The brown anole, Anolis sagrei, is a native species to the Caribbean; however,
A. sagrei has invaded multiple parts of the USA, including Florida, Louisiana, Hawai'i
and more recently California. The biological impacts of A. sagrei invading California
are currently unknown. Evidence from the invasion in Taiwan shows that they
spread quickly and when immediate action is not taken eradication stops being a
viable option. In Orange County, California, five urban sites, each less than 100 ha,
were surveyed for an average of 49.2 min. Approximately 200 A. sagrei were seen
and verified across all survey sites. The paucity of native lizards encountered during
the surveys within these sites suggests little to no overlap between the dominant
diurnal western fence lizard, Sceloporus occidentalis, and A. sagrei. This notable lack
of overlap could indicate a potentially disturbing reality that A. sagrei are driving
local extirpations of S. occidentalis.
The arroyo southwestern toad is a specialized and federally endangered amphibian endemic to the coastal plains and mountains of central and southern California and northwestern Baja California. It is largely unknown how long these toads live in natural systems, how their population demographics vary across occupied drainages, and how hydrology affects age structure. We used skeletochronology to estimate the ages of adult arroyo toads in seven occupied drainages with varying surface water hydrology in southern California. We processed 179 adult toads with age estimates between 1 and 6 years. Comparisons between skeletochronological ages and known ages of PIT tagged toads showed that skeletochronology likely underestimated toad age by up to 2 years, indicating they may live to 7 or 8 years, but nonetheless major patterns were evident. Arroyo toads showed sexual size dimorphism with adult females reaching a maximum size of 12 mm greater than males. Population age structure varied among the sites. Age structure at sites with seasonally predictable surface water was biased toward younger individuals, which indicated stable recruitment for these populations. Age structures at the ephemeral sites were biased toward older individuals with cohorts roughly corresponding to higher rainfall years. These populations are driven by surface water availability, a stochastic process, and thus more unstable. Based on our estimates of toad ages, climate predictions of extreme and prolonged drought events could mean that the number of consecutive dry years could surpass the maximum life span of toads making them vulnerable to extirpation, especially in ephemeral freshwater systems. Understanding the relationship between population demographics and hydrology is essential for predicting species resilience to projected changes in weather and rainfall patterns. The arroyo toad serves as a model for understanding potential responses to climatic and hydrologic changes in Mediterranean stream systems. We recommend development of adaptive management strategies to address these threats.
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii
extimus) were conducted at Marine Corps Base Camp Pendleton, California, between 15 May
and 28 July 2012. Twenty-nine transient flycatchers of unknown subspecies were observed
during Base-wide surveys. Transients occurred on 8 of the 16 drainages surveyed in 2012.
No Willow Flycatchers were detected at Aliso Creek, Cristianitos Creek, De Luz Creek,
Horno Canyon, Newton Canyon, Roblar Creek, San Onofre Creek, or Windmill Canyon.
Transients occurred in a range of habitat types including mixed willow (Salix spp.) riparian,
willow-sycamore (Platanus racemosa) dominated riparian, oak (Quercus sp.)-sycamore
dominated riparian, and riparian scrub.
Monitoring to document breeding success of California least terns (Sternula antillarum browni)
continued in 2012, with observers at 41 nesting sites providing data. An estimated 4293-6421
California least tern breeding pairs established 6636 nests and produced 557-628 fledglings at 49
documented locations. The fledgling to breeding pair ratio was 0.09 to 0.15. Statewide, 11,036
eggs were reported, with a Site Mean clutch size of 1.66 eggs per nest (St Dev = 0.134) and a
Statewide clutch size of 1.65 eggs (St Dev = 0.492) for Type 1 sites. Numbers of nesting least
terns were not uniformly distributed across all sites. Naval Base Coronado, Point Mugu,
Batiquitos Lagoon Ecological Reserve, Camp Pendleton, Huntington State Beach, and Alameda
Point represented 74% of the breeding pairs. Fledgling numbers were also unevenly distributed
as the two sites with at least 90 fledglings each (Hayward and Huntington State Beach)
contributed 38% of the state’s production, and the five sites with greater than 35 fledglings each
(Hayward, Huntington State Beach, Oceano Dunes, Seal Beach, and Lindbergh Field)
contributed 59% of the state’s production. The 2012 chick mortality rate was 49%, continuing
the upward trend observed in the previous four years. With the exception of Batiquitos Lagoon
and Camp Pendleton, the larger nesting colonies experienced chick mortality rates less than the
average, which is opposite that documented in 2011. The most commonly-reported possible,
suspected, or documented predators were common ravens (Corvus corax), American crows
(Corvus brachyrhynchos), peregrine falcon (Falco sparverius), great-blue herons (Ardea
herodias), American kestrels (Falco sparverius), and red-tailed hawks (Buteo jamaicensis). The
predators known to be responsible for the greatest number of depredated least terns in 2012 were
American kestrel, coyote (Canis latrans), common raven, American crow, unknown avian
species, unknown gull species, gull-billed tern (Gelochelidon nilotica), red-tailed hawk,
peregrine falcon, and northern harrier (Circus cyaneus). The monitoring effort of 2012 is
scheduled to continue in 2013.
Monitoring to document breeding success of California least terns (Sternula antillarum browni)
continued in 2014, with observers at 41 nesting sites providing data. An estimated 4232-5786
California least tern breeding pairs established 6038 nests and produced 2136-2859 fledglings at
48 documented locations across California. The fledgling to breeding pair ratio was 0.37 to 0.68.
Statewide, 10,827 eggs were reported, with a Site Mean clutch size of 1.7 eggs per nest (St
Dev=0.29) and a Statewide clutch size of 1.8 eggs (St Dev = 0.45) for Type 1 sites where
monitors walk within the colony. Numbers of nesting least terns were not uniformly distributed
across all sites. Camp Pendleton, Naval Base Coronado, Huntington Beach, Point Mugu, and
Batiquitos Lagoon represented 60% of the breeding pairs. Fledgling numbers were also
unevenly distributed as the sites with at least 90 fledglings each (Camp Pendleton, Alameda,
Batiquitos, Huntington Beach, Point Mugu, Naval Base Coronado, and Hayward), contributed
74% of the state’s production, and the sites with greater than 35 fledglings each (including the
seven aforementioned sites plus Bolsa Chica, Venice Beach, Mariner’s Point, Napa Sonoma
Marsh, and Oceano Dunes), contributed 90% of the state’s production. The 2014 statewide nonpredation chick mortality rate was 20%, similar to that in 2013 (22%). With the exceptions of
Camp Pendleton and Naval Base Coronado, the larger nesting colonies experienced nonpredation chick mortality rates less than the average, similar to that documented in 2013. The
predators known to be responsible for the greatest number of depredated least terns in 2014 were
common ravens (Corvus corax), followed by American crows (Corvus brachyrhynchos),
peregrine falcons (Falco peregrinus), coyotes (Canis latrans), gull species, western
meadowlarks (Sturnella neglecta), unknown species, corvid species, raptor species, great horned
owls (Bubo virginianus), northern harriers (Circus cyaneus), opossums (Didelphis virginiana),
unknown avian species, and American kestrels (Falco sparverius). The monitoring effort of
2014 is scheduled to continue in 2015.
