paintbrush used for clouds:

http://www.youthedesigner.com/2010/07/08/31-sets-of-free-photoshop-paint-brushes/


Clouds used for first drawing...

http://www.publicdomainpictures.net/view-image.php?image=12630&picture=clouds&large=1
 

Image used for making bird.


http://www.flickr.com/photos/reemul/5796585687/sizes/m/in/photostream/

Sketch

Finished Bird: