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The annual hummingbird migration is one of the incredible feats of the animal kingdom. Each year, birders, residents, and scientists alike, get thrilled as hummingbirds travel between wintering and breeding grounds.
Thousands of dazzling hummingbirds swarm through fields and forests. Some even stop by at feeders and gardens for refreshments and nourishment.
Weighing less than a nickel, a hummingbird will travel thousands of miles to winter in Central America or Mexico. And it will cover the same distance back to their breeding grounds in the United States and Canada.
They don’t chatter on a plane, hitch a lift, or drive a car like you and me. This little bird uses two tiny wings powered by even smaller muscles to make the epic journey amidst many challenges on the way.
And to better understand and appreciate why and how hummingbirds undertake seasonal pilgrimages, let’s join them in their journey.
Hummingbird Migration Triggers
According to backyard birders, hummingbirds have predictable migration patterns. They travel within the same time each season, arriving and departing within a day or two. But what triggers the migration of hummingbirds?
No one knows for sure what triggers birds and animals to embark on their migration. Scientists and birders, however, have formulated various theories to explain what triggers hummingbird migration. One or more of the following could trigger the migration:
- Daylight: biologists believe the angle and length of daylight trigger birds’ hormones, and they instantly know it’s time to travel. In response, they start to fatten in preparation for the long journey. And as days get shorter at the end of summer, the instinctual urge to travel to wintering grounds gets stronger.
- Instincts: genetic predisposition enables birds to know when it’s time to travel. Despite numerous challenges, nothing can entice a hummingbird to not undertake the long journey. For instance, studies have shown that providing hummingbirds with plenty of food resources will not deter them from migrating. They will still move on due to instinct, leaving behind feeders and flowers full of food. The food does not stop or delay the bird from traveling; instead, it is a welcome stopover point to fill up. Instinctively, even young hummers know the way, when to travel, and the stopover points along the way just by themselves.
- Changes in the abundance of nectar and insects. This is especially important during hummingbirds’ spring migration. During this season, the hummingbirds will migrate to their breeding grounds with sufficient food resources for the growth and development of their hatchlings.
According to ornithologists, caged birds often exhibit restlessness during spring and fall, fluttering towards one side of the cage. Owners of caged birds have also echoed this fluttering behavior during the migratory seasons in fall and spring.
Others, though, believe a higher being engineered the various migration processes in the animal kingdom. To them, each bird has an innate migration map, an inbuilt compass, and biological processes to complete the migration. These attributes enable juvenile hummingbirds to travel to and from their destination for the first time without being accompanied.
Hummingbird Migration Facts and Figures
Out of about 360 hummingbird species currently identified by science, about 20 are found in North America. About 15 species regularly migrate to wintering grounds in Mexico and Central America, with fewer reaching Canada.
Here are some of the migratory hummingbird species in North America:
- Rufous Hummingbird
- The Ruby-throated Hummingbird
- Magnificent Hummingbird
- Lucifer Hummingbird
- Costa’s Hummingbird
- CalliopeHummingbird
- Buff-bellied Hummingbird
- Allen’s Hummingbird
- Black-chinned Hummingbird
- Broad-tailed Hummingbird
From banding research, hummingbirds are faithful to their breeding and wintering grounds. They are also creatures of habit, often stopping at the same locations each year and even at the same feeder.
Hummingbirds Migrate for a Variety of Reasons
Hummingbirds migrate to areas with abundant food for survival, minimizing competition for food and territories. In most cases, the food supply diminishes with the changing seasons. During fall, nectar and insects deplete in the north, so hummingbirds migrate southwards to their wintering grounds.
Migration is important for hummingbirds as it allows them to winter in one place and breed in another.
Severe weather like chilly winters and simmering summers drives these migratory birds in search of more favorable conditions.
In essence, the search for resources and escape from elements of weather influences drive these tiny birds to migrate with the changing seasons.
Prior to Migration
Hummingbirds’ migration coincides with the four seasons in North America. When temperatures drop, hummingbirds prepare for the trip involving a pre-migratory fueling strategy. For the weeks before migration, they feed ferociously to build up fat reserves (a behavior known as hyperphagia) for the long and gruesome pilgrimage. And at night, minimize the depletion of the stored fat through nocturnal torpor.
