(DRAFT) - Taxonomy
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
TAXONOMY
NAME - VIREO, BLACK-CAPPED
OTHER COMMON NAMES - VIREO and BLACK-CAPPED;VIERO DE ANTIFAZ; VIERO DE GORRA NEGRA
ELEMENT CODE -
CATEGORY - Birds
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - AVES,
ORDER AND SUBORDER - PASSERIFORMES,
FAMILY AND SUBFAMILY - VIREONIDAE,
GENUS AND SUBGENUS - VIREO,
SPECIES AND SSP - ATRICAPILLUS,
SCIENTIFIC NAME - VIREO ATRICAPILLUS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Black-capped Vireo
Vireo atricapillus Woodhouse, 1852
KINGDOM: Animal GROUP: Bird
PHYLUM: Chordata CLASS: Aves
ORDER: Passeriformes FAMILY: Vireonidae
The adult male black-capped vireo is olive green on the upper
surface, white beneath, with flanks faintly yellowish green. The
crown and upper half of the head is black with a partial white
eye-ring and lores. This pattern is unique in the family Vireonidae.
The iris is brownish red, the bill black. The adult female is duller
colored with the crown slate gray instead of black and the underparts
washed with greenish yellow (01).
A more detailed description of the plummage is as follows (02):
Adults, nuptial plumage: Acquired by wear from winter plumage. Top
and side of head and cervix rather glossy black; sides of forehead,
lores, and eye-ring white; remainder of upper surface rather grayish
or yellowish olive green; wings and tail light chaetura drab, tail
and wing-quills edged with serpentine green, but not tertials; lesser
wing-coverts like back, tips of median and greater coverts, with outer
webs of tertials, broadly barium yellow, forming two wing-bars; sides
Taxonomy - 1 (DRAFT) - Taxonomy
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
of neck like back; lower parts white or creamy white; sides and flanks
serpentine green, mixed with citrine yellow; lower tail-coverts washed
with citrine yellow; lining of wing citrine yellow. Bill above black;
mandible plumbeous; cutting edges and tip of bill dull white; iris
light brick red; legs and feet plumbeous. Adults, winter: Acquired
by complete postnuptial molt. Similar to nuptial adults, but upper
parts brighter, of rather more yellowish (less grayish) olive green,
feather of occiput and cervix edged with deep neutral gray.
Natal: None; chicks hatch naked. Juvenile: Acquired by
complete postnatal molt. Upper surface dull drab; wings and tail
similar to first winter male and female, but wing-coverts more
brownish drab; loral stripe and eye-ring light buff; remainder of
sides of head dull buff; all lower parts buffy white. First winter,
second winter, and first and second nuptial plumages also described in
detail in (02).
There has never been any controversy over the name or taxonomic
delineation of this very distinctive species. This species was
originally described as Vireo atricapilla (female) Woodhouse (14).
The type specimens were two adult males collected by S.W. Woodhouse on
26 May 1852 along the Rio San Pedro (now called Devil's River) in
Sutton County, Texas (03,04). One male is deposited in the National
Museum of Natural History, Division of Birds (USNM no. 15040). A
specimen from Sarpy County, Nebraska is located in the Hastings
Museum (09). Other common names include viero de antifaz and viero
de gorra negra (Mexico) (15).
There is no doubt that the black-capped vireo is a distinct
species; however, the dwarf vireo (V. nelsoni) is the most closely
related congener (05), and it may be a "hen-feathered" subspecies of
the V. atricapillus (06).
Taxonomy - 2 (DRAFT) - Status
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
Federal Migratory
Non-consumptive recreational
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The black-capped vireo (Vireo atricapillus) has been designated
as Endangered 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 States of
Kansas, Nebraska, Oklahoma, Texas, and in Mexico.
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.
The species is protected by the Migratory Bird Treaty Act
(16 U.S.C. 703-711 et seq.) under Vireo atricapillus (50 CFR 10.13).
