Aves | Ciconiiformes
Environment: milieu / climate zone / depth range / distribution range
Others; freshwater; brackish. Tropical
Indo-Pacific, Atlantic Ocean and the Arctic. Tropical to polar.
Length at first maturity / Size / Weight / Age
Maturity: Lm ?  range ? - ? cm Max length : 66.0 cm TL male/unsexed; (Ref. 8812); max. published weight: 1.1 kg (Ref. 356)
Culmen: 5.09 cm; tarsus: 5.715 cm; wing: 41.15 cm.
Total Length: 56 to 66 cm; Wingspan: 137 (Ref. 8812) to 147 cm (Ref. 84934). Total population is unknown but with over 1,000,000 pairs in the Palearctic and over 150,000 pairs in eastern North America. Population has expanded and is now considered a pest in some European countries (Ref. 84934). Colonies of these birds can extend to 2 km (Ref. 87784). It has a 70% dispersal rate (Ref. 87790). Dipping; surface seizing; shallow plunge diving; coastal; <100 km (Ref. 356). Largely dependent on freshwater and terrestrial environments. Feeds mostly on non-fish vertebrate prey. In the North Sea off the coasts of Scotland and northern England, is known to partially feed on the sandeel, Ammodytes marinus (Ref. 95711). Breeds colonially in a wide variety of habitats including roofs in North America, Europe and northeast Asia (Ref. 84934). One of its observed behavior is to balance between attack and fleeing, these birds redirects their aggression and attack to a substitute object like grass pulling (Ref. 87789). As for coloniality, they visit breeding colonies for a year to select a colony, a potential nesting site, and to obtain a mate to determine if the site is where young are successfully reared (Ref. 84934).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Stiles, F.G. 1984. (Ref. 5856)
IUCN Red List Status (Ref. 115185)
CITES status (Ref. 108899)
Threat to humans
| FishSource |
Estimates of some properties based on models
): 2.6 - 24.3, mean 10.1 (based on 3678 cells).
Moderate to high vulnerability (46 of 100)