2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
The extent of these habitats varies greatly (Table 1-3). When standardized by the area of each habitat
type, bird densities in February were greatest in the freshwater areas such as mulefat scrub (1,478
birds/ha), freshwater marsh (121 birds/ha), and willow/riparian (81 birds/ha). In April the bird
densities were highest in mulefat scrub (455 birds/ha), mudflat (134 birds/ha), and decaying
transitional vegetation (104 birds/ha). June had the highest bird densities on the intertidal sand shoal
(199 birds/ha). August bird densities were greatest on the mudflat (128 birds/ha), the intertidal sand
shoal (99 birds/ha), and on the nest site (60 birds/ha). In October the birds densities were highest on
the mulefat scrub (398 birds/ha), decaying transitional vegetation (78 birds/ha), salt panne and
inundated salt panne (39 species/ha), and disturbed salt marsh (37 birds/ha). December bird densities
were greatest in the foraging and resting area such as decaying transitional vegetation (732 birds/ha),
mudflat (82 birds/ha), and the intertidal sand shoal (67 birds/ha).
Flying birds were recorded in the habitat over which they were flying at the time of observation,
though they may not necessarily use that habitat on the ground. Thirteen percent of all birds were
flyovers. To look at species richness, all birds recorded as flying were disregarded and only birds on
the ground considered. Species richness was highest in the salt marsh (85 species), open water (74
species), mudflat (66 species), and inundated salt panne (62 species) (Figure 1-18). All other habitats
had 50 species or less in 2008.
As noted in the prior annual report, the heavy usage of the intertidal sand shoals in Zone 73 (inlet) at
low tide by gulls, cormorants, terns, and pelicans was not fully captured by these surveys, though
observed regularly in late afternoon low tides at the site. The survey also cannot account for
movement of birds into and out of the survey area from Bolsa Chica State Beach and from Inner and
Outer Bolsa Bay.
Gulls on sand shoal in the Full Tidal Basin.
Discussion
The Bolsa Chica Lowlands Restoration Project included several elements that have enhanced the avian
community within the project area. The creation of the FTB is the most notable, which involved
removing existing oil wells, excavating a basin, and constructing a permanent opening to the ocean in
2006. Its new mudflats and open water were the most used area in 2008, providing expansive foraging
and loafing habitat to 91 species, including seven that were found in no other area of the site: brant,
common loon (Gavia immer), common merganser (Mergus merganser), glaucous-winged gull (Larus
glaucescens), pelagic cormorant (Phalacrocorax pelagicus), surf scoter, and western grebe
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