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
Status - 1 (DRAFT) - Status
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
NPS -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public lands under their control. Also responsible
for conservation (Nat. Park System Organic Act - 16
U.S.C. 1, 2-3)/management/recovery on National Park
Service lands. Taking, possessing, or disturbing of
Federally listed species is prohibited on NPS lands
(36 CFR 2.1, 2.2, and 2.3).
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:
STATE: Kansas, Nebraska
DESIGNATED STATUS: Recognized Endangered
ADMINISTRATIVE AGENCY: Kansas Fish and Game Commission,
Nebraska Game and Parks Commission
STATE STATUTE: (KS) Kansas Stat. Annot. 32-502 (d),(e),(j), 503
& 504,
(NE) Rev. Stat. of NE 37-430 to 438; NE Admin.
Rules and Regs. Vol. 13, 6-(4) (1984).
STATE: Oklahoma
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Oklahoma Department of Wildlife Conserv.
STATE STATUTE: Title 29; Game and Fish Sect. 2-109, 2-135,
5-412, 7-501, 7-502, 7-504, 7-602.
STATE: Texas
DESIGNATED STATUS: Threatened
ADMINISTRATIVE AGENCY: Texas Parks and Wildlife Department
STATE STATUTE: Tex. Admin. Code Sect. 43 and 67.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The black-capped vireo is covered under the Convention for the
Protection of Migratory Birds and Game Mammals, February 7, 1936,
United States - Mexico, 50 Stat. 1311, T.S. No. 912.
ECONOMIC STATUSES:
This species has a value as a component of Oklahoma's, and Texas'
natural heritage of biotic diversity. The black-capped vireo is
especially attractive to ornithologists and amateur birders. Nests
have failed or been abandoned due to excessive activities of
photographers; one territory was possibly abandoned because of
frequent harassment from tape-recorded songs (06).
Status - 2 (DRAFT) - Status
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
82/12/30:47 FR 58454/58460 - Notice of Review
85/04/05:50 FR 13708/13722 - Protected list under Migratory Bird Act
85/09/18:50 FR 37958/37967 - Notice of Review
86/12/12:51 FR 44808/44812 - Proposed rule - Endangered
87/10/06:52 FR 37420/37423 - Final rule - Listed as Endangered
Status - 3 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
TERRESTRIAL
SOCIETY OF AMERICAN FORESTRY TYPES
SAF TYPE STAGE CLOSURE
Shortleaf Pine-Oak shrub--seedling
Shortleaf Pine-Oak young tree
LAND USE -
Shrub and Brush Rangeland
Mixed Forest Land
COMMENTS ON HABITAT ASSOCIATIONS -
Vireo atricapillus (black-capped vireo) use habitats
restricted to areas with scrub-oak growth of irregular height and
distribution, with spaces between the small thickets and clumps, and
with vegetation cover down to ground level for breeding (08). The
presence of junipers and even taller trees are tolerated if they match
or do not disrupt the generally "wooly" vegetational configuration
(09). These taller trees are often used as singing perches. However,
overgrazing will negatively impact the vegetation cover near ground
level, making areas unsuitable for nesting vireos.
The habitats preferred by vireos are potentially ephemeral
subclimax growths which can be maintained best under edaphic
conditions in gulleys, edges of ravines, and on eroded slopes. Other
areas can be suitable as they recover from clearing or burning. These
successional conditions may have been maintained during pre-settlement
times over larger areas than at present times by wild fires or fires
set by native Americans. Two areas in Texas and one in Oklahoma with
local populations in 1985, among the largest known, have been burned
within the past six to ten years (09).
Floristic and physiognomic features of habitat were compared
between areas occupied by vireos and other scrub land areas where no
vireos were present (12). In Texas, Juniper ashei (mountain cedar)
was less common in vireo territories while Quercus harvardii
(shin-oak) was more common. The analysis of cover types indicated
that 55 percent of vireo habitat is relatively open and comprised of
non-woody elements. Vireos are seldom seen in anything but woody
vegetation. The openness may enhance prey (insect) availability.
