The Papuan or Melanesian Region (New Guinea, Bismarck Archipelago,
Solomon Islands) has supplied to Micronesia its greatest number of
endemic land and fresh-water residents. Fifty kinds of birds belonging
to the following species reached Micronesia from Melanesia: _Nycticorax
caledonicus_, _Megapodius lapérouse_, _Ptilinopus roseicapillus_,
_Gallicolumba xanthonura_, _G. canifrons_, _Caloenas nicobarica_,
_Halcyon cinnamomina_, _Trichoglossus rubiginosus_, _Collocalia
inquieta_, _Edolisoma tenuirostre_, _Rhipidura rufifrons_, _Metabolus
regensis_, _Monarcha godeffroyi_, _M. takatsukasae_, _Colluricincla
tenebrosa_, _Aplonis opacus_, _A. pelzelni_, _A. corvinus_ (extinct?),
_Cleptornis marchei_, _Myzomela cardinalis_ (probably by way of Southern
Melanesia), _Rukia palauensis_, _R. oleaginea_, _R. ruki_, _R.
sanfordi_, _Erythrura trichroa_. The colonization of Micronesia by these
species has probably extended over a considerable period of time.
_Megapodius_, _Trichoglossus_, and _Aplonis corvinus_ may represent
older colonizations which have become well differentiated from the
ancestral forms; _Nycticorax_, _Myzomela_, and _Erythrura_ may have
become established later and have had "less time" to become modified
from the ancestral forms. Birds from Melanesia have reached Micronesia
probably by direct flight to the Caroline Islands. Aided by favorable
winds which blow from the southwest, south and southeast during the
period from May to November, birds, particularly the young of the year,
might conceivably be blown in the direction of the Carolines, where 57
percent of the birds derived from Melanesia reside. The Palaus are
populated with 15 percent, the Marianas with 28 percent, and the
Marshalls (lacking "high" islands) with none; these may be secondary
colonizations from the Carolinas excepting _Ptilinopus_, _Megapodius_,
_Gallicolumba canifrons_, _Cleptornis_, and _Colluricincla_. The
Marshall Islands have received no avian components from Melanesia. The
absence of "high" islands in the Marshalls and the possible inability of
birds accustomed to life on the luxuriant islands of Melanesia to become
established on relatively barren atolls are logical reasons for this.
Instead of New Guinea itself, the outlying islands of Melanesia
(Bismarck Archipelago, Solomons, Southern Melanesia) probably have been
the principal "taking-off" places for birds invading Micronesia.