Observation of the week – July 17-23, 2022

It’s time to highlight one of my favourite groups of butterflies – the hairstreaks. Last week in the Butterfly Blitz we saw two observations of Striped Hairstreaks, by Lorysa (@lorysa) and Kevin (@kkerr). We couldn’t choose just one, so we featured both: here and here.

At first glance, it may seem difficult to tell the Striped Hairstreak apart from similar species like the Banded and Hickory Hairstreaks. When you look closer, there are key differences in wing patterns – including the width of their bands and the size and arrangement of the grey/blue and orange spots. Striped Hairstreak has very wide wing bands, and an orange ‘cap’ on the blue/grey spot in the far corner of the hind wing.

Both Lorysa and Kevin found the input of others on iNaturalist to be helpful in their hairstreak identification. Lorysa says: “I don't know enough to narrow down to specific Hairstreak it was, but comments from other members of the iNaturalist society helped me learn how to tell this was a Striped Hairstreak.” And Kevin agrees: “I'm still relatively new to butterflies but I remembered reading your comments on how to distinguish species of hairstreaks from someone else's earlier submission, so the blitz has definitely helped advance my ID skills.

Hairstreaks in Ontario all have a little tail sticking out of the end of their hind wings. The combination of these tails, their hindwing spot patterns, and the way the butterflies rub them together, are used to fool predators into thinking there is a head on the butterfly’s wings. This trick seems to work, as it is common to see hairstreaks with a bit of their hind wing missing where a bird has taken a bite!

Striped Hairstreaks are usually seen in woodland openings and on forest edges. Like all hairstreaks, they spend a lot of time in the trees and shrubs where their caterpillars eat and only come out to nectar on favourite plants like milkweed and dogbane. Once they’ve landed to feed, it’s easy to get photos of them as they are not as skittish as other butterflies.

Both of these hairstreaks were observed while our Butterfly Blitz participants were out doing something else: Lorysa was doing a favour for a neighbour and Kevin was out for a walk with his kid. I love this kind of observation, as I’m also likely to notice butterflies at any time – my family knows that I’ve seen a butterfly if I randomly run away with my phone out. Once you start butterflying, it’s hard to stop. As Lorysa says: “Now I carry my phone at all times because you just never know when you'll see something.

Posted by lltimms lltimms, July 28, 2022 18:56


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