Male: Every marking on the Black Breasted finch is altered in some way. The cheek patches are enlarged, feathering at the outer edges. The tear mark is missing. The flank spots are elongated and enlarged, sometimes to the point that it looks as though the flank has been replaced with chestnut colored spots or streaks. The upper tail coverts are buff colored and the tail bars are elongated so that they run vertically on the tail coverts (see below). The breast bar is enlarged, giving the mutation its name. Often, there is also some orange or white lacing on the wings.
Female: The tear mark is missing and the rump and tail are buff colored like the males (see below). As with the males, there can be some orange or white lacing on the wings.
Fledgling: Black Breasted chicks can be identified in the nest. They resemble females with buff cheeks and tail coverts. The tail lacks the bars. They look a little like Penguin Zebra finches.
Black Breasted chicks in the nest (click to view)
Black Breasted Black Face fledgling (click to view)
Black Breasted Zebra finches - Male (L), female (R)
Male: Males that are split for Black Breast can often show many signs. The cheek patches can be enlarged, the flanks spots can be oval in shape, the tear mark can be thin and reduced and the tail bars will have an 'hourglass' shape to them (see below)
Female: The tear mark is often reduced and the tail bars have the same 'hourglass' shape of males that are split for Black Breast.
The Tell Tale Tail - Black Breasted split (left), full Black Breasted (right). Both are fawns and the right is also an Orange Breast.
The Black Breasted mutation is like hot sauce. If you like it, it goes with just about everything! Since it alters the shape of the markings, it does not conflict with other mutations that change the color of the mutation. For example, it can be combined with the Orange Breast mutation to change the now enlarged breast bar to orange or the Lightback mutation to create large dilute cheek patches. It is often used as a 'key ingredient' in many combination mutations. When combined with the Florida Fancy mutation, the resulting bird is often referred to as a 'Phaeo'. When combined with the Orange Breast, Black Face and Florida Fancy mutations, the resulting bird is orange colored from its head to vent. Just the wings are white with lots of orange lacing. Quite attractive. Another combination that is attractive is Black Breast and Penguin. This creates a Penguin Zebra with enlarged cheek patches. The Penguin mutation will suppress the breast bar to create the white breast. As a result, some breeders have been calling the combination an 'Orange-headed Penguin', because the genetic name Black Breasted Penguin is something of a misnomer since there is no 'black breast.'
I have also been breeding birds to combine the black Breasted mutation with the other 'black' mutations - Black Face and Black Cheek. The Black Breast Black Face combination (BFBB) is really attractive with lots of orange and black on the bird. An unusual thing occurs with the Black Breast Black Cheek combination however. The cheek patches are not enlarged as you would expect them to be with any BB combination. The flanks, breast and tail all have Black Breast characteristics, but not the cheeks. This apparently applies to both sexes, although I have not produced BB BC females yet. The suppression of the enlarged cheek patch seems to also apply to the Fawn Cheek mutation as well.
Lightback Black Breasted combination (Male)
Black Breasted Fawn (click to view)
Black Breasted Fawn female (click to view)
Black Breasted Black Face (click to view)
Black Breasted Black Face Fawn (click to view)
Black Breasted Lightback (click to view)
Black Breasted Black Cheek (click to view)
Black Breasted Black Cheek Black Face - 'Triple Black' (click to view)
Black Breasted Silver Isabel - (click to view)
Black Breasted Florida Fancy - 'Phaeo' (click to view)
Black Breasted Orange Breasted (click to view)
Black Breasted Orange Breasted Fawns (click to view)
While it is possible to produce Black Breasted males with black from the beak to the breast bar, they usually have a white chin with some 'pearling' in the upper breast. When combined with the BF mutation, more males are produced that have the black that goes from beak to vent.
There seems to be an inverse relationship between the size of the cheek patch and the size of the breast bar. Those that have large cheek patches, often do not show the largest breast bars and the reverse holds true as well.
While it is an advantage to be able to visually identify birds that are split for Black Breast, these altered markings can be considered faults on the showbench for birds entered as normals, yet not strong enough for them to be entered as Black Breasted either.