Here is that unique Yellow-rumped Warbler which I mentioned in a previous post. Can you see what looks different about it? I noticed it naked eye while tracking various subjects in a loose flock through the trees last week including more Yellow-rumps, Black-and-white Warblers, Blue-headed Vireos, and Blue-gray Gnatcatchers.
After I got my binoculars on it I realized this bird was partially leucistic, and I quickly raised my camera to snap off a record photo. Leucism in birds is when melanin pigments are produced at less than normal levels or in an unexpected pattern. In this case many of the feathers on the head of this bird do not have typical pigmentation as it lacks all of the cells a typical Yellow-rump would. It is likely at a disadvantage being more visible to predators and potentially less attractive to a mate. A bird’s plumage and the overall appearance of a species have evolved over thousands of generations, and a drastic alteration like this could mean a lot for an individual. Leucism may also leave the feathers more vulnerable to wear and tear. I wish this cute bird luck and safety in its journey north.
Scott Kruitbosch
Conservation & Outreach Coordinator