Shrubs were taller in vireo territories and bushes were spaced
slightly closer, though the differences were not statistically
significant. Dominant plants in vireo territories vary throughout
their breeding range, even within 100 km distances. Black-capped
vireo habitat appears to be an intermediate successional stage (12).
Habitat Associations - 1 (DRAFT) - Food Habits
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
OMNIVORE
LIFESTAGE FOOD FOOD PART
General
General Deciduous Shrubs-Flowers/Fruit/Seed
General Arthropods
Food Habits - 1 (DRAFT) - Environment Associations
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
Environment Associations - 1 (DRAFT) - Life History
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
The black-capped vireo rarely leaves the trees and shrubs. It
feeds mainly in the upper strata of this vegetation, gleaning insects
from trees, especially oaks. The bulk of its food is larvae, and most
of these are Lepidoptera. It has been observed eating small
butterflies (Pieridae) and, on one occasion, a large dragon-fly
(Odonata, Aeschnidae). The young are fed mainly small larvae,
sometimes spiders, and small flies. As they grow, the items brought
to them are larger; bigger larvae, small grasshoppers, and katydids.
As much as a third of their food may be orthopterans (08).
Stomach contents of 11 black-capped vireos were summarized by
Graber (08). Lepidopterans were found in 10 and Coleopterans in nine
of the 11 stomachs. Spiders and Hemipterans were each found in four
stomachs while Homopterans were found in three. Centipedes,
Orthoperans, Neuropterans, Odonatans, and Dipterans were found in only
one or two of the 11 stomachs sampled. Most of the items found have
also been found in stomachs of other vireos (08,10).
Black-capped vireos, like other vireos (10), eat some vegetable
matter in fall and winter. The stomachs of two immatures taken in
Mexico in December, contained over 50 percent seeds (08). The weather
was cool and these birds may have resorted to vegetable food in the
absence of insects. An adult taken in a warmer locale a few days
earlier had only two small seeds in its stomach. No vegetable matter
was found in the stomachs of specimens collected in summer.
The black-capped vireo can live without surface water. Much of
its food (insect larvae) has a high water content. Birds take
advantage of dew and rain when it occurs.
HOME RANGE/TERRITORY:
On arrival on the breeding grounds, the male chooses a territory
which remains his as long as he defends it. Banded birds were
observed for three successive years in a study area in Caddo County,
Oklahoma (08). Of 12 males banded in 1954, nine returned in 1955 and
five in 1956. Four of five males banded in 1955 returned in 1956.
Seven of the 13 returnees occupied identical territories in their
second season, five occupied territories adjoining those of the
previous season, and one moved nearly one half mile. Of the five
males that returned for a third season, three occupied the same
territory all three years and the other two occupied the same one
during the last two years.
Seven of 21 banded females returned for a second year to the
study area. Three returned to the same territory in year 2, two were
in adjacent territories, and two moved about one quarter mile. Two of
12 females from year 1 returned in year 3; one to the same territory
it had occupied in year 1 (not seen in year 2), and the other to her
third new territory (all adjacent).
The territory included the space in which the pairs engaged in
all their daily activities, though in some instances they left their
territories to reach water sources shared by all. The boundaries of
territories changed little during the three years. If a territory was
unoccupied, neighboring birds tended to occupy it, thus enlarging
Life History - 1 (DRAFT) - Life History
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
their own territory. Territories ranged from 2.5 to 4.6 acres
(average of 3.7 acres).
Males maintain territory by song. There is a special territorial
song, a rapid, bubbling song, much like the courtship song but usually
louder (08). Graber (08) saw males flying (pouncing) at one another,
but no actual fighting.
PERIODICITY:
This species is diurnal; birds may be more active early in the
day (08). Males will sing throughout the day (06).
