A Bird of a Different Color
In my position as ombudsman, I receive a number of photos from the public of unusual birds. Earlier this year, I received several contacts regarding northern cardinals with “bald” heads. There were no feathers on the birds’ heads, making their dark-skinned heads appear proportionately much smaller and their beaks larger--almost parrot-like. The condition can also occur in blue jays and possibly other species as well, but my contacts were from observers of bald cardinals. Apparently, the condition is temporary and occurs during the normal molting period, with some small number of individuals becoming temporarily bald. It may be exacerbated by the bird rubbing its head in response to the itching from lice. Normally a bird replaces its feathers sequentially during a molt, with no feathered portions of the body becoming bare.
Another bird anomaly is unusual colorations, ranging from true albinos to birds with overall pale coloration or particular areas being pale or white due to the lack of the normal pigments. Animals with darker pigments present, but dispersed unevenly or in lower amounts, are referred to as leucistic individuals. I received reports this year of leucistic northern cardinals, eastern bluebirds and the pileated woodpecker pictured above beside a normally colored bird.
Seeing the odd variations in bird appearances is a reminder of the role of genetics in the natural world. A species has been defined as a group of individuals that are more like each other than they are like any other individuals. That definition recognizes that no two individuals are genetically identical (with the exception of cloning), even within a species. The odd-looking birds give us a look at some of the extremes of variation within a species.