Invertebrates provide protein, while water-sugar nectar provides carbohydrates for hummingbirds.
Guided by instincts and hormones, a hummingbird’s body changes are necessary for the success of the migration. It feeds ferociously, gaining 30 to 40 percent of its body weight.
Once a hummingbird completes the preparations, it begins a journey leading to a feeding ground it would use during winter. And along the way, it must deal with predators, exhaustion, and other challenges.
Biological Processes That Enable Hummingbirds To Succeed In Their Epic Journey
Taking a cue from an internal urge to migrate, hummingbirds take off, each bird embarking on the journey alone but all following a general direction.
While traveling, the bird’s heart rate shoots over 1250 times per minute. And its wingbeat increases to 80 wingbeats per second. The high energy demand for such a small bird means it must have energy reserves and constantly stop to refuel along the way.
And so, before the start of the journey, a hummingbird consumes more food, gaining about 40 percent of its body weight. The extra body fat is critical in providing energy on the journey. Hummingbirds constantly burn energy to maintain their busy lifestyle, and migration seasons intensify the energy demand. But their low energy reserves cannot sustain long-distance travel, so they need many replenishments before reaching their destinations.
After the exhaustion of a long flight, nothing beats the relief of refreshments of sucrose from feeders and flowers. And whenever they come across flowers, feeders, or water along their route, they take some time to refresh and fill up.
Hummingbirds need to refill their energy tanks constantly, but it does not mean they feed throughout the day or night. To maintain their bodies while traveling, hummingbirds eat early in the morning, travel midday, and forage again in the late afternoon before settling for the night.
While most birds find safety in numbers, hummingbirds fly alone, often using the same route every year of their entire lifespan.
Interestingly, juveniles are never accompanied by adults. They must travel alone to their destinations without getting lost, and safely arrive at a wintering ground, a place they have never seen before. Here they will enjoy a warmer climate, safe from the freezing winters where they were born.
Hummingbirds need frequent stops to replenish their high energy demands. This means hummingbirds must travel during the daytime when food is abundant. And they must fly low so they can spot food sources. Hummingbirds rely on sight and not smell to identify food.
Like all migrating birds, hummingbirds have learned to save energy and time by using tailwinds.
Hummingbirds migrating short distances typically travel 23 miles in a day. With favorable wind conditions, long-distance migrating hummers from Florida to the Yucatan cover the 600-mile distance in 18 to 22 hours non-stop.
The Lonely Journey of Hummingbird Migration
Forget birds of a feather flocking together. Hummingbirds travel alone. Unlike other bird species, such as geese and goldfinches, each hummingbird goes through the entire journey independently. Even juvenile hummers make their maiden trip on their own without the help of the adults. Relying only on instincts, the young navigate alone to the wintering grounds and back.
Most birds travel at night, but hummers travel and refuel during the day; and rest during nightfall. Taking advantage of the warm sunshine, hummingbirds fly fairly low over trees and water bodies, looking for feeders or flowers along the way.
Instincts dictate all aspects of hummingbird migration, including migration triggers, routes, destinations, and stopovers. The instincts have evolved over the years and have ensured the continued survival of the hummingbirds.
During spring, when they move north to their breeding grounds, they depend solely on instinct since they cannot know the weather at the destinations. Often, within a few days, they arrive at their destination and stopovers at the same time of the year. Incredibly, they arrive at the onset of flowering and when icy weather has elapsed.
Food shortages or bad weather do not drive them out when they move south during the fall or late summer. Driven only by strong desire, they migrate even if food is plentiful or favorable weather.
And during peak migration season, you will often witness hummingbirds zooming and darting around found sources. Some even spar in midair while competing for nectar.
They land in areas with abundant nectar and insects one at a time and depart the same way—not in flocks. Essentially, a hummingbird migration pattern comprises short flights with several replenishing stops.
In eastern North America, migrating hummers often follow the same route each year when moving to the wintering grounds. The same applies to moving back to the breeding grounds, but only in the reverse direction.
But the migratory path is quite complicated in the west, with many mountain ranges. This is because the ranges have stark weather differences at different elevations. So hummers in these regions follow different migratory corridors going to wintering grounds and different ones traveling back.
