Taking shape

How do I arrive at the design for a piece of grass stitching.

Assuming it is not a basket which i intend to make, the shape for which can be developed as I stitch the materials into a spiral form.
I am continuing a collection of birds which will sit on the edge of an old pram, their shapes are becoming like sacred ibis.(pictured here)
I caste my mind around for meanings in birds and there are so many but I wanted mine to be more or less alert to their task which is attending to a clutch of grass eggs.
So I am thinking birds alert, birds in various stages of perching, birds being inquisitive, birds having an hierarchy and so on.
I have decided to do the bodies and heads first, getting all the major foundation developed. Then when I am satisfied that the forms are as I want them then comes the actual attitude of each bird. How the wings sit, how the head is cocked, all things that make each form speak.
All the time i am attending to the crafting, stitching firmly, making the shapes solid.
These birds are going on a long journey. so their structure needs to be guaranteed not to shed grass or become soft.
This process indicates how any shape can be developed using a malleable fibre.