Broad-tailed hummingbirds (Selasphorus platycercus) are a small species of hummingbird found in the western United States. They are known for their iridescent green backs, white chests, and long, squared off tail feathers. A key question many people have about broad-tailed hummingbirds is – do they migrate? Here we will examine the evidence and research on broad-tailed hummingbird migration patterns.
Quick Summary
Broad-tailed hummingbirds do indeed migrate. They breed during the summer months primarily across the Rocky Mountains and parts of the southwest United States. Prior to winter, they migrate south to Mexico and parts of the southern United States. Their migration seems to be influenced by food availability, cold temperatures, and snow cover.
Breeding Range
During the spring and summer months, broad-tailed hummingbirds can be found breeding across much of the western United States including:
- Idaho
- Wyoming
- Montana
- Colorado
- Utah
- Nevada
- New Mexico
- Arizona
Within these states, they tend to be found in mountain meadows, pine forests, aspen groves, and riparian areas. Their breeding range centers on the Rocky Mountains but can extend to elevations as high as 12,000 feet.
Ideal breeding habitat provides both food sources and nesting sites. Broad-tailed hummingbirds have adapted to more urban environments and can also breed around parks, backyards, and gardens if flowers are available.
Winter Range
As winter approaches, broad-tailed hummingbirds begin migrating south to their wintering grounds. Their winter range includes:
- Southern Arizona
- New Mexico
- Texas
- Mexico
In Mexico, they are found primarily in the central highlands. Some birds may overwinter as far south as Oaxaca.
On their winter range, broad-tailed hummingbirds utilize a variety of habitats including subtropical woodlands, scrub, forest edges, and thornforest. They can be found visiting nectar plants in parks and gardens in urban areas as well.
Migration
Broad-tailed hummingbirds migrate relatively long distances between their breeding and wintering grounds. Some key aspects of their migration include:
- Males tend to migrate earlier in the summer, as early as late June and July.
- Females and young follow later, from late July through August.
- Fall migration occurs from late August through September.
- They migrate primarily at night.
- Modeling suggests migration occurs over a broad front across the southwest United States and Mexico.
Their migration seems to be triggered primarily by food availability, temperatures, and snow cover. As flowers begin to die off and freezing temperatures set it, the birds move to warmer climates with adequate food supplies.
Why Do They Migrate?
There are several key reasons why broad-tailed hummingbirds migrate including:
Food Availability
Broad-tailed hummingbirds rely heavily on flower nectar for food. As the weather gets colder in the fall, many of their key food plants and flowers die off or go dormant. This decrease in food availability likely triggers the birds to move south where flowers and plants are still actively blooming.
Cold Temperatures
Broad-tailed hummingbirds are tiny birds with high metabolisms. This makes them susceptible to cold temperatures which increase their risk of starvation. As temperatures drop across their breeding grounds, the birds migrate to warmer climates.
Snow Cover
Related to decreasing temperatures, snow accumulation in the mountains makes food harder for the birds to access. The birds may struggle landing and feeding from snow-covered flowers. Heavy snow also can damage or kill many plants the birds rely on.
Lack of Nesting Sites
With leaves fallen from trees and flowers died back, broad-tailed hummingbirds also lose nesting sites and materials on their breeding grounds. The birds seem to migrate south prior to when nesting habitats become unavailable under winter conditions.
Competition
As food resources dwindle on the breeding grounds, competition between broad-tailed hummingbirds likely increases for the remaining food. This may motivate the birds to migrate to areas with less competition.
Navigation and Route
Broad-tailed hummingbirds, like other migrating birds, have a natural internal compass and navigation system that guides them on their biannual migrations. Some strategies they likely employ include:
- Using the earth’s magnetic fields to orient themselves.
- Navigating by the stars and sun positioning.
- Following landscape contours and features.
- Remembering sites and routes from previous migrations.
Research indicates broad-tailed hummingbirds take a fairly direct migratory path between their summer and breeding grounds. Their route funnels down through Arizona, New Mexico, and western Texas. From there they fan out to winter sites primarily in Mexico.
Threats During Migration
During their long migration, broad-tailed hummingbirds face a variety of threats including:
- Lack of food sources along the migration route
- Inclement weather such as storms, rain, and high winds
- Collisions with buildings and structures
- Nighttime collisions with vehicles
- Exhaustion leading to predation
- Habitat loss reducing stopover sites
Conservationists work to protect key migration corridors and sites to help the birds safely complete their biannual travels. Homeowners can support migrating hummingbirds by providing nectar feeders, planting native flowers, and turning off unnecessary lights during peak migration periods.
When Do They Migrate?
Here is an overview of when broad-tailed hummingbirds migrate:
Spring
- February to March: Birds begin leaving winter grounds in Mexico.
- Late March to May: Birds arrive on breeding grounds across the western United States.
- Early April to Mid-May: Spring migration peaks.
Fall
- Mid-July to Mid-August: Adult males begin fall migration.
- Late July to September: Adult females and young migrate south.
- September: Fall migration peaks.
- October to November: Last hummingbirds depart breeding grounds.
The exact timing can vary slightly based on weather conditions and location. Generally though, broad-tailed hummingbirds spend late summer to early fall on their breeding grounds and the rest of the year on their wintering grounds.
How Far Do They Migrate?
Broad-tailed hummingbirds undergo a relatively long distance migration compared to their tiny body size. Some key facts about their migration distances include:
- Birds breeding in Idaho, Montana, and Canada may migrate over 2,000 miles one-way.
