Esther Ehrlich 
Nest [EPUB ebook] 

I run all the way to my tree, so that once I get there, my body’s nice and warm. Most people would say it’s too cold now to hang out in a salt marsh, even with the sun and even with a baby blanket wrapped around me, but I’m not most people.
Eleven-year-old Naomi ‘Chirp’ Orenstein and her family live an idyllic life on Cape Cod on the east coast of America. Surrounded by sandy beaches, fresh air and wildlife, Chirp is free to roam as she pleases. But when Chirp’s mum is diagnosed with a life-threatening disease, her happy little world begins to collapse around her.
Chirp finds solace in her beloved birdwatching, and her friendship with mysterious outsider Joey. Chirp and Joey take on the world together, dreaming up a host of daring adventures. They explore the woods and the salt marshes – they want to see everything they can. But Chirp cannot keep running forever.