WhenToBird

Chroicocephalus philadelphia · Laridae

When Do Bonaparte's Gulls Arrive in North Dakota?

Adult Bonaparte's Gull
Photo: Kevin Krebs, CC BY 4.0 via iNaturalist

Bonaparte's Gulls are winter birds in North Dakota: they arrive in early September, peak in late October (4.1% of checklists), and most are gone by the second week of December.

When to look

First arrivalsSep 1-7early September
Common bySep 1-7early September
PeakOct 22-31late October
Most gone byDec 8-14the second week of December

Best: late October. First arrivals early September; most are gone by the second week of December. Peak: on about 4.1% of North Dakota checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marnot usually seen
  4. Aprcommon
  5. Maycommon
  6. Junrare
  7. Julrare
  8. Augrare
  9. Sepcommon
  10. Octpeak season
  11. Novpeak season
  12. Deccommon

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

0%2%4%6%Jan 1-7: 0% of 1694 checklistsJan 8-14: 0% of 1210 checklistsJan 15-21: 0% of 1263 checklistsJan 22-31: 0% of 1984 checklistsFeb 1-7: 0% of 1209 checklistsFeb 8-14: 0% of 1307 checklistsFeb 15-21: 0% of 1655 checklistsFeb 22-28: 0% of 1619 checklistsMar 1-7: 0% of 1653 checklistsMar 8-14: 0% of 1818 checklistsMar 15-21: 0% of 2103 checklistsMar 22-31: 0% of 3714 checklistsApr 1-7: 0.1% of 2955 checklistsApr 8-14: 0.9% of 3550 checklistsApr 15-21: 1.9% of 4104 checklistsApr 22-30: 3.8% of 5712 checklistsMay 1-7: 2.4% of 5328 checklistsMay 8-14: 0.4% of 5885 checklistsMay 15-21: 0.6% of 5344 checklistsMay 22-31: 0.4% of 7512 checklistsJun 1-7: 0.3% of 4329 checklistsJun 8-14: 0.1% of 4287 checklistsJun 15-21: 0.1% of 3798 checklistsJun 22-30: 0.1% of 4361 checklistsJul 1-7: 0.1% of 2939 checklistsJul 8-14: 0.1% of 2407 checklistsJul 15-21: 0.2% of 2254 checklistsJul 22-31: 0.3% of 2852 checklistsAug 1-7: 0.6% of 2119 checklistsAug 8-14: 0.2% of 2044 checklistsAug 15-21: 0.3% of 2124 checklistsAug 22-31: 0.5% of 3168 checklistsSep 1-7: 0.7% of 2449 checklistsSep 8-14: 0.6% of 2310 checklistsSep 15-21: 1.0% of 2092 checklistsSep 22-30: 1.6% of 2565 checklistsOct 1-7: 2.4% of 2071 checklistsOct 8-14: 2.9% of 1918 checklistsOct 15-21: 3.8% of 1907 checklistsOct 22-31: 4.6% of 2589 checklistsNov 1-7: 3.8% of 1858 checklistsNov 8-14: 3.7% of 1753 checklistsNov 15-21: 2.8% of 1483 checklistsNov 22-30: 3.0% of 1928 checklistsDec 1-7: 1.2% of 1337 checklistsDec 8-14: 1.1% of 1309 checklistsDec 15-21: 0% of 1642 checklistsDec 22-31: 0% of 1830 checklistsJanFebMarAprMayJunJulAugSepOctNovDec
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 North Dakota 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
Second week of November

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.

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Where in North Dakota

Best counties

Share of checklists at the peak
  1. Mercer CountyBest mid November · 38 checklists that week, 2,518 in all52%
  2. Benson CountyBest the second week of November · 11 checklists that week, 986 in all30%
  3. Eddy CountyBest late October · 15 checklists that week, 360 in all30%
  4. Nelson CountyBest late October · 20 checklists that week, 470 in all26%
  5. Pierce CountyBest the second week of October · 13 checklists that week, 403 in all24%
  6. Dickey CountyBest mid April · 19 checklists that week, 360 in all20%

Best spots

Share of checklists at the peak
  1. Sakakawea Recreation AreaMercer County, best mid November · 20 checklists that week, 617 in all69%
  2. Hobart Lake National Wildlife RefugeBarnes County, best late April · 29 checklists that week, 191 in all15%
  3. Kellys Slough National Wildlife RefugeGrand Forks County, best late April · 29 checklists that week, 305 in all14%

Busy spots report more of everything; compare the checklist counts before you drive anywhere.

Best time of day

In North Dakota, the Bonaparte's Gull is most often listed on checklists started between 1 and 3 pm (1.3% of those checklists).

0%0.5%1%1.5%12 am: too few checklists (74) to judge1 am: too few checklists (45) to judge2 am: too few checklists (42) to judge3 am: too few checklists (68) to judge4 am: too few checklists (274) to judge5 am: too few checklists (1538) to judge6 am: 0.4% of 4242 checklists7 am: 0.5% of 9520 checklists8 am: 0.8% of 13065 checklists9 am: 1.0% of 13356 checklists10 am: 1.2% of 12128 checklists11 am: 1.1% of 10772 checklists12 pm: 1.2% of 10316 checklists1 pm: 1.3% of 9169 checklists2 pm: 1.2% of 8880 checklists3 pm: 1.2% of 8688 checklists4 pm: 1.0% of 8201 checklists5 pm: 1.2% of 6687 checklists6 pm: 1.0% of 5455 checklists7 pm: 0.7% of 3926 checklists8 pm: too few checklists (2024) to judge9 pm: too few checklists (602) to judge10 pm: too few checklists (181) to judge11 pm: too few checklists (89) to judge12a3a6a9a12p3p6p9p
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
MonthDays 1-78-1415-2122-end
January0%0%0%0%
February0%0%0%0%
March0%0%0%0%
April0.1%0.9%1.9%3.8%
May2.4%0.4%0.6%0.4%
June0.3%0.1%0.1%0.1%
July0.1%0.1%0.2%0.3%
August0.6%0.2%0.3%0.5%
September0.7%0.6%1.0%1.6%
October2.4%2.9%3.8%4.6%
November3.8%3.7%2.8%3.0%
December1.2%1.1%0%0%

Neighboring states

  • South Dakota: arrives late September, 3 weeks later than North Dakota
  • Minnesota: arrives early April, 20 weeks earlier than North Dakota
  • Nebraska: arrives early October, 4 weeks later than North Dakota
  • Iowa: arrives mid September, 2 weeks later than North Dakota

Common questions

When do Bonaparte's Gulls arrive in North Dakota?
Bonaparte's Gulls are winter birds in North Dakota: they arrive in early September, peak in late October (4.1% of checklists), and most are gone by the second week of December.
When do Bonaparte's Gulls leave North Dakota?
Most Bonaparte's Gulls have left North Dakota by the second week of December, when reports fall below half their usual rate.
When is the best time to see a Bonaparte's Gull in North Dakota?
The Bonaparte's Gull is reported most often in late October, on about 4.1% of North Dakota checklists.
Where in North Dakota are Bonaparte's Gulls seen most often?
By county, Mercer County, Benson County, and Eddy County have the highest peak reporting rates for the Bonaparte's Gull (counties with at least 200 checklists).