When do swallows leave Idaho?

Most Barn Swallows have left Idaho by mid September, when reports fall below half their usual rate. Stragglers are still reported until mid October.

When is the best time to see swallows in Idaho?

The Barn Swallow is reported most often in late August, on about 26% of Idaho checklists.

Which swallows are in Idaho?

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

5 swallow species in Idaho

When Do Swallows Arrive in Idaho?

Photo: Diego González Dopico, CC BY 4.0 via iNaturalist

Barn Swallows, Tree Swallows, and Violet-green Swallows are the swallows you are most likely to see in Idaho. Barn Swallows reach Idaho in the second week of April, are common by late April, peak in late August (26% of checklists), and most are gone by mid September.

When to look

First arrivalsApr 8-14the second week of April

Common byApr 22-30late April

PeakAug 22-31late August

Most gone bySep 15-21mid September

Best: late August. First arrivals the second week of April; most are gone by mid September. Peak: on about 26% of Idaho checklists.

Jannot usually seen
Febnot usually seen
Marnot usually seen
Aprcommon
Maypeak season
Junpeak season
Julpeak season
Augpeak season
Seppeak season
Octuncommon
Novnot usually seen
Decnot usually seen

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

Swallows in Idaho, species by species

Species	First arrivals	Common by	Peak	Most gone by	Peak %
Barn Swallow	Apr 8-14	Apr 22-30	Aug 22-31	Sep 15-21	26%
Tree Swallow	Mar 15-21	Apr 8-14	May 22-31	Jul 22-31	19%
Violet-green Swallow	Mar 15-21	Apr 8-14	Jun 15-21	Aug 8-14	15%
Cliff Swallow	Apr 1-7	Apr 22-30	Jun 22-30	Aug 8-14	14%
Bank Swallow	Apr 15-21	Apr 22-30	Aug 8-14	Sep 1-7	7.5%

Barn Swallow
Tree Swallow
Violet-green Swallow
Cliff 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 Idaho 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 Idaho

Best counties for Barn Swallow

Share of checklists at the peak

Minidoka CountyBest late July · 31 checklists that week, 1,365 in all73%
Power CountyBest late August · 117 checklists that week, 2,278 in all59%
Jefferson CountyBest mid August · 145 checklists that week, 5,319 in all51%
Lincoln CountyBest mid May · 11 checklists that week, 218 in all50%
Jerome CountyBest mid August · 14 checklists that week, 804 in all49%
Oneida CountyBest early August · 34 checklists that week, 1,750 in all49%

All swallows in Idaho

6 species are reported regularly: 6 are summer visitors.

#	Species	Pattern	First arrivals	Peak	Peak %
1	Barn Swallow	Summer visitor	Apr 8-14	Aug 22-31	26%
2	Tree Swallow	Summer visitor	Mar 15-21	May 22-31	19%
3	Violet-green Swallow	Summer visitor	Mar 15-21	Jun 15-21	15%
4	Northern Rough-winged Swallow	Summer visitor	Mar 22-31	May 8-14	15%
5	Cliff Swallow	Summer visitor	Apr 1-7	Jun 22-30	14%
6	Bank Swallow	Summer visitor	Apr 15-21	Aug 8-14	7.5%

Common questions

When do swallows arrive in Idaho?: Barn Swallows reach Idaho in the second week of April, are common by late April, peak in late August (26% of checklists), and most are gone by mid September.
When do swallows leave Idaho?: Most Barn Swallows have left Idaho by mid September, when reports fall below half their usual rate. Stragglers are still reported until mid October.
When is the best time to see swallows in Idaho?: The Barn Swallow is reported most often in late August, on about 26% of Idaho checklists.
Which swallows are in Idaho?: Barn Swallow, Tree Swallow, Violet-green Swallow, Cliff Swallow, and Bank Swallow are reported regularly; the Barn Swallow is the most common.