Early Promise

The 2022 butterfly year in eastern Washington started with much promise. There were some warm days in February and I saw my first butterfly on the 11^th, an overwintered Milbert’s Tortoiseshell sunning itself at Waterworks Canyon west of Yakima. However, it was another month before I saw the first newly-eclosed Cabbage White and overwintered nymphalids like Hoary Commas, California Tortoiseshells and Mourning Cloaks were common around Yakima.

We had some warm weather in late March so a few other spring species started eclosing, including Beckers Whites, Large Marbles and Sheridan’s Hairstreaks. By early April they were joined by Silvery Blues, Gray Hairstreaks and Orange Tips. On April 7 at Snow Mountain Ranch, west of Yakima, I counted 45 individuals of 7 species of butterflies in 90 minutes. Of these, 20 were Sheridan’s Hairstreaks.

Return of Winter

Then the week of April 11-14 happened. I woke up on Monday April 11 to find three inches of snow on the ground. Okay, I thought, sometimes it snows in April (humming the Prince song), but it never lasts long…. Wrong! It snowed all day Monday and again overnight… and there was a further five inches by Tuesday morning. Snow continued on and off until Thursday April 14, when the temperature finally rose above 32F for the first time in four days.

We had a three-to-six inch blanket of snow covering the ground for three to four days. The snow then began to melt rapidly, but unfortunately the clearing skies ushered in some killing frosts. The temperature sank to as low as 23F for at least two nights.

The combination of prolonged ‘deep’ snow followed by rapid melting and very cold overnight temperatures, inevitably had an impact on plants and insects. However, most native plants coped fairly well beyond being flattened by the weight of the snow. The Desert Parsley at Snow Mountain Ranch was flat to the ground after the snow melted but still happily flowering! Balsamroot which had just begun flowering before the snow, suffered badly in some locations with flowers and buds destroyed by the cold nights. However, in protected locations, they survived well. Orchardists are waiting to see how much of the local cherry, apple and pear crops were affected.

On April 15, with the snow just melted, sun shining and temperature in the 50s, I checked Snow Mountain Ranch for butterflies. I saw just one Orange Tip. There was not a single Sheridan‟s Hairstreak to be seen.

At the time of writing, 10 days after the cold snap ended, the hairstreaks are still absent but the Beckers, Cabbage Whites, Marbles and Orange Tips are all flying in numbers again. All look very fresh and I suspect that all of them eclosed after the cold snap. The “tough” overwintered Mourning Cloaks, Tortoiseshells and Commas are still flying of course and were probably unaffected by the cold, since they likely roosted in bushes and trees and probably still had a little bit of overwintering antifreeze in their hemolymph.

Low-roosting butterflies like Silvery Blues and Sheridan’s Hairstreaks likely fared poorly, covered with snow for days then exposed to very low night temperatures. Fortunately, both of these species and in fact probably all early spring butterflies that eclose from overwintered pupae, have a staggered emergence pattern. Most Orange Tips, Marbles and Beckers Whites that were flying in early April, likely succumbed to the cold weather, but they have since been replaced by later-eclosing individuals. The same is hopefully happening with the Hairstreaks and Blues. Jon Pelham actually co-authored a paper years ago showing that staggered emergence was characteristic for populations of Sheridan’s Hairstreaks.

This is a classic example of “bet-hedging” where a species doesn’t put all of its eggs in one basket (so to speak), to ensure that a catastrophic event (like our mid-April snow and ice) doesn’t wipe out a species in an area.

What about Summer Butterflies?

April 2022 in eastern Washington was one of the coldest on record. Consequently, the progression of spring in terms of flowering plants and butterflies in the shrub-steppe will be delayed. By how much is still uncertain at the moment.

The butterfly formerly known as Lucia’s Blue started eclosing at Cowiche Canyon, Yakima on April 23, which is a good three weeks later than “normal”. I am guessing that most late spring-early summer butterflies in eastern Washington will appear two-three weeks later than the average appearance date. For example, Coronis Fritillaries, whose larvae were buried under the snow, will likely appear in late May/early June rather than early-mid May.

May will begin with substantial snow still present in mid to upper elevations. On April 25 the hills around Yakima are still snow-capped.  Consequently, mountain butterfly populations will likely also be delayed by two to three weeks, maybe more. Fortunately, our Blue Mountains WBA conference this summer is scheduled for mid- July which should be early season for mountain butterflies!

Return of the Monarch!

One butterfly that I am predicting will appear on schedule this summer is the Monarch! For about 15 years, until 2016, Monarchs unerringly appeared in numbers in Washington during the first week of June. Since 2016, the number of Monarchs migrating into Washington from California each summer has been pitifully small. 2022 will be different!

The size of the overwintering population of Monarchs in California in 2021/22 was the largest since 2016 when many were seen during summer in Washington including a population of about 300 at Lower Crab Creek. At the time of writing, the offspring of overwintered Monarchs are beginning to eclose in California and will be heading north during May and into June. I predict we will see a “wave” of Monarchs entering Washington during the first week of June.

If the wave is strong enough, some of those Monarchs should establish the first summer breeding population at Lower Crab Creek for four years! If this eventuates, we may be able to hold the third WBA Monarch Tagging Day in late August!

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