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5.7 Biological Resources

In the early 1980s, the total population for this species was estimated at fewer than
20 individuals. By the end of 1986, all but two condors had been taken into captivity. On April
19, 1987, the last wild condor was captured and taken to the San Diego Wild Animal Park
(Bloom 2009). Decline of this species has been attributed to many factors, including
reduction or modification of foraging habitat, decrease in available food, disturbance around
nest sites, shooting, poisoning, pesticide residues, and general senescence (growing old;
aging) of the species (Garrett and Dunn 1981). A captive breeding program was initiated and
birds have since been reintroduced into the wild at the Sespe Reserve, at Big Sur, and in the
Grand Canyon. Currently, there are over 400 condors in the world population (both captive
and wild), 128 of whom are in California (CDFW 2015a). Due to the combination of captive
breeding and limited wild nest reproduction, the condor population is steadily increasing
(Bloom 2009). In more recent years, the greatest cause of death is believed to be lead
poisoning from eating carcasses with lead shot in them. Efforts to reduce lead poisoning in
the region have been led by Tejon Ranch by voluntarily placing a ban on lead shot
ammunition on Tejon Ranch lands. Most recently, the State of California has followed suit by
enacting into law the Ridley-Tree Condor Preservation Act, which bans lead shot
ammunition within the range of the California condor (Bloom 2009).

Nesting California condors, prior to the use of radio telemetry in the wild, were not known
to travel more than 50–75 kilometers (31–43.5 miles) from an active nest. As opportunistic
scavengers, California condors may travel tremendous distances in search of food
(Bloom 2009); in some instances they can travel up to 225 kilometers (about 140 miles;
Meretsky and Snyder 1992). As a resident, non-migratory species, the California condor has
the largest home range of any terrestrial bird in North America studied to date. The
Centennial Project site is about 30 kilometers (18.5 miles) from current active nest sites
known since 2000, and approximately 10 kilometers (6 miles) from the closest known
historical nesting site (Bloom 2009). Current satellite and radio-telemetry location data have
shown that California condors occasionally travel in the perimeter of the Project site, but
rarely occur actually on the Project site. There is one recorded instance of a bird landing on
the site (Bloom 2009).

Condors apparently avoid valley floors for foraging; they rarely fly over valley floor habitat
and almost never land there (Bloom 2009). By example, from 1982 to 1987, no condors with
transmitters were known to cross the Central Valley. Instead, all birds followed the foothills
and mountains surrounding the valley floor to move from the Sierra Nevada foothills to the
Coast Ranges and back. Observations of flying condors prior to 1987 indicate that, on the few
instances that they were known to have flown over valley floor habitat (including the
Centennial Project site), the birds were usually flying high over the landscape, probably at
an altitude of over 1,000 feet. During these flights, the condors rarely, if ever, landed and
their movements appeared transitory. To date, four GPS location points out of many
thousands were in the vicinity of the Centennial Project site. Numbers of GPS locations of
released birds are increasing in the region as the number of condors in the wild increases
(Bloom 2009).

Observations and data from telemetered birds (by radio and satellite) indicate that the
Project site is not used for diurnal or nocturnal roosts, but may rarely be used for foraging
or flyovers. It contains no features suitable for nesting, no cliffs or large trees of the height

R:\Projects\PAS\CEN\000306\Draft EIR\5.7 Bio_051117.docx 5.7-119 Centennial Project
Draft EIR