But not all hummingbirds are migratory. Some are permanent residents, especially in regions with favorable conditions all year round. For instance, Anna’s hummingbirds are common among Arizona, California, and northern British Columbia residents on the Pacific Coast. Other species are only visible during the more comfortable days of the year.
Various studies and observations by backyard birders show many hummingbirds now overwinter on the Gulf Coast more often than in the past. This could be attributed to climate change and habitat destruction, among other reasons. During mild winters, many visit hummingbird feeders as they look for food.
It’s common to spot several species of hummingbirds in South Louisiana during winter. You can spot Ruby-throated, back-chinned, Rufous, Buff-bellied, and Calliope. Broad-tailed, Allen’s, Broad-billed, and Anna’s are common too.
Hummingbird Migration Strategy—Who Migrates When and Where?
The hummingbird’s males usually begin migration ahead of females. The head start enables the males to arrive in good time to identify and establish themselves in the wintering and breeding grounds.
After a week or two, females follow the males.
Juveniles are usually the last to start the journey and also the last to arrive. They are inexperienced and are never accompanied by adults. Besides, they have to grow up, develop muscles and need enough time to build body fat reserves.
Threats to Hummingbird Migration
While many hummers successfully migrate to the wintering grounds and back, it is not smooth sailing. Many face serious challenges, and a higher percentage die each year along the route.
Severe weather and natural disasters can get in the bird’s way. But human activities pose greater challenges to migratory birds than ever before.
Birds flying into buildings and windows at full speed are responsible for over one billion bird deaths in the United States alone.
With the continued shift towards renewable and clean energy away from fossil fuels, birds face a new threat, especially from wind turbines. Many birds collide with the rotating blades. Some of these turbines are installed in birds’ migratory corridors, and the rotating blades interfere with wind flow, severely affecting the migration of the birds.
But along the migratory route, hummingbirds face myriad threats, including those from our backyards. Outdoor cats kill millions of hummingbirds and other birds on migration every year.
Agrichemicals on gardens and farms contaminate birds and other animal foods, leading to contamination and death. Unhygienic hummingbird feeders could cause diseases to the birds.
The spring hummingbird migration can be hard as they move from their wintering grounds in Central America and southern Mexico. The birds often enjoy a few stops along the way at places with abundant food resources. But flying across the gulf of Mexico is a demanding task for the little bird. First, hummingbirds must contend with heavy rain and headwinds over long distances nonstop without shelter. They also have to do their best with their little energy reserve as food is unavailable in the open waters.
Hummingbirds have a lengthy list of predators, including snakes, lizards, birds of prey, and cats. Dogs and other smaller mammals consider hummingbirds easy targets.
Seasonal Migration Patterns of Hummingbird
Hummingbird spring migration from Mexico and South America to the United States, Alaska, and Canada is a solitary journey. Each bird aims to arrive at their destination early enough to establish feeding territories. This competition for feeding territories drives some birds to migrate as early as February in Mexico, arriving in Canada and Alaska in mid-May.
A similar situation occurs during the fall migration of hummingbirds. Early migrants begin their journey in July, and slow movers will struggle to cross the southern US border until October.
The Spring Hummingbird Migration
Many hummingbird species spend their winter in Mexico or Central America. And as the weather becomes favorable in their breeding grounds in the western states and the southern US, hummingbirds travel as early as January and February.
In early spring, hummers appear in Louisiana, Texas, and along the Gulf coast. Other species of the hummer migrate farther north in late spring.
Males usually arrive first to stake out breeding territories, and juveniles come in later.
The long-distance migrating hummingbirds deal with harsh conditions like strong winds, storms, long journeys over water bodies, and less food.
Birders track spring migration between mid-January and mid-May and report sightings in their areas for hummingbird migration mapping. You could also volunteer to participate in the sighting and mapping of hummingbirds in your backyard or location.
By January and February, early migrants are on the road heading to their breeding grounds.
The Fall Migration
Like clockwork, hummingbirds move south in August and September to their wintering homes. Around this time, several species of hummingbirds can be seen around feeders and flower gardens.
For instance, ruby throats gather in Louisiana, Florida, and the coastal region of south Texas as they head south. Some of the rufous take a straight flight over the gulf of Mexico, and others take a long detour moving over the land looking for flowers and insects. It is not clear why some take the long flight of about 800 miles over the water while others take the long route overland,
Some species winter in the coastal region of the south Atlantic and along the United States gulf coastal areas from Florida to Texas. Other species travel further south, moving across rocky terrains to Central America and Mexico.