Many of the watersheds in northern coastal San Diego County south of MCBCP are severely impacted
by aquatic nonnative species and pond turtles are at high risk of extirpation in these drainages, if they
are not already extinct in most locations. Similar to the restoration for pond turtles at SPER, the
removal of nonnative aquatic species can release this pressure on extant pond turtle populations or
prepare a site for reintroduction of pond turtles (Brown et al. 2012). However, in the MHCP region, the
extent to which nonnative species are impacting pond turtle populations and habitat is unknown. Before
successful active management can be implemented in the northern coastal drainages of San Diego
County, the distribution and status of pond turtles and aquatic nonnatives must be determined and
suitable habitat must be identified. In 2012, USGS began work on the TransNet Environmental
Mitigation Program grant agreement 5001976 regarding the western pond turtle in order to assess the
distribution of native and nonnative turtles and suitable habitat for pond turtles in coastal northern San
Diego County south of MCBCP.
We surveyed for Southwestern Willow Flycatchers
(Empidonax traillii extimus; flycatcher) along the upper
San Luis Rey River near Lake Henshaw in Santa Ysabel,
California, in 2021. Surveys were completed at four locations:
three downstream from Lake Henshaw, where surveys
occurred from 2015 to 2020 (Rey River Ranch [RRR],
Cleveland National Forest [CNF], Vista Irrigation District
[VID]), and one at VID Lake Henshaw (VLH) that has been
surveyed annually since 2018. There were 78 territorial
flycatchers detected at 3 locations (RRR, CNF, VLH), and
1 transient flycatcher of unknown subspecies was detected
at VID. Downstream from Lake Henshaw, five flycatchers,
including three males and two females, were detected at
RRR and CNF. In total, three territories were established,
consisting of two pairs and one male of undetermined
breeding status. At VLH, we detected 73 flycatchers, including
32 males, 38 females, and 3 flycatchers of unknown sex.
In total, 43 territories were established, containing 38 pairs
(22 monogamous pairings, 7 confirmed polygynous groups
consisting of 7 males each pairing with 2 different females,
and 1 suspected polygynous group consisting of 1 male and
2 females), and 5 flycatchers of undetermined breeding status
(2 males and 3 flycatchers of unknown sex). Brown-headed
cowbirds (Molothrus ater; cowbird) were detected at all four
survey locations.
Flycatchers used five habitat types in the survey
area: (1) mixed willow riparian, (2) willow-cottonwood,
(3) willow-oak, (4) willow-ash, and (5) sycamore-oak.
Eighty-seven percent of the flycatchers were detected in
habitat characterized as mixed willow riparian, and 94 percent
of the flycatchers were detected in habitat with greater than
95-percent native plant cover. Exotic vegetation was not
prevalent in the survey area.
There were 15 nests incidentally located during surveys:
1 was successful, 2 were seen with eggs or nestlings on the
last visit, 9 failed, and the outcome of the remaining 3 nests
was unknown. Three of these nests were parasitized by
cowbirds. There were 13 juveniles detected at VLH during
surveys; no juveniles were detected at RRR or CNF.
Of the 10 banded flycatchers detected during surveys,
7 were resighted and confirmed to be adults that held
territories in previous years. Three flycatchers with a single
dark blue federal band, indicating that they were banded as
nestlings in the former demo
The Hermes copper (Lycaena hermes) is a rare butterfly endemic to San Diego County and
northern Baja California. This species is threatened by urbanization, wildfires, and drought
throughout its range in the United States. Since most individuals and the single (known)
remaining large population are found in the southern portion of San Diego County, one large
fire could extirpate the species in this country.
Past efforts have contributed to our understanding of the distribution of the Hermes copper, so
it is fairly well understood. This includes wildfires in 2003 and 2007 causing several extirpations
with few recolonizations, and more recent droughts further restricting the distribution of this
butterfly. We conducted widespread surveys in 2018 with the goal of detecting unknown
populations; however, conditions were suboptimal due to below average rainfall. Efforts in
2019 and 2020 followed winters with closer to average precipitation. In 2018, one large
population (Roberts Ranch South) was discovered to be larger than previously documented. No
new populations were documented and there was no evidence of recolonization within the
2003 or 2007 wildfire at selected sites. The objective of this project (2022 surveys) was to
further assess the distribution and annual population sizes, possibly with the goal of future
translocations of individuals to reestablish populations. We conducted surveys in many of the
areas sampled during 2019-2021.
The 2022 status of the Hermes copper populations is similar to the last couple years, with the
addition of observations at the San Diego Gas and Electric Substation near Bell Bluff Truck Trail.
However, the number of butterflies were lower than past counts at this site and at Roberts
Ranch South. Sites with fewer than five individuals have been relatively steady over the last few
years. Given these patterns, the long-term viability of the species still appears to be highly
dependent on the Robert Ranch South population.
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 28 July
2009. Thirty-five transient flycatchers of unknown sub-species were observed during Base-wide
surveys. Transients occurred on 10 of the 16 drainages surveyed in 2009. No Willow
Flycatchers were detected at Aliso Creek, Cristianitos Creek, Fallbrook Creek, Horno Canyon,
Piedra de Lumbre Canyon, or Roblar Creek. Transients occurred in a range of habitat types
including mixed willow (Salix spp.) riparian, willow-sycamore (Platanus racemosa) dominated
riparian, oak (Quercus sp.)-sycamore dominated riparian, riparian scrub, and upland scrub. The
distance from transient locations to the nearest surface water averaged 451 ± 593 m (std, n = 35).
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 31 July
2010. Twenty-five transient flycatchers of unknown sub-species were observed during Basewide surveys. Transients occurred on 6 of the 16 drainages surveyed in 2010. No Willow
Flycatchers were detected at Cockleburr Canyon, De Luz Creek, Fallbrook Creek, French Creek,
Horno Canyon, Newton Canyon, Piedra de Lumbre Canyon, Pilgrim Creek, Roblar Creek, or
Windmill Canyon. Transients occurred in a range of habitat types including mixed willow (Salix
spp.) riparian, willow-sycamore (Platanus racemosa) dominated riparian, oak (Quercus sp.)-
sycamore dominated riparian, riparian scrub, and upland scrub. The distance from transient
locations to the nearest surface water or saturated soil averaged 245 ± 240 m (std, n = 25).