MIGRATION PATTERNS:
Vireos regularly arrive on territory about a week after the
average date of the last frost (08); mid- to late March in southern
Texas (11) and about a month later at the northern extent of its range
(08,12). Males regularly arrive a week or two before the females
(08).
The young of the year leave the breeding grounds first. Adult
females may leave next, and adult males remain the longest. The
earliest arrival record in western Mexico is August 27 (adult female).
Latest sighting dates (and locations) recorded for adult females are:
August 28, 1955 (Kerrville, TX) (08); September 6, 1884 (San Angelo,
TX) (13); and September 9, 1954 (Caddo Co., OK) (08). For males,
latest sighting dates (and locations) are: September 11, 1955 (Hays
Co., TX) (08); September 25, 1884 (San Angelo, TX) (13); and September
17, 1954 (Caddo Co., OK) (08).
COVER/SHELTER REQUIREMENTS:
This species has no special cover/shelter requirements other than
its preferred habitat (see N-HABITAT). Trees and brush provide
shelter during inclement weather (08).
Vireo atricapillus (black-capped vireo) use habitats restricted
to areas with scrub-oak growth of irregular height and distribution,
with spaces between the small thickets and clumps, and with vegetation
cover down to ground level for breeding (08).
The habitats preferred by vireos are potentially ephemeral
subclimax growths which can be maintained best under edaphic
conditions in gulleys, edges of ravines, and on eroded slopes. Other
areas can be suitable as they recover from clearing or burning.
Floristic and physiognomic features of habitat were compared
between areas occupied by vireos and other scrub land areas where no
black-capped vireos were present (12). In Texas, Juniper ashei
(Mountain cedar) was less common in vireo territories while Quercus
harvardii (Shin-oak) was more common. The analysis of cover types
indicated that 55 percent of vireo habitat is relatively open and
comprised of non-woody elements. Vireos are seldom seen in anything
but woody vegetation. The openness may enhancee prey (insect)
availability. Shrubs were taller in vireo territories and bushes were
spaced slightly closer, though the differences were not statistically
significant. Dominant plants in vireo territories vary throughout
their breeding range, even within 100 km distances.
REPRODUCTIVE SITE REQUIREMENTS:
Life History - 2 (DRAFT) - Life History
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
Black-capped vireos build an open nest of dead leaves, dried
grasses, strips of bark, spider webs, and numerous other materials
(08). The nest is a cupped, pensile structure; generally six inches
deep and wide and walls one inch thick (08). The nest is placed in a
crotch between limbs. The height of 67 Oklahoma nests ranged from 18
to 66 (mean 34.5) inches. Thirty-four Texas nests ranged from 37 to
74 inches (mean 44) (08). Most recent nests were between 15 and 35
inches in height (12).
Of 70 Oklahoma nests from the 1950's, the majority were in
blackjack oaks (Quercus marilandica - 51) and post oaks (Q. stellata -
12) (08). Of 37 Texas nests Spanish oak (Q. texana - 12), evergreen
sumac (R. virens -11) and mountain cedar (Juniperus ashei - 9) were
the most important nest sites. Four of five 1950's Mexican nests were
in scrubby oak (Quercus sp.) (08). In the 1980's, nests sites were
again recorded. In Oklahoma blackjack oak was still the prevelant
nest site. Shin-oak (Q. harvardi) was most used on Kerr WMA in Texas,
and sumacs (Rhus sp.) at Wild Basin, Texas. Compared with available
species, juniper was under-represented and yaupon holly
(Ilex vomitora) was over-represented at Wild Basin, while at Kerr WMA,
shin-oak was over represented and live-oak (Q. virginiana) was
under-represented in the nest site sample. A variety of other shrubby
plants have been used as nest sites (08).
REPRODUCTIVE CHARACTERISTICS:
Pairs are formed immediately upon arrival of the females, who
appear to choose the male and territory together. Courtship consists
of song and display. Birds can breed during their first spring, but
it was uncommon in the 1950's in Oklahoma (08). Females unsuccessful
in their first nesting attempt will renest nearby, usually with the
same mate. Double-brooding does occur. In one recorded case of
double-brooding, the female changed mates for the second nesting
because the first male was preoccupied with the first brood. Several
territories contained the same birds for two or more years, but others
changed mates each year or occasionally at mid-season (08).
