===========+=========+=====+=========+=======+========+========
| | | | | Full |
LOCATION | Sex | No. | Wing | Tail | culmen | Tarsus
-----------+---------+-----+---------+-------+--------+--------
Yap, Truk | males | 6 | 132 | 43 | 56 | 44
| | | 130-134 | 41-47 | 54-59 | 42-47
| | | | | |
Guam | males | 11 | 134 | 47 | 57 | 46
| | | 127-138 | 45-50 | 55-60 | 45-47
| | | | | |
Guam | females | 10 | 130 | 46 | 57 | 45
| | | 127-134 | 44-49 | 55-59 | 43-47
-----------+---------+-----+---------+-------+--------+--------
_Weights._--The author (1948: 44) records the weights of eight
adult males from Guam as 82-103 (92) and eight adult females from
Guam as 84-109 (95).
_Specimens examined._--Total number, 69 (34 males, 27 females, 8
unsexed), as follows: Mariana Islands, USNM--Saipan, 1 (Sept.
30)--Tinian, 1 (Oct. 13)--Guam, 29 (May 16, June 4, 6, 7, 8, 14,
18, 19, July 10, 16, 18, 24, 27, Aug. 4); AMNH--Saipan, 1 (Aug.
6)--Tinian, 3 (Sept. 13)--Guam, 14 (Feb. 1, Mar. 13, 29, July 11,
13, 25, Aug. 1, 7, 13, Sept. 4, 10, Dec. 8); Palau Islands,
AMNH--exact locality not given, 6 (Nov. 19, 21, 23, 25, Dec. 1,
18); Caroline Islands, USNM--Truk, 1 (Feb. 16); AMNH--Yap, 1 (not
dated)--Truk, 12 (Feb. 9, Mar. 5, 17, May 7, June 13, 14, 15, Oct.
3, Nov. 1, 5, Dec. 20).
_Nesting._--The author (1948:44) records a nest found by the NAMRU2
party near Achang Bay on Guam on June 6, 1945. It was found in a
cane thicket at the edge of a fallow rice paddy, approximately four
feet from the ground and was constructed of about three quarts of
reeds and cane. Two eggs found in the nest are oval, white with a
greenish cast and measure 33 by 24 and 34 by 24. On February 1,
1945, the writer found two recently occupied nests of the Chinese
Least Bittern at Oca Point, Guam. These nests were in dense
inkberry brush approximately five feet above the ground. The area
was not marshy, the nearest water being at the beach some 300 yards
away. Nearby one of the nests was found a young bittern, which
apparently had only recently left the nest. The pin feathers were
growing. A parent bird remained in the vicinity with the young bird
until it left the area after March 9.
_Food habits._--The Chinese Least Bittern feeds on animal foods
obtained along waterways, marshes and beaches as well as in
forests and fields. The NAMRU2 party observed several types of
insects in the stomachs of birds taken at Guam. Seale (1901:27)
found black crickets in stomachs of bitterns taken at Guam.
Coultas (field notes) learned from the natives of the Palau
Islands that the bittern feeds on land mollusks.
_Parasites._--Wharton (1946:174) obtained the chigger (Acarina),
_Trombicula acuscutellaris_, from the Chinese Least Bittern at
Guam.
_Remarks._--The Chinese Least Bittern has been regarded by many workers
as consisting of several geographic races; as many as eight have been
recognized. Other workers have concluded that _I. sinensis_ is made up
of highly variable populations and that it lacks well-fined geographic
variation. Hartert (1920:1260), Hachisuka (1932:365), and Mayr
(1945a:285) have reached the latter conclusion. As yet this problem has
not been satisfactorily solved; a thorough study is needed, but may not
be possible until additional material, especially from the continental
areas, can be obtained. In coloration there appears to be little
difference between birds from the various localities in Micronesia.
These birds may average slightly paler than populations from the
continental areas, but on this basis I doubt that a person could
recognize the Micronesian birds in a group of skins from many other
localities. Birds in fresh plumage may show geographic differences
better than slightly worn specimens. Measurements made by the author
offer no clear-cut differences either.
_I. sinensis_ was first recorded in Micronesia by Quoy and Gaimard
(1824:536), whose ship, the "Uranie," stopped at Guam. They called the
bird "Petit Héron aux ailes noires." Most of the ornithological
collectors in the years following Quoy and Gaimard obtained this bittern
in Micronesia. At Guam, its abundance and the ease with which it may be
approached and shot is attested by the large series obtained by
collectors: Seale (1901:27) took eight birds; Marche (Oustalet,
1896:36) took eighteen skins; the NAMRU2 party took twenty-nine skins.
The Chinese Least Bittern is found in habitats associated with both salt
water and fresh water, as well as in upland habitat in Micronesia. The
bird appears to be well adapted to areas of open forest and coconut
groves. Coultas (field notes) found the birds in taro patches in the
Palaus. Although a considerable amount of field observing was done in
the southern Palaus, the NAMRU2 party saw only one bird (September 13,
1945, at Peleliu). Perhaps the birds prefer Babelthuap and other large
islands farther north in the chain. McElroy found bitterns in taro
patches at Truk in December, 1945. The NAMRU2 party did not find any
birds at Rota in October and November, 1945. Downs (1946:91) found the
birds in upland sugar cane and beach habitats on Tinian.
Regarding the bittern in the Palaus, Coultas (field notes) writes,
"Always found alone, never a pair. A bird that is not easily frightened.
In the heat of the day, one finds it standing in the shade of a taro
leaf quietly viewing the intruder and very reluctant about moving. I
have tossed pieces of earth and sticks at the bird to encourage him to
fly so that I would not blow him to pieces when I shot, but my efforts
at dislodgement have been rewarded by harsh scolding squawks. It became
necessary for me to move into proper gun range. I have also found them
perched in low trees at the edge of taro swamps. In flight they are
atrociously awkward. They can't keep a course and their legs dangle
every-which way. Their jerky, slow flight usually ends abruptly when the
bird becomes entangled in weeds or the branches of trees. Extracting
himself from his predicament he is soon in another and invariably
resorts to blasphemy."
=Ixobrychus eurhythmus= (Swinhoe)