02
Dec
15

Dolphins off Titchwell

There were two dolphins reported off Titchwell last week. When I received the phone calls from various people several species were muted including Striped, Risso’s, Common and Bottlenose. Strangely enough White beaked, which is the commonest dolphin sighted off Norfolk was not mentioned. In addition Common Dolphins appear to have been sighted up the East North Sea coast in the last few months indicating a small influx.

Various discussion and emails were exchanged and it became obvious that some people weren’t sure what they had seen; and there’s no shame in that. The identification of dolphins, unless you are literally on top of them, is just not easy. It takes some careful observation of habits, swimming style and body markings. If you are hoping to identify them from fin shape alone you’re in for a hard slog. I can rarely do it. The fin shape of many species of dolphin is just so variable.  

Striped and Risso’s are not on the Norfolk list but that doesn’t mean they will not occur at some point and that ‘some point’ could have been last week.

Because Risso’s Dolphin was widely quoted as the identification of the Titchwell animals. I just thought I’d show some photographs of Risso’s taken both in the Atlantic and Pacific to clarify a few points of fin height, beak length and the pale scaring. The first four photos below are Risso’s. They are often quoted as being tall finned; they are, but not overly so. Scaring on the body is frequently obvious, to such an extent that as an animal gets into late adulthood it can attain a skin colour that is almost completely white. The species has a very short stubby beak.

The two individuals off Titchwell were quoted by some as two different species due to their colour and size difference. Different species of dolphin are occasionally seen together but rarely in a duo. Such a sighting would ‘normally’ be within larger groups.

As it happens going by the descriptions offered the species were Bottlenose Dolphins, an adult and calf. This in itself is a species rarely sighted off Norfolk.

The British race of Bottlenose Dolphin is larger than some other inshore races; so they can look chunky and large finned compared to illustrations in books. The paleness of a young animal compared to an older adult would account for the size and colour difference of the smaller Titchwell individual. Very young animals may also show vertical lines down the body. These foetal folds are remnants of the way the calf was folded up in the womb of the mother. The last two photos are of Bottlenose adults with calves for comparison of colour and a photo of a young Bottlenose showing beak length.

I am indebted to the individuals who reported the animals to me especially Marcus Nash who made some very valid observations. If you saw the dolphins or photographed them please get in touch to complete a records form. It’s important just like it is for bird records that the sighting is documented. Many thanks.

Risso's 1 Risso's 2 Risso's 3 Risso's 4

Bottlenose 1 Bottlenose Dolphin 2

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