Egg-laying reaches a peak in June in Oklahoma and May in Texas
(08). Four eggs generally comprise a clutch; three egg clutches are
also common. Both sexes incubate. Incubation varies from 14 to 17
days. Young leave the nest when 10 to 13 days old (08).
PARENTAL CARE:
The male begins to bring food to the nest within a few hours of
hatching. The chicks are brooded by the female during the cooler
portions of the day, and at night usually until they are 7 days old.
One or the other adult is usually present at or near the nest. Males
provide approximately 75 percent of all food brought to the nest.
There is generally a peak in feeding in early morning and late
afternoon. After each feeding the adults look for fecal sacs, which
appear to normally be discharged only at this time. The nests are
kept clean not only of excreta and egg shells but also of other
debris. The young in the nest are actively defended by the adults who
threaten, pounce, and snap their bills at intruders. Adults may care
for fledged young for as long as 44 days (08).
Life History - 3 (DRAFT) - Life History
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
POPULATION BIOLOGY:
Thirteen of 17 (76 percent) banded males returned the following
year to Graber`s Oklahoma study area and 5 of 12 (42 percent)
returned in year 3 (08). Nine of 21 (43 percent) banced females
returned in year 2 to Graber's Oklahoma study area and 2 of 12
(17 percent) returned in year 3 (08). One year survivorship between
1985 and 1986 of banded males was 61 percent (17 of 28) and 27 percent
(4 of 15) for banded females (12). Estimates for females may be low
because of the difficulty in locating them, and their lower site
fidelity.
Minimum population estimates of vireos in 1985; Texas - 188 to
374 pairs; Oklahoma - 20 pairs; Mexico - 48 to 131 pairs (06). Not
all sites were revisited in 1986, but the two largest colonies known
at the time (Rock Pasture of the Kerr WMA and Wild Basin) remained
stable. However, the Buck Pasture colony at Kerr WMA dropped from
16-17 males in 1985 (12). On the plus side, intensive surveys of
Ft. Hood showed that perhaps 100 pairs were present there in 1987
(13).
Adults do not appear to be reproducing at a rate capable of
replacing themselves during their average lifespan (12). Using an
average lifespan of 3 years (about 65 percent annual survival), about
1.3 young/pair/year are needed for replacement. Since only 0.85
young/pair were produced in Texas populations where cowbird control
was not practiced, this implies that vireo populations there are
declining (12).
It appears that neighboring males help to maintain the intensity
of breeding activity later into the summer (12). Thus many of the
smaller breeding populations may be contributing little to the overall
population of black-capped vireo.
SPECIES INTERRELATIONSHIPS:
The most significant interrelationship between another species
and the black-capped vireo is with its nest parasite, the brown-headed
cowbird (Molothrus ater). The cowbird can cause almost complete
nesting failure in a population of vireos. For example, in the vireo
population at Ft. Hood in 1987, 37 nests were found and 35 were
parasitized by cowbirds. Only three young vireos were fledged (13).
High rates of parasitism have been reported previously (06,08,09).
High rates of parasitism is one of the major reasons this species was
listed as endangered (01).
During the 1986 breeding season at Wild Basin, Texas, decreased
productivity may have been in part due to predation by scrub jays
(Aphelocoma coerulescens) (12). Predation by other birds and mammals
undoubtedly also occurs.
OTHER LIFE HISTORY DESCRIPTORS:
None.
