Rose-breasted Grosbeaks reach New Jersey in mid April, are common by late April, peak in the second week of May (13% of checklists), and most are gone by early October.
When to look
First arrivalsApr 15-21mid April
Common byApr 22-30late April
PeakMay 8-14the second week of May
Most gone byOct 1-7early October
Best: the second week of May. First arrivals mid April; most are gone by early October. Peak: on about 13% of New Jersey checklists.
Jannot usually seen
Febnot usually seen
Marnot usually seen
Aprcommon
Maypeak season
Juncommon
Juluncommon
Augrare
Sepuncommon
Octuncommon
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 New Jersey 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.
Passaic CountyBest the second week of May · 1413 checklists that week, 24,933 in all32%
Mercer CountyBest the second week of May · 2095 checklists that week, 56,614 in all31%
Sussex CountyBest late May · 1355 checklists that week, 30,305 in all31%
Hunterdon CountyBest the second week of May · 1949 checklists that week, 57,610 in all25%
Somerset CountyBest the second week of May · 1936 checklists that week, 58,057 in all24%
Morris CountyBest the second week of May · 2452 checklists that week, 59,212 in all23%
Best spots
Share of checklists at the peak
Baldpate MountainMercer County, best the second week of May · 183 checklists that week, 1,816 in all80%
West Essex ParkEssex County, best the second week of May · 43 checklists that week, 1,556 in all70%
Watchung Reservation (west)Union County, best the second week of May · 24 checklists that week, 253 in all69%
Voorhees State ParkHunterdon County, best the second week of May · 77 checklists that week, 362 in all67%
Watchung ReservationUnion County, best the second week of May · 34 checklists that week, 577 in all66%
Busy spots report more of everything; compare the checklist counts before you drive anywhere.
Best time of day
In New Jersey, the Rose-breasted Grosbeak is most often listed on checklists started between 6 and 8 am (6.4% 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%
0.1%
February
0.1%
0%
0.1%
0%
March
0%
0%
0%
0%
April
0%
0.1%
0.3%
4.4%
May
15%
14%
10%
7.1%
June
5.9%
5.3%
4.9%
4.1%
July
3.4%
2.4%
2.2%
1.3%
August
1.0%
1.1%
1.4%
1.7%
September
2.3%
4.2%
5.5%
5.3%
October
2.7%
0.7%
0.2%
0.1%
November
0.1%
0%
0.1%
0.1%
December
0.1%
0.1%
0.1%
0%
Neighboring states
Delaware: arrives early September, 18 weeks later than New Jersey
Connecticut: arrives mid April, in the same week than New Jersey
Pennsylvania: arrives mid April, in the same week than New Jersey
New York: arrives mid April, in the same week than New Jersey
Common questions
When do Rose-breasted Grosbeaks arrive in New Jersey?
Rose-breasted Grosbeaks reach New Jersey in mid April, are common by late April, peak in the second week of May (13% of checklists), and most are gone by early October.
When do Rose-breasted Grosbeaks leave New Jersey?
Most Rose-breasted Grosbeaks have left New Jersey by early October, when reports fall below half their usual rate. Stragglers are still reported until the second week of October.
When is the best time to see a Rose-breasted Grosbeak in New Jersey?
The Rose-breasted Grosbeak is reported most often in the second week of May, on about 13% of New Jersey checklists.
Where in New Jersey are Rose-breasted Grosbeaks seen most often?
By county, Passaic County, Mercer County, and Sussex County have the highest peak reporting rates for the Rose-breasted Grosbeak (counties with at least 200 checklists).