Crested
A variant of Zebra finch (Taeniopygia guttata)
A trait producing a circular tuft of feathers on the crown. The crest is incompletely dominant and behaves like a lethal/semi-lethal when doubled.
Keeper tips for this variant
Genetics caveat: never pair crested x crested, as the double-crest combination causes high embryo/chick mortality; always breed crested to a plain-headed (non-crest) partner.