Duck Typing

I was reading a blog by Bill Venners about duck typing and kind of liked the following extract

...Don't check whether it IS-a duck: check whether it QUACKS-like-a duck, WALKS-like-a duck, etc, etc, depending on exactly what subset of duck-like behaviour you need...

Its funny how we advocate the same thing in Java in spite of being statically typed , when we talk about programming to interface not to implementation. As long as it QUACKS, WALKS like a duck, we shouldn't care about its type.