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii
extimus) were conducted at Marine Corps Base Camp Pendleton, California, between 24 June
and 12 August 2011. Surveys in 2011 began later than usual (late June vs. 15 May) because
of contract delays. Consequently, data collected in 2011 may not be directly comparable to
other years and represents a minimum population estimate. Drainages containing riparian
habitat suitable for flycatchers were surveyed one to three times.
No transient flycatchers of unknown sub-species were observed during Base-wide
surveys.
The Hermes copper (Tharsalea hermes) is a rare butterfly endemic to San Diego County and northern Baja California. This species is Federally listed as Threatened, with its decline attributed to urbanization, wildfires, and drought throughout its range in the United States. Since most individuals and the two (known) remaining large populations are found in the southern portion of San Diego County, one large fire could extirpate the species in this country.
Past efforts have contributed to our understanding of the distribution of the Hermes copper, so it is fairly well understood. This includes wildfires in 2003 and 2007 causing several extirpations with few recolonizations, and more recent droughts further restricting the distribution of this butterfly. We conducted widespread surveys in 2018 with the goal of detecting unknown populations; however, conditions were suboptimal due to below average rainfall. Efforts in 2019 and 2020 followed winters with closer to average precipitation. In 2018, one large population (Roberts Ranch South) was discovered to be larger than previously documented. No new populations were documented and there was no evidence of recolonization within the 2003 or 2007 wildfire at selected sites. The objective of this project (2024 surveys) was to further assess the distribution and annual population sizes, possibly with the goal of future translocations of individuals to reestablish populations. We conducted surveys in 2024, covering more sites than sampled during 2019 – 2023.
The 2024 status of Hermes copper populations is similar to the last couple years, with the addition of an observation in Lawson Valley (and continued observations at Lyons Valley and Lawson Peak). These suggest a local population (occupied habitat) in the Lawson Peak area likely survived the recent drought. However, given these data, the long-term viability of the species still appears to be highly dependent on the Roberts Ranch South-Bell Bluff area.
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii
extimus) were conducted at Marine Corps Base Camp Pendleton, California, between 15 May
and 26 July 2013. Forty-five transient Willow Flycatchers of unknown subspecies were
observed during Base-wide surveys. Transients occurred on 10 of the 16 drainages surveyed
in 2013. No Willow Flycatchers were detected at De Luz Creek, Horno Canyon, Newton
Canyon, Piedra de Lumbre Canyon, Roblar Creek, or Windmill Canyon. Transients occurred
in a range of habitat types including mixed willow (Salix spp.) riparian, willow-sycamore
(Platanus racemosa)- dominated riparian, oak (Quercus sp.)-sycamore dominated riparian,
and riparian scrub.
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 20 May and 29 July
2014. Ninety-seven transient Willow Flycatchers of unknown subspecies were observed during
Base-wide surveys. Transients occurred on 9 of the 16 drainages surveyed in 2014. No Willow
Flycatchers were detected at Cockleburr Canyon, Cristianitos Creek, Fallbrook Creek, French
Creek, Newton Canyon, Roblar Creek, or Windmill Canyon. Transients occurred in a range of
habitat types including mixed willow (Salix spp.) riparian, willow-sycamore (Platanus
racemosa)- dominated riparian, oak (Quercus sp.)-sycamore dominated riparian, and riparian
scrub.
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 28 July
2015. Eighty-nine transient Willow Flycatchers of unknown subspecies were observed during
Base-wide surveys. Transients occurred on 10 of the 16 drainages surveyed in 2015. No Willow
Flycatchers were detected at Aliso Creek, Cockleburr Canyon, De Luz Creek, French Creek,
Roblar Creek, or Windmill Canyon. Transients occurred in a range of habitat types including
mixed willow (Salix spp.) riparian, riparian scrub, willow-sycamore (Platanus racemosa)
dominated riparian, willow-cottonwood (Populus fremontii) dominated riparian, and upland
scrub.
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 16 May and 28 July
2016. One hundred and seven transient Willow Flycatchers of unknown subspecies were
observed during Base-wide surveys. Transients occurred on 12 of the 16 drainages surveyed in
2016. No Willow Flycatchers were detected at Cristianitos Creek, Horno Canyon, Roblar Creek,
or San Onofre Creek. Transients occurred in a range of habitat types including mixed willow
(Salix spp.) riparian, riparian scrub, and willow-sycamore (Platanus racemosa) dominated
riparian vegetation. Exotic vegetation including poison hemlock (Conium maculatum) and
black mustard (Brassica nigra) was present in the majority of flycatcher locations.
Surveys for the endangered Southwestern Willow Flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 31 July
2017. Twenty-one transient Willow Flycatchers of unknown subspecies were observed during
Base-wide surveys. Transients occurred on 5 of the 16 drainages surveyed in 2017. No Willow
Flycatchers were detected at Aliso Creek, Cockleburr Canyon, Fallbrook Creek, French Creek,
Horno Canyon, Piedra de Lumbre Canyon, Pilgrim Creek, Roblar Creek, San Mateo Creek, San
Onofre Creek, or Windmill Canyon. Transients occurred in a range of habitat types including
mixed willow (Salix spp.) riparian, riparian scrub, willow-sycamore (Platanus racemosa), and
sycamore-oak (Quercus agrifolia) dominated riparian vegetation. Exotic vegetation including
black mustard (Brassica nigra) and poison hemlock (Conium maculatum) was present in the
majority of flycatcher locations.
Surveys for Harbison’s dun skipper adults were conducted to assess year to year variation in
population size and to collect non-lethal genetic samples. Field visits were also used to
document plants used for nectar sources. The 2017 counts were generally low, and there was
not a clear relationship between the 2016 and 2017 counts as some were higher and some
lower. We were able to collect 16 genetic samples including the first from Santa Margarita Trail,
a second from Fox Springs, and samples three and four from Pamo Valley. Efforts were focused
on sites with small populations and few previous samples, likely the reason for the low number
of 2017 samples.
While past years have been dry, the 2016-2017 winter had several rainstorms, each with
several inches of precipitation. Soil and vegetation, including San Diego sedge, were removed in
locations, altering the skipper’s habitat within the oak woodlands. It was also commonly
observed that the sedge leaves were knocked down by water. Removal of sedge by high water
flow is clearly a threat to the skipper, but it is unknown if short-term flooding of the sedge is a
threat to the larvae. To provide a complete report, we included all 2017 Harbison’s dun skipper
survey data, including our surveys not funded by this project.
