Western Bluebirds in Colorado
When western bluebirds are present in Colorado, when they nest, which native Colorado plants feed them, and how to host them in a USDA 3a–7b yard.
- Status in Colorado
- Summer breeder
- Nesting window
- April–July
- Broods
- 1–2 per season
- Hardiness zones
- USDA 3a–7b
- Nest box
- 1 1/2 in hole, 5 × 5 in floor, 5–10 ft
When to expect western bluebirds in Colorado
Western Bluebirds are summer residents in Colorado, arriving shortly before nesting begins in April and leaving after the young are independent. Through the season they feed on beetles and grasshoppers.
Semi-arid high plains in the east and the Rocky Mountains through the center, with most backyards between 5,000 and 7,000 ft.
Nesting in Colorado
Across Colorado, western bluebirds typically nest from April–July. Nest site: cavity or nest box. Females lay 2–8 eggs, incubate for 12–17 days, and young leave the nest after 19–25 days.
Warm, dry days and cool nights; afternoon storms are common in July and August.
- Have boxes cleaned and mounted before March — western bluebirds begin prospecting ahead of egg-laying.
- Use a 1 1/2 in entrance on a 5 × 5 in floor, mounted 5–10 ft.
- Fit a pole baffle or hole guard; ventilation gaps and drainage holes are essential.
- Clean out old nests after each brood and again after July.
Native Colorado plants that attract western bluebirds
Of the regional native plants we track for Colorado, these 8 provide food or cover western bluebirds use:
Red fruit heads hang on through winter.
Blue fruit on red stems in early fall.
Late nectar for insects and fall seed for sparrows.
Insect-rich in fall and seed in winter.
Fast-growing northern cherry with midsummer fruit.
Dark summer fruit and heavy caterpillar load.
White fruit and red winter stems; good thicket cover.
Berry-like cones feed bluebirds, solitaires and waxwings in winter.
Feeding western bluebirds through the Colorado year
Uses 1 1/2 in nest boxes in open oak and pine woodland; boxes have helped recovery in the Pacific Northwest.
- Best foods: Mealworms, Suet nuggets.
- In Colorado's summer: offer water and insect foods; natural food is abundant.
Full diet breakdown for western bluebirds · Best feeder for western bluebirds
Frequently asked
Are western bluebirds in Colorado year-round?
No. Western Bluebirds are summer breeders in Colorado and leave for the winter.
When do western bluebirds nest in Colorado?
Nesting in Colorado typically runs April–July, with 1–2 per season. Clutches are 2–8 eggs, incubated for 12–17 days.
What native plants attract western bluebirds in Colorado?
Smooth sumac, Virginia creeper, New England aster, Tall goldenrod, Pin cherry, Chokecherry, Red-osier dogwood, Rocky Mountain juniper are native plants in Colorado that provide food or cover for western bluebirds.
What size birdhouse hole do western bluebirds need?
1 1/2 in, with a floor of 5 × 5 in mounted 5–10 ft.
Western Bluebirds in other regions
Other backyard birds in Colorado
Sources
- Western Bluebird — All About Birds, Cornell Lab of Ornithology
- Western Bluebird life history — Cornell Lab of Ornithology
- Western Bluebird — Audubon Guide to North American Birds
- NestWatch nest box plans and species requirements — Cornell Lab
- eBird region overview and bar charts — Colorado
- USDA Plant Hardiness Zone Map (2023)
- Audubon Native Plants Database
Timing reflects typical patterns for the region as a whole; local dates vary with elevation and year. Check the linked eBird bar charts for your county.