(DRAFT) - Taxonomy
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
TAXONOMY
NAME - BROADBILL, GUAM
OTHER COMMON NAMES - BROADBILL, GUAM;BROADBILL, MICRONESIAN; FLYCATCHER, FREYCINET'S;FLYCATCHER and GUAM; CHIGUANGUAN;CHUGUANGUAN
ELEMENT CODE -
CATEGORY - Birds
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - AVES,
ORDER AND SUBORDER - PASSERIFORMES,
FAMILY AND SUBFAMILY - MUSCICAPIDAE,
GENUS AND SUBGENUS - MYIAGRA,
SPECIES AND SSP - FREYCINETI,
SCIENTIFIC NAME - MYIAGRA FREYCINETI
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Guam Broadbill
Myiagra freycineti Oustalet, 1881
KINGDOM: Animal GROUP: Bird
PHYLUM: Chordata CLASS: Aves
ORDER: Passeriformes FAMILY: Muscicapidae
A small flycatcher with head and neck bluish with a metallic
luster, lores and anterior forehead gray; back and upper wing coverts
near green-blue; rump grayer than back; chin and throat white; breast
light cinnamon, fading to pale buff and white on abdomen and under
tail coverts; tail bluish-slate with tips of tail feathers edged with
white; bill and feet black; iris dark brown. Adult female: more
gray-brown above with less of a metallic luster, tibia less brownish.
Immature: resembles adult but more brown and less blue on back;
underparts generally more buffy than adult (01,02).
The accepted scientific name for the Guam broadbill is Myiagra
freycineti Oustalet, 1881 (03). In the past, this species has been
referred to as Submyiagra freycineti (04), Myiagra oceanica freycineti
(02,05) and Myiagra oceanica (06).
Common name synonyms found in the literature include: Freycinet's
flycatcher (07), Micronesian broadbill (02,08) and Guam flycatcher
Taxonomy - 1 (DRAFT) - Taxonomy
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
(09). The Chamorro name is Chiguanguan or Chuguanguan (01).
The type specimen was collected on Guam (03). The U.S. National
Museum has 26 specimens from Guam (02). The American Museum of
Natural History has 38 specimens from Guam (02). Locations of other
specimens are unknown. Photographs are located at the Guam Division
of Aquatic and Wildlife Resources.
Taxonomy - 2 (DRAFT) - Status
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
Non-consumptive recreational
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Guam broadbill (Myiagra freycineti) 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:
TERRITORY: Guam
DESIGNATED STATUS: Endangered
Status - 1 (DRAFT) - Status
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
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:
This species is not listed by CITES, nor by the IUCN (as of the
1986 IUCN Red List of Threatened Animals).
ECONOMIC STATUSES:
This species was a common, endemic insectivore sought by bird
watchers.
79/05/18:44 FR 29128/29130 - Notice of review of status.
79/06/13:44 FR 33915/ - Extension of comment period.
83/11/29:48 FR 53729/53733 - Proposed listing.
84/08/27:49 FR 33881/33885 - Final listing.
Status - 2 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
LAND USE -
Evergreen Forest Land
COMMENTS ON HABITAT ASSOCIATIONS -
Myiagra freycineti (Guam broadbill) formerly appeared in all
habitats on Guam with the exception of southern savannas (09).
Broadbills have been recorded in woodland areas (10), forested areas
with brushy undercover (02), areas dominated by Leucaena leucocephala
(08), and in southern riparian habitats (06). Broadbills have also
been observed on coastal strand habitats and mangrove swamps in
addition to forest habitats (14).
In 1979, Jenkins (09) reported that broadbills were restricted
to the mature limestone forest of the relatively undisturbed northern
cliffline and were rare in mixed woodlands and second growth of the
extreme northwestern portion of the northern plateau on Guam.
A U.S. Fish and Wildlife Service survey done in primary and
second growth forest in 1981, estimated 460 Guam broadbills remaining
in extreme morthern Guam (15). In early 1983, broadbills were
primarily restricted to a 150 hectare patch of mature limestone forest
at the northern tip of Guam (14). By December 1983, a survey of this
area by Guam Aquatic and Wildlife Resources found no remaining
broadbills (16).
Habitat Associations - 1 (DRAFT) - Food Habits
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
LIFESTAGE FOOD FOOD PART
General Arthropods
Food Habits - 1 (DRAFT) - Environment Associations
Species BROADBILL, GUAM
Species Id ESIS101033
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 BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Myiagra freycineti (Guam broadbill) is apparently entirely
insectivorous and feeds both by gleaning insects from twigs and
foliage, as well as hawking insects from the air (09). When hawking
insects it is rather tyrannid-like, making repeated sallies for prey
and returning to the same, or sometimes, a different perch, where the
bird bobs its tail to maintain balance (09).
