5.4.8 Psittacula krameri (Rose-Ringed Parakeet)
The Rose-ringed Parakeet is a popular caged bird that has established populations in
35 countries on five continents (Menchetti et al. 2016; Shwartz et al. 2009). Native to
a broad swath of central and West Africa, and the Indian subcontinent, individuals
have been seen in South Africa ever since caged birds were brought here. Records
include 1850 for Cape Town and birds were common in Durban by the 1970s (Picker
and Griffiths 2011). In South Africa, Rose-ringed Parakeet populations are rapidly
expanding their range (Symes 2014), with animals established in Gauteng (Roche
and Bedford-Shaw 2008), Pietermaritzburg, Cape Town, Steytlerville (in the Eastern
Cape), and Durban where the population currently occupies ~730 km
2 with four
main roosts of between 20 and 100 birds (Hart and Downs 2014).
Physiological experiments on caged South African parakeets suggest that these
birds are tolerant of a wide range of ambient, especially low temperatures, and are
therefore equipped to cope with a variety of climatic situations in the country
(Thabethe et al. 2013). However, occurrence of the Rose-ringed Parakeet in
South Africa is currently best predicted by human density (Hugo and van Rensburg
2009). Despite their known impacts as an invasive species, these birds are still
popular as cage birds in South Africa, and 55 of 78 properties issued with notices
under the Regulations were for Rose-ringed Parakeets, with the majority of these
being for traders (van Wilgen and Wilson 2018). Similarly, the Rose-ringed Parakeet
was the second-highest species that had permits issued for use of a listed invasive
species within South Africa for (108) (van Wilgen and Wilson 2018). Impacts
include competition with other cavity-nesting birds and frugivores, as well as
potential impacts on certain agricultural crops (Menchetti et al. 2016). In addition,
Rose-ringed Parakeets are known reservoirs of chlamydiosis and other diseases
(Menchetti and Mori 2014). Their impact is considered to be Moderate based on
competition and predation mechanisms (Evans et al. 2016). Details of their control
are covered by Davies et al. (2020), Chap. 22. See also Potgieter et al. (2020),
Chap. 11 for their impact in the urban context.
5.4.9 Corvus splendens (House Crows)
House Crows are native to the Indian sub-continent, but have invaded countries
in the Middle East, East Africa (Kenya, Tanzania, Mozambique) and offshore
islands (Madagascar, Mauritius, Reunion and Seychelles Nyári et al. 2006). The
first published records of House Crows arriving in South Africa date to the 1970s:
Durban in 1972, and Cape Town in 1979 (Dean 2000; Hockey et al. 2005). These
birds are known to use marine vessels to move from colonies on the east coast of the
continent into South African ports. In the urban context, House Crows are aggressive
toward people, and thrive in densely populated areas where litter and food waste
collects. In Cape Town, they were reported to harass primary and pre-school
136
J. Measey et al.
The Rose-ringed Parakeet is a popular caged bird that has established populations in
35 countries on five continents (Menchetti et al. 2016; Shwartz et al. 2009). Native to
a broad swath of central and West Africa, and the Indian subcontinent, individuals
have been seen in South Africa ever since caged birds were brought here. Records
include 1850 for Cape Town and birds were common in Durban by the 1970s (Picker
and Griffiths 2011). In South Africa, Rose-ringed Parakeet populations are rapidly
expanding their range (Symes 2014), with animals established in Gauteng (Roche
and Bedford-Shaw 2008), Pietermaritzburg, Cape Town, Steytlerville (in the Eastern
Cape), and Durban where the population currently occupies ~730 km
2 with four
main roosts of between 20 and 100 birds (Hart and Downs 2014).
Physiological experiments on caged South African parakeets suggest that these
birds are tolerant of a wide range of ambient, especially low temperatures, and are
therefore equipped to cope with a variety of climatic situations in the country
(Thabethe et al. 2013). However, occurrence of the Rose-ringed Parakeet in
South Africa is currently best predicted by human density (Hugo and van Rensburg
2009). Despite their known impacts as an invasive species, these birds are still
popular as cage birds in South Africa, and 55 of 78 properties issued with notices
under the Regulations were for Rose-ringed Parakeets, with the majority of these
being for traders (van Wilgen and Wilson 2018). Similarly, the Rose-ringed Parakeet
was the second-highest species that had permits issued for use of a listed invasive
species within South Africa for (108) (van Wilgen and Wilson 2018). Impacts
include competition with other cavity-nesting birds and frugivores, as well as
potential impacts on certain agricultural crops (Menchetti et al. 2016). In addition,
Rose-ringed Parakeets are known reservoirs of chlamydiosis and other diseases
(Menchetti and Mori 2014). Their impact is considered to be Moderate based on
competition and predation mechanisms (Evans et al. 2016). Details of their control
are covered by Davies et al. (2020), Chap. 22. See also Potgieter et al. (2020),
Chap. 11 for their impact in the urban context.
5.4.9 Corvus splendens (House Crows)
House Crows are native to the Indian sub-continent, but have invaded countries
in the Middle East, East Africa (Kenya, Tanzania, Mozambique) and offshore
islands (Madagascar, Mauritius, Reunion and Seychelles Nyári et al. 2006). The
first published records of House Crows arriving in South Africa date to the 1970s:
Durban in 1972, and Cape Town in 1979 (Dean 2000; Hockey et al. 2005). These
birds are known to use marine vessels to move from colonies on the east coast of the
continent into South African ports. In the urban context, House Crows are aggressive
toward people, and thrive in densely populated areas where litter and food waste
collects. In Cape Town, they were reported to harass primary and pre-school
136
J. Measey et al.