Tuesday, July 24, 2012

Dowitcher Identification by Shape

With species as similar and variable as the dowitchers it is sometimes more useful to use field marks that are not as variable, in the identification process.  This includes the shape of both the body and bill.  The differences in shape are usually apparent in the field and with enough experience you should be able to identity lone dowitchers, if you have a good enough look to note the shape of the body and bill.

A quick guide to the dowitchers.
Click on the image to make it larger.  

Body Shape

The most obvious shape difference is the back shape when the birds are feeding.  The Long-billed has a much more rounded back and looks more plump than the Short-billed Dowitcher (SBDO).  The SBDO is slim and has an overall attenuated appearance while the Long-billed Dowitcher (LBDO) is plump.  As always, there can be overlap but this is the norm.

Bill Shape  

The bill shape and thickness are also distinguishing features.  The bill of the LBDO is slimmer and straighter on average while the bill of the SBDO is thicker and usually has a slight dip near the end of the bill.  LBDOs can also look as if they have a slightly decurved bill but it is not just a slight droop near the tip of the bill like the SBDO shows.


These differences in shape are usually noticeable from a long distance, such as across a mudflat, and can be used to identify birds of all ages and in all seasons.

In a later dowitcher identification post, I will explain differences in plumage and voice that are also useful when identifying the dowitchers.

-Eric

1 comment:

Dan Huber said...

very helpful post