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2020 Establishment of brown anoles (Anolis sagrei) across a southern California county and potential interactions with a native lizard species journal article

Lead author: Samuel R. Fisher
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.

2018 Longevity and population age structure of the arroyo southwestern toad (Anaxyrus californicus) with drought implications journal article

Lead author: Cheryl Brehme
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.

2008 Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine Corps Base Camp Pendleton, California report

Lead author: James W. Rourke
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

2008 Final Report: Cactus Wren (Campylorhynchus brunneicapillus) 2007 Telemetry Study and the 2007 Monitoring Results of the 2006 Cactus Wren Translocation Study in Orange County, California report

Lead author: Dana Kamada
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

2018 Final survey report willowy monardella (monardella viminea) census and monitoring, Marine Corps Air Station Marimar, San Diego County, California report

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.

2016 Rare Plants Project 10th Quarterly Report (FINAL) report

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.

2003 Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine C report

Lead author: Kimberly Ferree
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.

2005 Post-Cedar Fire Arroyo Toad (Bufo californicus) Monitoring Surveys at Cuyamaca Rancho State Park, 2004 report

Lead author: Mark Mendelsohn
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

2001 CALIFORNIA LEAST TERN BREEDING SURVEY 1999 Season report

Lead author: Kathy Keane
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.

2008 Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine Corps Base Camp Pendleton, California report

Lead author: James W. Rourke
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

2018 Rare Butterfly Monitoring and Translocation report

Lead author: Dan Marschalek
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.

2001 Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine Co report

Lead author: Barbara Kus
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.

2004 MCB Camp Pendleton Arroyo Toad (Bufo californicus) Monitoring Results, 2003 report

Lead author: Cheryl Brehme
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

2003 Report of Coastal California Gnatcatcher Juvenile Dispersal across Interstate-8 at the MSCP Southe report

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

2003 Distribution, Abundance, and Breeding Activities of the Southwestern Willow Flycatcher at Marine C report

Lead author: Kerry E. Kenwood
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.

2002 The Utility of High Spatial Resolution Multispectral Imagery for Mapping and Monitoring Vernal Pool Habitat in Transitional Urban Environments report

Lead author: Keith Greer
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

2008 CALIFORNIA LEAST TERN BREEDING SURVEY 2007 Season report

Lead author: Dan Marschalek
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.