Migration Pattern of Dominant hummingbirds
Hummingbirds have different breeding and wintering ranges, and some even overlap. Let’s look at the four dominant hummingbirds in North America: Ruby-throated, Rufous, Anna’s, and Black-chinned.
Ruby-Throated Hummingbird
The ruby-throated hummingbird is the only species that nest in the great plains and spend a summer in the United States and Canada. During summers, you can spot them in southeastern Canada and nearly all parts of the United States. As the weather turns chilly, few braze the cold days in the southeastern states, while most travel to wintering grounds in Panama and Mexico. To a ruby-throated hummingbird, covering 2000 miles to and from the wintering grounds each year is crucial for the survival of its population.
Male Rubythroat hummers travel to their wintering grounds as early as late July and early August. Females and juvenile ruby-throated hummingbirds join the migration two or four weeks later.
Many ruby-throated hummingbirds can cross the Texas coastline between mid-September and early October. They arrive in Costa Rica in October or November.
The spring migration for the ruby starts in late February and arrives in southeastern states in April.
Rufous Hummingbird Migration
For long-distance migration, rufous hummingbirds are the champions.
They travel 4000 miles to wintering grounds in Mexico and Alaska and cover the same distance back. Every year for its entire adult lifespan of about five years, a rufous hummer must undertake this crucial journey for the survival of its population.
The rufous hummingbird follows an unusual migration pattern. While most migrating hummers travel north in spring and south during fall, the rufous travels southeast in late summer and northwest in late winter. It’s common for males to leave their wintering homes in January and arrive in the western United States in February.
Rufous follows a migratory route with abundant food supplies. Lowland deserts and coastal areas provide plenty of insects and nectar for them.
In the middle of June, rufous hummingbirds start the epic journey towards their wintering areas in Mexico. They move east and southeast, targeting mountains and meadows filled with flowers and insects.
Anna’s Hummingbird
Anna’s hummingbird is a territorial and permanent resident within its range along the Pacific coast. It breeds in Arizona, Nevada, Texas, Utah, California, Vancouver, and Canada.
As most hummingbirds migrate during winter, Anna’s hang around even during icy conditions. A few move out of their range to Alaska, Louisiana, and Florida.
Even though Anna’s hummingbird does not migrate, it prepares for winter. During the cold seasons, it eats a lot and converts extra sugar into fat, gaining almost 40 percent of its body weight. The bird uses the excess fat to preserve its body through the long, chilly nights; by morning, its body weight has to return to normal. The process is repeated every day until the winter is over.
Anna’s hummingbird also employs a torpor technique to survive the cold nights, especially with low fat and plumage. During this period, the bird lowers its metabolic rate and enters a deep state of sleep.
The Black-Chinned Hummingbird
The black-chinned hummingbird is another common bird among the hummers. Despite its small size, it has a wide breeding range stretching from the United States to Canada and Mexico. Birders have spotted a few outside these ranges.
It migrates southward during springtime to escape the cold winter, searching for warmer temperatures and better food sources. It flies to Mexico, southern California, southern Arizona, and southern Texas for the winter.
Hummingbird Migration: Frequently Asked Questions (FAQS)
Answer: if hummingbirds pass through your region in their seasonal journeys to the breeding and wintering grounds, you can ensure they have a comfortable journey in several ways.
First, you can install hummingbird feeders early in spring and leave them late in the fall. This strategy ensures hummingbirds will never miss nourishment, whether early arrivals or late departures in your backyard.
Second, ensure the hummers are safe and healthy by cleaning their feeders and replacing spoiled nectar feeds with fresh water and sugar.
Third, provide nesting materials during spring migration. This ensures the breeding hummingbirds can build nests and raise young ones in good time.
Fourth, support conservation activities to protect hummingbirds and their habitats in the breeding and wintering grounds.
Fifth, ensure the hummingbirds’ nectar during chilly days does not freeze. You can assist by heating the nectar, insulating feeders, placing feeders in protected areas, and adding more sugar to the nectar to lower the freezing point.
