Egretta garzetta -- (Linnaeus, 1766) ANIMALIA -- CHORDATA -- AVES -- PELECANIFORMES -- ARDEIDAE Common names: Little Egret; Assessment Information European Red List Status LC -- Least Concern, (IUCN version 3.1) European Red List Assessment Year published: 2015 Date assessed: 2015-03-31 Assessor(s): BirdLife International Reviewer(s): Symes, A. Compiler(s): Ashpole, J., Burfield, I., Ieronymidou, C., Pople, R., Van den Bossche, W., Wheatley, H. & Wright, L. Assessment Rationale European regional assessment: Least Concern (LC) EU27 regional assessment: Least Concern (LC) In Europe this species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern in Europe. Within the EU27 this species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 10% in ten years or three generations, or with a specified population structure). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern in the EU27. Occurrence Countries/Territories of Occurrence Native: Albania; Armenia; Austria; Azerbaijan; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Cyprus; Czech Republic; Denmark; France; Georgia; Germany; Greece; Hungary; Ireland, Rep. of; Italy; Macedonia, the former Yugoslav Republic of; Malta; Moldova; Montenegro; Netherlands; Poland; Portugal; Romania; Russian Federation; Serbia; Slovakia; Slovenia; Spain; Switzerland; Turkey; Ukraine; United Kingdom; Gibraltar (to UK) Vagrant: Finland; Latvia; Liechtenstein; Luxembourg; Norway; Sweden Population The European population is estimated at 66,700-84,800 pairs, which equates to 133,000-170,000 mature individuals. The population in the EU27 is estimated at 43,600-51,700 pairs, which equates to 87,200-103,000 mature individuals. For details of national estimates, see Supplementary PDF. In Europe and the EU27 the population size is estimated to be decreasing by less than 25% in 19.8 years (three generations). For details of national estimates, see Supplementary PDF. Trend Habitats and Ecology All populations of this species undergo post-breeding dispersive movements (Martínez-Vilalta et al. 2014). Populations breeding in the Palearctic are highly migratory (Hancock and Kushlan 1984). The timing of
breeding varies geographically (Martínez-Vilalta et al. 2014) although, in general, European populations breed in spring and summer (March to July). The species usually nests in colonies sometimes of thousands of pairs and often with other species. Some populations also breed solitarily or in small single-species groups of under 100 pairs. It inhabits fresh, brackish or saline wetlands (Martínez-Vilalta et al. 2014) and shows a preference for shallow waters (10 15 cm deep) in open, unvegetated sites where water levels and dissolved oxygen levels fluctuate daily, tidally or seasonally, and where fish are concentrated in pools or at the water's surface (Kushlan and Hancock 2005). Habitats frequented include the margins of shallow lakes, rivers, streams and pools, open swamps and marshes, flooded meadows, flood-plains (Martínez-Vilalta et al. 2014), lagoons, irrigation canals, aquaculture ponds (Kushlan and Hancock 2005), saltpans (Martínez-Vilalta et al. 2014) and rice fields (which are especially important in areas with few remaining natural wetland habitats) (Hancock and Kushlan 1984, Kushlan and Hancock 2005). The species also occupies dry fields and cattle pastures (Martínez-Vilalta et al. 2014) and some populations are almost entirely coastal, inhabiting rocky or sandy shores, reefs, estuaries, mudflats, saltmarshes and tidal creeks (Martínez-Vilalta et al. 20140). It is a highly opportunistic feeder (Kushlan and Hancock 2005), taking mainly small fish under 20 g in weight and less than 10 cm long (Martínez-Vilalta et al. 2014), aquatic and terrestrial insects (e.g. beetles, dragonfly larvae and crickets) (Kushlan and Hancock 2005) and crustaceans as well as amphibians, molluscs (Martínez- Vilalta et al. 2014) (snails and bivalves) (Kushlan and Hancock 2005), spiders, worms, reptiles and small birds (Martínez-Vilalta et al. 2014). The species may nest on the ground in protected sites (Kushlan and Hancock 2005) or up to 20 m high on rocks, in reedbeds, bushes or trees (Martínez-Vilalta et al. 2014). It usually nests in single- or mixed-species colonies (Kushlan and Hancock 2005). It may feed up to 7 13 km away from breeding colonies during the breeding season (Martínez-Vilalta et al. 2014). Habitats & Altitude Habitat (level 1 - level 2) Importance Occurrence Artificial/Aquatic - Canals and Drainage Channels, Ditches suitable resident Artificial/Aquatic - Ponds (below ha) suitable resident Artificial/Aquatic - Seasonally Flooded Agricultural Land suitable resident Forest - Subtropical/Tropical Mangrove Vegetation Above High Tide Level suitable breeding Forest - Subtropical/Tropical Mangrove Vegetation Above High Tide Level suitable non-breeding Grassland - Subtropical/Tropical Seasonally Wet/Flooded major breeding Grassland - Subtropical/Tropical Seasonally Wet/Flooded major non-breeding Marine Coastal/Supratidal - Coastal Brackish/Saline Lagoons/Marine Lakes suitable resident Marine Coastal/Supratidal - Coastal Freshwater Lakes suitable resident Marine Coastal/Supratidal - Sea Cliffs and Rocky Offshore