Aves | Ciconiiformes
Environment / Climate / Range
Pacific Ocean, Atlantic Ocean, Mediterranean and the Arctic.
Length at first maturity / Size / Weight / Age
Maturity: Lm ?  range ? - ? cm Max length : 51.0 cm TL male/unsexed; (Ref. 8812); max. published weight: 580.00 g (Ref. 356)
Culmen: 5.503 cm; tarsus: 5.08 cm; wing: 33.02 cm.
Total Length: 45 to 51 cm; Wingspan: 102 to 112 cm (Ref. 8812). A northern hemisphere species of medium to large birds. Ability to delay fertilization of ovum during breeding by presence of microtubules in the uterovaginal area as sperm-storage glands (Ref. 87784) Surface seizing; shallow plunging; up to 300 km from colony; ice-associated (Ref. 356). A northern hemisphere species and one of the largest global population of seabirds at >10 million individuals. Often scavengers; foraging technique of being able to harvest prey underwater (Ref. 87784). Largely dependent on pelagic prey. In the North Sea off the east coast of Scotland and northern England, is known to feed on the sandeel, Ammodytes marinus (Ref. 95711). Before pair formation, female prospecting period characterized by visiting different parts of the colony and even different colonies. Older breeders often return to breeding colony earlier than young birds and have the highest nesting success. Copulation takes place inshore and the delayed fertilization of the ovum happens out at sea, allowing birds to feed while egg is forming and prior to the long fasts during egg incubation. Monogamy important due to intensive nest site defense, that may extend for months prior to egg-laying; also as male and female share feeding and guarding shifts during brooding. Chicks accumulate huge amount of nonstructural body fat during development, up to 30% of body mass, prior to fledging; prefledging mass recession completely due to water loss in tissues as they attain functional maturity. Field Metabolic Rates (FMR) decrease with wind speed in this species. Vulnerable to long-line fisheries (Ref. 87784).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Gray, C.M., R.A. Phillips and K.C. Hamer. 2003. (Ref. 91621)
IUCN Red List Status (Ref. 115185)
CITES status (Ref. 108899)
Threat to humans
| FishSource |
Estimates of some properties based on models
Moderate vulnerability (40 of 100)