WhenToBird

Osprey · Pandion haliaetus

When Do Ospreys Arrive in Pennsylvania?

Adult female Osprey
Photo: Bill Levine, CC BY 4.0 via iNaturalist

Ospreys reach Pennsylvania in mid March, are common by late March, peak in mid August (9.7% of checklists), and most are gone by early October.

When to look

First arrivalsMar 15-21mid March
Common byMar 22-31late March
PeakAug 15-21mid August
Most gone byOct 1-7early October

Best: mid August. First arrivals mid March; most are gone by early October. Peak: on about 9.7% of Pennsylvania checklists.

  1. Jannot usually seen
  2. Febnot usually seen
  3. Marcommon
  4. Aprpeak season
  5. Maypeak season
  6. Juncommon
  7. Julcommon
  8. Augpeak season
  9. Seppeak season
  10. Octuncommon
  11. Novrare
  12. Decnot usually seen

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

Ospreys in Pennsylvania, species by species

SpeciesFirst arrivalsCommon byPeakMost gone byPeak %
OspreyMar 15-21Mar 22-31Aug 15-21Oct 1-79.7%
0%5%10%15%OspreyJanFebMarAprMayJunJulAugSepOctNovDec
  • Osprey
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 Pennsylvania 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 Pennsylvania

Best counties for Osprey

Share of checklists at the peak
  1. Philadelphia CountyBest early August · 1366 checklists that week, 96,503 in all38%
  2. Mercer CountyBest mid August · 257 checklists that week, 17,853 in all35%
  3. Erie CountyBest mid August · 657 checklists that week, 49,012 in all27%
  4. Bucks CountyBest late August · 2392 checklists that week, 95,030 in all23%
  5. Perry CountyBest the second week of September · 146 checklists that week, 10,281 in all21%
  6. Lancaster CountyBest the second week of August · 1329 checklists that week, 97,892 in all20%

Common questions

When do ospreys arrive in Pennsylvania?
Ospreys reach Pennsylvania in mid March, are common by late March, peak in mid August (9.7% of checklists), and most are gone by early October.
When do ospreys leave Pennsylvania?
Most Ospreys have left Pennsylvania by early October, when reports fall below half their usual rate. Stragglers are still reported until late October.
When is the best time to see ospreys in Pennsylvania?
The Osprey is reported most often in mid August, on about 9.7% of Pennsylvania checklists.