A molecular phylogeny of the blackbirds (Icteridae): Five lineages revealed by cytochrome-b sequence data

New World blackbirds (Icteridae) have long served as model systems for stud ies of avian ecology, evolution, and behavior. However, this work has been conducted in the absence of a strong phylogenetic hypothesis for the group. We sequenced 890 base pairs (bp) of the mitochondrial cytochrome-b gene fo r 28 of the 29 icterid genera and subgenera recognized by Blake (1968). We found strong evidence of five lineages of blackbirds: grackles and allies; caciques and oropendolas; orioles; meadowlarks and allies; and a monotypic cup-nesting cacique lineage. However, we found little support for any furth er structure among these five lineages and no strong evidence supporting ic terid monophyly. Our results set the stage for forthcoming work on relation ships within lineages and for higher-level studies that address blackbird m onophyly and relationships among lineages.