(DRAFT) - Taxonomy
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
TAXONOMY
NAME - RAIL, GUAM
OTHER COMMON NAMES - RAIL and GUAM; KOKO; QUAIL
ELEMENT CODE -
CATEGORY - Birds
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - AVES,
ORDER AND SUBORDER - GRUIFORMES,
FAMILY AND SUBFAMILY - RALLIDAE,
GENUS AND SUBGENUS - RALLUS,
SPECIES AND SSP - OWSTONI,
SCIENTIFIC NAME - RALLUS OWSTONI
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Guam Rail
Rallus owstoni (Rothschild, 1895)
KINGDOM: Animal GROUP: Bird
PHYLUM: Chordata CLASS: Aves
ORDER: Gruiformes FAMILY: Rallidae
The Guam rail ia a large rail with dark brown head, neck, back,
rump, tail, legs, feet, and bill (01). The throat and upper breast
and superciliary stripe are grey (02). The wings, lower breast,
abdomen and under tail coverts are barred black and white (01).
Plumage of both sexes are similar (03,02) but males are larger than
the females (02,01,04).
Taxonomic names and synonyms that have been used to describe
Rallus owstoni are listed below (02,05,06):
Rallus philippinus Gray 1859
Rallus pectoralis Finsch and Hartlaub 1867
Eulabeornis forsteri Gray 1871
Hypoyaenidia philippensis Pelzeln 1873
Hypotaenidia owstoni Hartert 1873
Hypotaenidia owstoni Rothschild 1895
Taxonomy - 1 (DRAFT) - Taxonomy
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
Hypotaenidia marchei Oustalet 1896
Hypotaenidia oustini Seale 1901
Rallus owstoni Peters 1934
Gallirallus owstoni Olsen 1973
Rallus owstoni Ripley 1977
The indigenous people of Guam, the Chamorros, call this bird the
"Koko" and sometimes "quail."
Baker (02) lists 13 specimens from Guam deposited in the U.S.
Museum of Natural History, Washinton, D.C. There are six specimens
in the American Museum of Natural History, New York (07). There is
one specimen in the Denver Museum of Natural History, Colorado (08).
There are two specimens at the Guam Division of Aquatic and Wildlife
Resources (09). There may be specimens in additional museums.
Photographs of Guam Rail are held by the Guam Division of Aquatic
and Wildlife Resources.
Taxonomy - 2 (DRAFT) - Status
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
Non-consumptive recreational
Game (Consumptive Recreational)
Commercial/consumption
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Guam rail (Rallus owstoni) has been designated an
Endangered species pursuant to the Endangered Species Act of 1973
(50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540), as
amended. The species has this status wherever found including the
Territory of Guam.
This species is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild
animal (alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation, or foreign law; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
DOD -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
Status - 1 (DRAFT) - Status
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
TERRITORY: Guam
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Department of Agriculture, Division of
Aquatic and Wildlife Resources.
STATE STATUTE: Endangered Species Act of Guam 1982; Guam Public
Law 15-36, June 18, 1979.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The Guam rail is listed as vulnerable in the IUCN Red Data Book
(1979) and in the 1986 IUCN Red List of Threatened Animals.
ECONOMIC STATUSES:
Recreation-nonconsumptive (bird watching),
Recreation-consumptive & food-human use (hunting)
79/05/18:44 FR 29128/29130 - Notice of review of status.
79/06/13:44 FR 33915/ - Extension of comment period.
81/05/12:46 FR 26464/26409 - Petition acceptance and status.
83/11/29:48 FR 53729/53733 - Proposed listing.
84/01/20:49 FR 2485/2488 - Notice: proposed listing warranted.
84/04/11:49 FR 14356/ - Emergency listing.
84/08/27:49 FR 33881/33885 - Final listing.
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
TERRESTRIAL
TERRESTRIAL
LAND USE -
Residential
Cropland and Pasture
Evergreen Forest Land
Mixed Forest Land
COMMENTS ON HABITAT ASSOCIATIONS -
The Guam rail was distributed over much of Guam in all habitats
except wetlands although Jenkins (01) considered both savanna and
mature mixed forest marginal habitat. As Guam was probably mostly
limestone forest before the arrival of man (11), the rail may have
been more common after much of the mature forest had been converted to
scrubby second growth or mixed forest (14).
In the past, the Guam rail was also observed in association with
areas such as rural residential, golf courses, cropland (vegtables,
melons, and fallow), pasture, and evergreen and mixed forests (09).
Habitat Associations - 1 (DRAFT) - Food Habits
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General
General Forb Flowers/Fruit/Seed
General Crustaceans
General Worms
General Amphibia
General Reptilia
General Carrion
Food Habits - 1 (DRAFT) - Environment Associations
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Coastal Features: Vegetated offshore islands
Environment Associations - 1 (DRAFT) - Life History
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
The Guam rail while an omnivorous feeder, appears to prefer
animal over vegtable food (01). It is known to eat gastropods,
skinks, geckos, insects, and carrion as well as seeds and palm
leaves (01).