Life History - 4 (DRAFT) - Management Practices
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Prescribed/controlled burning of habitat
Beneficial Selective Thinning
Beneficial Restricting/regulating human disturbance of populations
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Land Acquisition
Beneficial Controlling/Restricting Herbicide Use
Beneficial Maintaining Later Stages of Succession
Beneficial Controlling/Removing Native Vegetation
Beneficial Controlling/Removing Native Vertebrates
Beneficial Controlling/Removing Exotic Vertebrates
Beneficial Controlling/Removing Feral Animals
Beneficial Controlling/Removing Domestic Animals
Adverse Harassment/Vandalism/Indiscriminate Killing
Existing Harassment/Vandalism/Indiscriminate Killing
Adverse
Existing
Adverse Parasites
Existing Parasites
Adverse Rural Residential/Industrial Areas
Existing Rural Residential/Industrial Areas
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Transmission Lines/Towers
Existing Transmission Lines/Towers
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse Grazing
Existing Grazing
Adverse
Existing
Adverse Suppressing wildfire
Existing Suppressing wildfire
Adverse Vegetation Composition Changes
Existing Vegetation Composition Changes
Adverse Forest Alteration
Existing Forest Alteration
Adverse Harvesting
Existing Harvesting
COMMENTS ON MANAGEMENT PRACTICES -
Major threats to black-capped vireo habitat include possible
real estate development; grazing by sheep, goats, and other introduced
exotic herbivores (which remove vegetation cover near ground level
that is necessary for vireo nesting); and range improvement that
involves the removal of broad-leaved, woody vegetation (06). In
addition, any activity such as agricultural development, construction
of highway or utility rights-of-way that divides the habitat into
narrow strips, making the vireo's nests more vulnerable to cowbird
Management Practices - 1 (DRAFT) - Management Practices
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
parasitism, poses a threat (07). In the Austin area, which contains
one of the largest known concentrations of black-capped vireos,
88 percent of the vireo population may be extirpated by development
and road construction. The City of Austin's Department of Planning
and Growth Management estimates that most of the habitat for this
population will be lost in the next 5 to 10 years (01) if the
anticipated rate of development is realized. Also extensive evidence
of heavy grazing, trampling, and browsing exists on Edwards Plateau.
In addition to a substantial Angora goat industry, the Plateau
contains a variety of herbivorous, exotic game species. The area is
extensively overgrazed (06).
Graber believed that land use (overgrazing) and climatic
conditions (drought) made former habitat in southern and southwestern
Kansas unaccepatable (08).
Vegetational sucession may also lead to a reduction in vireo
habitat. On level terrain with good soil, succession will convert
vireo habitat either to prairie grass, closed-canopy hardwood forest,
or cedar brakes so dense that the necessary understory is suppressed
(07).
The black-capped vireo is especially attractive to ornithologists
and amateur birders. Nests have failed or been abandoned due to
excessive activities of photographers; one territory was possibly
abandoned because of frequent harassment from tape-recorded songs
(06).
Cowbird parasitism: In the 1950's, 55 percent of all vireo eggs
laid were lost before hatching and of this 72 percent was due to nest
parasitism by brown-headed cowbirds (Molothrus ater) (08). Cowbirds
lay their eggs in vireo nests before the clutch is completed. The
cowbirds eggs hatch 2-4 days before the vireos and by the time the
vireos hatch the cowbird nestlings outweigh them tenfold. In all
cases anywhere cowbird nestlings occupied the nest, no vireo chicks
survived (08). In a recent study, cowbird nest parasitism was 79
percent in selected areas in Oklahoma and Texas. When cowbird
trapping was initiated in the same areas, nest parasitism declined to
22 percent. Nest success increased from 14 percent pre-trapping to
39 percent with cowbird removal (09). Man-made changes in landscape
and land-use patterns, especially the opening up of forests for
agricultural practices and the spread of cattle in the last 150 years,
appear to have favored the brown-headed cowbird. The clearing of
brush and scrub has inter-spersed good vireo habitat with good cowbird
habitat (ecotone or edge), increasing the chance of parasitism of
vireos occurring.
UNAPPROVED PLAN:
No projected date for the formation of a recovery plan has been set.
The species was listed as Endangered on October 6, 1987.
