Cormorant on the riverbank

Cormorant on the River Taff in Cardiff, October 2015

I often fail in my attempts to capture an image of a cormorant or its close relative the shag, but this time the bird was very placid as I watched from the opposite side of the river. In fact looking at the picture I think its tail feathers might be broken. So I am guessing it’s either an old injured bird or a young one not quite fledged. Adults have white patches on their throats and thighs during the breeding season, but it’s not the breeding season, so that doesn’t help.

Adult cormorant pictured on the RSPB website – click on the picture to read more

This cormorant is the common one in Britain and is sometimes known as the great cormorant. The word cormorant probably comes from a contraction of the old Latin corvus marinus, meaning “sea raven”, although it might have passed down into English through a Celtic or Germanic version of the word.

Its modern scientific Latin name is Phalacrocorax carbo, from the ancient Greek phalakros, meaning “bald” and korax, meaning “raven”. This refers to the white cheeks of some species, while carbo, meaning “coal”, refers to the black plumage. See more about the bird on Wikipedia.

A longer view of the cormorant on the River Taff

It is common in the Northern hemisphere around the Atlantic and there are several southern hemisphere subspecies including Phalacrocorax carbo novaehollandiae, known in Australia as the black cormorant and in New Zealand as the black shag.

The cormorant family Phalacrocoracidae includes around 40 species of seabirds and according to Wikipedia there is confusion about the naming of species. Some are called cormorants and some are called shags, harking back to the two species in Great Britain that were first named. I always confuse these two – the great cormorant and the common or European shag, Phalacrocorax aristotelis.

Common shag – an image from the RSPB – click on it to go to the RSPB page

The two birds can be roughly the same size, although I always imagine the cormorant to be slightly bigger. Both can often be seen holding out their wings to dry. By the time I finished writing this post I had found out why they need to do this, so please read on!

Cormorants are often seen inland on rivers and reservoirs, and increasingly build their nests in trees as well as on cliffs, while shags tend to stick to the coasts.

In the breeding season they are probably a bit easier to differentiate, as the shag has quite glossy green plumage and the cormorant has the white throat and thigh patches mentioned above. The easiest way to spot a shag is probably by the steep forehead and the shaggy crest that gives the bird its name. There’s more about the shag on Wikipedia.

One more “interesting fact” – the biggest producer of guano (droppings) in the world is the Guanay cormorant or Guanay shag (Phalacrocorax bougainvillii) found on the Pacific coast of Peru and northern Chile. The guano is rich in nitrogen, phosphorus and potassium so makes great fertiliser, which is sold commercially.

I wonder if anyone out there remembers the wonderful old cartoon series Noggin the Nog? There was a great green bird in it called Graculus , which became Noggin’s guide and counsellor. I always thought it was a cormorant (or shag), but now I am not so sure, as the Latin word graculus means “jackdaw”.

The great green bird Graculus from Noggin the Nog

Finally the gannet. I (quite illogically) think of cormorants as black gannets. There are three species of gannets, but the one we have here is the northern gannet, Morus bassanus. The Latin word morus means “stupid”, referring to the behaviour of the very closely-related boobies. The bassanus part of the name comes from Bass Rock, a small island off the coast of Scotland, where a colony of gannets was first recorded in 1448.

Beautiful image of a gannet from Wikipedia. Click on the picture to go to the source

Are gannets related to cormorants and shags? Well, slightly. Gannets and boobies belong to the family Sulidae. Cormorants and shags belong to the Phalacrocoracidae. Both these families are classified in the order Suliformes, along with the frigate bird family (Fregatida) and tropical darters and snakebirds (Anhingidae).

There is one interesting difference between gannets and cormorants. Although both have sebaceous “preen” glands, cormorants don’t use them to cover themselves with waterproofing as much as gannets do.

I think I now see why, thanks to a coastal studies centre in Massachusetts (see here), which points out that while gannets and cormorants both eat the same small fish, gannets dive from a great height into the water and then bob to the surface with their catch, while cormorants, with much shorter wings, are swimmers – they dive from the water’s surface and chase the fish. Allowing themselves to get waterlogged means they sink like a stone, which helps in their chosen way of fishing.

And that’s why cormorants hang out their wings to dry…