Another crucial thing you can do for hummingbirds is to plant flowers to provide ample nectar for the birds. Include early and late flowering plants for a continued food supply during spring and fall.
Answer: Various factors influence the hummingbird’s migration, including:
• Regional weather patterns: regional storms, powerful winds, and chilly winters influence bird migration, often forcing birds to seek refuge in safer places. During severe weather, migrating birds might be caught up in bird fallout. This condition forces the migrating birds to hang out in safer places for several weeks as they wait for the weather to improve.
• Migration distance: long-distance migrating hummingbirds start their journey earlier. In spring, early migrants glide northwards as early as January, taking several months to arrive at their breeding grounds in mid-May. While most migrating hummingbird species travel back from late August to mid-September, the long-distance migrants hit the road much earlier, mostly in July.
• Sex of the bird: Males travel earlier than females in most species of hummingbirds. The early start gives males ample time to establish breeding and foraging territories. This strategy enables the males to court and competes for the females. The same pattern plays out in fall, with the males arriving early to establish wintering grounds.
• Age: Mature and experienced hummingbirds often start migrating earlier than juveniles. Young hummers need enough time to grow and develop their muscles for the long journey. Fledglings that hatched earlier in the breeding season often start traveling earlier than broods bred late in the season.
Answer: Some hummingbird species, particularly the rufous, travel thousands of miles. A crucial key to their tremendous vitality lies in their aeronautical body designs. Robust, lightweight structure comprising hollow bones, a narrow body, sleek tail, and narrow graceful wings. The physical ingredients for lengthy flights enable the bird to glide smoothly over the sky while expending the least energy.
In addition, the bird must also know the direction of its destination. It uses the sun’s position, the earth’s magnetic fields, or specialized proteins in their eyes.
Answer: I recommend you should leave your hummingbird feeder up for several weeks after the last hummingbird has left your yard. This could help a late migrant that may pass by the feeder looking for nectar to energize before continuing with its journey.
Leaving a hummingbird feeder longer, especially if no bird is around, requires a huge commitment. Hummingbirds need cleaning and changing nectar every three to five days, even if it has not been used. Yes, it is a huge demand, but you could help save a struggling bird’s life.
Also, leaving your hummingbird feeder longer could help other birds arriving from the north, like the evening grosbeak.
It could tempt you to think that keeping hummingbird feeders for longer will influence birds from migrating. It is just a myth, and hummers will migrate anyway, with or without the feeder.
Factors such as day length and instinct trigger birds to migrate to the breeding and wintering grounds.
Conclusion
In many ways, hummingbird migration is an epic one, paved with threats, predators, and exhaustion. But immediate survival is not their only objective. During this period, they undergo critical preparations necessary for the success of their journey, with the farthest being 4000 miles.
Most hummingbirds in North America cover these long distances every year. They draw energy from their fat reserves and refuel on nectar and insects along the way.
Usually, by the start of November, most of the migrating hummingbirds have left the United States for their wintering grounds. Early arrivals trickle in around March.
Despite a fragile body, hummers are well equipped for the journey. Traveling over 20 miles per day, they navigate precisely to their destinations. Juveniles do not follow adults or have prior knowledge of their destination, yet they will find their way to the wintering and breeding grounds.
So next time you see them busy at the hummingbird feeders—a migrating hummingbird paradise—know that they are packing up fat for their migration. Think of ways to enhance their success in travel and survival for the next generations.
References
- Hummingbird migration and flowering synchrony in the temperate forests of northwestern Mexico
- (PDF) The global ecology of bird migration: Patterns and processes
- Premigratory ruby-throated hummingbirds, Archilochus colubris, exhibit multiple strategies for fuelling migration – ScienceDirect
- (PDF) Torpor and metabolism in hummingbirds | Comparative Biochemistry and Physiology Part A Physiology
- Hummingbird metabolism, flight, and migration | Ask A Biologist
- Tailwind Definition & Meaning – Merriam-Webster
- Glass windows kill billions of birds a year. Scientists are working to change that | Global Ideas | DW | 19.04.2022
- Winter conditions influence biological responses of migrating hummingbirds – Graham – 2016 – Ecosphere – Wiley Online Library
- Hummingbird Migration Map 2022. Updated Hourly With Your Sightings
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