So, I now have a pair of mini bulldozers to add to my owl girl. I think that's enough to get my imagination working.

How about you? Can you feel a story coming on? Can you think of a way of linking the owl girl with the bulldozers? If not, try answering these questions:

1. Is the owl girl a goody or a baddy?
2. Are the bulldozers goodies or baddies?
3. Is the owl a regular owl or does it have any special powers?
4. Does the girl have any special powers?
5. What are the bulldozers doing?
6. Does the girl want to stop them?
7. How will she stop them?

If your imagination is anything like mine, you may have come up with a plot something like this:

The bulldozers are clearing a wood in preparation for the building of a new road.
The girl is concerned about all the creatures which live in the wood.
With the help of her friend, the owl, she decides to stop the bulldozers and save the wood.

This sounds like a good plot.
Apart from a good plot, a story must have a good beginning. If your readers don't like the beginning of your story they'll go away and look for something more interesting to do such as picking their spots or scratching their armpits.
Try this for an opening:

Susie stirred. Her eyes flickered open and, for a moment, she wondered where she was. What was that noise? The usual silence of the garden was being shattered by the roar of engines and . . .
And something else!
There was a crashing sound as if something heavy was being pushed over.
Susie swung her legs over the side of the hammock and nimbly jumped down onto the lawn.
She listened again but couldn't decide what was causing the din. Putting two fingers to her mouth, Susie let out a piercing whistle. Once, twice, three times she called.
A moment later a dark shadow swooped silently through the trees and settled on her outstretched arm.
Hunter, she said to the owl, what's making that dreadful noise?
Hunter blinked sadly.

Does that make you want to read on? I hope so!
I've an idea. Why don't you write the rest of the story?