Mammal field guide · Evening Bats

Photographing the Tri-coloured Bat

How to photograph the Tri-coloured Bat (Perimyotis subflavus): the right lens for its size, shutter speeds for perched and moving animals, and when it's most often seen (March and April).

6–12 cm1/20,000 s flash durationVU
6–12 cm
Typical length (family range)
1/250 s
Shutter: perched / still
1/20,000 s flash duration
Shutter: action / flight
f/8–f/11
Aperture
2,954
Research-grade sightings in N. America
ModeManual + Auto ISOLock shutter & aperture, let ISO float
Shutter (still)1/250 s
Shutter (action)1/20,000 s flash duration
Aperturef/8–f/11
FocusAF-C + subject/eye detectionBats need high-speed flash with an IR beam trigger; never photograph roosting bats in winter hibernation.
DriveHigh-speed burst
Lens200–600 mmFull-frame equivalent

Focal length needed to frame it#

For a subject about 9 cm long filling a third or half of the frame width horizontally. Small birds demand long lenses and a close approach — a blind or feeder setup helps.

Distance⅓ of frame (FF)½ of frame (FF)⅓ of frame (APS-C)⅓ of frame (MFT)
5 m (16 ft)583 mm833 mm389 mm292 mm
10 m (33 ft)1,166 mm1,667 mm777 mm583 mm
15 m (49 ft)1,749 mm2,500 mm1,166 mm875 mm
20 m (66 ft)2,332 mm3,333 mm1,555 mm1,166 mm
30 m (98 ft)3,498 mm5,000 mm2,332 mm1,749 mm
50 m (164 ft)5,830 mm8,333 mm3,887 mm2,915 mm

When to find it#

Jan: 10% Jan Feb: 10% Feb Mar: 16% Mar Apr: 15% Apr May: 9% May Jun: 4% Jun Jul: 5% Jul Aug: 6% Aug Sep: 7% Sep Oct: 7% Oct Nov: 6% Nov Dec: 5% Dec
Share of iNaturalist observations by month across North America. Peak months: March and April.

About the Tri-coloured Bat#

Formerly known as the eastern pipistrelle, technically an inaccurate classification, the new more descriptive common name tricolored bat (Perimyotis subflavus) was chosen because of the distinct tricoloration of each hair, which is black at the base, yellow in the middle and brown at the tips. This species of bat is widely distributed throughout the eastern parts of America and Canada, ranging west until Kansas, Oklahoma, and Texas, from Honduras up north until southern Ontario. It is...

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

Field-craft tips#

  • Photograph emerging bats at dusk with high-speed flash — never at roosts in winter.
  • Bats need high-speed flash with an IR beam trigger; never photograph roosting bats in winter hibernation.
  • Sightings peak in March and April, which is when you'll have the most chances.
  • Tiny subjects: get close with a hide or feeder perch rather than cropping heavily.

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 Evening Bats#

Big Brown Bat Big Brown BatEptesicus fuscus Eastern Red Bat Eastern Red BatLasiurus borealis

Frequently asked questions#

What lens do I need to photograph a Tri-coloured Bat?

At about 9 cm long, a tri-coloured bat fills a third of a full-frame image at 10 m with roughly 1,166 mm, or at 20 m with 2,332 mm.

What shutter speed should I use for a Tri-coloured Bat?

1/250 s when it's still; 1/20,000 s flash duration for action.

When is the best time to photograph a Tri-coloured Bat?

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

Sources & licences#

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