- Birds in Colorado migrate 800 to 1,500 miles to Mexico.
- Arizona breeders travel 500 to 1,000 miles.
- New Mexico and Texas breeders migrate between 200 to 700 miles.
The farthest migrating broad-tailed hummingbirds make an incredible roundtrip journey of over 5,000 miles! Tracking technology has allowed scientists to document the amazing endurance of these tiny birds.
How Fast and High Do They Migrate?
During migration, broad-tailed hummingbirds have been recorded traveling:
- An average migration speed of 20-22 mph
- Peak speeds of up to 35 mph
- Altitudes between 100 to 10,000 feet, primarily from 1,500 – 4,500 feet
They migrate primarily at night, covering an average of 300 miles per night for 7-8 hours. Their pace and altitude may vary based on weather conditions and topography.
Population Changes During Migration
Broad-tailed hummingbird populations undergo dramatic seasonal shifts between their summer breeding and wintering grounds. For example:
- Colorado may host up to 300,000 birds in summer, declining to 30,000 by winter.
- New Mexico’s population plummets from 150,000 to 18,000 between seasons.
- Conversely, southern Arizona may increase from 5,000 to 125,000 birds in winter.
The ebb and flow of migrating populations creates a surge of hummingbirds across the southwest states in late summer as the birds head south. Backyard feeders can provide critical fueling stops along their route.
What Do They Eat and Drink During Migration?
To fuel their long migration, broad-tailed hummingbirds rely heavily on:
- Flower nectar – Provides carbohydrates and sugars.
- Small insects and spiders – Supplies protein.
- Saps and tree nectar – Additional energy source.
- Artificial feeders – Manmade nectar source.
Access to adequate food resources along migration routes is critical to their survival. Homeowners and parks can help provide fueling stops by planting native flowers and providing clean hummingbird feeders.
What is Their Migration Like?
Here is an overview of key facts on what broad-tailed hummingbirds’ migration journey is like:
- They migrate alone, not in flocks.
- Males migrate earlier than females and young.
- They fly mostly at night and rest during the day.
- Wind patterns and fronts may affect timing and pace.
- They can double their weight prior to migrating to build fat stores.
- Most fly nonstop 500-600 miles over 18-20 hours.
- They lose 20-40% of weight during nonstop flight.
Their migration is an incredible feat of endurance for a bird that weighs just 3-5 grams. Tracking technology has provided invaluable insights into their migratory physiology and behaviors.
Banding Studies on Migration
Scientists have banded broad-tailed hummingbirds for decades to study their migration. Banding involves placing a small numbered metal band on a bird’s leg. Some key banding discoveries include:
- A banded broad-tail recaptured over 2,000 miles from banding site.
- Oldest known broad-tail was 12 years old after being banded.
- Shows connectivity between specific breeding and winter sites.
- Highlights migration timing and pathways.
- Provides insight into lifespan, fidelity, dispersal.
Advances like geolocators and nanotags that track migration in real-time have supplemented banding. But banding remains a valuable method to glean migration knowledge. Over 6,800 broad-tailed hummingbirds have been banded since 1960.
Changes in Migration Patterns
Some aspects of broad-tailed hummingbird migration that may be changing include:
Earlier Spring Migration
There are indications migration is shifting earlier in spring, likely in response to climate change and warmer temperatures allowing earlier growing seasons and flower blooms.
Expanding Range
Broad-tails are expanding north and east into habitat opened up by climate change. They are being spotted more regularly into Nevada, Utah, Nebraska, Iowa, and Illinois during migrations.
Altered Stopover Sites
Habitat loss in urban areas has decreased native plants that provide migratory refueling stops. But parks, gardens, and feeders may provide alternative stopover resources.
Impacts of Climate Change
A warmer climate may provide more overwintering grounds decreasing need to migrate south. But climate impacts to plants and nectar availability could disrupt migrations if food resources decline.
Importance of Migration
The seasonal migration of broad-tailed hummingbirds facilitates:
- Taking advantage of optimal breeding conditions in the summer.
- Fattening up for winter when food is more available.
- Reducing competition for limited resources.
- Allowing plants to regrow and replenish.
- More flexibility in weather and conditions they can endure.
- Opportunity to expand total range.
Without migration, broad-tailed hummingbirds would be restricted to smaller geographical areas and limited by local resource availability. Migration supports their adaptation and survival.
| Season | Location | Key Aspects |
|---|---|---|
| Summer | Rocky Mountains, Southwest United States | Breeding, nesting, raising young. Taking advantage of plentiful flowers, bugs, nesting material. |
| Fall Migration | Southwest United States | Travelling to southern wintering grounds. Fueling up on flowers and feeders. |
| Winter | Southern Arizona, New Mexico, Texas, Mexico | Overwintering until spring. Accessing flowers, tree sap, and some insects. |
| Spring Migration | Southwest United States | Travelling back north to breeding areas. Refueling along the way. |
Conclusion
In conclusion, broad-tailed hummingbirds definitely migrate annually between breeding grounds primarily in the Rocky Mountains and wintering areas in the southwestern United States and Mexico. Their migration seems driven by seasonal changes in flower and food availability, cold temperatures, snow accumulation, and lack of nesting sites. Though tiny, they are built to endure an incredible migratory journey thanks to specialized physiology and navigational abilities. Their migration patterns allow broad-tailed hummingbirds to flourish across a much wider range than if they did not migrate seasonally. Understanding their migration provides key insights into broad-tailed hummingbird conservation and supporting these amazing birds.
