Taxonomic name: Pycnonotus jocosus (Linnaeus, 1758)
Common names: bilbil krwawnik (Polish), bilbil zbroczony (Polish), bulbul (Mauritius), bulbul baffirossi (Italian), bulbul cervenouchý (Czech), bulbul dai mustacchi rossi (Italian), bulbul de bigotes rojos (Spanish), bulbul de bigoti vermell (Catalan), bulbul mustacchi rossi (Italian), bulbul orfeo (Spanish), bulbul orphée (French), bulbul rudoocasý (Czech), bylbyl cervenosluchý (Slovak), Crested Bulbul (English), kouraun (Japanese), kyläbulbuli (Finnish), le kondé (Mauritius), merbah telinga merah (Malay), merl konde (Seychelles), Merle de Maurice (French-
Reunion (La Réunion)), punapõsk-bülbül (Estonian), punaposkibulbuli (Finnish), raudonskruostis biulbiulis (Lithuanian), red-whiskered bulbul (English), Rödörad bulbyl (Swedish), rødørebylbyl (Norwegian), rødøret bulbul (Danish), rødøret bylbyl (Norwegian), roodoorbuulbuul (Dutch), roodoor-buulbuul (Dutch), Rotohrbülbül (German), tepeli arapbülbülü (Turkish)
Organism type: bird
Pycnonotus jocosus (red-whiskered bulbul) is a bird native to Asia which has become invasive to several parts of the world. It has been found to damage crops, compete with native species and spread invasive plants.
Pycnonotus jocosus (red-whiskered bulbul) is a passerine avian. Adults measure 17-23cm in length with a wingspan of 28cm and weigh 23-42 g. Identifiable characteristics include its distinctive red ear patch and undertail coverts, a dark brown upperside, tan flanks, and white underside, a thin and notched beak, oval-shaped bristled nostrils, and a black shoulder spur and black head with a pointed crest. The legs and toes are usually short and have little strength. Males and females are alike in colour. Immature bulbuls resemble adults except that they lack the red ear patch (Honolulu, undated; Islam and Williams, 2000; Sibley, 2003). During the non-breeding season in North America, they assemble in communal roosts beginning in July and August and ending in January. Roosts usually consist of 40–100 individuals and inhabit a range of about 5.1 km2. Birds disperse following gonadal enlargement and begin seeking a mate. After the breeding season they return to their same roost (Carleton and Owre, 1975).
agricultural areas, coastland, natural forests, planted forests, ruderal/disturbed, scrub/shrublands, urban areas
Pycnonotus jocosus (red-whiskered bulbul) has colonized many different terrestrial habitats in temperate, tropical, and subtropical climates (Clergeau & Mandon-Dalger, 2001). In its native range it prefers wet habitats 500–2000m elevation and is common along forest edges, woodlands, cultivated areas and urban parks and gardens. In its introduced range it is mostly found in suburban areas, parks and gardens. However, it is also well adapted to native woodland, scrubland and forest of higher elevations (e.g. Islam & Williams, 2000; Linnebjerg et al., in press). P. jocosus is known to nest in shrubs, small, trees, hedges, trellises and verandas of buildings or other available ledges or sites 1–9m off the ground. Since they are well adapted to human-altered environments much of their spread is facilitated by human development (Islam & Williams, 2000) but they are also known to reach high numbers on remote and largely unpopulated islands (e.g. Roberts, 1988).
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 & Mandon-Dalger, 2001; Linnebjerg et al. 2009; Linnebjerg et al., in press). In California this species has signficantly damaged citrus crops. On Oahu Island, Hawai'i it consumes commercial fruits and flowers such as papaya and orchids. Damage to agriculture has been documented in other parts of its introduced range in Florida, La Réunion and Mauritius. On Mauritius P. jocosus has also reduced populations of endemic 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 & Williams, 2000). P. jocosus is also known to distribute invasive alien 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), privet (Ligustrum robustum) and Indian laurel (Litsea glutinosa) in the Mascarene Islands (Simberloff & Von Holle, 1999; Mandon-Dalger, 2004; Linnebjerg et al., in press); and Brazilian jasmine (Jasminum fluminense), Brazilian peppertree (Schinus terebinthifolius), Bengal fig (Ficus benghalensis), and Lantana spp. in Florida (Carleton & Owre, 1975).
Pycnonotus jocosus (red-whiskered bulbul) is a popularly kept cage bird (Clergeau & Mandon-Dalger, 2001).
Pycnonotus jocosus (red-whiskered bulbul) is very gregarious in the nonbreeding season and can often be seen foraging in large communal roosts (Islam & Williams, 2000). Their song is a chattering and musical scolding. Their call is a staccato kink-a-jou (Sibley, 2003).
Native range: India, Andaman Is., Burma, Nepal, Bhutan, Bangladesh, Myanmar, Thailand, Vietnam, Northern Malaya, Laos, Cambodia, and South China (Islam & Williams, 2000).
Known introduced range: Nicobar Islands, Australia, Southern Malaya, Singapore, La Réunion, Mauritius, Seychelles (Assumption), North America (Southern Florida, and Southern California) and the Hawai'ian Islands and possibly introduced to Sumatra and Java (Long, 1981; Islam & Williams, 2000).
