This quick gesture sketch captures the pose and approximate markings, though the outer edges of the wren's tail are white--I missed that!
If you've ever heard of Thomas Bewick, artist/naturalist and wood engraver (and if you're a birder you'll remember Bewick's Wren and perhaps Bewick's Swan, though he also illustrated a book on quadrupeds and did a great many humorous illustrations as well), you'll enjoy this post by Katherine Tyrrell on her terrifically helpful blog, "Making a Mark."
Here's a direct link to today's post--you'll enjoy it!
More on the artist from the Bewick Society, http://www.bewicksociety.org/
Bewick’s Wren, known scientifically as Thryomanes bewickii, was collected by John James Audubon on its winter quarters in Louisiana in 1821. Audubon reportedly described this tiny bird and named for his friend, Thomas Bewick, a British engraver. It occurs in Great Britain and elsewhere, as well. Its range on the North American Continent ranged from southern Canada to Mexico, largely in the East to Midwest--we have them here in Missouri, but they're not as common as house wrens or winter wrens.