Puerto Vallarta, Mexico - As if Vallarta's birdlife wasn't fascinating enough, every so often a real doozy shows up. This time, one individual of the otherwise locally common Yellow-winged Cacique (Cassiculus melanicterus) has a yellow head and crest (both normally black), and has created quite a stir at the Vallarta Botanical Garden's feeders, which are stocked at 1:00 pm daily.

This freak of nature has bewildered more than a few birders; each with their own hypothesis: Is it a hybrid? An aberrant albino? Does it exhibit what's known as Xanthochromism (replacement of normal color by yellow pigment)? All of these hypothesis and more have been expressed. Nobody seemed to know.

I spend quite a bit of time photographing birds with aberrant plumage characteristics, so I've done quite a bit of research over the years on the subject, and discovered that many so called Xanthrochroistic birds are actually what is known as Schizochroic!

Gross (1965), in his paper on North American birds, writes "...[in] non-melanic schizochroic individuals, the absence of melanin in their plumage leaves caratenoid pigments, which might be yellow or red, phenotypically."

This applies to members of the American Blackbird family (Icteridae), especially, & caciques are members of that family. That's what can be observed right now at the Vallarta Botanical Garden. Those interested in observing this amazing bird and other incredible Mexican bird species are encouraged to contact the author/photographer, Greg R. Homel, at BirdingInPuertoVallarta.com or birdingadventures(at)mac.com.

Pending a more thorough examination of available literature, this may very well be the first-ever documentation of this spectacular schizochroic anomaly in the near-endemic Yellow-winged Cacique.