HOME RANGE/TERRITORY:
The Guam rail defends a territory that is used for both breeding
and foraging (09). The size of its territory on a daily basis and
movements over a season are not known. A family group composed of
two parents and immatures as well as chicks have been observed
foraging through a territory and responding to the presence of
intruders entering it's territory (09). In recent years, high
densities of rails were often found in areas where the rail's
territory consisted of an open area with adjacent forest or shrubs in
which it could hide if threatened and in which it would build it's
nest (09).
PERIODICITY:
Guam rails concentrate their feeding during the day in the early
morning and late evening (09). Nothing is known of their nocturnal
activities although captive rails are known to feed at night (09).
Although the species nests year-round, Perez (15) suggested a peak
season during the rainy season from July through November.
MIGRATION PATTERNS:
The flightless Guam rail is non-migratory. Nothing is known of
seasonal wanderings if any.
COVER/SHELTER REQUIREMENTS:
The Guam rail appears to require forest or scrubby areas in which
it builds it's nest. Part of it's territory may be open grassy areas
in which it forages for insects (01,09).
REPRODUCTIVE SITE REQUIREMENTS:
The Guam rail appears to require forest or scrubby areas in which
to build it's ground nest (01,09). The Guam rail builds a nest of
interwoven loose and rooted grass and or leaves elevated one or two
inches above the ground. The nest is approximately 30.5 cm (1 ft.) in
diameter with an approximately 15 cm (6 in.) diameter nest cup (09).
REPRODUCTIVE CHARACTERISTICS:
The monogamous Guam rail nests all year round although Perez (15)
suggested that breeding peaks during the rainy season from July to
November, based on data gathered from the number of broods seen during
roadside counts.
Both sexes share in the construction of the shallow ground nest
The typical clutch consists of 3-4 eggs in the wild (01,09) and 2-5
eggs in captivity (09,16) that are white to pinkish with small spots
of pink or blue concentrated at the large ends (01). Jenkins (01)
reported nine eggs from the wild averaging 39 mm (37-41 mm) in
Life History - 1 (DRAFT) - Life History
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
length and 29.3 mm (28-30 mm) in width. Both sexes share in
incubation (01). One clutch in the wild hatched at 19 days (01) while
in captivity clutches hatched at 20-21 days with both artificial
incubation (98-99 percent dry bulb, 85-90 percent wet bulb humidity)
and incubation by parents (09,16).
Eggs hatched asynchronously and the young are highly precocial,
leaving the nest 24 hours after hatching (01). The eggshells are
consumed by the adults presumably the female (01). Of 173 broods
observed in the wild, there were 54 nests with one chick, 77 with two,
36 with three, and 6 nests with four chicks (01,09). The young hatch
with black natal down which persists through the first 3-4 weeks when
the juvenile contour feathers begin developing (01). By the 16 week
the first year birds are indistinguishable from adults in the field.
The age for sexual maturity in the wild is unknown but captive
bred pairs have laid eggs at as early as four months of age, although
5-6 months seems average (09,16). Recycling in the wild has not
been observed, but family groups have been observed consisting of
adults, immatures and chicks (09). In captivity, pairs have recycled
and laid eggs while still raising 14-35 day old chicks (09,16) and one
captive pair successfully recycled six times in six months (09).
PARENTAL CARE:
The highly precocial young which leave the nest within 24 hours
(01) are fed by the parents until they are 7-10 days old (16) after
which they forage with the family group often consisting of adults,
immatures, and chicks (presumably until sexual maturity and the
establishment of independent territories) (09). Sexual maturity
occurred at 4-6 months of age in captive bred birds (09,16). In the
wild and in captivity, both sexes have been observed defending the
nest (16,09).
POPULATION BIOLOGY:
The present decline of the Guam rail is apparently due to
predation by the brown tree snake, Boiga irregularis (10). Other
limiting factors affecting the Guam rail before the apparently
accidental introduction of the brown tree snake are not known.
The Guam rail will likely be extirpated from the wild on Guam in
the very near future (17). However owing to the high reproductive
potential demonstrated by Guam rails breeding in captivity on Guam and
at several mainland zoos in a program set up by the Aquatic and
Wildlife Resources Division, Guam Department of Agriculture in
cooperation with the American Association of Zoological Parks and
Aquariums (18,19,20,04), the potential for successful recovery of this
species is high providing that predation by the brown tree snake can
be controlled (13).
SPECIES INTERRELATIONSHIPS:
None known.
OTHER LIFE HISTORY DESCRIPTORS:
None known.
