adult

1 week

A while back we had some problems with our old strain of black runners. A couple of the ducklings turned out a dark brown colour rather than black. After a few weeks of wondering whether we had fawn, chocolate or something else it began to dawn it was 'something else'.

The juvenile moult uncovered birds that looked like trout runners without eyestripes (below) with strong black chevrons on a light brown background. Sadly the 2 ducks were from an incubator hatch that had humidity problems and had to be put down at 4 weeks due to brain damage we had no females to compare development.

I contacted Mike Ashton who has a great interest in and knowledge of duck genetics and he identified the chromotype as 'dusky mallard' (md md). Later on we confirmed they were 'Light duskies' (md md li li), very similar to trouts (M+ M+, li li). The main differences are:

grey bill and webs

lack of neckring

green/violet speculum (wing flashes - trouts' are blue)

This is infact the colour that underlies many of the non-mallard colours, and may infact be present in epistatic blacks and white. With regard to the latter this colour reveals itself when and impure black-looking bird is bred with another. Then, in accordance with the laws of Mendel, 1/4 of the offspring will be true black, 1/2 impure black adn 1/4 dusky mallard. I finally worked out that my original stock must have consisted of pure black ducks but an impure black drake. Their breeder was unaware of this as she had been using the same (presumably pure) black drake with various ducks and had never tested the offspring.

Despite the disappointment of having to start again with the blacks, I was quite keen to keep and experiment with the duskies. I kept one of the impure females and the dusky drake. Sadly the drake died soon after in a fox attack, and we lost the duck later too.

juvenile moult