We were also in Sunriver last week and were amazed by the number of these butterflies. We floated the Deschutes and in places it appeared as if every blade of tall grass had one on it.
I saw 4 Nighthawks over the Sunriver poo ponds last night but overall were more scarce than usual.
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> On Jul 30, 2017, at 7:56 PM, Nicholas Mrvelj <nickmrvelj...> wrote:
> I spent some time in the greater Sunriver area myself this weekend. I can confirm seeing extraordinary numbers of California Tortoiseshells. During a hike around the Todd Lake area, we counted about 5-8 per second on average. All were heading in the same direction, often seeming to be at the mercy of the wind. Many perished on the roadways.
> Just south of Sunriver proper I saw 4-5 Common Nighthawks in flight each evening.
> Good birding,
> -Nick Mrvelj
>> On Sun, Jul 30, 2017 at 6:09 PM Larry McQueen <larmcqueen...> wrote:
>> Ok, this is not about birds, but something to behold in the Cascades right now. Nymphalis californica, the California Tortoiseshell, is now doing a mass movement. I have been on a family trip this past week, staying at Sunriver. We encountered thousands of these butterflies, first near the top of the McKenzie Pass and again on the Cascades Lakes Highway, south of the 3 Sisters. We found them in great numbers everywhere, all seemingly flying in the same direction, maybe down slope. This had to be a movement of the entire population (at least local), not millions, but billions of this species. Pyle describes this phenomenon in “The Butterflies of Cascadia”, as a release caused by a build-up of numbers over years, and then followed by scarcity for years. I don’t know how well studied this migration is, or where the butterflies end up.
>> This was not a birding trip, but I always love watching the Pygmy Nuthatches. Crossbills were common around Sunriver. There was a single Nighthawk on the entire trip, where there ought to have been many.