Saturday, April 2, 2016

(Lepidopteran) Signs of Spring

Here on the high desert of Oregon, the last few days have been warm and beautiful, with highs in the 70's. It's as though we left winter behind overnight. Oh, we'll still have some chances of (even significant) frosts, and we'll have to be diligent about protecting some of our sprouting plants from those. But it seems that every living thing recognizes that spring is here.

The Turkey Vultures and Osprey have been back for more than a week, after spending our winter months in South America and southern Mexico, respectively. Golden Eagles and Great Horned Owls have been incubating for weeks, and the pair of American Kestrels is staking its claim to the nest box in the juniper stump. But while those raptors--and birds in general--mostly key in on day length to guide the initiation of migration, courtship, and breeding, it is warm days like those we're now experiencing that bring about the awakening of insect life.

For me, spring really begins when the male Sara's Orangetips come out.

The first butterfly we see each year is usually a Mourning Cloak (Nymphalis antiopa). One of the few species to overwinter as adults in our neck of the desert, these showy insects can appear on even a February or late January day if the temperature rises high enough. But I know that we're in for a stretch of several nice days when the orangetips are on the wing.

Sara's Orangetips (Anthocaris sara) are small members of the Pieridae family, which contains the marbles, the whites, and the sulphurs. Males, like the one pictured above, appear in pretty large numbers on such warm March or April days as we've been having. And, as Jasper and I experienced yesterday, even on those first days they have seemingly boundless energy.

We were both armed with cameras, and while the primary goal was to monitor a couple of Golden Eagle nesting territories, the secondary goal was to get a picture of one of these small butterflies. Each time one of us locked on to one of them, it would lead us on a merry chase, in and out of the sagebrush, around and back again. Their flight was strong, never above a few feet off the ground, and wandering, not heading in a single direction or leaving the area. And though they frequently teased us by briefly hovering over a patch of phlox or other flower, they rarely alit. We followed one individual for more than ten minutes, without its ever landing, before it flew beyond the canyon rim and left us. It was Jasper who finally captured the pic above, as that one landed at his feet while he was busy chasing two others.

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