This Robin and juvie photo was rejected. Can anyone help me out? I am new to stock contributors.

Lighting, contrast & colors need to be improved. 

Professional users want commercial quality artwork.

Read the 4-part section on Photography Requirements from your Contributor User guide, starting here:

https://helpx.adobe.com/stock/contributor/submit-your-content/submit-photos/photo-submission-overview.html

Also, compare your best work with similar content in Stock’s inventory to see what you’ll be competing with for views & sales.

https://stock.adobe.com/search?k=robin

https://stock.adobe.com/search?k=robin+bird

Hope that helps.