Rainbow Duck and the Burglar Birds

Book two in the Troll Stories series, about seven rainbow coloured trolls, various other unusual creatures, granny Besti, her dog Lula and her grandchildren.
One day Blue Troll, Yellow Troll and Water Troll go to visit Rainbow Duck. They come to the stream but Rainbow Duck isn’t there, and her nest is all torn and broken!
Beside the nest is a little red troll, and she is crying.
‘Help, help!’ cries Red Troll, ‘Something terrible must have happened to Rainbow Duck. Look at her nest! It’s all in a mess, and Rainbow Duck NEVER leaves her nest in a mess!’…
Blue Troll, Yellow Troll, Water Troll and Red Troll all set off in different directions to look for Rainbow Duck.
What has happened to her and where can she be?