Mr Hare........

........thought he was invisible in the long grass!!
 The little plover chicks were all too easy to see, whilst their frantic parents  put on aerial displays in an attempt to draw my attention.
The skylark was quite unconcerned and boldly looked me in the eye :-)  
And in the dusk (at 11pm! ) the drumming snipe are hard to see !

But the masters of invisibility are those bloody corn crakes that creck-creck all night long and nobody  ever sees them !!