HOME RANGE/TERRITORY:
M. freycineti is territorial. Broadbills have a swift direct
flight and use this, coupled with their aggressivness, to drive other
species and conspecifics from its territory (09). M. freycineti
harrasses the much larger yellow bittern and repeatedly displaces it
from low perches. It utters harsh scolding notes and frequently
dives at its enemies. Its crown feathers become erect, when agitated.
This bird has also been observed to drive kingfishers and fantails
from their territories (09). Males engage in these agnostic
encounters more frequently than females, but females drive
conspecfics, possibly juveniles, from their well-defined territories
(09).
PERIODICITY:
Guam broadbills have been observed feeding during the day (14).
MIGRATION PATTERNS:
Guam broadbills have been observed or collected throughout the
year and do not appear to migrate (14).
COVER/SHELTER REQUIREMENTS:
Guam broadbills formerly utilized all habitats on Guam with the
exception of southern savannas (09). Specific environmental
parameters required by this species are largely unknown.
REPRODUCTIVE SITE REQUIREMENTS:
Exact requirements for broadbill display are unknown. The
following description of broadbill nests and placement is taken
directly from Jenkins (09). Nests of M. freycineti are firmly
constructed, usually in the fork of branches of middle-sized trees or
shrubs. The nest is made of thin twigs, roots, pieces of Hibiscus
leaves and grasses, woven and held together by spider webs and
mucus-like substance. One nest measured 53.5 mm in outer diameter,
28.0 mm in height, and 14.8 mm deep. Nests are constructed by both
sexes and have been found in trees or shrubs of Bambusa sp.,
Neisoperma oppositifolia, Hibiscus tiliaceus, A. alba, Leucaena
leucocephala, Casuarina equisetifolia, and Oxalis corniculata. Six
nests averaged 2.7 meters (range = 1.2-5.2 m ) above the ground. One
pair began constructing a new nest in August, 1979, immediately after
a storm destroyed their first nest. The birds repeatedly salvaged
material from the destroyed nest and used it in the new one located
about 10 meters from the first. Nest construction required 7 or 8
days (09).
Life History - 1 (DRAFT) - Life History
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
Strophlet (06) observed a pair of broadbills buildling a nest on
20 September, 2.1 m off the ground. The nest was near the end of a
horizontal branch of H. tiliaceus, located in a partially cleared area
of low trees, along a stream in the grasslands. The nest was
completed on 4 October but the pair deserted it soon after (06).
REPRODUCTIVE CHARACTERISTICS:
Nests of M. freycineti have been recorded in all months except
November and December (17). The number of clutches per year is
unknown although one pair raised three clutches in 10 months during
1980-81. Both sexes incubate eggs and brood young (09). Jenkins (09)
observed three clutches, each containg one egg. Hartert (18) and
Baker (02) found nests with one egg, but Seale (19) described a nest
with two eggs. Two eggs measured by Jenkins (09) were 19.1 mm by
15.3 mm, and 19.2 mm by 14.2 mm, and were cream-colored with a band of
brown splotches around the widest part of the egg. During several
hours of observation at one nest, the female performed most of the
incubation, but the male also participated (09). The eggshells were
consumed by an adult, probably the female. No data is available on
length of incubation or nesting period.
PARENTAL CARE:
Very little is known on parental care. The length of time in
development and duration of family bond are unknown. Broadbills
actively defend their nests (09).
POPULATION BIOLOGY:
Data indicate predation by the brown tree snake (Boiga
irregularis) is responsible for the virtual extinction of
M. freycineti on Guam (11). Data was not obtained on the population
dynamics of the species. The last observations of broadbills
indicated the sex ratio was skewed towards males (20), possibly a
result of the increased vulnerability of nesting females to predation.
The species is unfortunately probably beyond recovery (17).
SPECIES INTERRELATIONSHIPS:
None are known.
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 2 (DRAFT) - Management Practices
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Land Acquisition
Beneficial Reforestation
Beneficial Stocking captive-reared wild-strain animals
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 -
The entire native forest avifauna on Guam has undergone a
drastic decline. Introduced diseases and predation were considered as
possible causes for the range reductions and extinctions. To date,
no infectious organisms have been isolated on Guam that could account
for the decline (11). Feral dogs, cats, and rats are a problem on all
major islands in the Marianas, but the only predator unique to Guam
is the brown tree snake, Boiga irregularis. Data indicates the snake
is the major cause of the decline (11). There is a close correlation
between the range expansion of the snake and the forest bird
contraction, and through experiments, predation by snakes was shown
to be high in areas where native forest birds had gone extinct locally
(11).
