LC
Green-backed Heron Butorides striata



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). 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). The population size has not been quantified, but is not believed to 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 global population has not been estimated following recent taxonomic changes.

Trend justification
The overall population trend is decreasing, although some populations may be stable and others have unknown trends (Wetlands International 2006).

Ecology

Behaviour The majority of this species is sedentary although northern breeding populations are migratory and populations in Africa may perform local movements relating to seasonal rainfall (del Hoyo et al. 1992). The timing of breeding varies geographically but often occurs during the rains in the tropics (del Hoyo et al. 1992, Kushlan and Hancock 2005). The species is highly territorial and often forages and nests singly (del Hoyo et al. 1992, Kushlan and Hancock 2005), occasionally also nesting in loosely spaced single-species groups of 5-15 pairs, or even in larger breeding aggregations of several hundred (300-500) (del Hoyo et al. 1992) pairs (Kushlan and Hancock 2005). Habitat The species shows a preference for forested water margins (Hancock and Kushlan 1984, Kushlan and Hancock 2005) such as mangrove-lined shores and estuaries, or dense woody vegetation fringing ponds, rivers, lakes and streams (Hancock and Kushlan 1984, del Hoyo et al. 1992, Kushlan and Hancock 2005). Other suitable habitats include river swamps, canals, artificial ponds, salt-flats (Kushlan and Hancock 2005), mudflats, tidal zones, exposed coral reefs (del Hoyo et al. 1992), reedbeds, grassy marshland, pastures, rice-fields and other flooded cultivation (del Hoyo et al. 1992). Diet Its diet varies considerably over its range (del Hoyo et al. 1992) but usually consists predominantly of fish (del Hoyo et al. 1992, Kushlan and Hancock 2005) as well as amphibians (del Hoyo et al. 1992) (e.g. frogs) (Kushlan and Hancock 2005), insects (del Hoyo et al. 1992) (e.g. water beetles, grasshoppers and dragonflies) (Kushlan and Hancock 2005), spiders, leeches, crustaceans (e.g. crabs and prawns), molluscs (del Hoyo et al. 1992), earthworms, polychaete worms, birds (Kushlan and Hancock 2005), small reptiles and mice (del Hoyo et al. 1992). Breeding site The nest is a small, shallow structure of twigs (Kushlan and Hancock 2005) placed well hidden amongst the branches of trees or bushes (especially mangroves Rhizophora spp. and Avicennia spp., or Allocasuarina spp., Myoporum spp., Callistemon spp., Hibiscus spp., Casuarina spp., Syzygium spp. and Inga spp.) (Kushlan and Hancock 2005) 0.3-10 m above the surface of water or above the ground (del Hoyo et al. 1992).

Threats

The species is threatened by human disturbance, pesticides (del Hoyo et al. 1992) and habitat destruction (e.g. the loss of mangroves) (Kushlan and Hancock 2005). Utilisation The species is taken for food in some areas (del Hoyo et al. 1992).

Acknowledgements

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


Recommended citation
BirdLife International (2019) Species factsheet: Butorides striata. Downloaded from http://www.birdlife.org on 15/02/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/02/2019.