Welcometo another edition of Habitat Happenings, a newsletter provided by San Diego Habitat Conservancy (SDHC).
In May, we continued conducting protocol surveys for the federally threatened coastal California gnatcatchers at Bridges & Santa Fe Creek Preserve. These surveys were successful as we found a number of breeding pairs throughout the preserve area. At Vallecitos Ridge Preserve, Black Sage Environmental conducted extensive trail work in an effort to repair and prevent further damage as a result of illegal trail building. So far their efforts have been paying off and we will continue to closely monitor the site.
In June, we began managing Seacliff Preserve in Oceanside. This is our first preserve in Oceanside and is just steps from the ocean! Don, along with SDHC Board members Eric and Trish, visited the site with Oceanside's Deputy Mayor Chuck Lowery to let him know about SDHC and the resources at Seacliff Preserve. At our Eureka Springs Preserve and Woods Valley Springs Preserve, we installed traps for the gold-spotted oak borer (GSOB). Although it is likely that the poor health of the oaks at these sites is due to the ongoing drought, Jim and Sarah would like to be certain that the invasive GSOB is not the culprit.
Later in July, we move on to the next step in the application process for accreditation with the Land Trust Accreditation Commission (LTAC). This will consist of a phone call with staff from LTAC to answer their questions and provide further detail about the way SDHC does business. Wish us luck!
San Diego Habitat Conservancy's vision is a healthy natural environment that engages the commitment of people and communities, creates a legacy, and improves the quality of life for all living things.
Coastal California gnatcatcher nest.
Don and Oceanside's Deputy Mayor Chuck Lowery at Seacliff Preserve.
Volunteers, Andrew Orozco and Vince Rivas, install a purple flight-intercept prism trap at Woods Valley Ranch Preserve to detect the presence of the gold-spotted oak borer (GSOB). Purple traps are used since this color has been shown to be more effective than green traps in catching female GSOBs.
SDHC Now Working in Oceanside!
In June, after 5 years of restoration by Merkel & Associates, SDHC began managing Seacliff Preserve in Oceanside, California. Restoration of this nearly 3-acre preserve included creation of 1.71 acres of Diegan coastal sage scrub and enhancement of 1.16 acres of Diegan coastal sage scrub. This preserve was required to be set aside as mitigation for construction of the Seacliff residential development project which impacted 0.87 acres of Diegan coastal sage scrub. SDHC will visit the preserve on a monthly basis and conduct outreach with the HOA on an annual basis.
Boundary of Seacliff Preserve.
San Diego Ambrosia
Jim mapping location of spiny rush while great-tailed grackles perch in background.
Jim and Sarah made their initial visit to the preserve in early June to remove trash and begin mapping sensitive and invasive plant species. During this visit, they documented the locations of a number of sensitive plant species, including San Diego marsh-elder (Iva hayesiana), spiny rush (Juncus acutus ssp. leopoldii), San Diego ambrosia (Ambrosia pumila), and sticky dudleya (Dudleya viscida).
Like many of SDHC's preserves, this site is in a heavily populated area which raises many issues for successful management of the preserve, such as trash and illegal encampments. We will work with the City of Oceanside to address any ongoing trespassing issues to ensure the long-term health and viability of the restored area as well as the safety of neighboring residents.
Discoveries at Bridges & Santa Fe Creek Preserve
Every 3 years, SDHC is required to conduct protocol surveys for the federally threatened coastal California gnatcatcher at Bridges & Santa Fe Creek Preserve. Over the course of the 6 surveys, Jim, Sarah, and volunteer Vince made some exciting discoveries. Below are some of the species they encountered.
