The Black Catbird (Melanoptila glabrirostris) is a species endemic to the Yucatan Peninsula and Cozumel Island. The species is closely related to the North America’s Gray Catbird (Dumetella carolinensis), and together this clade is related to Caribbean mimids. We have studies its social ecology and breeding behavior on Cozumel and in the Sian Ka’an Biosphere Reserve in mainland Quintana Roo.
Our early field observations suggested that these catbirds occurred in some localities at very high density, and that they might have a complex social organization such as cooperative breeding (like the White-breasted Thrasher, a not-too-distantly related cousin). This turned out not to be the case. Rather, Black Catbirds can live at high local density without rigid territory borders, in a semi-colonial pattern.