Islands suitable resident Marine Intertidal - Mud Flats and Salt Flats suitable resident Marine Intertidal - Sandy Shoreline and/or Beaches, Sand Bars, Spits, Etc suitable resident Marine Intertidal - Shingle and/or Pebble Shoreline and/or Beaches suitable resident Marine Intertidal - Tidepools suitable resident Marine Neritic - Estuaries major breeding Marine Neritic - Estuaries major non-breeding Wetlands (inland) - Permanent Freshwater Lakes (over ha) major breeding Wetlands (inland) - Permanent Freshwater Lakes (over ha) major non-breeding Wetlands (inland) - Permanent Rivers/Streams/Creeks (includes waterfalls) major breeding Wetlands (inland) - Permanent Rivers/Streams/Creeks (includes waterfalls) major non-breeding Wetlands (inland) - Permanent Saline, Brackish or Alkaline Lakes suitable resident Wetlands (inland) - Seasonal/Intermittent Freshwater Lakes (over ha) suitable resident Wetlands (inland) - Seasonal/Intermittent Freshwater Marshes/Pools (under ha) suitable resident Wetlands (inland) - Seasonal/Intermittent Saline, Brackish or Alkaline Lakes and Flats suitable resident Altitude max. 2000 m Occasional altitudinal limits Threats The species is threatened by wetland degradation and loss through drainage for agriculture, changes in current management practices and contamination from agricultural and industrial operations (Kushlan and Hancock 2005). The species is also susceptible to avian influenza so may be threatened by future outbreaks of the virus (Ellis et al. 2004, Melville and Shortridge 2006), and it previously suffered from hunting for the plume trade (although this is no longer a threat) (Kushlan and Hancock 2005, Martínez-Vilalta et al. 2014).
Threats & Impacts Threat (level 1) Threat (level 2) Impact and Agriculture & Agro-industry aquaculture farming Ongoing Majority (50-90%) Unknown Unknown Agriculture & aquaculture Climate change & severe weather Human intrusions & disturbance Invasive and other problematic species, genes & diseases Natural system modifications Natural system modifications Residential & commercial development Transportation & service corridors Wood & pulp plantations (scale Ongoing Majority (50-90%) Slow, Significant Medium Impact unknown/ unrecorded) Ecosystem conversion; ; Species disturbance Droughts Ongoing Majority (50-90%) Slow, Significant Medium Impact Recreational activities Ongoing Majority (50-90%) Slow, Significant Medium Impact Species disturbance Avian Influenza Virus (H subtype) Future Majority (50-90%) Slow, Significant Low Impact Species mortality Abstraction of surface water Ongoing Minority (<50%) Slow, Significant (unknown use) Low Impact Other ecosystem modifications Ongoing Majority (50-90%) Slow, Significant Medium Impact Ecosystem conversion Commercial & industrial areas Ongoing Minority (<50%) Slow, Significant Low Impact Ecosystem conversion Roads & railroads Ongoing Minority (<50%) Negligible declines Low Impact Ecosystem conversion; Conservation Actions Underway The species is listed on Annex I of the EU Birds Directive and Annex II of the Bern Convention. Conservation Conservation Actions Proposed An artificial island nesting site created in the Camargue, France succeeded in attracting nesting pairs to the area (Hafner 2000). A study in north-west Italy suggests that existing nesting sites should be protected and that breeding habitats should be actively managed in order to maintain suitable habitat characteristics (Fasola and Alieri 1992). The creation of a network of new nesting sites spaced at 4 10 km in relation to available foraging habitats in zones currently without suitable nesting sites is also recommended (Fasola and Alieri 1992). Freshwater habitats need to be sustainably managed. Establish non-intrusion zones around colonies.
Bibliography Ellis, T. M.; Bousfield, R. B.; Bissett, L. A.; Dyrting, K. C.; Luk, G. S. M.; Tsim, S. T.; Sturm-Ramirez, K.; Webster, R. G.; Guan, Y.; Peris, J. S. M. 2004. Investigation of outbreaks of highly pathogenic H5N1 avian influenza in waterfowl and wild birds in Hong Kong in late 2002. Avian Pathology 33(5): 492-505. Fasola, M.; Alieri, R. 1992. Conservation of heronry Ardeidae sites in North Italian agricultural landscapes. Biological Conservation 62: 219-228. Hafner, H. 2000. Heron nest site conservation. In: Kushlan, J. A.; Hafner, H. (ed.), Heron conservation, pp. 201-217. Academic Press, San Diego. Hancock, J.; Kushlan, J. 1984. The herons handbook. Croom Helm, London. Kushlan, J. A.; Hancock, J. A. 2005. The herons. Oxford University Press, Oxford, U.K. Langrand, O. 1990. Guide to the birds of Madagascar. Yale University Press, New Haven, USA. Martínez-Vilalta, A., Motis, A., Christie, D.A. & Kirwan, G.M. (2014). Little Egret (Egretta garzetta). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2014). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/52694 on 15 April 2015). Melville, D. S.; Shortridge, K. F. 2006. Migratory waterbirds and avian influenza in the East Asian- Australasian Flyway with particular reference to the 2003-2004 H5N1 outbreak. In: Boere, G.; Galbraith, C., Stroud, D. (ed.), Waterbirds around the world, pp. 432-438. The Stationary Office, Edinburgh, UK. Map (see overleaf)