This document presents a monitoring protocol for the Stephens’ kangaroo rat (Dipodomys stephensi, SKR) on Marine Corps Base Camp Pendleton (MCBCP). A two-day scientific workshop was held in 2004 for the purpose of designing this program. The workshop attendees included a four member Scientific Peer Review Panel with expertise in spatial and statistical monitoring design and SKR biology, and additional biologists from several federal, state, and local wildlife agencies. The panel and other members reviewed and discussed SKR life history, conceptual models, monitoring schemes, and detection methods before reaching consensus on the basics of a monitoring program. Protocol specifics were determined by consultation among the USGS, the scientific panel, and MCBCP after the workshop.
There is a large body of evidence to show that SKR populations are both spatially and temporally dynamic. SKR abundance and capture probabilities are highly variable making detection of demographic trends problematic and time intensive. Suitable habitat for SKR may also vary through time and space in relation to disturbance and vegetation succession. This is particularly true on MCBCP, where there is a relatively high level of disturbance from frequent fires and military training activities. In consideration of these and other factors, we designed a relatively simple, multi-tiered, habitat-based, adaptive monitoring program for SKR. This monitoring program will track yearly trends in the total area occupied by SKR on base over a large number of fixed sample plots. It includes measurement of habitat and environmental variables that are hypothesized to affect the probability of occupancy, rate of colonization, and/or rate of extinction over time. Predictors that are found to be significant will be used for habitat-based recommendations for management.
It is unknown whether trends in SKR distribution are directly related to trends in SKR abundance; therefore, the program includes a density index. We considered active burrow counts for use as an index, as they have been shown to correlate and trend with SKR density estimates from live-
1
trapping. However, previous monitoring efforts on MCBCP have shown that even in optimum habitat, SKR frequently co-exist with the sympatric Dulzura kangaroo rat (Dipodomys simulans, DKR), and that the proportion of SKR/DKR is both spatially and temporally variable. As a result, we cannot expect a consistent relationship between kangaroo rat burrow co
Vernadero Group Inc. (Vernadero) was contracted by Naval Facilities Engineering Command Southwest on behalf of Marine Corps Air Station (MCAS) Miramar to conduct a Stationwide census for willowy monardella (Monardella viminea) and monitor the species within long-term monitoring plots at MCAS Miramar in San Diego, California. We surveyed and mapped all willowy monardella on MCAS Miramar, identifying adults, mature plants, juveniles, and seedlings. A total of 972 willowy monardella clumps was found during the 2017 census; 278 clumps that had been observed and tagged during previous surveys were not found again during the 2017 census. Clumps were found in six of the nine canyons surveyed and a total of 141 living willowy monardella clumps was recorded in the 17 monitoring plots. The results from the 2017 census and plot monitoring indicate a continuing decline in the number and health of willowy monardella clumps at MCAS Miramar. The cause of the decline in willowy monardella clumps and reproduction is unknown; however, stress to plants from the long-term drought conditions that occurred for the five years prior to the 2017 surveys accompanied by large scouring events in the stream channels from large rainfall events in the 2016 and 2017 growing seasons could have caused mortality in adult willowy monardella plants, reduced the production of viable seeds during drought conditions, and displaced all viable seed produced when drought conditions were relieved by above-average precipitation in 2016 and 2017.
This report provides methods, results, discussion, and recommendations for a study of California Gnatcatcher (Polioptila californica) natal dispersal at a 200 acre (80-hectare) area of open space divided by an interstate highway, in the Lakeside area of San Diego County, California. The study area lies 23 miles east of the Pacific Ocean at the inland edge of a coastal plain and has a relatively warm, dry Mediterranean-type climate. Topography consists predominantly of moderate slopes on either site of Interstate-8 (I-8) with the more southerly parcel of steeper grade. Elevation ranges from about 700 to 1100 feet.
The primary goal of the study was to evaluate whether California Gnatcatcher movement across I-8 occurs at the study area and thus shed light on whether this area serves as a functional corridor - at least for the California Gnatcatcher - as assumed in the MSCP Subarea Plan.
Field work was conducted during dry conditions, and simple nest success (that is, the number of nests that produced fledged young) of the subject species was less than 50%. We found and monitored seven pairs of California Gnatcatchers in our study area. We found a total of 11 nests during the study period, an average of about 1.6 nests per pair of California Gnatcatchers; however only six of the pairs constructed nests. Of the 11 found nests, four were successful, that is, they produced young that fledged; five were abandoned prior to egg deposition; and two were destroyed by causes unknown. We banded young at the nest, or we captured juvenile California Gnatcatchers soon after fledging by strategically placing mist nets within natal territories at locations past which we expected family groups to move. We determined the banding strategy based on our assessment of whether approaching a nest would have a high or low likelihood of affecting the nest outcome. We banded all seven successfully fledged young from the site with no mortality (Table 1). Six of these were banded as fledglings; one was banded as a nestling.
On 23 July 2002 Kylie Fischer documented the occurrence in the Pembroke parcel of a juvenile (left leg white; right leg silver USGS) that had been banded on 11 June 2002 in Territory C-01b-02 of the CalTrans parcel, that is, north of I-8. This bird had been observed on the CalTrans parcel during the previous week (15 July). On 13 September 2002 William Haas detected a banded juvenile (left leg purple; right leg silver USGS) on the Gatlin parcel. This bird
Vernal pools are seasonal, depression-type wetlands which function as micro-habitats that support multiple rare, threatened and endangered species. Vernal pools largely occur on tops of mesas within the western half of San Diego County. Due to decades of expansive urban development, only 5% of the original vernal pool population exists today and many of the remaining pools are severely degraded and are at risk of being destroyed. Vernal pools are now considered sufficiently critical that local, state and federal laws require the protection of vernal pools even when they occur on private property. Successful stewardship of vernal pools is dependent on the ability to locate and monitor the status of the pools and the species that occur within them. Currently, the management and monitoring of vernal pools is performed through field surveys which is time consuming, costly, and limited in spatial coverage. Remote sensing offers the opportunity to derive valuable habitat information at spatial and temporal scales that are not possible with ground sampling.
The utility of high spatial resolution, multispectral imagery was evaluated for multiple tasks associated with vernal pool mapping and characterization, including: locating unknown pools and delineating pool basin extents, mapping vernal pool plants, estimating pool depth, and characterizing land use and land cover adjacent to sensitive vernal pool habitats. ADAR 5500 multispectral imagery was acquired at multiple resolutions within two San Diego County study sites during February and May of 2001. The first site at Otay Mesa was reconstructed in 1998 as part of a land mitigation project and contains over 300 vernal pools within a small geographic area. Naturally occurring pools in this area were scraped and destroyed in the 1970s. The second site at Marron Valley contains a small number of naturally occurring vernal pools. This site is the subject of biological monitoring, as recent fires and many years of cattle grazing have degraded the habitat surrounding the vernal pools.
