Which Butterfly Is This?

Yellow Eastern Tiger Swallowtail (Papilio glaucus) Photo: Ty Smith

CEFR Level C1-C2

Can you tell the difference between a spicebush swallowtail and a black eastern tiger swallowtail?

In early July 2025, I posted a YouTube short with a black butterfly. For various reasons, the farthest I could get in making an identification was knowing the butterfly was some type of swallowtail. So I used Google Lens. It identified the butterfly as a spicebush swallowtail (Papilio troilus). It looked close enough, so that’s what I labeled my video. 

Keep in mind that my channel is not a nature channel. I care about accuracy, but nature shorts are just a fun extra and I have to think about how much time to invest in things that are just for fun.

Now, before you think I’m a complete idiot when it comes to field markers, my thought process was that a species can have so many variations that for a newbie like me, field markers feel almost pointless. And yes, I know about iNaturalist and Co. for insect IDs, but I find iNat cumbersome and the app eats up my phone battery. 

Google Was Wrong

After I posted the video, a viewer commented that they believed the butterfly was actually a dark eastern tiger swallowtail (Papilio glaucus). If they had been a jerk with their comment, I may have ignored them, but they weren’t, so I went back to “field markers are variable” and took a closer look. I also conferred with some Master Naturalists. 

Ty Smith of Herping Virginia confirmed the black eastern tiger swallowtail ID. I updated the title of the video and asked Ty if he had a photo of a spicebush swallowtail for comparison. He kindly sent me all the photos in this post and gave me permission to use them here.

Black Eastern Tiger vs Spicebush Swallowtail

Here’s my I’m Not an Expert guide to the differences between a black eastern tiger swallowtail and a spicebush swallowtail.

​I’m avoiding any X is bigger/smaller, lighter/darker than Y comparisons because those require a specimen of both species, which makes them useless to me when I’m looking at only one butterfly.

Eastern Tiger Swallowtail (Papilio glaucus) Photo: Ty Smith

Black Eastern Tiger Swallowtail

• White, cream, or pale yellow spots along forewing edge are small and may be difficult to see, at least in comparison to those on the hindwing
• Spots on outside edge of hindwing may be white, cream, pale yellow, or orange
• Spots on hindwing are larger than on forewing
• Blue on the hindwings is mottled and sprinkled like fairy dust up the wing, past the black border

Spicebush Swallowtail (Papilio troilus) Photo: Ty Smith

Spicebush Swallowtail

• White, cream, or pale yellow spots along the outside edge of the forewing
• Spots on outside edge of hindwing may be pale blue
• Blue on hindwings has a sharp line where the black starts, at least from a distance

If you want to spend a lot of time staring at forewing shapes, back and forth between species photos, you might see differences there, too. 

To make things more complicated, there are other black or dark swallowtails. There is even a distinct species called a black swallowtail (Papilio polyxenes). That many options is overwhelming right now. Let’s stick with two species and their variations for the moment. 

It's Not Just Butterflies

Many animals have a black variation (morph). I listed a few of them here.