The Black and Yellow Mud Dauber (Sceliphron caementarium) is a sphecid wasp species that builds mud nests, often on man-made structures. It is not a particularly aggressive species, but it can sting if pestered. The mud dauber on the right was gathering mud near the banks of the Rio Grande at Bentsen State Park, Hidalgo Co., Texas, in October, 2009. This shot was taken with a Canon EOS 1D Mark III and an EF 300mm F/4 L IS lens and 2X extender.
The next three shots show a Black and Yellow Mud Dauber gathering mud at the edge of a water hole near Rio Grande City, Starr Co., Texas, in May, 2010. These images were taken with the same lens as the 1st image but with a Canon EOS 1D Mark IV body.
The mud dauber nest on the right was in Austin, Travis Co., Texas, in August, 2010.