How Butterflies, Hummingbirds & Pikas Brave Yellowstone's Harsh Summers | BBC Earth

Over 60 species of butterfly feed in Yellowstone each summer. But they're not the only ones searching for nectar. Hummingbirds are also fuelling up. Some have travelled from as far away as Mexico to be here. This Calliope hummingbird weighs just 3 grams, making him the smallest bird in North America. Rufous hummingbirds have also come here. This female has travelled over 2,000 miles to raise her chicks in the Yellowstone summer. But this year, even up at these elevations, temperatures have been higher than normal. Leading to stunted growth and fewer blooms for some flower species. Further up in the mountains, one very specialist mammal requires an abundance of this alpine vegetation. The pika. During winter, this whole area will be buried beneath 3 metres of snow. Rather than hibernate or migrate away, the pika will tough it out. So to make sure they have enough to eat, they spend the whole summer stockpiling food. It's a race against time to get the harvesting done before the short growing season comes to an end. Every journey means running a gauntlet of predators. And at the first sign of trouble, the alarm is raised. The pika's rather odd appearance is all about keeping warm. Their plump, round shape minimises their surface area. And thick fur covers their entire body. Even their toes. But being dressed for sub-zero temperatures can cause pika to overheat during the height of summer. So they can only survive at the very highest elevations.