Wednesday, May 25, 2016

Chuck Island, The Northern Range of Chuck-Will's-Widows

It's almost Memorial Day, which reminds me that chuck-will's-widows, Caprimulgus carolinensis, are sitting on eggs or have possibly already left their "nest" with fuzzy chuck chicks.  Its really not much of a nest since they simply lay their eggs on the leaf littered ground.  Soon after hatching, the chicks are on the move.  This leaves very little time to observe these large nightjars, kin to whip-poor-wills, while sitting on eggs. 

Chuck-will's-widow on eggs.
Chuck-will's-widows are a rare breeding bird in Ohio. The only place it annually breeds in Ohio is in or near the Ohio Brush Creek valley of Adams and possibly Highland County.  Occasionally, these birds show up elsewhere in the state, but for some reason, this valley bordering the preserve, supports a large population which is the only reliable place in Ohio to hear, or if you're lucky, see a chuck.

Amazing camouflage of a Chuck-will's-widow on the ground.
 Even though they are large birds (up to a foot long), they are incredibly difficult to see while on the ground.  So difficult, that the few times I've stumbled upon one on eggs, I almost stepped on the bird before he/she flushed.  I say he/she because a few years back, a student named Ryan O'Conner was researching chucks on the preserve and captured this video of a male flying in and swapping duties with a female already sitting with chicks.  Until then, it was unknown that males played this role.  The video below shows the male flying in and the chicks moving underneath the male.

Typical "nest" and 2 eggs of chuck-will's-widows.  (Photo by Rich McCarty)
Chuck-will's-widows feed on moths at night.  Its mouth is very large and the beak is rimmed with bristles that act as a basket to help catch moths as they intercept them in mid air.  There are even reports of chuck's being able to catch and eat small birds with this large mouth.  The video below, also captured by Ryan O'Conner, shows the size of the birds open mouth.  If you've never heard the song of the chuck's, I added the song to this video of a bird I recorded this 4th week of May in the Ohio Brush Creek Valley.

Never wanting to disturb the chuck on its eggs, photos can be taken through a scope from a safe distance.
Roosting near the barrens during the day, if you're lucky, you might find one sitting on a tree. Can you see the bird in the middle of the picture? (Photo by Rich McCarty)
It is somewhat of a mystery as to why chucks choose this valley over the rest of southern Ohio.  Why haven't they been breeding in the hills surrounding Scioto Brush Creek of Scioto County for example?  I have one theory and it has to do with their nesting preferences. These birds almost always seem to nest around the same kind of habitat.  This habitat is about the same elevation due to the geology of the area.  It seems they are always near a post oak (Quercus stellata) or blackjack oak (Quercus marilandica) barren, and they lay eggs somewhere near the edge of these barrens.  There are a lot of these barrens around the Ohio Brush Creek valley, but not around valleys in the surrounding counties.  In fact, if you go across the river, south into Kentucky, you would have to travel at least 100 miles before you get into chuck-will's-widow breeding territory.  So we really do have a small island of chuck-will's-widow's breeding in southern Ohio. 

Posted by: Mark Zloba