Bird field guide · Gulls, Terns, and Skimmers

Photographing the Forster's Tern

How to photograph the Forster's Tern (Sterna forsteri): the right lens for its size, shutter speeds for perched and moving animals, and when it's most often seen (April and May).

20–75 cm1/2500–1/4000 s
Forster's Tern (Sterna forsteri)
Photo: © Kathy Richardson, some rights reserved (CC BY), uploaded by Kathy Richardson via iNaturalist
20–75 cm
Typical length (family range)
1/1000 s
Shutter: perched / still
1/2500–1/4000 s
Shutter: action / flight
f/7.1–f/8
Aperture
31,862
Research-grade sightings in N. America
ModeManual + Auto ISOLock shutter & aperture, let ISO float
Shutter (still)1/1000 s
Shutter (action)1/2500–1/4000 s
Aperturef/7.1–f/8
FocusAF-C + subject/eye detectionBright sand and surf fool meters — dial in exposure manually or with auto-ISO and compensation.
DriveHigh-speed burst
Lens300–500 mmFull-frame equivalent

Focal length needed to frame it#

For a subject about 48 cm long filling a third or half of the frame width horizontally.

Distance⅓ of frame (FF)½ of frame (FF)⅓ of frame (APS-C)⅓ of frame (MFT)
5 m (16 ft)122 mm183 mm81 mm61 mm
10 m (33 ft)244 mm365 mm163 mm122 mm
15 m (49 ft)366 mm548 mm244 mm183 mm
20 m (66 ft)488 mm730 mm325 mm244 mm
30 m (98 ft)732 mm1,095 mm488 mm366 mm
50 m (164 ft)1,220 mm1,826 mm813 mm610 mm

When to find it#

Jan: 7% Jan Feb: 5% Feb Mar: 6% Mar Apr: 15% Apr May: 15% May Jun: 8% Jun Jul: 9% Jul Aug: 10% Aug Sep: 9% Sep Oct: 5% Oct Nov: 5% Nov Dec: 5% Dec
Share of iNaturalist observations by month across North America. Peak months: April and May.

About the Forster's Tern#

The Forster's tern (Sterna forsteri) is a tern in the family Laridae. The genus name Sterna is derived from Old English "stearn", "tern", and forsteri commemorates the naturalist Johann Reinhold Forster.

Summary adapted from Wikipedia via iNaturalist (CC BY-SA 4.0).

Field-craft tips#

  • Terns dive — use 1/3200 s and continuous tracking AF.
  • Bright sand and surf fool meters — dial in exposure manually or with auto-ISO and compensation.
  • Sightings peak in April and May, which is when you'll have the most chances.

Ethics#

  • The welfare of the animal comes first: if it changes its behaviour because of you, you are too close.
  • Stay on trails, respect closures around nests, leks, dens and haul-outs.
  • Avoid playback and baiting in sensitive seasons; never bait predators.
  • Don't share precise locations of rare, nesting or roosting animals publicly.

More Gulls, Terns, and Skimmers#

Ring-billed Gull Ring-billed GullLarus delawarensis Laughing Gull Laughing GullLeucophaeus atricilla American Herring Gull American Herring GullLarus smithsonianus Western Gull Western GullLarus occidentalis Royal TernThalasseus maximus California GullLarus californicus Caspian TernHydroprogne caspia Bonaparte's Gull Bonaparte's GullChroicocephalus philadelphia

Frequently asked questions#

What lens do I need to photograph a Forster's Tern?

At about 48 cm long, a forster's tern fills a third of a full-frame image at 10 m with roughly 244 mm, or at 20 m with 488 mm.

What shutter speed should I use for a Forster's Tern?

1/1000 s when it's still; 1/2500–1/4000 s for action.

When is the best time to photograph a Forster's Tern?

Observations in North America peak in April and May. Early morning and late afternoon give the best light and activity.

Sources & licences#

Last updated October 03, 2026 · How we calculate · Sources