R. K. Selander, 1954 C. chiapensis 6 3.5 mi. W Tonda', 100 ft., Chiapas March 21 A pair building a nest in 10ft acacia. Both birds carrying dry straw-like material in frequent trips to nest. Time 8:30 - 9:15 and more, Occasionally both birds sing together when they both are in the nest tree. Both birds fly up from the ground into the tail partially fanned out. Nesting material mostly long blades of grass and dried vines, Getting nest material either on ground or within 2 feet of the ground. Seen to be making trips to gather nest material together. Except for an occasional duet they are silent when gathering material. Heard a lone bird sing cha - clomp-clomp, cha - clomp-chomp in about fast waltz tempo. Last two notes are gurgling. This song was given from nest tree. Then the lone flew to the ground where the other joined her in a few moments. Counted 7 trips to nest in 5 minutes (both birds included). Other birds frequenting the same fence row are Deteros pustulatus, social flycatcher, grove-billed ani, an Empidonax, Cassiculus roraimensis melanchry flycatcher. Another pair seen 40 yards from the nest of the first pair. Seen foraging about leaves of mango tree high up in two huge trees. Two nests placed in a large bull-horn acacia - one well-built about 10 feet above ground and a partially completed nest 2 1/2 feet above it.