title: Dramatic niche shifts and morphological change in two insular bird species.
abstract: Colonizations of islands are often associated with rapid morphological divergence. We present two previously unrecognized cases of dramatic morphological change and niche shifts in connection with colonization of tropical forest-covered islands. These evolutionary changes have concealed the fact that the passerine birds madanga, Madanga ruficollis, from Buru, Indonesia, and São Tomé shorttail, Amaurocichla bocagii, from São Tomé, Gulf of Guinea, are forest-adapted members of the family Motacillidae (pipits and wagtails). We show that Madanga has diverged mainly in plumage, which may be the result of selection for improved camouflage in its new arboreal niche, while selection pressures for other morphological changes have probably been weak owing to preadaptations for the novel niche. By contrast, we suggest that Amaurocichla's niche change has led to divergence in both structure and plumage.
authors.affiliation: Swedish Species Information Centre , Swedish University of Agricultural Sciences , PO Box 7007, Uppsala 75007, Sweden ; Key Laboratory of Zoological Systematics and Evolution , Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District , Beijing 100101, People's Republic of China.
authors.forename: Per
authors.identifier: 0000-0001-7182-2763
authors.initials: P
authors.lastname: Alström
authors.affiliation: Center for Macroecology, Evolution and Climate at the Natural History Museum of Denmark , University of Copenhagen , Copenhagen, Denmark ; Department of Life Sciences , Imperial College London , Silwood Park Campus, Ascot SL5 7PY, UK ; Department of Life Sciences , Natural History Museum, Cromwell Road , London SW7 5BD, UK.
authors.forename: Knud A
authors.initials: KA
authors.lastname: Jønsson
authors.affiliation: Center for Macroecology, Evolution and Climate at the Natural History Museum of Denmark , University of Copenhagen , Copenhagen, Denmark.
authors.forename: Jon
authors.initials: J
authors.lastname: Fjeldså
authors.affiliation: Department of Animal Ecology , Uppsala University , Norbyvägen 18D, Uppsala 75236, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Ödeen
authors.affiliation: Department of Zoology, and , Swedish Museum of Natural History, PO Box 50007 , Stockholm 10405, Sweden.
authors.forename: Per G P
authors.initials: PG
authors.lastname: Ericson
authors.affiliation: Department of Bioinformatics and Genetics , Swedish Museum of Natural History, PO Box 50007 , Stockholm 10405, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Irestedt
keywords: adaptive change; morphological divergence; niche shifts; speciation