[Mystery bird] Green Heron, Butorides virescens, photographed at Brazos Bend State Park, Texas. [I will identify this bird for you in 48 hours]
Image: Joseph Kennedy, 2 July 2009 [larger view].
Nikon D200, Kowa 883 telescope with TSN-PZ camera eyepiece 1/320s f/8.0 at 1000.0mm iso400.
Please name at least one field mark that supports your identification.
Green heron (Butorides virescens). The black cap and reddish-brown neck are quite the giveaway.
I believe this is a Green-Backed Heron. Dark plumage on head could be greenish, with the brown cheeks/neck a dark chestnut coloring. The bill is long and slender, and appears to have the appropriate coloring dark up, yellow-ish lower. There also appears to be white on the "chin" or throat area which would be consistent with the Green Backed Heron.
I don't think it's a Chachalaca--wrong coloring, but the pictured bill is long and slender, and the Chachalaca has a curved bill.