General Impact
Pycnonotus jocosus (red-whiskered bulbul) has been found to damage commercial crops, compete with and displace native passerines, prey on endemic young birds and arthropods, and spread invasive plant species (Clergeau, 2001). In California, they significantly damaged citrus crops. On Oahu Island, Hawaii, it consumes commercial fruits and flowers such as papaya and orchids. Damage to agriculture has been documented in other introduced ranges Florida, La Réunion and Mauritius. On Mauritius P. jocosus has also reduced populations of endemics passerine native white-eyes (Zosterops spp.), spiders of the genus Neophilia, and geckos. In Southern Florida it competes for resources with migratory and wintering birds (Islam, 1999). P. jocosus is also known to be a distributer of invasive plant species. Among these include: giant bramble (Rubus alceifolius), jujube tree (Cordia interrupta), Koster's curse (Clidemia hirta), largeleaf lantana (Lantana camara), bugweed (Solanum mauritianum), Brazilian peppertree (Schinus terebinthifolius), strawberry guava (Psidium cattleianum), and Indian laurel (Litsea glutinosa) in the Mascarene Islands (Simberloff, 1999; Mandon-Dalger, 2004); and Brazilian jasmine (Jasminum fluminense), Brazilian peppertree (Schinus terebinthifolius), Bengal fig (Ficus benghalensis), and Lantana spp. in Florida (Carleton, 1975).
Location Specific Impacts:Mauritius 
Agricultural: Pycnonotus jocosus is reported to damage crops in Mascarenes Reunion and Mariutius (Clergeau, 2001).
Interaction with other invasive species: Pycnonotus jocosus is known to spread plant invasives and noxious weeds such as giant bramble (Rubus alceifolius), jujube tree (Cordia interrupta), Koster's curse (Clidemia hirta), largeleaf lantana (Lantana camara), bugweed (Solanum mauritianum), Brazilian peppertree (Schinus terebinthifolius), strawberry guava (Psidium cattleianum), and Indian laurel (Litsea glutinosa) in Mauritius (Simberloff, 1999; Mandon-Dalger, 2004). Reunion (La Réunion)
Agricultural: Pycnonotus jocosus is reported to damage crops in Mascarenes Reunion and Mariutius (Clergeau, 2001).
Interaction with other invasive species: Pycnonotus jocosus is known to spread plant invasives and noxious weeds such as giant bramble (Rubus alceifolius), jujube tree (Cordia interrupta), Koster's curse (Clidemia hirta), largeleaf lantana (Lantana camara), bugweed (Solanum mauritianum), Brazilian peppertree (Schinus terebinthifolius), strawberry guava (Psidium cattleianum), and Indian laurel (Litsea glutinosa) in Mauritius (Simberloff, 1999; Mandon-Dalger, 2004). Reunion (La Réunion) 
Agricultural: Pycnonotus jocusus is regarded as a pest of crops (Mandon-Dalger et al., 1999 ; Clergeau & Mandon, 2001 ; Clergeau et al., 2002).
Competition: Pycnonotus jocusus is an aggressive bird that could compete with some endemic birds such as the olivaceous bulbul (Hypsipetes borbonicus).
Interaction with other invasive species: Pycnonotus jocusus contributes to the dispersion and germination of seeds of many invasive exotic plants: Clidemia hirta, Psidium cattleianum, Rubus alceifolius, Solanum mauritianum, Lantana camara, Ardisia crenata, Schinus terebinthifolius (Mandon-Dalger, 2002 ; Mandon-Dalger, 2004). Dade County (United States (USA))
Agricultural: Pycnonotus jocosusis a threat to Florida's agriculture industry. They have been reported to damage mango, raspberry, and mulberry crops (Islam, 1999, Carleton, 2001). However, a study demonstrated that they were unable to consume whole oranges, mangos, and avacados because their mandibles were too small. However, they could eat fruits that had been previously punctured (Carleton, 2001).
Interaction with other invasive species: Pycnonotus jocosus spreads plant invasives including: Brazilian jasmine (Jasminum fluminense), Brazilian peppertree (Schinus terebinthifolius), Bengal fig (Ficus benghalensis), and Lantana spp. in Florida ( Carleton, 1975). Oahu Is. (United States (USA))
Agricultural: Pycnonotus jocosus is reported to damage fruit orchards and flower nurseries (Islam, 1999).
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