Bat (big brown / little brown) Scat and Tracks: How to Identify Them (Eptesicus fuscus / Myotis lucifugus)

Bats leave no tracks; their sign is guano, small dark pellets that crumble to glittering insect fragments, piled below a roost entrance or in an attic. Do not sweep it dry: bat and bird droppings can carry a fungus that spreads in dust. The measurements below for Bat (big brown / little brown) are quoted from the wildlife agencies linked at the bottom of the page.

• Shape: Glossy in appearance, crumbly in texture
• Contents/color: Crumbly in texture because it contains insect remains (easily crushed into powder)
• Where: Usually found in piles near roosting sites

• Watch entry/exit points at dusk: Building exteriors can be watched at dusk to locate bat roost entry/exit points

Mouse droppings are hard, small cylindrical pellets, usually scattered, whereas bat droppings are glossy and crumbly The House Mouse page has its own sign list.

Soil and, in some parts of the U.S., bird and bat droppings can contain the fungus that causes histoplasmosis, a lung infection If you need to clean it up, wear gloves and a mask, wet it down first, and bag it; see the CDC guidance linked in the sources.

Put something of known size next to it (a coin, a pen, a boot) and shoot straight down in soft light; low side light brings out the shape of tracks in mud or snow. For scat, photograph the whole deposit and one close-up showing contents. Note where it was: on a log, in the open, on a trail, near water. The app suggests the likely animal; confirm with the size and shape notes above.