When do grackles and blackbirds leave Delaware?

Red-winged Blackbirds never fully leave Delaware: numbers fall back below half their usual rate by late July, but some are still reported in every week, about 14% of checklists at the low.

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

The Red-winged Blackbird is reported most often in late May, on about 62% of Delaware checklists.

Which grackles and blackbirds are in Delaware?

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

6 blackbird species in Delaware

When Do Grackles and blackbirds Arrive in Delaware?

Photo: infiniteuniverse, CC0 1.0 via iNaturalist

Red-winged Blackbirds, Common Grackles, and Brown-headed Cowbirds are the grackles and blackbirds you are most likely to see in Delaware. Red-winged Blackbirds are in Delaware all year, but most are here in spring: numbers build from mid February, peak in late May (62% of checklists), and fall back by late July. In the quietest week (mid September) they are still on about 14% of checklists.

When to look

Numbers buildFeb 15-21mid February

PeakMay 22-31late May

Fall back byJul 22-31late July

FewestSep 15-21mid September

Best: late May. Here all year; numbers build from mid February and fall back by late July. Peak: on about 62% of Delaware checklists.

Jancommon
Febcommon
Marpeak season
Aprpeak season
Maypeak season
Junpeak season
Julpeak season
Augcommon
Sepuncommon
Octcommon
Novcommon
Deccommon

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

Grackles and blackbirds in Delaware, species by species

Species	First arrivals	Common by	Peak	Most gone by	Peak %
Red-winged Blackbird	Feb 15-21	Feb 15-21	May 22-31	Jul 22-31	62%
Common Grackle	Mar 15-21	Mar 15-21	Jun 8-14	Jul 15-21	47%
Brown-headed Cowbird	Mar 22-31	Mar 22-31	Apr 22-30	Jul 1-7	35%
Bobolink	Jul 8-14	Aug 15-21	Sep 1-7	Sep 22-30	7.2%
Eastern Meadowlark	Oct 8-14	Oct 8-14	Jun 15-21	Jul 22-31	2.4%
Rusty Blackbird	Oct 15-21	Oct 15-21	Apr 1-7	Apr 22-30	2.1%

Red-winged Blackbird
Common Grackle
Brown-headed Cowbird
Bobolink

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 Delaware 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 Delaware

Best counties for Red-winged Blackbird

Share of checklists at the peak

Kent CountyBest early June · 675 checklists that week, 36,693 in all72%
New Castle CountyBest mid April · 1979 checklists that week, 72,140 in all62%
Sussex CountyBest late May · 3653 checklists that week, 91,027 in all62%

Common questions

When do grackles and blackbirds arrive in Delaware?: Red-winged Blackbirds are in Delaware all year, but most are here in spring: numbers build from mid February, peak in late May (62% of checklists), and fall back by late July. In the quietest week (mid September) they are still on about 14% of checklists.
When do grackles and blackbirds leave Delaware?: Red-winged Blackbirds never fully leave Delaware: numbers fall back below half their usual rate by late July, but some are still reported in every week, about 14% of checklists at the low.
When is the best time to see grackles and blackbirds in Delaware?: The Red-winged Blackbird is reported most often in late May, on about 62% of Delaware checklists.
Which grackles and blackbirds are in Delaware?: Red-winged Blackbird, Common Grackle, Brown-headed Cowbird, Bobolink, Eastern Meadowlark, and Rusty Blackbird are reported regularly; the Red-winged Blackbird is the most common.