The Bear's Water Picnic (John Yeoman) Paperback / softback

 The bear has organized a picnic on the river for his friends.  It's the perfect day and everything is going swimmingly until they are disturbed by a loud croaking noise from among the lily pads.  It's the frogs!  They want to join in, but the friends don't fancy putting up with the noise, so they move on to a quieter part of the lake.  Unfortunately they soon find themselves stuck on a sandbank, and only the frogs can help them!