Mating Pairs of Coastal California Gnatcatchers
(Polioptila californica californica)
California gnatcatchers are found year-round in a limited range of coastal sage scrub and chaparral habitat from coastal southern California south through the Baja Peninsula. Unfortunately, urbanization has greatly reduced suitable habitat for these small blue-gray songbirds and the species was listed as federally threatened in 1993. It is estimated that fewer than 5,000 pairs of California gnatcatchers now occur in coastal southern California. (1)
Over the course of six weeks from the end of April to early June, Jim, Sarah, and Vince, conducted six surveys for the California gnatcatcher. They discovered a number of mating pairs and fledglings in addition to two of the gnatcatcher's "open cup" nests, one of which contained four nestlings as shown in the photo to the right.
California gnatcatcher nestlings.
Breeding male California gnatcatcher.
Breeding pairs are generally monogamous with both sexes contributing to construction of the nest, incubation, and caring for the young.(1) Due to the open cup style, California gnatcatcher nests are very vulnerable to predation, particularly by brown-headed cowbirds and western scrub jays. Brown-headed cowbirds will actually lay their eggs in the nests of California gnatcatchers and the California gnatcatchers will then treat these young as their own, sometimes at the expense of their own nestlings. In contrast, scrub jays may destroy the nest of the California gnatcatcher and even eat the eggs or nestlings.
Western scrub jay Female brown-headed cowbird (Photo credit: Scott Streit) (Photo credit: Scott Streit)
(1) Atwood, Jonathan L. and David R. Bontrager. 2001. California Gnatcatcher (Polioptila californica), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu /bna/species/574
(Danaus gilippus thersippus)
In May, we found a striated queen caterpillar feeding on climbing milkweed, one of the rarer milkweeds in San Diego County in an area where we had previously spotted adult striated queens flying around. The adult striated queen or queen butterfly looks similar to the monarch, is in the same genus, and also relies on milkweed as a host plant as well as a nectar and food source. You may find these butterflies in flight from March through November.
Striated queen larvae
(Funastrum cynanchoides var. hartwegii)
Adult striated queen
Wrentit Nest with Nestlings
Wrentits are one of the most abundant birds in San Diego County, preferring mature chaparral, sage scrub, and the understory of riparian and oak woodland habitat. These wrentits were nesting in a southern honeysuckle plant and when we approached, they quickly became silent and motionless, a natural reaction in order to avoid predators.
Wrentit nest with 3 nestlings.
Wrentits, year-round residents along the Pacific Coast from the northern border of Oregon south to Baja, mate for life and remain in one small territory. The song of the wrentit sounds much like a bouncing ball and you are more likely to hear, rather than see, these long-tailed birds. Wrentits do not adapt well to the urban environment, instead making their homes in the ever dwindling pockets of San Diego's undeveloped canyons.
Townsend's Warbler (Dendroica townsendi)
In early May we discovered a male Townsend's warbler at the preserve which was the first sighting of this species at the site at least since we began managing in 2012! Males are distinguishable by the black on their throat, eye patch, and crown whereas females are duller with little black on the throat. This species breeds in coniferous forests from Alaska to Oregon and may be seen migrating through San Diego County in a small window from mid-April through May. Like the wrentit and California gnatcatcher, the nests of these small songbirds are shaped like an open cup.
Townsend's Warbler (Photo credit: Slodocent (Townsend's Warbler on Flickr) [CC BY 2.0])
Meet Vince Rivas!
Vince Rivas recently joined the team at SDHC as a field volunteer. He's quite dedicated, getting up before sunrise to meet Jim and Sarah for long surveys for the coastal California gnatcatcher. Vince decided to volunteer in order to become familiar with San Diego's local flora and fauna and to gain real-world experience in ecological conservation. As a graduate of UC Santa Cruz with a Bachelor's in Environmental Studies and Biology, he truly enjoys spending time in the field and is determined to build a career that improves the conditions of natural ecosystems. Vince recently began working with I Love a Clean San Diego as Program Assistant and is always looking for opportunities in the areas of field biology, as well as environmental programs, consulting, and renewable energy. We are lucky to have him join us as he begins what is sure to be a successful career!
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