Competition with the introduced black drongo (Dicrurus
macrocerus), an aggressive, adaptable bird, is unlikely; as Maben (12)
found differences in habitat utilization, foraging techniques and
dietary preferences. Maben (12) suggested broadbills may have
suffered more from occasional predation by drongos rather than
competition for food or by displacement from nesting sites.
The extensive use of pesticides in the past for agriculture
and vector control could present a possible link to the general avian
population decline, and they may have imoacted certain bird
populations in the past. An intensive pesticide survey conducted in
1981 concluded pesticides were not a significant factor at present
(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 broadbill 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
Management Practices - 1 (DRAFT) - Management Practices
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
species problems of modern times. Current evidence points to an
efficient predator of small birds, the brown tree snake, as the
culprit. Because hope still remains that a few broadbills may yet
survive, the species is included in the Recovery Plan for the Forest
Birds of Guam and Rota.
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, (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 BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Marshall, J.T., Jr. 1949. The endemic avifauna of Saipan, Tinian,
Guam and Palau. Condor 51:200-221.
02 Baker, R.H. 1951. The avifauna of Micronesia, its origin,
evolution, and distribution. University Kansas Publ., Mus. Nat.
History 3:1-359.
03 Oustalet, M.E. 1881. Observations sur divers oiseaux de l'Asie
de la Nouvelle-Guinee. Bull. Soc. Philom. de Paris, ser. 7,
5:71-80.
04 Mathews, G.M. 1927-30. Systema Avium Australasianarum. British
Ornith. Union, pt. 1 (1927):1-426; pt. 2 (1930):427-1048.
05 Mayr, E. 1945. Birds of Southwest Pacific. The Macmillion Co.,
New york, xix + 316 pp., 3pls., 16 figs., 1 map.
06 Strophlet, J.J. 1946. Birds of Guam. Auk 53:539-540.
07 Bryan, E.H. Jr. 1936. Birds of Guam. Guam Recorder 13(2)
08 Kibler, L.F. 1950. Notes on the birds of Guam. Auk. 67:400-403.
09 Jenkins, J.M. 1983. The native forest birds of Guam. Ornith.
Monogr. No. 31. Am. Ornitholgists Union., Wash., D.C. 61 pp.
10 Stafford, W.E. 1902. Birds of the Mariana Islands and their
vernacular names. Osprey 6:39-42,65-70.
11 Savidge, J.A. In prep. The reasons for the decline of Guam's
avifauna. Ph.D. Thesis, Univ. Ill., Champaign-Urbana.
12 Maben, Anne F. 1982. The Feeding Ecology of the Black Drongo
Dicrurus macrocercus on Guam. Master's Thesis. Univ. Calif.,
Long Beach. p. 80-81.
13 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.
14 Guam Division of Aquatic and Wildlife Resources. [n.d.]. Field
Records. Guam Div. of Aq. and Wildl. Res., Agana.
15 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.
16 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 Agriculture, Gov. of Guam, Agana, Guam.
17 U.S. Fish and Wildlife Service. 1985. Recovery Plan for the
Native Forest Birds of Guam and Rota, Mariana Islands. Tech.
Draft. U.S. Fish and Wildl. Serv., Portland, OR. 110 pp.
18 Hartert, Ernst. 1898. On the Birds of the Marianne Islands.
Novitates Zool. 5(11):51-69.
19 Seale, A. 1901. Report of a mission to Guam. Occas. Pap. Bernice
P. Bishop Mus. 1:17-128.
20 Beck, R. 1985. Pers. comm. Guam Div. of Aq. and Wildl. Res.,
Agana, Guam 96910.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Baker, R.H. 1951. The avifauna of Micronesia, its origin,
References - 1 (DRAFT) - References
Species BROADBILL, GUAM
Species Id ESIS101033
Date 14 MAR 96
evolution, and distribution. University Kansas Publ., Mus. Nat.
History 3:1-359.
02 Jenkins, J.M. 1983. The native forest birds of Guam. Ornith.
Monogr. No. 31. Am. Ornitholgists Union, Wash., D.C. 61 pp.
03 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
Wildlife Service FWS/OBS-84/20. 54 pp.
04 Aguon, C.F. 1983. Survey and inventory of native birds on Guam.
In: Guam Div. of Aquatic and Wildl. Res. Annual Report. FY 1983.
Dept. of Agriculture, Guam.
05 Beck, Robert E., Jr. 1984. Survey and inventory of native land
birds on Guam. In: Guam Div. of Aquatic and Wildl. Res. Annual
Report. FY 1984. Dept. of Agriculture, Guam.
References - 2