=========+===========+===========+===========+=========+=========
| Number | | | Full |
LOCATION | and sex | Wing | Tail | culmen | Tarsus
---------+-----------+-----------+-----------+---------+---------
Guam | 9 males | 236 | 165 | 55 | 51
| | (229-244) | (158-170) | (51-57) | (49-52)
| 19 females| 227 | 151 | 50 | 50
| | (222-241) | (143-166) | (47-54) | (46-54)
| | | | |
Rota | 3 males | 235 | 167 | 54 | 50
| | (233-236) | (166-169) | (53-56) | (49-51)
---------+-----------+-----------+-----------+---------+---------
_Specimens examined._--Total number, 49 (20 males, 27 females, 2
unsexed), as follows: Mariana Islands, USNM--Guam, 26 (May 25, 29,
June 4, 7, 8, 9, 18, 28, 29, July 10, 12, 18, Sept. 5, 11)--Rota, 4
(Oct. 22, 25, 29); AMNH--Guam, 19 (Jan., Feb., March, Aug., Sept.,
Dec.).
_Nesting._--In the spring of 1945, the NAMRU2 party obtained
records of nesting activities by crows. One nest was observed on
March 8 in a banyan tree. Specimens collected from May to September
were not in breeding condition, and it is thought that the nesting
period is concentrated in the winter and spring months. Watson
(1946:41) reports finding a young crow being fed on May 8 by an
adult.
_Molt._--The Marianas Crow molts in the period from May to August
or September. Most of the birds taken by the NAMRU2 party in this
period were in the process of molt. Skins obtained at Rota in late
October also exhibit signs of molt. Specimens taken in December,
January and February are in fresh or slightly worn plumage. The
crow presents an exceedingly shabby appearance in molt, because the
grayish and whitish basal parts of the feathers are exposed.
_Food habits._--The crow is an omnivorous feeder. Stomachs
examined contained both plant and animal food. Both Seale
(1901:55) and Safford (1905:79) comment on the damage which the
crow does to the corn crop at Guam. Seale remarks that the crow
has a reputation for plundering nests of other birds. The NAMRU2
party saw crows being chased by starlings on several occasions.
_Parasites._--Wharton (1946:174) obtained the chigger (Acarina),
_Trombicula_ sp., from the crow at Guam.
_Remarks._--The Marianas Crow is confined to the forested areas and to
the coconut plantations at Guam. The birds were seen as singles or in
small flocks, often along the roadways. In a count of the number of
birds seen along the roadways of Guam, the author (1947:124) found crows
to constitute 2.4 per cent of the total population of birds counted and
observed the crow on 21.6 per cent of the 125 roadway counts made.
Coultas (field notes) noted the birds at the northern part of Guam. The
NAMRU2 party found the birds distributed in most parts of the island but
usually they were infrequent near areas where large numbers of service
personnel were stationed. The birds were often noisy when flying in
small flocks or in pairs; Seale (1901:55) also notes this. When observed
in jungle areas, the birds were generally quiet, feeding and perching in
dense foliage. At Rota, the NAMRU2 party found the bird to be fairly
numerous and with habits resembling those of the crow at Guam. No
differences in color or structure could be found between the specimens
of crows obtained at the two islands.
Kittlitz (1836:305) was the first person to write an account of the crow
at Guam. He called it _Corvus solitarius_ and remarked that he later
found the same species in the Philippines. Wiglesworth (1891a:46) also
considered the crow at Guam to resemble one found in the Philippines and
called it _Corone phillipina_. Later Reichenow named the bird _Corvus
kubaryi_ with the type locality as the Palau Islands. This locality
proved to be erroneous and the bird was judged to be from Guam by
Hartert (1898:59), who did not use the name _C. solitarius_ because it
was a _nomen nudum_, and recognized _C. kubaryi_ as the correct name.
_Evolutionary history of Corvus kubaryi._--Meinertzhagen (1926:59)
writes that "Environmental influences seem to be mainly, if not
entirely, responsible for geographic differences in the genus _Corvus_."
Such may be the case in _C. kubaryi_, which is a small, dull-colored
crow with a relatively unmodified bill. In structure, it has little
resemblance to other crows found in the Pacific area. Kittlitz was the
first to note a resemblance between the bird at Guam and one in the
Philippines. Oustalet (1896:70) wrote that the bird at Guam is related
to crows of the Moluccas and New Guinea. Although not closely related to
the Hawaiian Crow, _C. tropicus_, both have little gloss on their
feathers, a character which is common to many of the insular populations
of crows. Mayr (1943:46) is of the opinion that the Hawaiian bird was
derived from a North American ancestor, although Bryan (1941:187)
suggests that it is related to _C. macrorhynchus_ of southeastern Asia
and remarks that the Hawaiian Crow, "has some relation to the Guam
Crow." In looking for the ancestral stock of _C. kubaryi_, the several
species of crows which occur to the north, west and south of the
Marianas have been examined. In size and general structure, _C. kubaryi_
appears to be closest to the _C. enca_ group, and not as closely related
to the _C. macrorhynchus_ group. The small size, the shape of the
culmen, the lack of pointed feathers on the breast, and the presence of
white on the basal parts of the feathers of the nape are characters
which _C. kubaryi_ has in common with _C. enca_. Nasal bristles cover
the frontal base of the culmen in _C. kubaryi_; this character is found
also in _C. enca florensis_. _C. kubaryi_ differs from the _C. enca_
group by lacking the purple sheen on the upper parts; this sheen is
conspicuous in the latter species. _C. kubaryi_ appears to have little
in common with _C. meeki_ of the Solomons and _C. orru_ of the Moluccas
and New Guinea area. There is apparently no close relation between the
Marianas Crow and the crow which reaches the Bonins. The latter crow,
according to the Hand-list of Japanese Birds (Hachisuka _et al._,
1932:1), is called _C. coronoides hondoensis_ Momiyama and is apparently
now extinct in the Bonins.
In summary, it may be said that _C. kubaryi_ is an isolated and modified
species of crow, which probably has been living at Guam and Rota for a
considerable length of time. Whether it once lived on other islands in
Micronesia is unknown, but it is entirely possible that the present
population may represent a remnant of one which formerly had a more
extensive distribution. The characters which show its distinctness from
possible ancestral species include its small size, its slender bill,
and its dull coloration. It is thought to have been derived from the _C.
enca_ group, _C. e. pusillus_ of the Philippines or _C. e. celebensis_
of the Celebean area.
=Luscinia calliope calliope= (Pallas)