Violet-green Swallows in Colorado
When violet-green swallows 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
- May–July
- Broods
- 1 per season
- Hardiness zones
- USDA 3a–7b
- Nest box
- 1 1/2 in hole, 5 × 5 in floor, 8–15 ft
When to expect violet-green swallows in Colorado
Violet-green Swallows are summer residents in Colorado, arriving shortly before nesting begins in May and leaving after the young are independent. Through the season they feed on flies and midges.
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, violet-green swallows typically nest from May–July. Nest site: cavity or nest box. Females lay 4–6 eggs, incubate for 13–18 days, and young leave the nest after 16–24 days.
Warm, dry days and cool nights; afternoon storms are common in July and August.
- Have boxes cleaned and mounted before April — violet-green swallows begin prospecting ahead of egg-laying.
- Use a 1 1/2 in entrance on a 5 × 5 in floor, mounted 8–15 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 violet-green swallows
Of the regional native plants we track for Colorado, these 8 provide food or cover violet-green swallows use:
Late nectar for insects and fall seed for sparrows.
Insect-rich in fall and seed in winter.
Dark summer fruit and heavy caterpillar load.
Seeds and bark insects; pygmy nuthatch and woodpecker habitat.
Acorns for jays and woodpeckers across the southern Rockies.
Late-season bloom supports insects; seed for sparrows.
Seed for crossbills, siskins and chickadees.
Early catkins draw insects for arriving warblers and hummingbirds.
Feeding violet-green swallows through the Colorado year
Uses nest boxes in western towns and forests.
- Best foods: .
- In Colorado's summer: offer water and insect foods; natural food is abundant.
Frequently asked
Are violet-green swallows in Colorado year-round?
No. Violet-green Swallows are summer breeders in Colorado and leave for the winter.
When do violet-green swallows nest in Colorado?
Nesting in Colorado typically runs May–July, with 1 per season. Clutches are 4–6 eggs, incubated for 13–18 days.
What native plants attract violet-green swallows in Colorado?
New England aster, Tall goldenrod, Chokecherry, Ponderosa pine, Gambel oak, Rabbitbrush, Douglas fir, Willow (Bebb) are native plants in Colorado that provide food or cover for violet-green swallows.
What size birdhouse hole do violet-green swallows need?
1 1/2 in, with a floor of 5 × 5 in mounted 8–15 ft.
Violet-green Swallows in other regions
Other backyard birds in Colorado
Sources
- Violet-green Swallow — All About Birds, Cornell Lab of Ornithology
- Violet-green Swallow life history — Cornell Lab of Ornithology
- Violet-green Swallow — 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.