Introduction pathways to new locations
Transportation of domesticated animals:
Local dispersal methods
Escape from confinement: The introduction of Pycnonotus jocosus in some cases is thought to be a result of their release from cages, avaries, gardens, etc. (Islam & Williams, 2000).
Natural dispersal (local):
It is recommended that management actions for Pycnonotus jocosus (red-whiskered bulbul) be taken within the first few years of introduction in order to be effective. This is to take advantage of its period of slow dispersal and population growth following introduction. Research has shown that P. jocosus spreads slowly for the first five or more years. After this initial period, which is variable by location with some instances taking as long as ten years, the populations spread and grow more rapidly, rendering eradication arduous and ineffective. Researchers cite its roosting behaviour as the cause of this low initial dispersion rate (Clergeau, 2001)
Preventative measures: Most of its spread may be contributed to human transport, be it accidental escape from zoos or gardens or intentional and unintentional release of cage birds. More care in the keeping and transport of red-whiskered bulbuls would greatly reduce its spread to new locations. Governmental preventative measures have been fairly successful in the United States. The U.S. Department of Agriculture Code of Federal Regulation strictly prohibits their importation to the U.S. and its territories. The Hawai'i Department of Land and Natural Resources distributed brochures and flyers to the public in the 1980s informing them about P. jocosus and requesting that any sightings be reported. No new populations were established outside of Oahu (Islam & Williams, 2000).
Cultural: Since red-whiskered bulbuls are common cage birds in many parts of the world, the public should be informed of environmental threats they impose and be cautious in their keeping and transport.
Physical: Eradication or relocation is an option in invaded areas. P. jocosus was successfully captured using cages with a decoy and fruit as bait by a pest control program in La Réunion (Amiot et al., 2007).
Chemical: The use of pesticides and bird lime by farmers to protect their crops from bulbuls in the Mascarenes has been successful (Clergeau & Mandon-Dalger, 2000). Repellents methiocarb, ziram, and methyl anthranilate were successfully used to reduce the consumption of papaya by the closely related red-vented bulbul (Pycnonotus cafer) by 65% (Islam & Williams, 2000).
Pycnonotus jocosus (red-whiskered bulbul) is a frugivore that also consumes insects, spiders, and small reptiles. They have been found to eat fruits, berries, figs, seeds, buds, nectar, pollen, flowers, and leaves from a wide variety of plants throughout the world. Insect diet includes caterpillars, scale insects, flies, moths, ants and beetles (Islam & Williams, 2000).
Oviparous. Sexual. Breeding usually occurs in early warm months. In Florida pairs are formed February through July and breeding occurs from March to June. Pycnonotus jocosus (red-whiskered bulbul) is capable of up to three broods per year as in India, but usually only rears two. Each clutch usually consists of 2-4 pale pink eggs with red spots. Incubation is done by both sexes and lasts 12-14 days (NatureServe, 2007; Australian Museum, 2003).
Altricial young are cared for and fed by both parents for about 13 days, and are completely independent after 3 weeks (NatureServe, 2007). The young are fed primarily soft-bodied insects in early stages and then drupes and berries (Islam & Williams, 2000). The longest recorded adult life span in the wild is 11 years .
Reviewed by: Jannie Linnebjerg, National Environmental Research Institute, Department of Arctic Environment, Aarhus University
Nancy Bunbury, Seychelles Island Foundation
Amiot, C., Lorvelec, O., Mandon-Dalger, I., Sardella, A., Lequilliec, P., & Cleargeau, P. 2007. Rapid morphological divergence of introduced Red-whiskered Bulbuls Pyconotus jocosus in contrasting environments. Ibis, 149: 482-489.
Carleton, A.R. &Owre, O.T. 1975. The Red-whiskered Bulbul in Florida: 1960-71. The Auk, 92(1): 40-57.
Clergeau, P. & Mandon-Dalger, I. 2001. Fast colonization of an introduced bird: the case of Pycnonotus jocosus on the Mascarene Island. Biotropica 33(3): 542-546.
Islam, K., & Williams, R.N. 2000. Red-vented Bulbul (Pycnonotus cafer) and Red-whiskered Bulbul (Pycnonotus jocosus). In A. Poole & F. Gills (Eds.), The Birds of North America, No. 520. The Birds of North America, Inc., Philadelphia, PA.
Linnebjerg, J.F., Hansen, D.M. & Olesen, J.M. 2009. Gut-passage effect of the introduced Red-whiskered Bulbul (Pycnonotus jocosus) on germination of invasive plant species in Mauritius. Austral Ecology 34:272–277.
Linnebjerg, J.F., Hansen, D.M., Bunbury, N. & Olesen, J.M. In press. Diet composition of the invasive red-whiskered bulbul Pycnonotus jocosus in Mauritius. Journal of Tropical Ecology.
Compiled by: National Biological Information Infrastructure (NBII) & IUCN SSC Invasive Species Specialist Group (ISSG)
Last Modified: Friday, 25 January 2008