Bluebirds are a beloved songbird species in North America, known for their brilliant blue plumage and cheerful songs. However, over the past several decades, bluebird populations have declined significantly due to loss of habitat, competition with invasive bird species, and lack of nesting cavities.
What is causing bluebird declines?
There are three main factors contributing to the decline of bluebirds across North America:
- Loss of habitat – Deforestation and development have dramatically reduced the open meadows and pastures that bluebirds rely on for nesting and foraging.
- Competition – Introduced bird species like house sparrows and European starlings often outcompete bluebirds for nesting cavities.
- Lack of nesting sites – Bluebirds nest in cavities in trees or birdhouses. But many older trees have been removed and dead trees are often cut down before natural cavities can form.
Where are bluebirds found?
Bluebirds are native to North America and can be found across much of the United States and southern Canada. Here is a map showing their range:
As you can see, bluebirds can be found from coast to coast. But their populations are concentrated east of the Rockies, in areas with a mix of open meadows and scattered trees. Some key states for bluebirds include Missouri, Tennessee, North Carolina and Michigan.
How many bluebirds are left in the wild?
According to data from the North American Breeding Bird Survey, there are currently estimated to be about 11 million breeding pairs of Eastern Bluebirds in North America. Populations peaked in 1966 at an estimated 16 million pairs before declining. Here is a chart showing the population trend:
While Eastern Bluebirds remain relatively common, their populations are a fraction of what they once were. Continued conservation efforts will be needed to stabilize populations and protect these beautiful backyard birds.
What can be done to help bluebirds?
Here are some tips for providing habitat and support for bluebirds in your area:
- Put up nest boxes – Installing nest boxes is one of the best ways to attract breeding bluebirds. Make sure to clean out old nests after each season.
- Provide open habitat – Keep areas of short grass with scattered trees to provide good bluebird habitat. Clear overgrown areas to create open space.
- Remove invasive competitors – House sparrows and starlings often take over nest boxes. Monitor boxes and remove nests of competing species.
- Reduce pesticide use – Insecticides reduce food sources for bluebirds. Avoid use or use sparingly.
- Keep cats indoors – Free roaming cats are a major predator of nestling bluebirds. Keep cats inside to protect local birds.
Starting a bluebird trail
One great way to boost bluebird numbers is to set up a system of nest boxes, known as a bluebird trail. Here are some tips for starting your own bluebird trail:
- Place boxes 100-300 feet apart in open habitat. Face entry hole towards an open area.
- Use a nest box design specifically for bluebirds – with 1 1/2″ diameter entry hole and dimensions at least 5x5x9 inches.
- Mount boxes 4-5 feet high on wooden posts or metal poles. Include predator guards.
- Clean out old nests after each season. Make any repairs needed.
- Keep nests safe from competitors and monitor for issues weekly during season.
- Keep accurate records of number of chicks fledged from each box.
By properly siting and maintaining a network of next boxes, you can significantly expand habitat and breeding opportunities for bluebirds in your area.
How can you help bluebirds on a landscape scale?
While actions by individual landowners are very helpful, conservation of bluebirds will require larger scale efforts as well. Some landscape-level strategies include:
- Protect large open spaces and prevent fragmented habitat. Larger meadows support more bluebirds.
- Encourage sustainable forestry practices that maintain a mosaic of open and wooded habitats.
- Work with parks and protected areas to provide bluebird habitat on public lands.
- Support land trusts and conservation groups that purchase and maintain habitat.
- Promote government policies and programs that benefit early successional bird species like bluebirds.
Coordinated efforts across states, provinces, and regions will be needed to reverse ongoing habitat loss and fragmentation.
Citizen science opportunities
Members of the public can also help scientists study and protect bluebirds by participating in citizen science projects. Here are some examples:
- NestWatch – Contribute nesting data and photos to a central database tracked by the Cornell Lab of Ornithology.
- eBird – Report bluebird sightings and numbers to help scientists track populations.
- Bluebird Trails – Join a local bluebird trail organization to assist with monitoring and maintaining nest box trails.
- State monitoring – Many state natural resource agencies coordinate bluebird monitoring efforts.
Contributing to these and other citizen science efforts helps strengthen our understanding of bluebirds and aids conservation efforts.
Conclusion
Bluebirds face ongoing threats from habitat loss, competition, and lack of nesting sites. But with active management of habitat, nest boxes, and competitors, combined with citizen science monitoring, it is possible to reverse the declines of recent decades. By working together at both local and landscape scales, we can ensure bluebirds remain a vibrant part of North America’s natural heritage for generations to come.