Partial Leucistic Red-breasted Nuthatch
On 2 January 2015, I finally got to see this little partially leucistic, male Red-breasted Nuthatch down in Fish Creek Park. I have added a previously posted photo of a "normal" male Red-breasted Nuthatch in a comment box below, for comparison.
"Many birders enjoy lifelong hobbies relying birds’ plumage alone to distinguish the hundreds of different species on their life lists, but not all birds have predictable plumage and conditions such as bird leucism can make identification more of a challenge.
Leucism is an abnormal plumage condition caused by a genetic mutation that prevents pigment, particularly melanin, from being properly deposited on a bird’s feathers. As a result, the birds do not have the normal, classic plumage colors listed in field guides, and instead the plumage have several color changes, including white patches where the bird should not have any; paler overall plumage that looks faint, diluted or bleached; or overall white plumage with little or no color discernable.
The degree of leucism, including the brightness of the white and the extent of pigment loss, will vary depending on the bird’s genetic makeup. Birds that show only white patches or sections of leucistic feathers – often in symmetrical patterns – are often called pied or piebald birds, while birds with fully white plumage are referred to as leucistic birds." From birding.about.com.
"An intense bundle of energy at your feeder, Red-breasted Nuthatches are tiny, active birds of north woods and western mountains. These long-billed, short-tailed songbirds travel through tree canopies with chickadees, kinglets, and woodpeckers but stick to tree trunks and branches, where they search bark furrows for hidden insects. Their excitable yank-yank calls sound like tiny tin horns being honked in the treetops." From AllABoutBirds.