative to time of day provides an orienteering signal.
• Fat reserves – Ample fat reserves give hummingbirds flexibility in their journey to stop and refuel or wait out inclement weather.

Through these varied cues, hummingbirds can successfully pinpoint optimal wintering sites thousands of miles away without getting lost along the way. Their navigational abilities are quite extraordinary.

Unique Hazards Faced During Migration

Hummingbirds encounter many threats and challenges during their migration journeys, including:

• Food scarcity – Finding adequate nectar supplies is an ongoing struggle, especially during droughts or unseasonal frost.
• Exposure – Cold temperatures, wind, rain, and collisions mean risk of injury, starvation, and fatigue.
• Predators – Birds of prey and even some insects prey on hummingbirds during migration.
• Storms – Flying through or around thunderstorms, hurricanes and other weather events.
• Habitat loss – Human development and habitat degradation can limit food resources.
• Communication towers/buildings – Bright lights and structures lure hummingbirds off course resulting in collisions.

Researchers estimate that up to half of juvenile hummingbirds fail to make the journey south in their first migration attempt. Adverse weather, inadequate fuel reserves, inexperience navigating and lack of suitable habitat reduce migrants’ chances of survival. Those that do reach wintering grounds may arrive in an emaciated state requiring rehabilitation. It’s a perilous journey for the tiny travelers.

Behavior and Habitat Use on Wintering Grounds

Once they reach their tropical wintering habitats, hummingbirds must find food resources and shelter to survive until spring. Here are details on their behavior and habitat use:

Diet

• Consume sugary nectar from tropical flowers, flowering trees, and shrubs.
• Also eat small insects for protein and fat.
• Aggressively compete for limited flower resources and feedings sites.
• Work to maintain enough weight and fat reserves.

Habitat Preferences

• Forest edges – Feed along borders between forests and open areas.
• Open meadows – Feed on flowers of shrubs and small trees.
• Orchards and gardens – Drawn to nectar sources provided by flowering plants.
• Arid scrubland – In drier regions, subsist on agave and other succulents.

Shelter and Resting

• Rest in shade trees and scrubs when not feeding.
• Reduce activity during midday when temperatures peak.
• May gather in communal roosts to share body heat on cold nights.
• Enter torpor (deep sleep) overnight to conserve energy.

Territoriality

• Males, in particular, defend prime feeding territories from competitors.
• Use wing buzzing displays and aggressive chasing when necessary.
• Females may also show some territorial behavior, but less so than males.

Understanding how hummingbirds make use of habitats and withstand weather in the tropics provides helpful clues for protecting them effectively during winter.

Threats to Hummingbirds on Wintering Grounds

Hummingbirds face substantial threats on their wintering grounds that can put them in peril. These include:

• Limited habitat – Logging, fires, agriculture, and development shrink available habitat.
• Drought – Lack of rainfall reduces nectar availability.
• Flowering mismatches – Climate change alters blooming schedules relative to arrivals.
• Competition – Other nectar feeders, like orioles, bees, and bats, vie for the same food sources.
• Loss of genetic variation – Low diversity may hinder adaptation to habitat changes.

Research in Mexico found that hummingbird populations declined 74% over a 10 year stretch due to habitat loss. Climate changes are also resulting in more variable rainfall and flower blooming mismatches that jeopardize overwinter survival. Protecting and restoring tropical winter habitats is crucial for hummingbirds’ future.

The Journey Back North in Spring

As days lengthen in January, hummingbirds’ instincts tell them to prepare to migrate north again:

• Feed heavily to store fat for the return trip.
• Become aggressive and territorial as migration approaches.
• Wait for optimal weather windows to cross the Gulf of Mexico.
• Males begin migrating north first to establish the best breeding territories.
• Females follow a short time later once flowers have started to bloom.

The northbound journey brings hummingbirds back to northern states and Canada in April and May. Here they enjoy spring and summer flowers while breeding and raising young before the cycle repeats. Their epic migratory journeys connect vital habitats across thousands of miles.

How to Support Migrating and Wintering Hummingbirds

Here are some tips to help provide for hummingbirds during migration and winter:

• Keep feeders clean, and use proper ratios of sugar/water to provide fuel. Do not discontinue feeders during winter.
• Plant a variety of native plants and flowers that bloom through fall and winter.
• Avoid pruning plants in fall so birds can access flowers and fruits.
• Provide water sources like drippers, fountains and misters.
• Report winter hummingbird sightings to help researchers track migration patterns.
• Support habitat conservation efforts in Mexico, Central America and the Gulf Coast region to protect wintering grounds.

With a welcoming habitat and safe migration routes, these energetic hummingbirds will continue gracing our summers with their beauty while avoiding perilous winter hazards. Their migratory endurance and resilience is a marvel of nature.

Conclusion

Hummingbirds truly are amazing creatures. Although they weigh only a few grams, they can migrate thousands of miles to escape harsh winters. Their physiological adaptations allow them to stock up on energy stores and fly incredible distances between summer breeding and wintering habitats. While the migration journey is full of perils, hummingbirds navigate using the sun, stars, terrain, compass senses and more. Their preferred tropical winter homes provide the food resources and shelter they require until they return to northern latitudes again in spring. Supporting migratory hummingbirds requires habitat protection across their full range – both summer and winter. If we provide the right conditions, these energetic travelers will continue their extraordinary seasonal journeys for generations to come. Their epic migrations are an inspirational part of nature.