European shag
A medium-large black seabird, the only member of genus Gulosus.
The European shag or common shag (Gulosus aristotelis) is a species of cormorant and the only member of the monotypic genus Gulosus. It breeds around the rocky coasts of western and southern Europe, southwest Asia and north Africa, mainly wintering in its breeding range except for the northernmost birds. In Britain this seabird is usually referred to as simply the shag.
- Scientific name
- Gulosus aristotelis
- Length
- 68 to 78 cm
- Number of subspecies
- 3
- Typical dive depth
- up to 61 m
- Typical dive time
- 20 to 45 seconds
Lore & Background
The European shag was formerly classified within the genus Phalacrocorax, but a 2014 study found it to be significantly more diverged than the clade containing Phalacrocorax and Urile, yet basal to the clade containing Nannopterum and Leucocarbo. It was thus classified in its own genus, Gulosus, a change followed by the IOC in 2021. The genus name derives from the Latin for glutton, and the species name aristotelis commemorates the Greek philosopher Aristotle. There are three subspecies: G. a. aristotelis (nominate, northwestern Europe), G. a. desmarestii (southern Europe and southwest Asia), and G. a. riggenbachi (northwest African coast). They differ slightly in bill size and the breast and leg colour of young birds. Recent evidence suggests that birds on the Atlantic coast of southwest Europe are distinct from all three and may be an as-yet undescribed subspecies. The European shag is one of the deepest divers among the cormorant family, recorded diving up to 61 m deep. It feeds predominantly on the sea bottom, with sand eel being its commonest prey. In UK coastal waters, dive times are typically around 20 to 45 seconds, with a recovery time of around 15 seconds between dives. When diving, it jumps out of the water first to give extra impetus.
Reader's Guide
The European shag is significant as the sole representative of the genus Gulosus, reflecting its evolutionary distinctiveness among cormorants. Its taxonomy was revised in 2014, placing it outside the main Phalacrocorax lineage, and this classification was adopted by the IOC in 2021. The species is a deep-diving, benthic feeder, and its diet has been the subject of substantial scientific interest due to perceived conflict with fisheries. The shag breeds on rocky coasts, nesting on ledges or in crevices, and has a long nesting season from late February to May or later. The species is also known as the green cormorant due to the metallic green-tinged sheen on its feathers. Its legacy includes being a model organism for studying the effects of climate change on seabird diets and diving behavior.
Did You Know?
- The European shag is the only member of the monotypic genus Gulosus.
- Its scientific name Gulosus aristotelis commemorates the Greek philosopher Aristotle.
- It is one of the deepest divers among the cormorant family, recorded diving up to 61 m deep.
- The shag's tail has 12 feathers, while the great cormorant's has 14.
Frequently Asked Questions
What are European shag's powers/role?
This seabird is a formidable underwater hunter, routinely diving to depths of around 61 meters and staying submerged for 20 to 45 seconds while chasing fish. It forages along rocky shorelines across western and southern Europe, southwest Asia, and north Africa.
How does European shag's story end?
Rather than undertaking long migrations, most European shags remain within their breeding range through the winter. Only the northernmost populations shift their range, and the species persists as three recognized subspecies across its coastal territories.
Why is European shag important?
As the sole representative of the genus Gulosus, it carries an entire evolutionary lineage on its own. Its dependence on rocky coastal habitats also makes it a useful indicator of marine ecosystem health in the regions it inhabits.
What makes European shag unique among cormorants?
Its status as the only member of genus Gulosus sets it apart from other cormorants that share larger, multi-species genera. Coupled with its remarkable 61-meter diving capability, it occupies a distinct ecological niche among coastal seabirds.
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