The black-capped vireo is threatened by brown-headed cowbird
(Molothrus ater) nest parasitism and by loss of habitat due to such
factors as urbanization, grazing, range improvement, and succession.
Already considerable effort is being made to assist the recovery of
this vireo.
Management Practices - 2 (DRAFT) - Management Practices
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
A recovery plan for this species is likely to call for:
1) Control of cowbirds in known vireo concentration areas.
2) Monitoring of known populations and their productivity.
3) Searches for currently unknown populations.
4) Cooperation with private landowners to improve and protect
vireo habitat through easements, agreements, or land
acquisition.
5) Acquisition of management responsibilities for populations
on private lands.
6) Controlled burns or selective thinning of natural
vegetation to improve habitat and maintain intermediate or
later successional stages.
7) Implementation of the full powers of the Federal and Texas
Endangered Species Acts to benefit the species (i.e., Sect.
7 consultations).
8) Passage of an Endangered Species Act in Oklahoma.
9) Controlling loss of habitat to urban development and
grazing (domestic, exotic, and feral livestock).
10) Conducting studies of the ecology of vireos and cowbirds.
11) Limiting human access during nesting season to areas of
known concentration, and
12) Limiting herbicide use for range improvement if the
herbicide is known to be harmful to this species.
Finally, public awareness of the uniqueness of the black-capped
vireo should be increased through the use of the local, state and
national broadcast and print media.
Current Recovery Activities: Brown-headed cowbird traps were
maintained in 1986 and 1987 at Methodist Camp, Canadian Co., Oklahoma;
Kerr Wildlife Management Area, Kerr Co., Wild Basin Wilderness
Preserve, Travis Co., (first three also in 1985), Big Bend National
Park, Brewster Co., Lost Maples State Natural Area, Bandera Co., Hill
Country State Natural Area and South Llano State Park, Kimble Co.,
Meridian State Park, Bosque Co., and Dinosaur Valley State Park,
Bosque Co., Texas. Populations and productivity of black-capped
vireos are being monitored at these and other sites (i.e., Ft. Hood,
Tex.). Studies on the ecology of vireos and cowbirds are also being
conducted by Gryzbowski and others. The City of Austin is close to an
agreement that will set aside a preserve of 200 acres of vireo
habitat near Wild Basin Wilderness.
Management Practices - 3 (DRAFT) - References
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 U.S. Fish and Wildlife Service. 1986. Endangered and threatened
wildlife and plants; proposal to determine the black-capped vireo
to be an endangered species. Fed. Reg. 51:44808-44812.
02 Oberholser, H.C. 1974. The bird life of Texas. E.B. Kincaid,
Jr. (ed.), Univ. Tex. Press; Austin and London.
03 Woodhouse, S.W. 1852. Descriptions of a new species of the genus
Vireo. Veill. and Zonotrichia. Swains. Proc. Acad. Nat. Sci.
Phil. 6:60.
04 Deignan, H.G. 1961. Type specimens of birds in the United States
National Museum. Bull. U.S. Natl. Mus. 221:1-718.
05 Phillips, A.R. 1968. A notable specimen of Vireo nelsoni.
Condor 70:90.
06 Marshall, J.T., R.B. Clapp, and J.A. Grzybowski. 1985. Status
report: Vireo atricapillus Woodhouse, Black-capped Vireo. U.S.
Fish and Wildl. Serv., Albuquerque, NM.
07 Gryzbowski, J.A., R.B. Clapp, and J.T. Marshall. 1984. Interim
status report on the Black-capped Vireo. U.S. Fish and Wildl.
Serv., Albuquerque, NM.
08 Graber, J.W. 1961. Distribution, habitat requirements, and life
history of the black-capped vireo (Vireo atricapillus). Ecol.
Monogr. 31:313-336.
09 Gryzbowski, J.A. 1985. Final report: population and nesting
ecology of the Black-capped Vireo (Vireo atricapillus). U.S. Fish
and Wildl. Serv., Albuquerque, NM.
