Eastern bluebirds have different plumage, eat different foods, and behave differently in winter. This article explains what you can expect from this bluebird when winter rolls around.
The eastern bluebird is a stunning natural specimen. Its jewel-bright colors and tone make it a favorite among ornithologists and backyard birdwatchers. The birds tend to spend time in low branches and clear areas, which makes them easy to observe.
Maybe the lovely eastern bluebird is already a favorite of yours – and if you pay attention to its seasonal habits, you might notice it is not around in the winter. Below is more information on the elusive eastern bluebird, its customs, and how to attract them as visitors.
About Bluebirds
The eastern bluebird is one of three types of bluebirds. The other two are the western bluebird and the mountain bluebird.
The eastern bluebird is the most widespread and ranges from parts of Canada down to Nicaragua.
Many of these fascinating animals shelter in tree cavities throughout the winter season, and some even shack up in fence cavities surrounding farmlands. However, the birds do not mate in winter and utilize the holes primarily for warmth.
Eastern bluebirds sometimes participate in communal nesting in particularly frigid winter temperatures to keep warm.
Eastern Bluebird Migration
The eastern bluebird is a partial migrant, which refers to the fact that some will migrate in the winter, and some do not. Most eastern bluebirds migrate between September to early December, with some returning home as early as February.
Partial Migrant: Some will migrate in the winter while others do not.
Like many birds, the eastern bluebird prefers warmer weather. If you live in the southern parts of America, you may get to enjoy these fascinating aviators year-round, as winter temperatures in the Southern states tend to be on the milder side.
If you live in the northern United States, you can expect the bird to migrate as far south as Mexico. Some may fly upwards of 2,000 miles from Manitoba to Texas. Southern eastern bluebirds will likely remain at their breeding nest all year and not change habitats unless they move further south.
Eastern bluebirds travel in small flocks throughout winter, although after finding their preferred feeding spot, they become territorial and may be more solitary. One study suggests that, upon observation, 4 out of 7 males and 5 out of 8 females returned to their winter spot for breeding in spring.
Diet
The eastern bluebird’s food of choice is insects, but due to a lack of availability in winter, their habits change. They snack primarily on fruits, including:
- Mistletoe
- Sumac
- Tupelo
- Currants
- Wild holly
During winter, eastern bluebirds disregard their standard foraging food practices and instead feed on low-hanging branches or bushes. Foraging in the winter is a moot point, as most insects or prospective meals die.
If you want to feed eastern bluebirds during winter, they will happily take mealworms, softened fruits, peanut butter, suet, or even crushed cornmeal. Ensure you wash any fruits before giving them to your avian friends, as pesticides and herbicides are toxic to birds.
Bluebirds do not typically eat standard bird seed, sunflower seeds (unless there are no other options), millet, or nectar. They much prefer fruits and insects!
Mealworms are by far the easiest way to attract eastern bluebirds to your home. They love them, especially in winter when mealworm populations are scarce.
Plumage
The eastern bluebird is among the most beautiful of North America’s feathered friends. As typically seen in birds, the female sports a more subdued and natural look, while the males are bright and eye-catching. They molt once a year (typically in late fall or early winter) but do not naturally lose plumage otherwise.
The female eastern bluebird has a brown chest and neck with subtly blue wing feathers. Her counterpart, the male, shows off a brilliant orange chest. He also has a deep, sky-blue head and wings. The rusty-orange feathers of the male wrap around the neck and chest, then flow into a white abdomen.
Juvenile eastern bluebirds have spotted gray wings. Young males generally have blue plumage, and females have muted gray. These colors may brighten in winter.
Worn-out feathers may have a grayish appearance, but this has more to do with wear and tear. When the birds molt their feathers in the summer and fall, fresh new feathers appear brighter and more vibrant – meaning they have bold plumage throughout the winter.
Winter Habitat
In general, Eastern Bluebirds prefer a semi-open habitat. Parklands, meadows, and areas with low ground cover are ideal for bluebirds. They can perch in cleared areas and scan the ground for prey – but, like most other eastern bluebird habits, that changes in the winter season.
If you have hosted eastern bluebirds in the past, you may know that they require specific housing during spring and summer. They love cedar birdhouses and nest boxes! During the colder months, you will likely not see them in bird houses – although they may still use a roost box for warmth.
If you choose to leave out a bluebird house in winter, you may need to modify it a bit to make it chilly-weather-friendly. Try filling any gaps with removable caulk to keep cold winds from blowing in, and drill new holes for perches that allow multiple bluebirds to roost at once.
You can also install a roosting box for bluebirds to stay warm in winter. Again, ensure all ventilated areas are filled in and face the box away from the north or northwest, as winter winds tend to blow from those directions.
How Do Eastern Bluebirds Survive the Winter?
Despite how mild southern winters may be, eastern bluebirds that do not migrate still feel the winter chill.
To stay warm at night, eastern bluebirds go through nocturnal hypothermia during the winter. As you can probably guess, this refers to their body temperature dropping between 10-15 degrees. They also slow their metabolisms to save energy.
You may notice bluebirds puffing their feathers or tucking their beaks into their chests, then shivering. This method helps them insulate their body heat. However, if they lack proper nutrition and have insufficient food sources, their feathers may not grow as thick – yet another reason to feed them from your yard!
They also roost together during winter, so keeping a birdhouse with plenty of perches ensures everyone has room to stay warm.
During winter, eastern bluebirds merge from an insect-heavy diet to berries and fruit, as those are readily available (such as hollies). Planting winter-growing berries in your yard will draw them in and provides a relatively secure food supply.
Be a Friend to Eastern Bluebirds
Make your backyard a safe place for the eastern bluebird, especially in the more dangerous winter months. While these birds are relatively robust, winter can be brutal if an unexpected winter storm pops up in the Southeastern United States (this rarely happens unless you live in a mountainous area).
Fortunately, due to diligent conservation efforts, the eastern bluebird is a somewhat common species in the United States. They are of least concern conservation-wise, despite a decline in the past due to predators.
Now, birders nationwide build Bluebird Trails to shelter their feathered friends throughout the winter. If you live in the eastern US and pay attention, it will not be long before you spot one of the 23 million alive today.
Why Should We Study Eastern Bluebirds in the Winter?
Getting to know these fascinating creatures that live right in your neighborhood is fun and makes an excellent hobby. Finding out a little bit more about what they do and where they go in the winter can help us understand how we can better serve this resilient little bird.
