Feral goat (Capra hircus) populations adversely impact
native insular biota and physical habitats worldwide. The
effectiveness of the Judas goat technique for eradicating
remnant feral goats was studied on San Clemente Island
(SCI), California from June 1989 through April 1991. By
April 1991, 263 feral goats were killed on SCI; only 2
adult females and their offspring were believed to remain.
The length of time required by radio-collared (Judas)
goats to establish initial contact with remnant goats was 1
to 5 days, and time to subsequent encounters with new goats
averaged 3.5 days. Duration of association between Judas
goats and remnant herds ranged from 1-60 days. Judas goat
home ranges averaged 4.4 km² and maximum distances Judas
goats traveled to find conspecifics averaged 4.8 km.
Observations of Judas goats that were associated with
remnant feral goats allowed individual identification of
most goats and prediction of their temporal and spatial
activity patterns. This knowledge greatly expedited the
eradication process and likely contributed to the
preservation of threatened and endangered endemic species
on SCI.
Natality, survivorship, and condition of SCI goats
were inversely related to decreases in population density
when compared to goat populations from other islands.
higher and mortality lower than in other feral goat
populations, presumably because of the unusually low
density of goats on SCI.
The Judas goat technique allows removal of low density
feral goat herds in a timely manner and should be used by
resource managers wherever feral goats threaten native
flora and fauna. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37022 |
| Date | 09 December 1991 |
| Creators | Seward, Dawn R'Lene |
| Contributors | Coblentz, Bruce E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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