Unarmored Threespine Stickleback
(gasterosteus
aculeatus williamsoni)
Photo ©1999 National Wildlife Federation |
Sticklebacks are small, rather inconspicuous fish with compressed,
spindle-shaped bodies, covered with a few bony plates or shields in place
of scales. Three sharp erectile spines precede the soft dorsal fin. The
mouth is small, with a projecting lower jaw. The ventral fins have sharp
erectile spines. Their color is greenish or olive above, grading to silvery
on the lower sides and belly. At spawning time, the males have a scarlet
throat and belly, blue eyes, and greenish fins. The females at this time
have a pinkish throat and belly.
The unarmored threespine stickleback, gasterosteus aculeatus williamsoni, (williamsoni for Lieut. R. S. Williamson, who first collected this subspecies), is usually unarmored, or may have 2 or 3 anterior plates. It is found in several coastal streams in southern California and has been introduced into the Mojave River. |
| Their food consists of small aquatic organisms, primarily
insects and crustaceans. Algae are also eaten. Breeding occurs in the late
spring and early summer. The male builds an elaborate nest of grass and
sticks stuck together by a glue-like secretion. The nests may be located
on the bottom or concealed in holes, cans, bottles, etc. Several females
may deposit eggs in one nest. The male guards the nest until the eggs hatch
and the young are on their own.
The stickleback provide a particularly interesting case of adaptive variation as each location typically contains a distinctive form of stickleback, quite comparable to the morphological variability in Darwin's finches. This species is known to be an efficient osmoregulator and can be found in the lower reaches of rivers and in the salty ditches draining into them. (Osmoregulation is the ability to control the volume and composition of body fluids, especially to adjust the salt balance to cope with different salinities.) The stickleback may be found in SEA#23, the Santa Clara River. |
Photo ©1999 National Wildlife Federation |
Least Bell's Vireo (vireo
bellii pusillus)
Photo ©1999 Jim Greaves |
The least Bell's vireo is predominately an insectivore.
During the early and mid portion of the nesting season most foraging occurs
in the vicinity of the nest site, predominately in willow, Salix spp.,
Both high and low shrub layers are used as foraging substrate. These birds
use non-riparian habitats occasionally and will travel an average of 15m
to forage. Birds using non-riparian areas for foraging tend to have territories
in the narrowest sections of riparian habitat.
The birds are easily identified by their distinct call, the first part of which sounds like cheedle- cheedle- chee, as if asking a question, and the second part, cheedle- cheedle- chew, as if answering. |
| A low, dense shrub layer is considered essential for nesting
, and a large degree of vertical stratification is preferred. Willow are
the most commonly used vegetation for this need. Plant species used for
nesting and foraging include the California wild rose, Rosa california,
and coastal live oak, Quercus agrifolia. Most nest sites are located
near the edges of thickets. Nest height on average is 1m above the ground
. Males are site tenacious and return to the same site to nest in succeeding
years. Average territory size is about 0.8ha.
Designated endangered by California in October, 1980; May, 1986 by the ferderal government. The vireo may also be found in SEA#23, the Santa Clara River. |
Photo Ricardo DeAratanha ©1999 L.A. Times |
Arroyo Southwestern
Toad (Bufomicroscaphus californicus)
Photo ©1999 National Wildlife Federation |
The arroyo toad is a small (2 to 3 inches), light
greenish gray or tan toad with warty skin and dark spots. Its underside
is buff colored and often without spots. A light-colored stripe crosses
the head and eyelids, and a light area usually occurs on each sacral hump
and in the middle of the back. Its movement consists of hopping rather
than walking. Its courtship vocalization is a high trill, usually lasting
8 to 10 seconds.
The arroyo toad is restricted to rivers that have shallow, gravelly
pools adjacent to sandy terraces. Breeding occurs on large streams with
persistent water from late March until mid-June. Eggs are deposited and
larvae develop in shallow pools with minimal current and little or no emergent
vegetation and with sand or pea gravel substrate overlain with flocculent
silt. After metamorphosis (June or July), the juvenile toads remain on
the bordering gravel bars until the pool no longer persists (3 to 8 weeks,
depending on site and year) Juveniles and adults forage for insects on
sandy stream terraces that have nearly complete closure of cottonwoods
(Populus spp.), oaks (Quercus spp.), or willows (Salix
spp.), and almost no grass and herbaceous cover at ground level. Adult
toads excavate shallow burrows on the terraces where they shelter during
the day when the surface is damp or during longer intervals in the dry
season.
|
Most remaining populations in the United States occur on privately owned lands, primarily within or adjacent to the Cleveland National Forest. Less than 50 percent of the known extant populations of arroyo toad occur in areas owned or managed by the Forest Service (Los Padres, San Bernardino, and Cleveland National Forests). Due mostly to habitat destruction, only eight drainages remain where populations of this species may be viable. In 1990, only seven pairs of arroyo toads were known to have bred anywhere within the toad's range. Due to the isolation and the small sizes, almost all populations are at great risk of extinction.
The Arroyo Toad can be found in SEAs 19
and 23. It was designated federally
endangered in January 1995.
Southwestern Pond Turtle
(Clemmys marmorata pallida)
Photo ©1999 National Wildlife Federation |
The southwestern pond turtle inhabits slow moving permanent
or intermittent streams, small ponds, small lakes, reservoirs, abandoned
gravel pits, permanent and ephemeral shallow wetlands, stock ponds, and
sewage treatment lagoons. Pools are the preferred habitat within streams.
Abundant logs, rocks, submerged vegetation, mud, undercut banks, and ledges
are necessary habitat components for cover as well as a water depth greater
than 2 meters. Additionally, emergent basking sites, emergent vegetation
and the availability of suitable terrestrial shelter and nesting sites
seem to characterize optimal habitat. Adjacent upland areas typically provide
overwintering and estivation sites.
The turtle's daily activity revolves around thermoregulation and foraging
patterns. It often suns itself at the edge of water, or on branches or
stones above water. It is secretive and will seek refuge at the bottom
of a pond or stream at the slightest disturbance. In the early morning
and evening, pond turtles may move up or down stream, moving from one pool
to the next in search of basking sites, mates or foraging. Northern populations
tend to forage early in the morning, then usually begin basking between
0900-1000, and continue basking intermittently throughout the day. They
usually terminate basking at around 90-95 degrees Fahrenheit (F.), maintaining
a body temperature of 75-90 degrees F. for most activities. Foraging may
occur during the late afternoon or early evening during the warmth of summer.
Often they will remain quietly on the bottom of pools to avoid a critical
thermal maximum of 104 degrees F.
|
The southwestern pond turtle inhabits SEAs 19
and 23.
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