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<br /> Habitat California clapper rail habitats typically have the following features: (1) marshes that
<br /> support an extensive system of tidal sloughs having direct tidal circulation sufficient to allow the full
<br /> tidal cycle, (2) pickleweed (Salicornia virginica) is the predominant vegetation, with extensive Pacific
<br /> cordgrass (Spartina foliora) at lower marsh elevations, (3) abundant, dense high mazsh cover (tall
<br /> stands of pickleweed, gumplant [Gnndelia spp.], and wrack), and (4) abundant invertebrate
<br /> populations. The preferred habitat is Spartina marsh (CDWR-IEP), which dominates the middle
<br /> marsh zone in the south Bay (USFWS-Sac). Optimum California clapper rail habitat needs both high
<br /> marsh, with dense vegetation for nesting, and low marsh, with sparse vegetation and tidal sloughs for
<br /> foraging (Albertson, 1996). Additionally, buffer areas between marsh and upland are critical aspects
<br /> of rail habitat, for use as escape cover from predators during high tide (1'�lbertson & Evens, 2000).
<br /> Feeding A 1941 study by Moffitt (cited in CDWR-IEP) found that by volume, most (>85
<br /> percent) of the stomach contents of clapper rails was animal matter, 14.5 percent was vegetable
<br /> matter. Of the animal matter, 56.5 percent was plaited horse mussel (Modiolu.r vol�etta demi.rru,r); the
<br /> remainder comprised spiders (15 percent), macoma clams (7.6 percent), mud crabs (3.2 percent), and
<br /> bones from brush rabbits, the latter presumably from carrion. The California clapper rail feeds by
<br /> walking a few steps, thrusting its beak into the mud up to eye level, then walking a few more steps
<br /> and repeating its probing (Wilbur and Tomlinson, 1976, cited in CDWR IEP). CDFG cites Zembel
<br /> and Massey (1983) indicating that the clapper rail forages in higher marsh vegetation, along the
<br /> mudElat/vegetation interface, and along tidal creeks; the rail "gleans, pecks, probes, and scavenges
<br /> from [the] surface," and takes mice during high rides, and may scavenge dead fish
<br /> (w�v�v.dfg.ca.gov/whdab/html/B144.htm1). Another writer indicates that clapper rails, although
<br /> opportunistic feeders, prefer crabs and crayfish (Garrison, 2000).
<br /> Reproduction The breeding season begins in February, when pair bonds are typically established
<br /> (USF�'S-Goude, 2002), with nesting extending from mid-March into August. The breeding season
<br /> is typicallv considered to end at the end of August, by which time the eggs laid during re-nesting
<br /> efforts have hatched and the young are mobile (LJSFWS, Sacramento on line). Clutch sizes are
<br /> variously reported as ranging from 5 to 14 eggs (USFWS-Sac), 6 to 8(Garrison, 2000), 6 to 10
<br /> (CDWR-IEP), and an average of 7.6, with a hatching success rate in the Bay Area of 38 percent
<br /> (Harve}�, 1980, in LSA, 2004). Both the male and female incubate the eggs for 18 to 29 days (LSA,
<br /> 2004). The young are precocial, i.e., they are covered with down and capable of moving about when
<br /> hatched (vv�vu�.pwrc.usgs.gov). The young usually accompany their parents for about 8 weeks,
<br /> learning to forage on their own. They fledge at about 10 weeks (Albertson & Evens, 2000).
<br /> Garrison states (2000) that high tides and heavy spring rains may destroy up to half of clapper rail
<br /> nests, but that the clapper rail will re-nest up to five times.
<br /> Clapper rail nests are normally built by the males and are described as a"mass" or "heap" of
<br /> vegetation, deep-cupped and woven to adjouung live plant material in a manner that allows it to float
<br /> during extreme high tides, although they are somewhat buoyant, they are not sturdy enough to
<br /> withstand a series of high tides (Zucca 1954 in CDWR-IEP). According to Harvey (1980) and
<br /> Zembel and Massey (1983), in saline emergent wedands, the birds nest mosdy in lower zones near
<br /> tidal sloughs and where cordgrass is abundant; nests are constructed as high as necessary to prevent
<br /> inundation while maintauung sufficient natural vegetation cover. Harvey (CDFG B144 online)
<br /> reports that the clapper rail builds a platform hidden by a canopy of woven cordgrass stems or
<br /> pickleweed and gumweed, but may use dead drift vegetation as a platform. In brackish to fresh
<br /> water, nests may be built in dense cattail or bulrush.
<br /> Diurnal cycle Peak California clapper rails activity occurs in the early morning and late evening,
<br /> when the�� forage; frequendy they roost at high tide during the day (USFWS/Sacramento).
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