Not a Feather

Wide, curved, tall or long, so many shapes but none are wrong.

~Hermione Little

It is a little harder (or at least less pleasant) to explore our yard and woodlands during a deluge like we have had the past few days. But, I was out filling bird feeders in the rain when a light-colored shape in the flowers caught my eye.

Plume moth

Plume moth resting in its characteristic T-shape position (click photos to enlarge)

As I got nearer, I recognized its distinctive T-shape as belonging to a plume moth. These unusual moths rest with their wings held out at a right angle to their slender body looking somewhat like an old airplane profile. These narrow wings actually are pleated or lobed and fold out wider when in flight.

Plume moth detail

Detail of wing

I looked in my field guides and online and am pretty sure this is the Groundsel Plume Moth (aka Baccharis Borer Plume Moth), Hellinsia balanotes, due its large size. As a group, they can be difficult to identify to genus or species, but this one had a wingspan the size of a quarter (greater than 30mm). Most plume moths are half that size.

Plume moth top view

Looking down on this unusual moth

The larvae of many plume moths bore into the stems of various shrubs and wildflowers or are leafrollers. The unusual shape of the adults is said to help them camouflage themselves when at rest in vegetation during the day as they tend to look more like dried plant stems than a tasty moth. Whatever the reason, they make for an interesting discovery on a rainy day (this moth stayed in this spot all day in spite of my intrusion).