When do grackles and blackbirds leave Montana?

Red-winged Blackbirds never fully leave Montana: numbers fall back below half their usual rate by the second week of July, but some are still reported in every week, about 3.2% of checklists at the low.

When is the best time to see grackles and blackbirds in Montana?

The Red-winged Blackbird is reported most often in early May, on about 54% of Montana checklists.

Which grackles and blackbirds are in Montana?

Red-winged Blackbird, Brown-headed Cowbird, Western Meadowlark, Common Grackle, Yellow-headed Blackbird, and Bobolink are reported regularly; the Red-winged Blackbird is the most common.

6 blackbird species in Montana

When Do Grackles and blackbirds Arrive in Montana?

Photo: infiniteuniverse, CC0 1.0 via iNaturalist

Red-winged Blackbirds, Brown-headed Cowbirds, and Western Meadowlarks are the grackles and blackbirds you are most likely to see in Montana. Red-winged Blackbirds are in Montana all year, but most are here in spring: numbers build from mid March, peak in early May (54% of checklists), and fall back by the second week of July. In the quietest week (late November) they are still on about 3.2% of checklists.

When to look

Numbers buildMar 15-21mid March

PeakMay 1-7early May

Fall back byJul 8-14the second week of July

FewestNov 22-30late November

Best: early May. Here all year; numbers build from mid March and fall back by the second week of July. Peak: on about 54% of Montana checklists.

Janrare
Febuncommon
Marcommon
Aprpeak season
Maypeak season
Junpeak season
Julcommon
Auguncommon
Sepuncommon
Octuncommon
Novrare
Decrare

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

Grackles and blackbirds in Montana, species by species

Species	First arrivals	Common by	Peak	Most gone by	Peak %
Red-winged Blackbird	Mar 15-21	Mar 15-21	May 1-7	Jul 8-14	54%
Brown-headed Cowbird	Apr 22-30	May 1-7	May 22-31	Jul 15-21	34%
Western Meadowlark	Mar 1-7	Mar 15-21	May 1-7	Oct 1-7	31%
Common Grackle	Apr 8-14	Apr 15-21	May 22-31	Oct 1-7	19%
Yellow-headed Blackbird	Apr 1-7	Apr 8-14	May 8-14	Aug 15-21	16%
Bobolink	May 15-21	May 15-21	Jun 1-7	Jul 1-7	3.9%

Red-winged Blackbird
Brown-headed Cowbird
Western Meadowlark
Common Grackle

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 Montana 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 Montana

Best counties for Red-winged Blackbird

Share of checklists at the peak

Wibaux CountyBest mid May · 31 checklists that week, 435 in all83%
Daniels CountyBest late July · 12 checklists that week, 481 in all71%
Fallon CountyBest early July · 25 checklists that week, 542 in all70%
Cascade CountyBest the second week of May · 440 checklists that week, 16,190 in all68%
Lake CountyBest early May · 563 checklists that week, 19,478 in all67%
Pondera CountyBest late May · 21 checklists that week, 659 in all66%

Common questions

When do grackles and blackbirds arrive in Montana?: Red-winged Blackbirds are in Montana all year, but most are here in spring: numbers build from mid March, peak in early May (54% of checklists), and fall back by the second week of July. In the quietest week (late November) they are still on about 3.2% of checklists.
When do grackles and blackbirds leave Montana?: Red-winged Blackbirds never fully leave Montana: numbers fall back below half their usual rate by the second week of July, but some are still reported in every week, about 3.2% of checklists at the low.
When is the best time to see grackles and blackbirds in Montana?: The Red-winged Blackbird is reported most often in early May, on about 54% of Montana checklists.
Which grackles and blackbirds are in Montana?: Red-winged Blackbird, Brown-headed Cowbird, Western Meadowlark, Common Grackle, Yellow-headed Blackbird, and Bobolink are reported regularly; the Red-winged Blackbird is the most common.