Chapters 1 - U.S. Fish and Wildlife Service

Chapter 4
Wandering Skipper. A butterfly of interest that occurs on the Refuge is the wandering skipper
(Panoquina errans), identified by the state as a highly imperiled species (CDFG 2008). Restricted
to the coastal zone, the larval form of this species is always found in association with salt grass. In
all, Moraes identified approximately 15 species of butterflies and moths on the Refuge (USFWS
1976).
Mosquitoes. Mosquitoes, generally considered a vector requiring some level of control, are also
present on the Refuge. A vector is any insect or other arthropod, rodent, or other animal of public
health significance capable of causing human discomfort, injury, or capable of harboring or
transmitting the causative agents of human disease. The mosquito is the vector of most interest
within this Refuge. Twelve mosquito borne viruses are currently known to occur in California.
The three forms of most concern in Orange County include western equine encephalitis virus, St.
Louis encephalitis virus, and West Nile virus. All are carried by wild birds. Infected birds are
then bitten by local mosquitoes that can pass the virus on to humans through future bites.
The Orange County Vector Control District (OCVCD) is responsible for the monitoring and
control of vectors, and in particular mosquitoes, in Orange County. OCVCD actively works with
NWSSB and Refuge staff to monitor and control mosquito populations on Navy and Refuge lands.
About 100 mosquito traps are monitored throughout the county to determine what mosquito
species are present and in what numbers. Mosquitoes are also tested to determine what, if any,
diseases they may be carrying. OCVCD uses two different types of traps: a carbon dioxide trap
and a gravid trap. The carbon dioxide trap is used as an attractant for recently mated females.
After females mate, they need to find a blood-source to be able to produce eggs. Carbon dioxide is
what all animals exhale when they are breathing so the trap mimics a potential blood-meal to the
mosquito. The gravid trap is a foul-smelling trap that egg-laying female mosquitoes are attracted
to as a potential place to lay their eggs. Some mosquito surveillance locations in the county also
include cowbird traps. These traps are used to catch and take blood samples from live wild birds to
determine which, if any, mosquito-borne diseases are present in the wild bird population.
Three mosquito surveillance trap stations are located in proximity to the Seal Beach NWR. These
include traps maintained adjacent to the Wintersburg flood control channel at the northwestern
corner of the Bolsa Chica marsh complex (17531 Bates Circle, Huntington Beach); at the western
end of Adolfo Lopez Drive in Seal Beach, just to the northwest of the Refuge across Seal Beach
Boulevard; and near the junction of State Route 22, Interstate 605, and Interstate 405, several
miles to the northwest of the Refuge. The first two locations, which are located closest to the
Refuge, include cowbird traps, as well as carbon dioxide and gravid traps. Two carbon dioxide
traps were also recently installed on or near the Refuge, including one at the Refuge office and one
at the drop tower. Another trap was installed just off the Refuge to the north of Case Road.
Based on results provided by OCVCD for all trap stations described above (Jim Green, pers.
comm. November 6, 2008), the following species of mosquitoes have the potential to be present on
the Refuge. Only the black salt marsh mosquito (Ochlerotatus [Aedes] taeniorhynchus), California
salt marsh mosquito (Ochlerotatus [Aedes] squamiger), and western encephalitis mosquito (Culex
tarsalis) have been collected or trapped on the Refuge in recent years.
Culex quinquefasciatus: The majority of Orange County’s mosquito abatement services and
related control activities are directed at this species. Females are active nearly year-around.
Larvae are commonly associated with all types of “urban waters” held in sources ranging from
swimming pools to flower pots. This species may serve as both Orange County’s primary and
secondary vector of St. Louis encephalitis virus and West Nile virus.
4-52 Seal Beach National Wildlife Refuge