The Red-vented Bulbul Pycnonotus cafer (Linnaeus, 1766) – a new invasive bird species breeding in Europe

The Red-vented Bulbul Pycnonotus cafer (Linnaeus, 1766) is an Asian bird species classified as one of the hundred most invasive species in the world. The breeding of the species (adults feeding the fledglings) was observed in 2018 in Costa Calma (Fuerteventura, Canary Islands, Macaronesia). This is the first breeding record for Europe of this species. The first observation of the species was made in Corralejo (Fuerteventura) in 2003. In the period 2013–2018, an important range expansion of the species was recorded in Fuerteventura. In 2018, the species was also recorded in Valencia (Spain) for the first time.


Introduction
The occurrence of bird species outside their natural range may be an accidental natural occurrence, resulting from widening their geographical range and adaptation to new environments, or it may be the result of escape from breeding places (zoological and botanic gardens, wildfowl collection, pets in captivity) or an intentional introduction (Shieh et al. 2006;Brochier et al. 2010;Fàbregas et al. 2010;Cassey and Hogg 2015;Canning-Clode 2015). Accidental escapees and single individuals usually survive in the environment quite briefly, and they are not likely to breed in the wild. Local populations, fairly persistent and increasing in number, may be formed in the case of pairs or groups of birds, in favorable circumstances that allow nesting and feeding young to reproductive age. Sol et al. (2002) indicated that the urban environment is conducive to the success of introduced species, and the features of this species often include larger brains.  (Lowe et al. 2000). The Red-vented Bulbul is divided into eight subspecies and inhabits the area from the western Himalayas (Pakistan, Jammu, Kashmir and Nepal) to Sri Lanka, and from the Indus valley in the west to the Myanmar area, N Thailand and SW China in the east. In the area of its typical range in Asia, it is associated with dry deciduous woodlands, sparse secondary forest, dry scrub, orchards, gardens, plains and cultivated lands. It was introduced to Polynesia (Fiji, Samoa, Tongatapu, Niuafo'ou), the Arabian Peninsula (Kuwait, Qatar, Bahrain, United Arab Emirates, Oman), Hawaii (Oahu), as well as to the United States of America and New Zealand, where it is spreading (del Hoyo et al. 2005;Shirihai and Svensson 2018;Fishpool and Tobias 2019). It has not been listed as a breeding species in the Palearctic beyond the Arabian Peninsula (near Persian Gulf), and the northern part of the range in Asia (https://avibase.bsc-eoc.org).

Results
On 27.07.-2.08.2018, we watched a pair of Red-vented Bulbul Pycnonotus cafer (Linnaeus, 1766) adult birds with three fledglings in the Costa Calma

Discussion
This is the first report of this species breeding in the Palearctic west of the Persian Gulf. The first record of the Red-vented Bulbul from Fuerteventura, Canary Islands was on 28.11.2003 in Corralejo, the next observations took place on 29.07.2006 in the same region of the island (https://avibase.bsceoc.org). There were 48 observations of 1 to 5 birds between 2013 and 2019 from Fuerteventura (https://avibase.bsc-eoc.org), but the species has not thus far been recorded as breeding -there are no records on the list of observations in the database. In 2013, it was recorded in Fuerteventura only in one region (La Lajita), in 2014, in two (La Lajita, Costa Calma). In Probably, the first birds on Fuerteventura are escapees from captivity or introduced birds. Bulbuls are popular birds kept in captivity, e.g. the Red whiskered Bulbul Pycnonotus jocosus (Linnaeus, 1758) is a common pet bird in Thailand (Mongkolphan et al. 2017). Shieh et al. (2006) reported that the Pycnonotidae, Sturnidae, Timaliidae and Cacatuidae families has significantly high probabilities of escaping from captivity in Asia, in comparison to other birds families. Escape from captivity, especially from zoos is one of the most common ways of spreading alien species of birds (Fàbregas et al. 2010;Cassey and Hogg 2015). One of the first documented information on Red-vented Bulbuls in Fuerteventura in wild is the observation of birds in Corralejo (2003) and in the zoological garden of La Lajita (2013). It seems likely that they started to create a breeding population around 2014-2015, when 4-5 individuals were observed in La Lajita. In the following years, they began to settle in other available areas. The species is classified as a sedentary species, showing possible movements depending on environmental conditions (del Hoyo et al. 2005). Thibault et al. (2019) reported that in New Caledonia, tropical archipelago of the South Pacific Ocean, the Red-vented Bulbul, which was introduced in 1983, expanded its range mainly in urban and suburban areas.
In Fuerteventura, which is a semi-arid island, there are not many habitats available for this species; they are limited only to cities and holiday resorts with gardens and parks, but also may inhabit agricultural plantation.
The situation may be different in the continent (Spain), where the species may spread in more typical, dry deciduous woodlands or in urban tree stands. In Spain in Tarifa (Cadiz) another representative of Pycnonotidae family was noted as breeding, the Common Bulbul Pycnonotus barbatus (Desfontaines, 1789), first reported in 2013 (Van der Berg and Haas 2013). The Red-vented Bulbul is classified as the world's worst invasive species in the IUCN-ISSG list (Thibault et al. 2018). Invasive species are considered to be one of the major threats to native biodiversity, and the impact of invasive alien species is a key component of global change of biodiversity (Sala et al. 2000;Simberloff et al. 2013). The Red-vented Bulbul often hybridizes with White-eared Bulbul Pycnonotus leucotis (Gould, 1836) and other species of the genus (Roberts 1992;Grimmett et al. 1998) and is competitive in relation to other species (Thibault et al. 2019). Similar to the Common Myna, the Red-vented Bulbul is aggressive and may outcompete native species (Navjot et al. 2011). These bulbuls can affect the reduction of reproductive success of critically endangered Tahiti Flycatchers Pomarea nigra (Sparrman, 1786) (Blanvillain et al. 2003).
It is a generalist and opportunist species; its diet includes fruits, nectar, buds, invertebrates and occasionally vertebrates. In Asia, this bird often comes into conflict with humans, as a species that damages fruit orchards (e.g. bananas and other soft fruits), flowers, beans, tomatoes and pea crops (Bhatt and Kumar 2001). They may also help in the spread of seeds of other invasive plant species (Brochier et al. 2010).
In an analysis of alien bird species impacts (Shirley and Kark 2009), species in the family Pycnonotidae were found to have moderately negative economic and biodiversity impacts. Generalist species from an Indo-Malayan native range such as the Red-vented Bulbul, particularly those forming flocks, were associated with higher impacts.