5.4.5 Alectoris chukar (Chukar Partridge)
Chukar Partridges were introduced to Robben Island in 1964 after six birds were
confiscated by customs officials (Picker and Griffiths 2011). They have a large native
range from eastern Europe to northeastern China. Invasive populations occur in
New Zealand and a large part of the western USA. The Robben Island population is
the only remaining population in South Africa, and is self-sustaining, and may even
be growing following the reduction in the feral cat population (see Davies et al.
2020, Chap. 22). Its impact is considered to be moderate due to hybridisation with
other partridge species (Evans et al. 2016), although impact on Robben Island is
thought to be negligible (van Wilgen and Wilson 2018). This species is listed under
the Regulations as Category 2 on the mainland, and 1b on offshore islands.
5.4.6 Columba livia (Rock Doves)
Rock Doves (aka Common Pigeons) are now widespread in most major urban areas
of southern Africa (Little 1994). This species often forms flocks with native Speckled Pigeons, C. guinea, but studies suggest that the resources used by Rock Doves do
not overlap with Speckled Pigeons (Little 1994). The invasion of Common Pigeons
is complicated by their use as pets and in sport (pigeon racing), and escapees from
captive collections regularly supplement invasive populations. This has led to a split
in public perception where pigeons are seen both as pests (e.g. regarded as flying
rats), or an important component of urban wildlife (Cox et al. 2018; Harris et al.
2016). In South African cities, building managers place deterrents to stop individuals
roosting and nesting, but most people in the buildings regard these measures as
unnecessary (Harris et al. 2016). Common pigeons are considered to have a moderate impact due to the spread of disease to native species (Evans et al. 2016), but are
not listed as invasive species under the Regulations in the region. Pigeons are known
to carry a considerable burden of parasites (Mushi et al. 2000), including paramyxovirus (Pienaar and Cilliers 1987). Pigeons undoubtedly carry West Nile Virus,
although the presence in invasive populations of C. livia in South Africa is ambiguous, although they likely act as reservoirs during outbreaks (Jupp 2001).
5.4.7 Starlings (Genus Sturnus)
Two bird species of the Sturnidae family are top avian invaders both globally and
regionally: Common Starlings, Sturnus vulgaris, and Common Mynas, Sturnus
(formerly Acridotheres) tristis. Their range expansion and evolutionary shifts in
morphology of populations have been studied extensively and are the subject of
Box 5.1.
5 Terrestrial Vertebrate Invasions in South Africa
131
Chukar Partridges were introduced to Robben Island in 1964 after six birds were
confiscated by customs officials (Picker and Griffiths 2011). They have a large native
range from eastern Europe to northeastern China. Invasive populations occur in
New Zealand and a large part of the western USA. The Robben Island population is
the only remaining population in South Africa, and is self-sustaining, and may even
be growing following the reduction in the feral cat population (see Davies et al.
2020, Chap. 22). Its impact is considered to be moderate due to hybridisation with
other partridge species (Evans et al. 2016), although impact on Robben Island is
thought to be negligible (van Wilgen and Wilson 2018). This species is listed under
the Regulations as Category 2 on the mainland, and 1b on offshore islands.
5.4.6 Columba livia (Rock Doves)
Rock Doves (aka Common Pigeons) are now widespread in most major urban areas
of southern Africa (Little 1994). This species often forms flocks with native Speckled Pigeons, C. guinea, but studies suggest that the resources used by Rock Doves do
not overlap with Speckled Pigeons (Little 1994). The invasion of Common Pigeons
is complicated by their use as pets and in sport (pigeon racing), and escapees from
captive collections regularly supplement invasive populations. This has led to a split
in public perception where pigeons are seen both as pests (e.g. regarded as flying
rats), or an important component of urban wildlife (Cox et al. 2018; Harris et al.
2016). In South African cities, building managers place deterrents to stop individuals
roosting and nesting, but most people in the buildings regard these measures as
unnecessary (Harris et al. 2016). Common pigeons are considered to have a moderate impact due to the spread of disease to native species (Evans et al. 2016), but are
not listed as invasive species under the Regulations in the region. Pigeons are known
to carry a considerable burden of parasites (Mushi et al. 2000), including paramyxovirus (Pienaar and Cilliers 1987). Pigeons undoubtedly carry West Nile Virus,
although the presence in invasive populations of C. livia in South Africa is ambiguous, although they likely act as reservoirs during outbreaks (Jupp 2001).
5.4.7 Starlings (Genus Sturnus)
Two bird species of the Sturnidae family are top avian invaders both globally and
regionally: Common Starlings, Sturnus vulgaris, and Common Mynas, Sturnus
(formerly Acridotheres) tristis. Their range expansion and evolutionary shifts in
morphology of populations have been studied extensively and are the subject of
Box 5.1.
5 Terrestrial Vertebrate Invasions in South Africa
131