LC
Cattle Egret Bubulcus ibis



Justification

Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be increasing, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Population justification
The population is estimated to number 4,000,000-9,850,000 individuals. The European population is estimated at 76,100-92,300 pairs, which equates to 152,000-185,000 mature individuals (BirdLife International 2015). The population is therefore placed in the band 4,000,000-9,999,999 individuals.

Trend justification
The overall population trend is increasing, although some populations may be stable, decreasing or have unknown trends (Wetlands International 2015). This species has undergone a small or statistically insignificant decrease over the last 40 years in North America (data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007) Note, however, that these surveys cover less than 50% of the species's range in North America. The European population is estimated to be decreasing by less than 25% in 24.3 years (three generations) (BirdLife International 2015).

Ecology

Behaviour Most populations of this species are partially migratory, making long-distance dispersive movements related to food resources in connection with seasonal rainfall (del Hoyo et al. 1992). Other populations (e.g. in north-east Asia and North America) are fully migratory (del Hoyo et al. 1992, Snow and Perrins 1998). The species breeds throughout the year in the tropics with different regional peaks (del Hoyo et al. 1992) depending on food availability (Kushlan and Hancock 2005). It breeds colonially, often with other species, in groups that number from a few dozen to several thousand pairs, even up to 10,000 pairs in Africa (del Hoyo et al. 1992). The nesting effort of the species is related to rainfall patterns, leading to an annual variation in productivity (Kushlan and Hancock 2005). Outside of the breeding season the species remains gregarious (Brown et al. 1982, del Hoyo et al. 1992), feeding in loose flocks of 10-20 individuals (Brown et al. 1982) and often gathering in flocks of hundreds or even thousands of individuals where food is abundant (del Hoyo et al. 1992). Nocturnal roosting sites in Africa commonly hold a few hundred to 2,000 individuals (Brown et al. 1982). The species is a diurnal feeder (del Hoyo et al. 1992) and commonly associates with native grazing mammals or domesticated livestock (Kushlan and Hancock 2005) and may follow farm machinery to capture disturbed prey (del Hoyo et al. 1992). Habitat The species inhabits open grassy areas such as meadows (del Hoyo et al. 1992), livestock pastures (Kushlan and Hancock 2005), semi-arid steppe (del Hoyo et al. 1992) and open savanna grassland subject to seasonal inundation (Kushlan and Hancock 2005), dry arable fields (del Hoyo et al. 1992), artificial grassland sites (e.g. lawns, parks, road margins and sports fields) (Kushlan and Hancock 2005), flood-plains (Hancock and Kushlan 1984), freshwater swamps, rice-fields, wet pastures (del Hoyo et al. 1992), shallow marshes (Kushlan and Hancock 2005), mangroves (Hancock and Kushlan 1984) and irrigated grasslands (with ponds, small impoundments, wells, canals, small rivers and streams) (Kushlan and Hancock 2005). It rarely occupies marine habitats or forested areas (del Hoyo et al. 1992) although in Australia it may enter woodlands and forests, and it shows a preference for freshwater (Marchant and Higgins 1990) although it may also use brackish or saline habitats (Kushlan and Hancock 2005). It occurs from sea-level up to c.1,500 m (Kushlan and Hancock 2005) or locally up to c.4,000 m (Peru) (del Hoyo et al. 1992). Diet Its diet consists primarily of insects such as locusts, grasshoppers (del Hoyo et al. 1992), beetles, adult and larval Lepidoptera, Hemiptera, dragonflies (Hancock and Kushlan 1984) and centipedes but worms (Brown et al. 1982), spiders (Hancock and Kushlan 1984), crustaceans, frogs, tadpoles, molluscs, fish, lizards, small birds, rodents and vegetable matter (e.g. palm-nut pulp) may also be taken (del Hoyo et al. 1992). Breeding site The nest is constructed of twigs and vegetation (Kushlan and Hancock 2005) and is positioned up to 20 m high in reedbeds (del Hoyo et al. 1992, Kushlan and Hancock 2005), marshes, mangroves, dense thickets (Kushlan and Hancock 2005), bushes or trees (del Hoyo et al. 1992, Kushlan and Hancock 2005), usually over or surrounded by water (Kushlan and Hancock 2005). The species nests colonially in single- or mixed-species groups with the nests placed close or touching (Snow and Perrins 1998). Management information The species can adversely affect the trees and bushes it uses for nesting, which may lead to the abandonment of the colony site if it is not managed (Kushlan and Hancock 2005).

Threats

Large colonies nesting in urban areas are perceived as a public nuisance and may be persecuted (e.g. by disturbance to prevent colony establishment, removal or direct killing) (Kushlan and Hancock 2005). In its breeding range the species is threatened by wetland degradation and destruction such as lake drainage for irrigation and hydroelectric power production (Armenia) (Balian et al. 2002), and in some parts of its range it is susceptible to pesticide poisoning (organophosphates and carbamates) (Kwon et al. 2004). Utilisation The species is hunted and traded at traditional medicine markets in Nigeria (Nikolaus 2001).

Conservation actions

Conservation Actions Underway
The species is not listed on priority lists of the Conventions.

Conservation Actions Proposed
The following information refers to the species's European range only: The species can adversely affect the trees and bushes it uses for nesting, which may lead to the abandonment of the colony site if it is not managed (Kushlan and Hancock 2005). Freshwater habitats need to be sustainably managed. Establish non-intrusion zones around colonies.

Acknowledgements

Text account compilers
Butchart, S., Ekstrom, J., Malpas, L., Symes, A., Ashpole, J


Recommended citation
BirdLife International (2019) Species factsheet: Bubulcus ibis. Downloaded from http://www.birdlife.org on 25/04/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 25/04/2019.