An experiment was performed with multiple resolutions of imagery at both study sites to determine to optimum spatial resolution for identifying and delineating vernal pools. One foot resolution image mosaics at each site were aggregated to simulate 2 ft, 4 ft, 8 ft, and 16 ft spatial resolutions. Nine interpreters visually identified apparent vernal pools beginning with the lowest resolution imagery and then with progressively higher sp
An estimated 3,451 to 3,674 pairs of California least terns nested at 36 nesting sites in 1999
and produced an estimated 671 to 711 fledglings. These estimates result in 0.18 to 0.21
fledglings per pair, the lowest productivity recorded since statewide censuses were initiated in
1976. Statewide pair estimates decreased 11% from 1998 values, but fledgling estimates
declined by 74.9% due to exceedingly high predation and chick mortality at many sites. Over
30% of the nesting population was concentrated at two sites (Mission Bay Mariner's Point and
Santa Margarita North Beach); ten sites supported a combined total of 76.6% of statewide pairs.
One site (Los Angeles Harbor) contributed nearly 24% of the state's fledglings in 1999; Los
Angeles Harbor and three other sites (NAS Alameda, Ormond Beach and Mission Bay Mariner's
Point) produced over 50% of 1999 statewide fledglings.
Four sites that supported least tern pairs in 1998 reported no nesting in 1999 (Batiquitos
Lagoon W-1 and E-2; Mission Bay Fiesta Island, Mission Bay South Shores); four additional
sites (Venice Beach, Seal Beach, Bolsa Chica, Chula Vista Wildlife Refuge) supported nesting
but had no productivity in 1999.
1999 pair estimates were 18% lower than corresponding statewide nest numbers; in 1998 they
differed by only 9%. Renesting may have occurred far less frequently in 1999 than in 1998 due
to far higher predation (16.5% of all eggs and 7.7% of chicks hatched) and other factors
contributing to chick mortality (26.5% of all hatched eggs) in 1999. The greatest egg losses in
1999 were attributed to coyotes, crows and ravens; highest chick/fledgling losses were to
American kestrels, coyotes and peregrine falcons. Chick mortality due to factors other than
predation was 26.5%, higher than 1997 and 1998 and is believed to be related to prey
deficiencies and unknown factors.
Monitoring to document breeding success of California least terns (Sternula antillarum browni) continued in 2007, with observers at 35 nesting sites providing data. An estimated 6744-6989 California least tern breeding pairs established 7667 nests and produced 2293-2639 fledglings at 48 documented locations. The fledgling to breeding pair ratio was 0.33-0.39. Statewide, 12,238 eggs were reported, with a Site Mean clutch size of 1.67 eggs per nest (St Dev = 0.133) and the statewide clutch size of 1.62 eggs (St Dev = 0.493) for Type 1 sites. Numbers of nesting least terns were not uniformly distributed across all sites. Camp Pendleton, Naval Base Coronado, Los Angeles Harbor, and Batiquitos Lagoon represented 55% of the breeding pairs while Venice Beach, Camp Pendleton, Huntington Beach and Naval Base Coronado produced 52% of the fledglings. Although the state experienced a lower chick mortality rate
(9%) for the third consecutive year, four of the largest sites (Alameda Point, Venice Beach, Batiquitos Lagoon and Camp Pendleton) experienced levels of chick mortality greater than the state average. These four sites reported 42% of the total chicks, but 79% of the dead chicks. The main predators of least terns in 2007 were unknown species, black-crowned night-herons
(Nycticorax nycticorax) and gull-billed terns (Gelochelidon nilotica). Coyote (Canis latrans) and American crow (Corvus brachyrhynchos) predation was lower compared to previous years, but predation due to protected species appears to be increasing. Gulls (Larus sp.) and peregrine falcons (Falco peregrinus) were reported from the most sites. The monitoring effort of 2007 is scheduled to continue in 2008.
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 31
August 2000. Eleven transient flycatchers of unknown subspecies were detected during
surveys, and two transients were captured in mist nets at MAPS (Monitoring Avian Productivity
and Survival) stations on De Luz Creek and the Santa Margarita River. Transients occurred in a
range of habitat types including mixed willow riparian, willow-sycamore dominated riparian,
and sandbar and mule fat scrub. All but one transient individual were sighted within 50 m of
surface water.
Eighteen southwestern willow flycatcher breeding territories were located. With the
exception of a new site at Lake O'Neill on Fallbrook Creek, all territories were along the lower
Santa Margarita River. The majority of territories (15/18) were located in mixed willow riparian
habitat. Resident flycatchers exhibited a bimodal distribution with regard to distance to surface
water, with 53 percent within 50 m, and the remainder from 150 to 575 m away from it.
The eighteen territorial males included ten confirmed pairs, five single males, and three
males of undetermined status. Nesting was documented for eight of the ten pairs, with each pair
attempting one nest. All nests were successful, and flycatchers fledged an average of 2.3 young
per pair. No instances of cowbird parasitism were observed. Pairs placed nests in five species of
plants, including black willow (Salix goodinggii), sandbar willow (S. exigua), stinging nettles
(Urtica dioica), blackberry (Rubus ursinus) and giant reed (Arundo donax).
Two resident males and one female were returning banded birds, including one male
banded as an adult in 1998 and one female banded as an adult in 1999. Four resident males and
one female were captured and color banded in 2000, and six nestlings in two nests were banded.
In addition, both of the transients captured at MAPS stations were banded. None of the
transients observed during surveys carried bands.
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 31
August 2001. Twenty-one transient flycatchers of unknown subspecies were detected during
surveys. Transients occurred in a range of habitat types including mixed willow riparian,
willow-sycamore dominated riparian, willow-oak dominated riparian, and mule fat scrub. The
distance from transient locations to the nearest surface water averaged 124  127 m (N = 21).
Nineteen southwestern willow flycatcher breeding territories were located. With the
exception of one territory at Lake O=Neill on Fallbrook Creek, all territories were along the
lower Santa Margarita River. Ninety-five percent (18/19) of territories were located in mixed
willow riparian habitat. Exotic vegetation, particularly poison hemlock (Conium maculatum)
and giant reed (Arundo donax), was present in all but one territory, and was dominant (% cover
> 50) in 32% (6/19) of territories. Resident flycatchers exhibited a bimodal distribution with
regard to distance to surface water, with 42% within 60 m, and the remainder 150-500 m away
from it.
The resident flycatcher population included one unpaired male and 18 pairs (16 males, 18
females). Two males were believed to be polygynous, each mating with two females. Nesting
was documented for 17 of the 18 pairs, which produced 1-3 nests each. Fifty-two percent
(15/29) of nests were successful, and flycatchers fledged an average of 1.9 young per pair. No
instances of cowbird parasitism were observed. Pairs placed nests in seven species of plants,
including black willow (Salix gooddingii), arroyo willow (S. lasiolepis), stinging nettle (Urtica
dioica), mule fat (Baccharis glutinosa), elderberry (Sambucus mexicana), poison hemlock, and
giant reed.
