Black-headed Grosbeaks reach Colorado in late April, are common by early May, peak in late May (16% of checklists), and most are gone by mid August.
When to look
First arrivalsApr 22-30late April
Common byMay 1-7early May
PeakMay 22-31late May
Most gone byAug 15-21mid August
Best: late May. First arrivals late April; most are gone by mid August. Peak: on about 16% of Colorado checklists.
Jannot usually seen
Febnot usually seen
Marnot usually seen
Aprrare
Maypeak season
Junpeak season
Julcommon
Augcommon
Sepuncommon
Octnot usually seen
Novnot usually seen
Decnot usually seen
Darker months: more checklists report it. Outlined: peak month.
Share of complete checklists reporting it, by week (4 per month). Grey bars: fewer than 10 checklists, not counted.
Frequency is the share of complete checklists in Colorado 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.
JanFebMarAprMayJunJulAugSepOctNovDec
today
0%few checklistsno data
Each county is shaded by the share of complete checklists there that listed the bird, blended with the weeks either side. Darker is more often. It follows where people watch birds, not how many birds there are. How to read it.
Busy spots report more of everything; compare the checklist counts before you drive anywhere.
Best time of day
In Colorado, the Black-headed Grosbeak is most often listed on checklists started between 6 and 8 am (7.5% of those checklists).
Share of checklists started in each local hour that reported it. It reflects when people go birding as well as when birds are active. Grey hours have too few checklists (under 2% of the state’s, or under 200) to judge.Week-by-week table
Month
Days 1-7
8-14
15-21
22-end
January
0%
0%
0%
0%
February
0%
0%
0%
0%
March
0%
0%
0%
0%
April
0%
0%
0.1%
0.5%
May
4.3%
11%
16%
16%
June
14%
13%
11%
11%
July
9.9%
8.7%
8.1%
8.4%
August
7.6%
7.2%
5.5%
3.9%
September
2.3%
1.1%
0.4%
0.2%
October
0.1%
0.1%
0.1%
0.1%
November
0%
0.1%
0%
0.1%
December
0%
0%
0%
0%
Neighboring states
Wyoming: arrives early May, 1 week later than Colorado
New Mexico: arrives mid April, 1 week earlier than Colorado
Utah: arrives late April, in the same week than Colorado
Nebraska: arrives early May, 1 week later than Colorado
Common questions
When do Black-headed Grosbeaks arrive in Colorado?
Black-headed Grosbeaks reach Colorado in late April, are common by early May, peak in late May (16% of checklists), and most are gone by mid August.
When do Black-headed Grosbeaks leave Colorado?
Most Black-headed Grosbeaks have left Colorado by mid August, when reports fall below half their usual rate. Stragglers are still reported until the second week of September.
When is the best time to see a Black-headed Grosbeak in Colorado?
The Black-headed Grosbeak is reported most often in late May, on about 16% of Colorado checklists.
Where in Colorado are Black-headed Grosbeaks seen most often?
By county, Huerfano County, La Plata County, and Las Animas County have the highest peak reporting rates for the Black-headed Grosbeak (counties with at least 200 checklists).