================+=========+=========+=============+=============
Number and Sex | Wing | Tail | Culmen | Tarsus
----------------+---------+---------+-------------+-------------
7 adult males | 80 | 89 | 15.5 | 23.3
| (77-83) | (85-94) | (14.5-16.0) | (23.0-24.0)
| | | |
7 adult females | 77 | 86 | 15.5 | 22.5
| (76-79) | (83-88) | (14.5-15.0) | (21.7-23.0)
----------------+---------+---------+-------------+-------------
_Specimens examined._--Total number, 18 (9 males, 9 females), as
follows: Palau Islands, USNM--Koror, 2 (Nov. 6, 18)--Babelthuap, 1
(Nov. 27)--Peleliu, 4 (Aug. 29, 30, 31); AMNH--exact locality not
given, 11 (Nov., Dec.).
_Molt._--Some of the birds taken in August are in molt. Specimens
taken in November and December are mostly in fresh plumage.
Apparently this bird molts in late summer and early fall.
_Remarks._--In 1945 the NAMRU2 party found the Palau Fantail in small
numbers at Peleliu, Garakayo and Ngabad. At Peleliu the birds were noted
as singles or in pairs in brushy undergrowth in forested areas. The
birds were observed also in the second growth vegetation in the battle
areas. Coultas (field notes) found the bird to be rare and restricted to
the true forest, when he visited the Palau Islands in 1931. The fantail
is one of the most attractive birds found in the jungles of the Palau
Islands. Its bright rufous coloring is conspicuously displayed by the
rapid movements of the wings and tail as the bird moves and feeds in the
undergrowth. The population is apparently not large, and the individual
or pair of birds probably ranges in a relatively large home territory.
_Evolutionary History of Rhipidura in Micronesia._--The evolutionary
history of _Rhipidura_ in Micronesia has been studied considerably more
than that of some of the other genera in the area. Oustalet (1896:70)
notes a close relation between _Rhipidura_ of the Marianas and _R.
rufifrons_ of Australia. Mayr (1941b:202, 203) regards the genus
_Rhipidura_ as typical of the Polynesian area and remarks that
speciation within this genus has proceeded at a relatively rapid rate.
Mayr and Moynihan (1946) have devoted a 21-page paper to a thorough
discussion of the _R. rufifrons_ group, based on the extensive
collections at the American Museum of Natural History. They remark that
no other genera are closely related to _Rhipidura_ and that evolution
has proceeded further in _R. rufifrons_ than in any other species of the
genus. These authors regard the Papuan area, probably New Guinea, as the
original home of this group. From their study they point out that many
of the subspecies of _R. rufifrons_ of the Papuan area, especially those
of the Louisiades and the Solomons, appear to be the least specialized
of the species, and that this lack of specialization in these subspecies
indicates that the ancestral stock of the species _R. rufifrons_
acquired its specificity somewhere in that area. With regard to the
kinds of _Rhipidura_ in Micronesia, Mayr and Moynihan (1946:fig. 2) have
logically found three separate colonizations within the area: one
represented today by _R. lepida_ at Palau; one of subspecies of _R.
rufifrons_ at Yap and in the Marianas; and one by _R. r. kubaryi_ at
Ponapé.
_R. lepida_, according to Mayr and Moynihan (1946), is a result of an
early colonization by _Rhipidura_. It is related to _R. dedemi_, _R.
superflua_, and _R. teijsmanni_, which are mostly monotypic or have only
two or three subspecies within the species. These three species are
found in the region including Celebes and the Moluccas. _R. lepida_
apparently invaded the Palau Islands from Celebes or an adjacent area
and, among named species, most closely resembles _R. teijsmanni_. Both
of these species have a white chin and throat, black breast patch, and
rufous abdomen. _R. lepida_ has become differentiated chiefly by the
presence of a rufous head and back, a more distinct breast band, and
proportionately different amounts of rufous and black coloration of the
tail feathers.
Mayr and Moynihan (1946:6) give as the chief characters of _R.
rufifrons_ the following: "a rufous forehead, a grayish brown head and
upper back, a well-defined rufous rump, a white chin and throat, a black
breast band with scaling at its lower edge, and a dark brown tail with a
distinct rufous base and a white tip." The Micronesian subspecies of _R.
rufifrons_ at Yap and in the Marianas display these characters. Of the
four subspecies found in the area including Yap and the Marianas, _R. r.
versicolor_, _R. r. saipanensis_, _R. r. mariae_ and _R. r. uraniae_,
the two first named most closely approach the ancestral stock, which may
have been _R. r. commoda_ Hartert of the northern Solomons or some near
relative in Melanesia. The amount of white on the chin and throat and on
the malar stripe, in _R. r. versicolor_ and _R. r. saipanensis_ is
probably nearer that which obtained in the ancestor. At Rota, _R. r.
mariae_, exhibits less white on the throat and a thinner, white malar
stripe, while at Guam, _R. r. uraniae_ possesses only a small amount of
white on the chin and only a very thin line of white in the malar
region. This variation in coloration suggests that the birds may have
originally become established at Yap, Saipan and Tinian and later, birds
from Saipan and Tinian spread to Rota and lastly to Guam.
_R. r. kubaryi_ of Ponapé, although considered as a subspecies of _R.
rufifrons_ by most workers, has lost the rufous coloring found in most
members of the species. Mayr and Moynihan (1946:6) point to its
evolution through subspecies in the Santa Cruz Islands, where in _R. r.
agilis_ Mayr the rufous of the lower back is restricted to the upper
tail-coverts, and in _R. r. melanolaema_ Sharpe and _R. r. utupuae_ Mayr
the rufous is absent. In the latter two subspecies, as well as in _R. r.
kubaryi_, the forehead is white instead of rufous.
The invasion of Micronesia by _Rhipidura_ has undoubtedly been the
result of abnormally long flights by a relatively weak flyer. The fact
that _Rhipidura_ has succeeded in establishing itself at only a few of
the seemingly suitable islands in Micronesia may indicate that the
possibilities for chance migration and resulting colonization are small,
but that new colonization may be expected in the future.
It is my opinion that the populations of _Rhipidura_, as I have observed
them in Micronesia, are small because each individual or pair of birds
is dependent on a relatively large area of woodland to satisfy its
habitat requirements, especially for food. This suggestion needs to be
tested by observation made in the field. In comparison with the insect
fauna of New Guinea or some other large island, that of Micronesia is
indeed small in number of kinds. Hesse, Allee and Schmidt (1937:524)
explain the absence of insectivorous animals such as "swallows, swifts,
flycatchers, and insectivorous bats" in island communities on the basis
of the small number of flying insects in these communities. Probably
_Rhipidura_ is able to forage for sedentary insect life as well as for
the flying forms.
=Metabolus rugensis= (Hombron and Jacquinot)