Coronation Day

Quick: What color is a Golden-crowned Sparrow’s crown?

As usual, it depends.

This one, photographed at Iona Beach, is wearing a particolored coronet, like many of its conspecifics this time of year. The dull gold is obvious on the forehead, but the rear crown between those huge black stripes seems to be white. How come?

It’s not the “h” word this time, but the “m” word: molt. The pre-alternate molt in this species, the molt that leads to alternate, “summer,” “breeding” plumage, includes all the feather tracts of the head, and in many birds it will still be evident through the end of April. What looks like white plumage in the crown is in fact the sheaths of pinfeathers still furled.

It’s evident that at least in this species, molt of the head proceeds from front to back.

Want to learn more about molt and what it can tell birders in the field? Steve Howell’s Peterson Reference Guide will be out next month. I’m reading the galleys right now, and can already predict with considerable confidence that that book, too, will be wearing a gold crown–as bird book of the year.