Ornithology, Evolution, and Philosophy 123

154 4 Ornithologist and Zoogeographer
Guinea and surrounding islands (568 breeding bird species in 1,400 forms of the
land and freshwater). Subspecies differentiation is conspicuous. For each form
the name is followed by reference to the original description, a complete list of
synonyms, and its range, and for each species there is a statement of habitat and
altitudinal distribution. Species limits employed are broad to express relationships
rather than differences among species and subspecies. Footnotes indicate which
species together form a superspecies. A gazetteer of reference maps and collecting
Fig.4.5. Distribution of the crow-sized Greater Birds of Paradise, Paradisaea apoda superspecies
of New Guinea (data from Gilliard 1969 and Cooper and Forshaw 1977). 1 P. rubra,
2 P. minor, 3 P. apoda, 4 P. raggiana, 5 P. decora. Adult males (illustrated) are maroon brown,
breast mostly blackish, crown and nape yellow with two elongated central tail wires (or
ribbons) and enormous flank plumes which are yellow (stippled) and white, orange or red
(shaded); females are very different, smaller and lack flank tufts and tail wires. Ernst Mayr
(1940c, 1942e) discussed geographical gradients in the color of back and flank plumes in
P. raggiana of eastern New Guinea which are probably due to southeastward introgression
of P. minor genes from the northcoastal lowlands. Hybridization (H) occurs in areas where
the mainland species meet. Note strongly differentiated species on small islands off the
coast of New Guinea near its northwestern and southeastern tips