The purpose of this article is not to establish an unstoppable rule for the recognition of a gray male carrying the black breast mutation. Rather, it aims to gather clues that can help you identify it.
For this, each point of detail of the mutation is resumed, as I observed during the selection of my black chestnut strain.
Before starting to analyze each possible clue, it seems important to me to bear in mind that the black breast mutation modifies the shape of the drawings. To identify a carrier of the black breast mutation, I also advise you to take into account all the clues described in this article.
Let's proceed and analyze the phenotype of a gray, black-breasted head to the rectrices compared to a gray carrying the black breast mutation. To identify each descriptive terms used, you can use this diagram : Descriptive terms in zebrafinch.
1. Mustachial trait
Black breast (pn) : The moustachial line will be pronounced and intense black.
Black chest carrier (/ pn) : The moustachial line may be more pronounced than on a gray, however this does not constitute for me a sufficient index.
2. Tear Trait
Black chest (pn) : The line of tear disappears (ideally following the standard) or only a fine line remains.