First description of nest and nesting behavior of the Nightingale Wren

Nests and nesting behavior of the Nightingale Wren (Microcerculus marginatu s) in Panama are described. Two nests were found at the ends of horizontal burrows in dirt banks, presumably excavated by other species. The nest cham bers were lined with dead leaf fragments. Clutch sizes were two and three e ggs. Incubation period was 19 or 20 days for one nest, and the nestling per iod was 16 or 17 days for the second nest. A comparison of nests in the Tro glodytidae shows the nests of M. marginatus to be most similar to those of the genera Salpinctes. Catherpes, and Hylorchilus, all of which are seconda ry cavity nesters. If nest type is a phylogenetically conserved characteris tic, then these four genera may be more closely related than is reflected i n current classifications.