Willow Flycatcher
Common
Name:
Willow
Flycatcher (WIFL)
Scientific
Name: Empidonax
traillii
Global/Continental
Conservation Status: Not
on the IUCN 2004 Red List
National-level
Conservation Status:
U.S. Endangered Species Act (ESA) - Endangered (
Southwestern WIFL
subspecies E. t. extimus)
Key
Reference(s):
BNA No. 533 (Sedgwick 2000); Recovery plan (
U.S.
Fish & Wildlife Service 2002); Ecology & conservation of the
Willow Flycatcher (Sogge et al. 2003)
Distribution:
Breeds
from c British Columbia, s Alberta, s Saskatchewan, sw Manitoba, n North
Dakota, w and s Minnesota, c Wisconsin, Michigan, s Ontario, sw Quebec, c
Maine, New Brunswick, Prince Edward Island and Nova Scotia (possibly)
south to s California (local, formerly widespread), n Baja California and
n Sonora (at least formerly), s Arizona (locally), s New Mexico, ne
Oklahoma, Arkansas (rarely), ne Louisiana, c Tennessee, n Georgia, w South
Carolina, w North Carolina, and c and e Virginia.
Winters in Middle America from Nayarit and sw
Oaxaca
south to
Panama
and possibly extreme nw
Columbia
(AOU 1998).
Habitat
Associations:
Breeds in moist, brushy thickets, open second growth, and riparian
woodland, especially with willow and buttonbush; winters in Tropical
Lowland Evergreen Forest Edge, Second Growth forest, and Second Growth
Scrub (AOU 1998).
Source(s)
of Research/monitoring Needs (Number in ( ) is Physiographic Area number):
Southern New England (09); California Bird Conservation Plan –
Riparian & Sierra Nevada Range; Oregon/Washington Bird Conservation
Plan - Columbia Plateau; Arizona Bird Conservation Plan; Nevada Bird
Conservation Plan; Montana Bird Conservation Plan; Texas Avian Research
Projects- TARP (Texas Partners in Flight 2001); Canadian Action Plans
(Dunn 2002); PIF Monitoring Needs document (Partners in Flight Science
Committee 2004)
PIF
Continental Plan Monitoring Needs Category: ** (Long-term population
trend monitoring considered adequate, but some issues (e.g., bias) may not
be accounted for)
RESEARCH/MONITORING NEEDS (source(s) of needs)
NOTE: See Recovery Plan
for additional research/monitoring needs.
Monitoring
- Priority
monitoring action – NOTE: Breeding
Bird Survey (BBS) provides acceptable data at the continental level (PIF
Monitoring Needs doc)
- Supplemental
WIFL Surveys
- Develop statewide bird monitoring efforts (including WIFLs) that
include riparian shrub habitats (
Montana
); Determine population status and trends for Southwest WIFLs (
Nevada
)
- Surveys
to identify breeding locations & suitable habitat
- Continue statewide surveys to identify WIFL breeding locations and
suitable habitat (Arizona); Determine if Southwestern WIFL breed in
these regions of Texas (include surveys of unoccupied, yet seemingly
suitable, breeding habitat) (TARP - Chihuahuan Desert & Mexican
Mts); Better knowledge of historic & current distribution &
habitats to understand causes & patterns of decline (BNA);
Identify meadows throughout the Sierra Nevada that are valuable to
breeding, dispersing, and migrating birds (including WIFLs)
(California)
Habitat
Needs/Ecology/Life History
- Study
the nesting ecology and habitat relationships of WIFLs
(Oregon/Washington)
- Determine
if riparian shrub habitat within an agricultural landscape can support
WIFLs (Oregon/Washington)
- see
needs under "Wintering"
Effects
of Management Practices
- Management
for Early-Successional Forests - Determine how various treatments in early-successional
stages affect shrub-associated bird species (including WIFLs)
(Oregon/Washington); Compare breeding densities & nesting success
in habitats w/ natural disturbance, forestry practices, & power
line rights-of-way (
Southern New England
)
- Determine
what mitigation measures replicate the effects of natural flows in
riparian deciduous forests (
Montana
)
- Effects
of livestock presence around WIFL nests on behavior & nesting
success (
California
)
- Effects
of water development, grazing, recreation, & pesticide use on WIFL
(BNA)
- see
needs under "Species Interactions" and "Effects of
human dev/disturb"
Effects
of Human Development/Disturbance
- Effects
of human presence around WIFL nests on behavior & nesting success
(
California
)
Landscape
- Effects
of landscape on nesting success - Determine if landscape components or adjacent land-uses are
significant to WIFL nesting success (Oregon/Washington); Determine
relationship between patch size & nesting success (
Southern New England
)
Species
Interactions
- Effects
of woodcock habitat management on breeding density & nesting
success of WIFL (
Southern New England
)
- see
needs under "Wintering"
Nest
Parasitism
- Effects
of Brown-headed Cowbirds (BHCO) - Determine how serious a threat BHCOs are, how it varies with
landscape, habitat, and cattle distribution (BNA); Monitor effects of
cowbird parasitism on reproductive success in WIFL (
Southern New England
); Determine the effect of cowbirds on WIFLs in agricultural
landscapes (Oregon/Washington)
Migration
- Identify
important migration stopovers, determine habitat use, and evaluate
migrant condition & stopover time (BNA)
Wintering
- Identify
winter habitat selection and preferences, factors limiting winter
survival, and inter- and intra-specific resource competition (BNA)
Invasives/Exotics/Disease/Parasites/Contaminants
- Effects
of exotic vegetation on WIFL reproductive success and prey abundance;
evaluate need for & potential effects of tamarisk control (BNA)
- see
needs under "Effects of Management Practices"
Demographics
- Studies
to gather key demographic information on WIFL - Monitor WIFL nests to determine nesting
success, parasitism rates, and predation rates (Arizona); Monitor
WIFLs and determine demographic parameters and population viability
(Nevada); Demographic studies to identify source/sink pops,
survivorship, fidelity, age structure, and recruitment (BNA);
Determine WIFL status, territory size, site fidelity, natal and adult
dispersal, and renesting attempts (Arizona)
- Determine
factors affecting demographics - Conduct selective monitoring at key riparian sites to determine
the factors influencing nest success (including WIFL) (
California
); Study reproductive success, site fidelity, survivorship, and
vegetative structure of selected populations to determine net
reproductive rate (
California
)
Habitat
Restoration
- Monitor
WIFL response to meadow revegetation & restoration (
California
)
Genetics/Taxonomy/Systematics
- Subspecies
issues
- Studies of geographical correspondence of morphological, genetic,
and vocal differentiation to better define geographical range of
Southwestern WIFL
(E. t. extimus) (BNA);
Clarify subspecies status in northern California & east of the
Sierra Nevadan crest (California)
- Effects
of small population size and reduced genetic variation on population
viability (BNA)
[Link
to References]
[Link
to PIF Bird Conservation Plans]
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