We completed our troll hunt! This is Vashon Island's Oscar the Bird King.
Here's a list of all 5 Seattle-area trolls and where to find them:
1️⃣ Bainbridge Island: Sakai Park, about a mile north of the ferry terminal
2️⃣ West Seattle: Lincoln Park, next to Colman Pool
3️⃣ Issaquah: Rainier Trail, a 3-minute walk from the Issaquah Community Center
4️⃣ Ballard: In front of the National Nordic Museum
5️⃣ Vashon: Next to the upper parking lot at Point Robinson Park
Here's a link to my story about the troll project for Seattle's Child.