Life History - 2 (DRAFT) - Management Practices
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Land Acquisition
Beneficial Reforestation
Beneficial Stocking captive-reared wild-strain animals
Beneficial Controlling/Restricting Noncommercial Harvest
Beneficial Restricting Poaching
Beneficial Controlling/Removing Exotic Vertebrates
Beneficial Controlling/Removing Feral Animals
Adverse Predation
Existing Predation
Adverse Applying pesticides
Existing Applying pesticides
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
COMMENTS ON MANAGEMENT PRACTICES -
Predation of eggs, young and adults by the introduced
nocturnal brown tree snake, Boiga irregularis, is thought to be
responsible for the present decline of the Guam rail and other forest
birds of Guam (10).
Recently, introduced diseases were considered as possible causes
for both the range reductions and extinctions noted for most native
forest birds on Guam, but to date, no infectious organisms have been
isolated on Guam that could account for the decline (10). Feral dogs,
cats, and rats which are found on Guam are thought to be a major
factor in the decline of the rail (10).
There have been major changes in Guam's vegetation before,
during, and after World War II (11). However, substantial native
habitat still remains on Guam and habitat degradation is not thought
to be a major factor at present.
While pesticides may have been a factor in the past, an intensive
pesticide survey conducted in 1981 on Guam, concluded that pesticides
were not a significant factor at present (12).
In the past, hunting may have stressed the Guam rail, but there
is no evidence to suggest that it was responsible for the Guam rail's
recent decline on Guam (13).
UNAPPROVED PLAN
U.S. Fish and Wildlife Srvice, 1985. Recovery Plan for the Native
Forest Birds of Guam and Rota, Marinana Islands. Tech. Review Draft.
U.S. Fish and Wildl. Serv., Portland, OR. 110 pp.
The Guam rail is included in the Endangered Native Forest
Birds (for Guam and Rota of the Mariana Islands) Recovery Plan.
The recent, drastic decline of forest bird populations on Guam
has been one of the most alarming and challenging endangered
species problems of modern times. Current evidence points to an
efficient predator of small birds, the brown tree snake, as the
Management Practices - 1 (DRAFT) - Management Practices
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
culprit. Once thought to be relatively resistent to snake predation,
the Guam rail population on Guam has dwindled to just a few birds.
The plan states among its primary objectives to prevent
extinction by initially establishing a sustainable population. In
addition, it is imperative to develop methods of reducing predation
by brown tree snakes; this action would then allow expansion of the
wild population and reintoduction of captive birds back into their
historic range. Down-listing to threatened status would occur once
predation from snakes is under control and broadbills again occupy
all essential habitat. The Recovery Plans recommends the following
actions for the Endangered forest birds of the Marianas:
(1) develop cooperative agreements among the USFWS, the Government of
Guam, and the Commonwealth of the Northern Marianas, towards
protection and recovery of forest birds;
(2) conduct annual status surveys of endangered forest birds;
(3) develop a captive breeding program for all species;
(4) reduce avian mortality in the field by monitoring for disease,
preventing diseases and their vectors from becoming established,
monitoring for pesticides, and particularly a program for controlling
predation by snakes, specifically by
(a) research on the biology and ecology of the tree snake,
particularly in its native geographical range,
(b) develop control methods,
(c) implement control measures, and
(d) prevent transport of snakes to Rota;
(5) protect and manage essential habitat;
(6) conduct additional research necessary for refinement recovery
tasks and goals, including rehabilitating regrowth in denuded areas,
controlling alien organisms, identifying habitat requirements of
endangered birds, and developing criteria for delisting these
endangered species;
(7) develop methods for reintroducing endangered birds to essential
habitat and implement where appropriate; and
(8) develop a public awareness program.
Recovery actions ongoing or accomplished for Guam's forest birds
include: (1) legal protection and law enforcement (i.e. prevent
poaching for individual use and in the past commercial harvest was and
may still be a problem), (2) protection of essential habitat,
including establishment of 6 small natural area reserves held by the
Territory or by the military, (3) ongoing captive breeding program,
(4) a completed public education program (which should profitably
be reinstated), (5) and extensive research on avian diseases and
biology of the brown tree snake. Virtually all of these activities
have been initiated and carried out by the Government of Guam, in
cooperation with the U.S. Fish and Wildlife Service.
Management Practices - 2 (DRAFT) - References
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Jenkins, J.M. 1979. Natural history of the Guam rail. Condor.
Monogr. No. 31. Am. Ornitholgists Union., Wash., D.C. 61 pp.
02 Baker, R.H. 1951. The avifauna of Micronesia, its origin,
evolution, and distribution. Univ. Kansas Publ., Mus. Nat.
Hist. 3:1-359.
03 Mayr, E. 1945. Birds of Southwest Pacific. The Macmillion Co.,
New York, xix + 316 pp., 3pls., 16 figs., 1 map.