One resident male and one female were birds banded previously at Camp Pendleton; the
male was banded as an adult in 1998, while the female was banded as an adult in 2000. Nine
resident males and eight females were captured and color banded in 2001, and 26 nestlings in 12
nests were banded. None of the transients observed during surveys carried bands.
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 31
August 2002. One hundred and two transient flycatchers of unknown subspecies were detected
during surveys. Transients occurred in a range of habitat types including mixed willow riparian,
willow-oak-sycamore dominated riparian, willow-cottonwood dominated riparian, riparian scrub
and upland scrub. The distance from transient locations to the nearest surface water averaged
489  603 m (N = 101).
Eighteen southwestern willow flycatcher breeding territories were located. With the
exception of one territory at Lake O=Neill on Fallbrook Creek, all territories were along the
Santa Margarita River, including a new site near the Base hospital, and one downstream of the
concentration of birds between Rifle Range Road and Ysidora Basin. Ninety-four percent
(17/18) of territories were located in mixed willow riparian habitat. Exotic vegetation,
particularly and giant reed (Arundo donax), tamarisk (Tamarix ramosissima), and poison
hemlock (Conium maculatum) was present in all territories, and was dominant (% cover > 50) in
11% (2/18) of territories. Resident flycatchers exhibited a bimodal distribution with regard to
distance to surface water, with 60% within 70 m, and the remainder 100-900 m away from it.
The resident flycatcher population included two non-territorial "floater" males, two
unpaired males, and 16 pairs. Nesting was documented for all 16 pairs, which produced 1-2
nests each. Fifty-three percent (10/29) of nests were successful, and flycatchers fledged an
average of 1.5 young per pair. No instances of cowbird parasitism were observed. Pairs placed
nests in five species of plants, including black willow (Salix gooddingii), arroyo willow (S.
lasiolepis), giant reed, tamarisk, and maiden's bower (Clematis ligusticifolia).
Fourteen resident males and seven females were birds banded previously at Camp
Pendleton between 1998 and 2001. Three birds (two males and one female) were immigrants
from the San Luis Rey River. In addition, a male color banded in Costa Rica during the winter
of 2001-2002 was resighted at the Base in July. Four resident males and four females were
captured and color banded in 2002, and 10 nestlings in five nests were banded. None of the
transients observed during surveys carried bands.
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 15
August 2007. Seventy transient flycatchers of unknown sub-species were observed during Basewide
surveys. Transients occurred on 12 of the 16 drainages surveyed in 2007. No willow
flycatchers were detected at De Luz, Horno, Roblar, or Windmill Creeks. Transients occurred in
a range of habitat types including mixed willow riparian, willow-sycamore dominated riparian,
oak-sycamore dominated riparian, riparian scrub, and upland scrub. The distance from transient
locations to the nearest surface water averaged 340 ± 424 m (std, n = 70).
In 2007, the resident southwestern willow flycatcher population on Base consisted of 14
females and 12 males. However, because of within season flycatcher movement, 16 territories
were established. One male defended territories in two locations, separated by more than 1 km,
pairing with a female in the second location. Another male remained single during the entire
2007 breeding season. In total, 14 females formed pair bonds with 11 male willow flycatchers.
Two of the 11 paired males were polygynous with two females each. Based on movement data,
two additional males were suspected to be polygynous with neighboring females. All territories
were located in mixed willow riparian habitat. Poison hemlock (Conium maculatum) was
present in all territories. Distance to surface water averaged 168 ± 244 m (std, n = 16), with 69%
(11/16) of territories located within 100 m of water.
Nineteen nesting attempts by willow flycatchers were documented during the 2007
breeding season. Nesting was initiated in early June and continued into August. Forty-two
percent (8/19) of nests successfully fledged at least one flycatcher young. Predation accounted
for 73% (8/11) of nest failures. The other documented cause of nest lost was substrate failure.
The cause of failure for two nests was unknown. It is possible that they were depredated in the
egg stage or abandoned prior to egg laying, as they failed during the time eggs should have been
laid, but no eggs were observed in the nests. Of the 12 pairs whose nests were monitored, 67%
(8/12) fledged young. Seventeen fledglings were produced, yielding an estimated seasonal
productivity of 1.4 young per pair (17 young/12 pairs). No instances of brown-headed cowbird
(Molothrus ater) parasitism were observed. P
In 2003, we implemented a new monitoring program for the endangered arroyo toad
(Bufo californicus) on Marine Corps Base Camp Pendleton (MCBCP). To address the
problems associated with large variations in adult toad activity, we employed a spatial and
temporal monitoring approach that tracks the presence of arroyo toad breeding populations
by documenting the presence of eggs and larvae. Unlike adult toads, eggs and/or larvae
remain visible in the water for months before metamorphosis and have a much higher
probability of detection. This year, we began monitoring 89 km of potential toad breeding
habitat within MCBCP. We divided the habitat into approximately 60 blocks, each divided
into 6 survey site lengths. One site length within each block is surveyed yearly, while the
other site lengths are surveyed on a 5 year rotation. We implemented the first year of this
rotating panel design by comprehensively surveying 120 randomly stratified survey site
lengths (30 km). We then used a loglinear modeling program to model the data and correct
for varying detection probabilities. The program provides the framework for powerful
statistical analysis of trends in metapopulation dynamics and breeding, as well as the effects
of habitat, aquatic variables, and management actions on arroyo toad populations.
In 2003, 78% of potential toad breeding habitat contained water during our survey
efforts. Of these areas, 87.4% (se = 9.5) of the habitat was occupied by breeding arroyo
toads. The greatest occupancy was recorded on the San Mateo watershed (97.9%), followed
by the San Onofre (90.9%) and Santa Margarita (83.8%) watersheds. We evaluated over 14
habitat and survey specific variables in the models. These included landscape variables,
environmental variables, and the presence of nonnative plant and aquatic vertebrate species.
Results showed that the absence of crayfish was the single most significant predictor of the
presence of arroyo toad larvae. Larvae were 20 times (95% CI: 2-249) more likely to be
detected when crayfish were absent. Although data on the relationship between crayfish and
arroyo toads are sparse, crayfish are known to prey upon amphibian eggs, larvae, and adults,
and have been linked with declines in some amphibian populations. It is unknown whether
this is a direct link or if crayfish are an indirect indicator of less than favorable habitat
conditions.
