Stroke bird's markings (8)
I believe the answer is:
patterns
'markings' is the definition.
'stroke bird's' is the wordplay.
'stroke' becomes 'pat' (I have seen 'Gentle stroke ' mean 'pat' so perhaps 'stroke' could also mean 'pat').
'bird's' becomes 'terns' (tern is a kind of bird).
'pat'+'terns'='PATTERNS'
(Other definitions for patterns that I've seen before include "Designs, shapes" , "Guides for making something" , "Repeated decorative designs" , "Models for making things" , "'Models, blueprints (8)'" .)