The only grackle I have ever seen with white feathers around the collar.
Well-known local birders Angel and Mariel commented as follows:
Great photo Tom, thanks for sharing. Leucistic birds always seem to generate lots of atte
ntion due to their different in appearance.
The Common Grackle in your photo shows a condition known as Leucism; which is also known
as pied or piebald some also refer to leucistic birds as dilute . Leucism results from de
fects in pigment cell differentiation during development, basically the pigmentation cell
s in a bird fail to develop properly. Leucism is often mistaken for albinism which result
s in the reduction of melanin production only, whereas leucism can cause a reduction in a
ll types of pigment.
Leucism usually affects portions of the bird where albinism always affects the whole bird
. Leucistic birds may also be affected over the whole bird but true albinos always have r
ed or pink eyes, bills, feet, and pink fleshy areas due to the lack melanin production wh
ereas leucism only affects the feather coloration. The eyes are not really red/pink but a
ppear to be due to the lack of melanin production in both the retinal and iris which allo
ws the underlying blood vessels to show through causing the appearance of red or pink eye
s. In contrast, leucistic birds have normally colored eyes, bill, and feet.
One interesting note about leucism is that the ratio of white to normal-colored feathers
can vary considerably not only between generations, but between different offspring from
the same parents.
Africa (entire continent rather than south of Sahara)
AN
Antarctica
AO
Atlantic Ocean
AU
Australasia (Wallacea (Indonesian islands east of Wallace's line), New Guinea and its islands, Australia, New Zealand and its subantarctic islands, the Solomons, New Caledonia, and Vanuatu)
PAL
Eurasia (Europe, Asia from the Middle East through central Asia north of the Himalayas, Siberia and northern China to Japan)
IO
Indian Ocean
LA
Latin America (Middle and South America)
MA
Middle America (Mexico through Panama)
NA
North America (includes the Caribbean)
NO
Northern oceans
OR
Oriental Region (South Asia from Pakistan to Taiwan, plus Southeast Asia, the Philippines, and Greater Sundas)