In order to provide continuity with previous monitoring efforts, monitor n
From 2002 to 2004, California State Parks contracted with the U.S. Geological Survey to
conduct daytime habitat evaluation and focused nocturnal surveys to determine the
distribution of suitable habitat and presence of arroyo toads (Bufo californicus) within
Cuyamaca Rancho State Park (CRSP). The 2002 and 2003 surveys documented breeding
populations of arroyo toads at four high-quality sites along the Sweetwater River, but the
effects of the Cedar Fire in late 2003 on these populations were unknown. The purposes
of the 2004 surveys were to determine if there were changes in the distribution of arroyo
toads and arroyo toad habitat as a result of the Cedar Fire, and to determine fire severity
levels at the four previously known high-quality habitat locations. To accomplish this, we
used daytime habitat evaluation surveys, fire severity transects, and nocturnal presence
surveys. Each 250-m stretch of the river was re-evaluated based on the presence of key
arroyo toad habitat characteristics: 1) the channel substrate and banks being
predominately composed of depositional sand, 2) flat, exposed sandy terraces
immediately adjacent to the channel, and 3) channel braiding. Furthermore, the reaches
were surveyed diurnally and nocturnally for all life history stages of the arroyo toad and
other riparian-associated animal species.
Of a total 17.0 km (10.6 mi) of riparian habitat surveyed, 7.8 km, or nearly half of the
river within CRSP, was rated as high- (3.7 km) or good-quality (4.1 km) habitat for
arroyo toads. Arroyo toads (particularly the immature stages) were abundant in the lower
third of the Sweetwater River, found virtually continuously along a 5.2-km stretch of
river. Breeding individuals and large numbers of young were also detected in the middle
of the river within CRSP, thus documenting the presence and breeding of arroyo toads in
all four sites from the previous two years. In addition, we recorded a large adult female at
the highest known elevation (1,354 m; 4,442 ft) for arroyo toad occurrences in the
Sweetwater River watershed, in a severely burned, dry portion of the river several
kilometers upstream from the nearest surface water. Chytridiomycosis, a major infectious
disease affecting amphibians, was detected in one arroyo toad and one Pacific treefrog
which were collected dead during the surveys, possibly representing the first cases of the
pathogen in amphibians in the watershed. According to the fire severity transect
Monitoring to document breeding success of California least terns (Sternula antillarum
browni) continued in 2011, with observers at 40 nesting sites providing data. An estimated
4826-6108 California least tern breeding pairs established 6435 nests and produced 1038-1195
fledglings at 49 documented locations. The fledgling to breeding pair ratio was 0.17-0.25.
Statewide, 11,140 eggs were reported, with a Site Mean clutch size of 1.76 eggs per nest (St Dev
= 0.111) and the Statewide clutch size of 1.75 eggs (St Dev = 0.459) for Type 1 sites. Numbers
of nesting least terns were not uniformly distributed across all sites. Camp Pendleton, Naval
Base Coronado, Batiquitos Lagoon Ecological Reserve, Huntington Beach, Pt. Mugu and
Alameda Point represented 79% of the breeding pairs while Alameda Point, Camp Pendleton,
Huntington Beach, Naval Base Coronado and Tijuana River NERR produced 55% of the
fledglings. The 2011 chick mortality rate of 20% is slightly greater than the last three years.
Alameda Point, Batiquitos Lagoon Ecological Reserve, Camp Pendleton, Huntington State
Beach and Naval Base Coronado represented 87% of the total reported chick deaths, but only
70% of the total chicks. The predators responsible for the greatest number of depredated least
terns in 2011 were unknown avian species, American crows (Corvus brachyrhynchos), gull
species (Laris sp.), peregrine falcons (Falco peregrinus), gull-billed terns (Gelochelidon
nilotica), and common ravens (Corvus corax). Common ravens, peregrine falcons, American
crows, American kestrels (Falco sparverius), red-tailed hawks (Buteo jamaicensis), and coyotes
(Canis latrans) were reported from the most sites. The monitoring effort of 2011 is scheduled to
continue in 2012.
This report documents the 2007 Nature Reserve of Orange County funded study to outfit fledgling cactus wrens with radio transmitters and to use a hand-held receiver and antenna to relocate the juvenile wrens as they attempted to disperse from their natal territories. It was initially planned to radio mark up to 14 juvenile wrens from several study sites located throughout the reserve system. However, the lack of nesting attempts and low productivity, likely due to low precipitation during the previous rainy season, provided few fledglings to radio mark. We radio tracked 7 fledglings and 3 adult males for 3 to 48 days. We also monitored a pair of banded wrens that were relocated to Upper Newport Bay in 2006.
We tracked two hatch-year wrens for more than 45 days. One moved away from its natal territory (area where the parents were located) and roamed the study site, but did not leave it, and the other was not observed to have left its natal territory. Three other young wrens? signals were lost after 14 to 24 days and another lost its transmitter after 10 days. None were ever relocated during the season. Another young wren?s partially eaten remains were found after three days of tracking. Two radio marked adult male parents were followed until the batteries failed and a third lost its transmitter after 21 days, but was resighted up to 48 days later. A banded male that was relocated to Upper Newport Back Bay in 2006 made a 0.7 km breeding dispersal and mated with a relocated female producing one fledgling in 2007.
In this report, the wren radio tracking observations from this study are compared to movement records from two multi-year cactus wren banding studies conducted in coastal Southern California. Cactus wrens near or at their adult size initially appear to be robust enough to tolerate having a small radio transmitter temporarily placed on them. They also appear to tolerate the translocation procedure and initially appear to quickly adjust to their new location. These activities do expose the wrens to an increased risk of injury and mortality and it is unknown what the impacts are on their long term survival and reproductive success; they should be used and conducted judiciously. It is important to understand cactus wren dispersal patterns in a fragmented landscape in order to manage and conserve their populations in the region and further study is encouraged. However, cactus wren habitat and populations in the reserve appear to continue to decli
The Hermes copper (Lycaena hermes) is a rare butterfly endemic to San Diego County and northern Baja California. This species is threatened by recent urbanization and wildfires throughout its range in the United States. Since most individuals and larger populations are found in the southern portion of San Diego County, one large fire could nearly extirpate the species. Wildfires in 2003 and 2007 have already caused extirpations in this region and few recolonizations have been observed.
Past efforts have contributed to our understanding of the distribution of the Hermes copper so it is fairly well understood. However, there may still be unknown populations. Surveys associated with the SDG&E Sunrise Powerlink Project discovered several populations by searching linear transects through Cleveland National Forest without specifically targeting Hermes copper. Based on these results, we thought that additional surveys through potential habitat could yield detections of unknown populations.
