The Bird Poop Caterpillar

This cleverly disguised caterpillar was found munching in our gardens this fall. Papilo cresphontes, common name bird poop caterpillar, uses camouflage to resemble bird droppings. Younger instars often rest in plain view on the upper surfaces of leaves where you would expect to find bird droppings.

Bird poop caterpillar extends bright red osmeterium or hornlike appendages. photo credit: I. Sevi

If the “poop” disguise doesn’t work , it can extend bright red osmeterium or hornlike appendages, to frighten away predators.

One of our largest butterflies, the Giant Swallowtail (Papilo cresphontes). photo credit: Amber Coakley-Birders Lounge

This unusual caterpillar is actually the larva of one of our largest butterflies, the Giant Swallowtail (Papilo cresphontes).  It can have a wingspan of 4 to 6 inches, and is mostly black with yellow bands and some red and blue markings. The adult butterfly is a welcome visitor to pollinator gardens and to general landscape plantings.

Homeowners, however, may find that just a few larvae of the giant swallowtail can defoliate small, potted or planted citrus plants. Larvae should be handpicked from these small plants so that potential blossom and fruit yield are not drastically reduced. Fortunately, mature trees are large enough to withstand some defoliation.

Giant Swallowtail sucking nectar from Echinacea purpurea. photo credit: E. Waters

The Giant Swallowtail is found mainly in deciduous forests in the east and citrus orchards in the south and west, where it is considered a major pest because of its habit of feeding on the foliage of most Citrus species. In these areas, it is also known as orange dog or orange puppy. Identified nectar sources include azalea, bougainvillea, Japanese honeysuckle, goldenrod, dame’s rocket, bouncing Bet, and swamp milkweed. These butterflies have also been known to sip liquid from manure.

In the Delaware Valley there can be two generations of Papilo cresphontes between May and August. They usually have a darty flight habit and can fly fairly high, making them difficult to notice, but the bird poop caterpillar can be found crawling in your garden.