04 Derrickison, S.R. 1985. A cooperative breeding program for the
Guam rail, Rallus owstoni. AAZPA Ann. Proceed. 1985:233-240.
05 Olsen, S.L. 1973. A classification of the Rallidae. Wilson Bull.
85:381-416.
06 Ripley, S.D. 1977. Rails of the world. David R. Godine, Boston,
MA.
07 Lanyon, W.E. 1986. Pers. comm. Am. Mus. of Nat. Hist., New York.
08 Ryder, R. Unpubl. data. Div. of Aquatic and Wildl. Res., Dept.
of Agric., Guam.
09 Beck, R.E., Jr. Unpubl. data. Div. of Aquatic and Wildl. Res.,
Dept. of Agric., Guam.
10 Grue, C.E., C.M. Fecko, and A.J. Krynitsky. In Press. Pesticides
are not responsible for recent declines in native bird populations
on Guam. Micronesica.
11 Fosberg, F.R. 1960. The vegetation of Micronesia. Bull. Am. Mus.
Nat. Hist. 119(1):1-75.
13 U.S. Fish and Wildlife Service. 1985. Recovery Plan for the
Native Forest Birds of Guam and Rota, Mariana Islands. Technical
Review Draft. U.S. Fish and Wildl. Serv., Portland, OR. 110 pp.
14 Engbring, J. and F.L. Ramsey. 1984. Distribution and abundance of
the forest birds of Guam: Results of a 1981 survey. U.S. Fish and
Wildl. Serv. FWS/OBS-84/20. 54 pp.
15 Perez, G.S. 1968. Notes on the breeding season of the Guam rail,
Rallus owstoni. Micronesica 4:133-135.
16 Savidge, J.A. Unpubl. data. Div. of Aquatic and Wildl. Res.,
Dept. of Agric., Guam.
17 Beck, R.E., Jr. 1984. Survey and inventory of the Native Land
Birds of Guam. In: Annual Report, FY 1984. Guam Aquatic and
Wildl. Res. Dept. of Agric., Guam.
18 Beck, R.E., Jr. 1983. Captive breeding of the Guam rail and
other native birds. In: Guam Div. of Aquatic and Wildl.
Res. Annual Report. FY 1983. Dept. of Agric., Guam.
19 Beck, R.E., Jr. 1984. Captive breeding of the Guam rail and
other native birds. In: Guam Div. of Aquatic and Wildl.
Res. Annual Report. FY 1984. Dept. of Agric., Guam.
20 Beck, R.E., Jr. 1985. Captive breeding of the Guam rail and
other native birds. In: Guam Div. of Aquatic and Wildl.
Res. Annual Report. FY 1985. Dept. of Agric., Guam.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
References - 1 (DRAFT) - References
Species RAIL, GUAM
Species Id ESIS101035
Date 14 MAR 96
01 Baker, R.H. 1951. The avifauna of Micronesia, its origin,
evolution, and distribution. Univ. Kansas Publ., Mus. Nat.
Hist. 3:1-359.
02 Jenkins, J.M. 1979. Natural history of the Guam rail. Condor.
Monogr. No. 31. Am. Ornitholgists Union., Wash., D.C. 61 pp.
03 Guam Division of Aquatic and Wildlife Resources Field Notes.
Guam Div. of Aquatic and Wildl. Res., Dept. of Agric., Guam.
04 Engbring, J. and F.L. Ramsey. 1984. Distribution and abundance of
the forest birds of Guam: Results of a 1981 survey. U.S. Fish and
Wildl. Serv. FWS/OBS-84/20. 54 pp.
05 Aguon, C. 1983. Survey and inventory of native birds on Guam.
In: Guam Div. of Aquatic and Wildl. Res. Annual Report. FY 1984.
Dept. of Agric., Guam.
06 Beck, R.E., Jr. 1984. Captive breeding of the Guam rail and
other native birds. In: Guam Div. of Aquatic and Wildl.
Res. Annual Report. FY 1984. Dept. of Agric., Guam.
07 Beck, R.E., Jr. 1984. Survey and inventory of the native land
Birds of Guam. In: Annual Report, FY 1984. Guam Aquatic and
Wildl. Res. Dept. of Agric., Gov. of Guam, Agana, Guam.
08 Beck, R.E., Jr. 1983. Captive breeding of the Guam rail and
other native birds. In: Guam Div. of Aquatic and Wildl.
Res. Annual Report. FY 1983. Dept. of Agric., Guam.
09 Beck, R.E., Jr. 1985. Captive breeding of the Guam rail and
other native birds. In: Guam Div. of Aquatic and Wildl.
Res. Annual Report. FY 1985. Dept. of Agric., Guam.
10 Engbring, J. 1987. Pers. comm. Honolulu, HI 96850.
References - 2