There are some nice bird brushes for free over at Blendfu.com. The brushes are for Photoshop and Gimp.

These are great brushes if you are going for the splatter, spray paint, grungy or dirty style of design… Download your 8 Free High Resolution Brushes

This is a set of 8 high resolution Photoshop hand drawn floral brushes which are made with a quill pen and india ink. Download them from Room122