10 Chapin, E.A. 1925. Food habits of vireos. U.S. Dept. Agr. Bull.
1355.
11 Lacey, H. 1911. The birds of Kerrville, Texas and vicinity.
Auk 28:200-219.
12 Gryzbowski, J.A. 1986. Interim report: population and nesting
ecology of the Black-capped Vireo (Vireo atricapillus). U.S. Fish
and Wildl. Serv., Albuquerque, NM. 57 pp.
13 Hoffman, S.F. 1987. Pers. comm. U.S. Fish and Wildl. Serv.,
Albuquerque, NM.
14 American Ornithologists' Union. 1983. Checklist of North American
birds, 6th edition. Allen Press, Inc., Lawrence, KS. 877 pp.
15 Birkenstein, L.R., and R.E. Tomlinson. 1981. Native names of
Mexican birds. U.S. Dept. of Interior, Fish and Wildl. Serv.,
Resour. Publ. 139, Wash., D.C. 159 pp.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Marshall, J.T., R.B. Clapp, and J.A. Grzybowski. 1985. Status
report: Vireo atricapillus Woodhouse, black-capped vireo. U.S.
Fish and Wildl. Serv., Albuquerque, NM.
02 Gryzbowski, J.A. 1985. Final report: population and nesting
ecology of the black-capped vireo (Vireo atricapillus). U.S. Fish
and Wildl. Serv., Albuquerque, NM.
03 McKinney, B.R. 1987. Population status of Vireo atricapillus
References - 1 (DRAFT) - References
Species VIREO, BLACK-CAPPED
Species Id ESIS102007
Date 14 MAR 96
Woodhouse in the Big Bend region of Texas, 1987. U.S. Fish and
Wildl. Serv., Albuquerque, NM.
04 Barlow, J.C. 1967. Nesting of the black-capped vireo in the
Chisos Mountains, Texas. Condor 69:605-608.
05 Oberholser, H.C. 1974. The bird life of Texas. E.B. Kincaid,
Jr., (ed.), Univ. Tex. Press; Austin and London.
06 Brewster, W. 1879. Notes upon the distribution, habits, and
nesting of the black-capped vireo (Vireo atricapillus). Bull.
Nuttall Ornith. Club 4:99-103.
07 Graber, J.W. 1961. Distribution, habitat requirements, and life
history of the black-capped vireo (Vireo atricapillus). Ecol.
Monogr. 31:313-336.
08 U.S. Fish and Wildlife Service. 1986. Endangered and threatened
wildlife and plants; proposal to determine the black-capped vireo
to be an endangered species. Fed. Reg. 51:44808-44812.
09 Bruner, L. 1896. Some notes on Nebraska birds. State Journal
Co., Lincoln, NE.
10 Weeks, L.T. 1902. U.S. Fish and Wildlife Service records,
Smithsonian Instit., Wash., D.C.
11 Cook, U.W. 1909. Migration of vireos. Bird-lore, Vol. 11
pp. 118-129.
12 Zimmerman, G.B. 1951. U.S. Fish and Wildlife Service records,
Smithsonian Instit., Wash., D.C.
13 Woods, W.P. 1916. U.S. Fish and Wildlife Service records,
Smithsonian Instit., Wash., D.C.
14 Tordoff, H.B. 1956. Checklist of the birds of Kansas. Univ. of
Kansas Mus. of Nat. Hist. Publ., Vol. 8. pp. 307-359.
15 Gryzbowski, J.A. 1987. Pers. comm. with William Gill and ref.
9-14 and 16. U.S. Fish and Wildl. Serv., Endangered Species,
Wash., D.C. 20240.
16 Imhof, T.A. 1978. Central southern region. Sept. 1978. Am.
Birds 32(5):1020.
17 Sheppard, J. 1987. Pers. comm. with William Gill, U.S. Fish and
Wildlife Serv., Endangered Species, Wash., D.C. 20240.
References - 2