John C. Landa Jr., “The Schulenbirder,” sends three photos that he took this past week. Landa can be found on Twitter, @Schulenbirder. The first photo is a green heron. These birds, which are seen in Schulenburg mainly from April through October, have a blue-green back and tend to crouch in vegetation, waiting for their prey. The second photo is a threesome of black-bellied whistling ducks with th…