California Gnatcatcher
Common
Name:
California
Gnatcatcher (CAGN)
Scientific
Name: Polioptila californica
Global/Continental
Conservation Status: Not on IUCN 2004 Red List
National-level
Conservation Status:
U.S.
– Endangered Species Act (ESA) -
Threatened (coastal CAGN subspecies – P.
c. californica)
Key
Reference(s):
BNA No. 574 (Atwood and Bontrager 2001)
Distribution:
Resident from sw
California
(north to
Los Angeles
County
, formerly in
Ventura
County
) and nw
Baja California
south locally to s
Baja California
(including Santa Margarita and
Espíritu Santo
islands) (AOU 1998).
Habitat
Associations:
Coastal sage scrub (in
California
), thorn forest, desert brush, and scrub (AOU 1998).
Source(s)
of Research/monitoring Needs: California Bird
Conservation Plan; BNA No. 574 (Atwood and Bontrager 2001); PIF Monitoring
Needs document (Partners in Flight Science Committee 2004)
PIF
Continental Plan Monitoring Needs Category: Mo1 (Essentially no data on
population trend); Mo4 (2/3 or more of the Western Hemisphere breeding
range is south of
U.S.
(PIF Monitoring Needs doc)
RESEARCH/MONITORING NEEDS (source(s) of needs)
Monitoring
- Priority
monitoring action – Conduct Mexican Breeding Bird Surveys (BBS) (PIF
Monitoring Needs doc)
- Second
priority monitoring action – Conduct border (U.S.-Mexico) bird
surveys (PIF Monitoring Needs doc)
- High
priority candidate for rapid status assessment (PIF Monitoring Needs
doc)
- Supplemental
CAGN Surveys
- Off-road monitoring should be applied in coastal scrub habitats (BBS
not adequate) (
California
); Directly monitor nest success & factors that influence it in
replicate sites to evaluate management options (
California
)
- Understanding
CAGN meta-populations - Better understanding of varying CAGN densities in coastal &
inland areas (territory size requirements, reproductive success,
recruitment, survivorship?) (BNA); Comparisons of northern and
southern populations; how do population dynamics & biology differ?
Are there morphological, behavioral or genetic differences? (BNA); see
needs under “Landscape”
- see
needs under "Landscape"
Habitat
Needs/Ecology/Life History
- How
do CAGN respond to fire (frequency, intensity, timing & extent)?
(BNA)
- Other
Information on CAGN Life History - Information on early pair bonding behavior that involves
juveniles less then 3 months old (BNA); Information on nutritional
& energetic strategies of females (BNA)
Effects
of Management Practices
- Determine
effectiveness of using archipelagos of small habitat islands rather
than large unbroken reserves in conservation (in light of
susceptibility of large tracts to fire) (BNA)
- Retrospective
analysis of land use planning decisions made in the NCCP process (BNA,
see details there)
- How
should protected lands be managed for CAGN and coastal sage scrub
community? (recreation? exotics? cowbird control? monitoring?) (BNA)
- See
needs under “Monitoring”
Landscape
- Examine
spatial & temporal effects of increased levels of habitat
fragmentation & isolation on CAGN population dynamics (BNA)
- Study
dispersal behavior & role of different landscape features in
maintaining connectivity among subpopulations (BNA)
- See
needs under “Monitoring”
Species
Interactions
- Information
on CAGN behavior in areas where it is sympatric with Black-tailed
Gnatcatcher (BNA)
Wintering
- Determine
combinations of temperature and rainfall that sometimes result in
substantial winter mortality (BNA)
Demographics
- More
information on CAGN survivorship, productivity, & dispersal
capability (
California
)
- Are
annual fluctuations in population size caused by reproductive success
or mortality? (BNA)
- See
needs under “Monitoring”
[Link
to References]
[Link
to PIF Bird Conservation Plans]
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