Doug5

100% yes. There is a twin of this bird at Stow lake in San Francisco! Normally full adults don't show barred. Those with dusky change to looking all black (or whatever background color is) by 4-5 months or so. Those with wildtype (4-spot when viewed from above, line posterior from eye) last with hints of barring longer. I've seen several birds myself and online that show hints of barring on the lower side just like this bird. I am unsure if they have some other gene influencing how long the barring lasts or not. The bird at Stow lake also has the white on the back. Possible that these birds could be Loonies (barred + brown-rippled, named because pattern reminded Dr. Hollander of the adult Common Loon) but such a combo is rare given its a double homozygous recessive. I've never knowingly seen a Loonie adult.

Mature female (condition of caruncles and white wing patch). Showing whitehead and barred phenotypes. Probably wildtype (spotted, not atipico=dusky) as juvenile, otherwise the barred phenotype would only be observable with underwing feathers at this age.

Adult female domestic (thus feral) muscovy duck. Amount of caruncling on head and especially full white wing patch indicate fully adult (past 18 months old). White on head is most probably the whitehead gene (dominant mutation, genotype C+C or CC, C=Canizie because mutation originally described in Italy by...Avanti?...can't rememer...in the 50's). She is fanning her primaries and tail feathers a bit probably to dry them, photo may have been taken while she was preening.

Also muscovy ducks have a 35 day incubation period during which they don't usually get off the nest for long.. This countdown doesn't start until after the last egg is laid. If you can't still see her in the cavity then the probability is that either the nest has been raided or the eggs have hatched. If she is still there do you know how long she has been sitting?

Hmmm, if eggshells are smashed then predation or young hens not very good about where they lay. If eggshell mostly intact with 1/3 large end popped off then ducklings could have hatched but I would think shells would have stayed in nest cavity (hen will eat some shells to regain calcium lost when eggshell made). Muscovy ducks and their closest living relative the Wood Duck both have same juvenile pattern (eyestripe posterior of eye only, in 4-spot wildtype pattern) and both have needle-sharp claws to climb out of nest cavity and then leap to ground without harm because they are so light. Commercial hatcheries sometimes hand drop the ducklings or they try to climb out of their enclosure for their jump! Check out youtube there are some cool videos like http://www.youtube.com/watch?v=s2cWIqDpH...

Juvenile barreds are yellow with colored tails. Color of tail will be color of adult. Because there are non-barred ducklings visible (and because barred is recessive) there must be at least 2 males involved in this clutch...and/or more than one female as egg dumping or nest takeover can occur. Let us know how they do. My bet is that the cavity nest is at high probability of getting raided by a raccoon.

So cool! Muscovies are tree cavity-nesters but most domestics make do with nests under something on the ground. Young female with wildtype (nonatipico) juvenile pattern as the barring is still somewhat apparent on chest sides. She shows barred and whitehead domestic mutant color effects (recessive and codominant respectively). Can you tell more about the circumstances? Around a lake? Farm?