Another Example of Nest Sharing by American Robins and Gray Catbirds

Abstract - In June 2020, we monitored a nest in Southampton, MA, that contained 2 Dumetella carolinensis (Gray Catbird) and 3 Turdus migratorius (American Robin) eggs. Females of both species alternately incubated the mixed clutch, and 2 catbird and 2 robin young successfully hatched and fledged from the nest. Adults of both species provided both intra- and interspecific parental care (e.g., nestling provisioning, brooding, and nest sanitation). The catbirds, in particular, often did not preferentially provision their own young. In fact, following earlier fledging of the catbird young, an adult catbird continued to visit the nest to care for the robin nestlings, including fecal sac removal on at least 2 occasions. After the 2 robin young fledged, we did not observe any crossover post-fledging care. Our study represents the most detailed and protracted account among the very few documented cases of nest sharing between these species.