The objective of this project was to search for these populations by conducting surveys in areas not previously searched. Surveys were also conducted in the Elfin Forest area, near previously occupied areas, and three sites that experiences wildfires since 2003 to assess recolonization. During the 2018 flight season, we conducted surveys for Hermes copper adults at 35 sites (transects) determined in consultation with USFWS and USFS biologists. These sites were selected based on habitat, proximity to known populations, and considered previous survey efforts and results.
The 2018 Hermes copper flight season started the last couple days of May and extended through the first three weeks of June. This flight season started later than in recent years. Hermes copper adults were detected along only three transects, including at least 55 different adults on the CNF07 transect, 8 on CNF08, and 1 along the maintained Boulder Creek Road. There were no observations at the other transects. Most sites were experiencing very dry conditions, represented by suppressed butterfly numbers, regardless of species, and water stressed plants.
(Contract: #5004388, Task Order #4)
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus) were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 15 August 2004. Eighty-two transient flycatchers of unknown subspecies were detected during surveys. Transients occurred in a range of habitat types including mixed willow riparian, willow-sycamore dominated riparian, oak-sycamore dominated riparian, riparian scrub, and upland scrub. The distance from transient locations to the nearest surface water averaged 274 ± 374 m (N = 72).
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus) were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 24 August 2005. Thirty-five transient flycatchers of unknown subspecies were detected during surveys. Transients occurred in a range of habitat types including mixed willow riparian, willow-sycamore dominated riparian, oak-sycamore dominated riparian, riparian scrub, upland scrub, and non-native. The distance from transient locations to the nearest surface water averaged 108 ± 173 m (N = 35).
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus) were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 15 August 2006. Thirty-five transient flycatchers of unknown subspecies were detected during surveys. Transients occurred in a range of habitat types including mixed willow riparian, willow-sycamore dominated riparian, oak-sycamore dominated riparian, riparian scrub, and upland scrub. The distance from transient locations to the nearest surface water averaged 328 ± 515 m (N = 35)
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 15 May and 31 July
2003. Thirty-nine transient flycatchers of unknown subspecies were detected during surveys.
Transients occurred in a range of habitat types including mixed willow riparian, willowsycamore
dominated riparian, riparian scrub, upland scrub and predominantly non-native
vegetation. The distance from transient locations to the nearest surface water averaged 200 ?
399 m (N = 39).
Twenty southwestern willow flycatcher territories were located. With the exception of
two territories at Lake O’Neill on Fallbrook Creek and one territory upstream of Basilone Road
on Las Flores Creek, all territories were along the Santa Margarita River. All territories were
located in mixed willow riparian habitat. Exotic vegetation, particularly poison hemlock
(Conium maculatum), giant reed (Arundo donax), and tamarisk (Tamarix ramosissima) was
present in all territories, and was dominant (% cover > 50) in 10% (2/20) of territories. Eightyone
percent of resident flycatchers were within 75 m of surface water, and the remainder 95-340
m away from it.
The resident flycatcher population included six non-territorial “floater” birds, four
unpaired males, and 16 pairs. Nesting was documented for all 16 pairs, which produced 1-3
nests each. Sixty-eight percent (17/25) of nests were successful, and flycatchers fledged an
average of 3.0 young per pair. No instances of cowbird parasitism were observed. Pairs placed
nests in ten species of plants, including black willow (Salix gooddingii), arroyo willow (S.
lasiolepis), sandbar willow (S. exigua), mule fat (Baccharis salicifolia), stinging nettle (Urtica
california), tamarisk, poison hemlock, wild rose (Rosa californica), coast live oak (Quercus
agrifolia), and wild grape (Vitis girdiana).
Ten territorial males, 11 territorial females, and three floaters were banded previously at
Camp Pendleton between 2000 and 2002. Fifty-five percent of the adults banded in 2002
returned in 2003, while 27% of nestlings and hatching year birds banded in 2002 returned to
Camp Pendleton in 2003. Thirty-three percent of returning adults changed breeding locations
within Camp Pendleton between 2002 and 2003. Six resident males and two females were
captured and color banded in 2003, and 34 nestlings in 12 nests were banded. None of the
transients observed during s
Surveys for the endangered southwestern willow flycatcher (Empidonax traillii extimus)
were conducted at Marine Corps Base Camp Pendleton, California, between 13 May and 1
August 2008. Fifty-five transient flycatchers of unknown sub-species were observed during
Base-wide surveys. Transients occurred on 10 of the 16 drainages surveyed in 2008. No willow
flycatchers were detected at Cockleburr, Cristianitos, French, Newton, Roblar, or Windmill
Creeks. Transients occurred in a range of habitat types including mixed willow riparian, willowsycamore
dominated riparian, oak-sycamore dominated riparian, riparian scrub, and upland
scrub. The distance from transient locations to the nearest surface water averaged 363 ± 472 m
(std, n = 55).
In 2008, the resident southwestern willow flycatcher population on Base consisted of
seven females, seven males, and one non-territorial “floater” bird. Nine territories were
established, consisting of seven pairs and two single males. In total, seven females formed pair
bonds with five male willow flycatchers. Two of the five paired males were polygynous with
two females each. All territories were located in mixed willow riparian habitat. Poison hemlock
(Conium maculatum) was present in all territories. Distance to surface water averaged 73 ± 39 m
(std, n = 10), with 70% (7/10) of resident flycatchers located within 100 m of water.
Eight nesting attempts by willow flycatchers were documented during the 2008 breeding
season. Nesting was initiated in late May and continued into August. Eighty-eight percent (7/8)
of nests successfully fledged at least one flycatcher young. Predation accounted for the one nest
failure. Of the seven pairs whose nests were monitored, 100% (7/7) fledged young. Twenty
fledglings were produced, yielding an estimated seasonal productivity of 2.9 young per pair (20
young/7 pairs). No instances of brown-headed cowbird (Molothrus ater) parasitism were
observed. Pairs placed nests in five species of plants, including black willow (Salix gooddingii),
arroyo willow (S. lasiolepis), sandbar willow (S. exigua), mule fat (Baccharis salicifolia), and
poison hemlock. Eighty-eight percent of nests were placed in native species.
Seven resident females and five males that were banded in previous years were present at
Camp Pendleton in 2008. Of the banded adult flycatchers present during the 2007 breeding
season, 67% (4/6) of males and 13% (1/8) of females returned to Camp Pendleton in 2008. Si
The Chaparral Lands Conservancy (TCLC) submits the tenth and final report for the Rare Plants Project. Project activities during this period included restoration and management (Task 2), and grant reporting and administration (Task 3).
TCLC has completed project tasks to carry out planning and permitting, restoration and management, and Project and grant management. Work to implement all grant contract tasks was conducted and most results were achieved. However, the success of one major deliverable – establishment of four new Orcutt’s spineflower populations through seeding – remains unknown due to poor environmental conditions. A summary of work under each category of the EMP grant agreement scope of work is provided below.