Record #210575

Turkey Vultures warm their wings on a cold morning at Bombay Hook NWR, Delaware (3/2/2008). Note that these birds are molting their primaries (and primary coverts), their outermost flight feathers. The ten primaries are numbered from the innermost to the outermost, from P1 on the inside to P10 on the outside. (I usually find it easier to count backward from the outside in.) This is also the order in which the feathers are replaced during molt. The fresh, darker feathers have just come in, while the worn lighter feathers are yet to be replaced. The center vulture has molted P1 to P3. Not only is molt an interesting part of birds' lives, but it can also be critical in identifying rarities.