Birds in Molt

As far as I know, all songbirds change their feathers twice a year.  The early spring changeover is dramatic enough because new breeding season plumage is usually brighter and more colorful than the winter plumage was.  But most of the birds don’t look terribly ragged as they go through it.  The changeover from breeding season plumage to winter plumage is another matter.  It can be so dramatic that it can be difficult to identify well known birds when they are fully in molt.

Let’s start in spring up north.  Most all of the species are fully in their breeding season plumage – American Goldfinches being an exception.  More about them later.  (1) Here is a male Chestnut-sided Warbler in May in northern New York State.  Note its bright chestnut flanks and bright yellow crown.  

Fast forward to early August. (2) Here it is (or more likely its cousin) a few miles from where the first photo was taken.  The chestnut areas are minimal and dull.  Its crown is a dull yellow.  In a few more weeks, it will sport a new wardrobe that will be quite handsome but will not be quite as bold and bright as its breeding season garb.

Now back to goldfinches.  Their breeding season calendar is a good deal different from that of most songbirds.  When they arrive in the north country in spring, the males are approaching their bright yellow color.  (3) But it’s not quite there yet as late as May 27 when this photo was taken.  

By the time most songbirds have completed their nesting activities, goldfinches have yet to lay eggs.  Their breeding cycle isn’t over until late August.  And by the time warblers and most other songbirds have completed their molt, goldfinches have hardly begun.  By late September they are in full molt. (4) Here is a goldfinch taken on a late September day a few years ago that bears little resemblance to the one photographed in May.  

So, September in the north can be quite interesting for bird folks.  Migratory species that have mostly or completely gained their winter plumage are on their way south.  Many pass through that nested in Canada.  Some, like goldfinches, buntings, and catbirds lag behind as they progress through their molting cycles.  Add to all this the young of the year.  Their presence and their plumage is different from the adults of their species.  That can make bird identification quite interesting and challenging.  For bird folks, outside is still the place to be in the morning when the weather cooperates.