When do swallows leave Wyoming?

Most Tree Swallows have left Wyoming by early August, when reports fall below half their usual rate. Stragglers are still reported until early September.

When is the best time to see swallows in Wyoming?

The Tree Swallow is reported most often in late May, on about 23% of Wyoming checklists.

Which swallows are in Wyoming?

Tree Swallow, Violet-green Swallow, Cliff Swallow, Barn Swallow, and Bank Swallow are reported regularly; the Tree Swallow is the most common.

5 swallow species in Wyoming

When Do Swallows Arrive in Wyoming?

Photo: Carter Dorscht, CC0 1.0 via iNaturalist

Tree Swallows, Violet-green Swallows, and Cliff Swallows are the swallows you are most likely to see in Wyoming. Tree Swallows reach Wyoming in early April, are common by mid April, peak in late May (23% of checklists), and most are gone by early August.

When to look

First arrivalsApr 1-7early April

Common byApr 15-21mid April

PeakMay 22-31late May

Most gone byAug 1-7early August

Best: late May. First arrivals early April; most are gone by early August. Peak: on about 23% of Wyoming checklists.

Jannot usually seen
Febnot usually seen
Marnot usually seen
Aprcommon
Maypeak season
Junpeak season
Julpeak season
Augcommon
Seprare
Octnot usually seen
Novnot usually seen
Decnot usually seen

Darker months: more checklists report it. Outlined: peak month.

Swallows in Wyoming, species by species

Species	First arrivals	Common by	Peak	Most gone by	Peak %
Tree Swallow	Apr 1-7	Apr 15-21	May 22-31	Aug 1-7	23%
Violet-green Swallow	Apr 22-30	May 15-21	Jun 15-21	Aug 8-14	19%
Cliff Swallow	Apr 22-30	May 8-14	Jul 8-14	Aug 8-14	19%
Barn Swallow	Apr 15-21	Apr 22-30	May 15-21	Sep 8-14	19%
Bank Swallow	Apr 22-30	May 1-7	May 22-31	Aug 22-31	5.3%

Tree Swallow
Violet-green Swallow
Cliff Swallow
Barn Swallow

Share of complete checklists reporting each species, by week (4 per month). Gaps: fewer than 10 checklists that week.

Frequency is the share of complete checklists in Wyoming that listed the bird, 2016–2025. It is not a head count, and it follows where and when people go birding. How to read it.

Where in Wyoming

Best counties for Tree Swallow

Share of checklists at the peak

Sheridan CountyBest late May · 352 checklists that week, 6,459 in all44%
Sublette CountyBest early June · 236 checklists that week, 6,738 in all39%
Teton CountyBest the second week of May · 1104 checklists that week, 34,686 in all37%
Lincoln CountyBest late May · 191 checklists that week, 3,169 in all34%
Uinta CountyBest the second week of June · 73 checklists that week, 1,881 in all32%
Albany CountyBest late May · 927 checklists that week, 21,857 in all31%

All swallows in Wyoming

6 species are reported regularly: 6 are summer visitors.

#	Species	Pattern	First arrivals	Peak	Peak %
1	Tree Swallow	Summer visitor	Apr 1-7	May 22-31	23%
2	Violet-green Swallow	Summer visitor	Apr 22-30	Jun 15-21	19%
3	Cliff Swallow	Summer visitor	Apr 22-30	Jul 8-14	19%
4	Barn Swallow	Summer visitor	Apr 15-21	May 15-21	19%
5	Northern Rough-winged Swallow	Summer visitor	Apr 15-21	May 15-21	8.6%
6	Bank Swallow	Summer visitor	Apr 22-30	May 22-31	5.3%

Common questions

When do swallows arrive in Wyoming?: Tree Swallows reach Wyoming in early April, are common by mid April, peak in late May (23% of checklists), and most are gone by early August.
When do swallows leave Wyoming?: Most Tree Swallows have left Wyoming by early August, when reports fall below half their usual rate. Stragglers are still reported until early September.
When is the best time to see swallows in Wyoming?: The Tree Swallow is reported most often in late May, on about 23% of Wyoming checklists.
Which swallows are in Wyoming?: Tree Swallow, Violet-green Swallow, Cliff Swallow, Barn Swallow, and Bank Swallow are reported regularly; the Tree Swallow is the most common.