WhenToBird

Polioptila caerulea · Polioptilidae

When Do Blue-gray Gnatcatchers Arrive in Maryland?

Adult Blue-gray Gnatcatcher
Photo: Laura Clark, CC BY 4.0 via iNaturalist

Blue-gray Gnatcatchers reach Maryland in late March, are common by early April, peak in late April (38% of checklists), and most are gone by the second week of September.

When to look

First arrivalsMar 22-31late March
Common byApr 1-7early April
PeakApr 22-30late April
Most gone bySep 8-14the second week of September

Best: late April. First arrivals late March; most are gone by the second week of September. Peak: on about 38% of Maryland checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marrare
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augcommon
  9. Sepcommon
  10. Octnot usually seen
  11. Novnot usually seen
  12. Decnot usually seen

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

0%10%20%30%40%Jan 1-7: 0.1% of 28716 checklistsJan 8-14: 0% of 21449 checklistsJan 15-21: 0% of 21267 checklistsJan 22-31: 0.1% of 29144 checklistsFeb 1-7: 0% of 21347 checklistsFeb 8-14: 0% of 22166 checklistsFeb 15-21: 0.1% of 29986 checklistsFeb 22-28: 0.1% of 22427 checklistsMar 1-7: 0% of 21389 checklistsMar 8-14: 0.1% of 22192 checklistsMar 15-21: 0.1% of 22823 checklistsMar 22-31: 1.6% of 33720 checklistsApr 1-7: 12% of 25513 checklistsApr 8-14: 25% of 27718 checklistsApr 15-21: 36% of 29328 checklistsApr 22-30: 40% of 42595 checklistsMay 1-7: 38% of 38532 checklistsMay 8-14: 33% of 42722 checklistsMay 15-21: 32% of 31936 checklistsMay 22-31: 26% of 36903 checklistsJun 1-7: 23% of 23191 checklistsJun 8-14: 20% of 21853 checklistsJun 15-21: 18% of 21000 checklistsJun 22-30: 17% of 25133 checklistsJul 1-7: 16% of 18715 checklistsJul 8-14: 16% of 16376 checklistsJul 15-21: 15% of 15793 checklistsJul 22-31: 14% of 21969 checklistsAug 1-7: 13% of 16013 checklistsAug 8-14: 14% of 15249 checklistsAug 15-21: 16% of 15674 checklistsAug 22-31: 19% of 24925 checklistsSep 1-7: 18% of 19808 checklistsSep 8-14: 13% of 18513 checklistsSep 15-21: 7.4% of 21901 checklistsSep 22-30: 3.0% of 22901 checklistsOct 1-7: 0.7% of 19111 checklistsOct 8-14: 0.3% of 18482 checklistsOct 15-21: 0.2% of 17380 checklistsOct 22-31: 0.1% of 23992 checklistsNov 1-7: 0.1% of 17915 checklistsNov 8-14: 0.1% of 18905 checklistsNov 15-21: 0.1% of 16259 checklistsNov 22-30: 0.1% of 22852 checklistsDec 1-7: 0.1% of 16108 checklistsDec 8-14: 0.1% of 16512 checklistsDec 15-21: 0.1% of 18952 checklistsDec 22-31: 0.1% of 29728 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 Maryland 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 Maryland

Best counties

Share of checklists at the peak
  1. Charles CountyBest late April · 379 checklists that week, 10,064 in all50%
  2. Prince George's CountyBest late April · 3254 checklists that week, 87,907 in all48%
  3. Baltimore CountyBest late April · 5644 checklists that week, 136,139 in all46%
  4. Harford CountyBest early May · 1576 checklists that week, 39,311 in all46%
  5. Montgomery CountyBest late April · 8918 checklists that week, 219,548 in all45%
  6. Howard CountyBest late April · 4510 checklists that week, 118,290 in all41%

Best spots

Share of checklists at the peak
  1. KingsleyMontgomery County, best the second week of May · 20 checklists that week, 197 in all97%
  2. Villa Nova ParkBaltimore County, best mid April · 20 checklists that week, 637 in all97%
  3. Patuxent Ponds ParkAnne Arundel County, best late April · 29 checklists that week, 321 in all96%
  4. Litttle Bennett Regional ParkMontgomery County, best mid April · 23 checklists that week, 947 in all95%
  5. Lake Roland (Roland Run)Baltimore County, best late April · 26 checklists that week, 477 in all95%

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

Best time of day

In Maryland, the Blue-gray Gnatcatcher is most often listed on checklists started between 6 and 8 am (19% of those checklists).

0%10%20%30%12 am: too few checklists (486) to judge1 am: too few checklists (451) to judge2 am: too few checklists (447) to judge3 am: too few checklists (766) to judge4 am: too few checklists (2076) to judge5 am: too few checklists (11098) to judge6 am: 24% of 56604 checklists7 am: 17% of 139255 checklists8 am: 14% of 148626 checklists9 am: 12% of 126820 checklists10 am: 10% of 106973 checklists11 am: 9.6% of 87483 checklists12 pm: 8.5% of 74808 checklists1 pm: 8.3% of 69428 checklists2 pm: 8.1% of 67800 checklists3 pm: 7.8% of 67688 checklists4 pm: 9.5% of 60927 checklists5 pm: 13% of 43876 checklists6 pm: 13% of 32930 checklists7 pm: too few checklists (19051) to judge8 pm: too few checklists (5708) to judge9 pm: too few checklists (1977) to judge10 pm: too few checklists (1170) to judge11 pm: too few checklists (635) 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
January0.1%0%0%0.1%
February0%0%0.1%0.1%
March0%0.1%0.1%1.6%
April12%25%36%40%
May38%33%32%26%
June23%20%18%17%
July16%16%15%14%
August13%14%16%19%
September18%13%7.4%3.0%
October0.7%0.3%0.2%0.1%
November0.1%0.1%0.1%0.1%
December0.1%0.1%0.1%0.1%

Neighboring states

  • District of Columbia: arrives late March, in the same week than Maryland
  • Delaware: arrives late March, in the same week than Maryland
  • Virginia: arrives mid March, 1 week earlier than Maryland
  • Pennsylvania: arrives early April, 1 week later than Maryland

Common questions

When do Blue-gray Gnatcatchers arrive in Maryland?
Blue-gray Gnatcatchers reach Maryland in late March, are common by early April, peak in late April (38% of checklists), and most are gone by the second week of September.
When do Blue-gray Gnatcatchers leave Maryland?
Most Blue-gray Gnatcatchers have left Maryland by the second week of September, when reports fall below half their usual rate. Stragglers are still reported until late September.
When is the best time to see a Blue-gray Gnatcatcher in Maryland?
The Blue-gray Gnatcatcher is reported most often in late April, on about 38% of Maryland checklists.
Where in Maryland are Blue-gray Gnatcatchers seen most often?
By county, Charles County, Prince George's County, and Baltimore County have the highest peak reporting rates for the Blue-gray Gnatcatcher (counties with at least 200 checklists).