Black and white ground dwellers

["Philip Veerman" <>]

Yes. It is a reasonably regarded as case of Muellerian mimicry. This refers to 
that these B & W passerines tend to be aggressive in nest defence and often can 
be found nesting in close proximity. Muellerian mimicry is well known among 
other groups of fauna, not too common in birds. The book by Chisholm is rather 
rambling but it comes up with several interesting ideas. Scientific writing is 
(hopefully) far more rigorous now, although given the time of his writing, he 
was probably well ahead of others in his thoughts. His book is findable at the 
occasional book fair.

Philip