HERE’S a good pub quiz question, “Which country’s national flag is the only one in the world to feature a parrot?” No? It’s the Caribbean island republic of Dominica, and apologies to readers shivering in the winter climes of Ryedale at the moment because, as I write, I am sat on a beach in said tropical idyll.

My reason for mentioning my whereabouts is not an excuse to gloat, but to discuss the principle of endemic species.

An organism is described as endemic to an area if it is naturally found there and no where else – kangaroos in Australia and llamas in South America for instance.

The usual reason for this phenomenon is that the creatures concerned have become separated from others similar to them in the dim and distant past and then evolved into new species in isolation.

Oceanic islands are isolated by their very nature so tend to be hotbeds of endemism, as Charles Darwin famously discovered when he visited the Galápagos Islands in the 1830s.

There are thought to be only 300 imperial amazon parrots (Amazona imperialis) in the world and they all live in the northern rainforests of Dominica.

This rarity and exclusivity has made Dominicans very proud of their unique parrot, known as the “sisserou” in the local patois dialect, and consequently it became the national bird and found its way onto the country’s flag.

The island has many other endemics, including another parrot, three lizards, two snakes and a tree frog.

Most are rare and seldom seen but during the day, Dominica anole lizards are everywhere and during the night, noise from Dominica whistling frogs has been keeping me awake.

“How very interesting”, you may be saying, “but what has all this got to do with Ryedale?” Well, Britain is also an island of course and, although we are not particularly isolated, we do possess some endemic organisms of our own.

Evolution takes time so, because we have only been disconnected from the rest of Europe for 8,000 years, very few new species have appeared.

Most of them are plants, as they are much less mobile, but there is the odd animal on the list as well, such as the brilliantly named horrid ground-weaver spider.

If Britain had a national invertebrate Nothophantes horridus would get my vote.

What we do have are a few animals that have managed to evolve partway to full species status so scientists call them sub-species and give them an extra third bit to their Latin name.

Thus the UK sub-species of the red deer becomes Cervus elaphus scoticus and our mountain hare Lepus timidus hibernica.

With birds able to fly across the English Channel very easily it’s maybe surprising that there are any endemic avian sub-species but even in Ryedale we have three.

Our endearing, white-breasted dipper is sufficiently different to those in Europe to be classified as Cinclus cinclus gularis and visiting continental bird watchers get very excited by our relatively common pied wagtails because they don’t have Motacilla alba yarrellii over there but Motacilla alba alba instead, a bird we know as the white wagtail.

Our most endemic bird, the red grouse, is so different to the continental willow grouse that some ornithologists feel it should be a full species – Lagopus scoticus – but the consensus at present is Lagopus lagopus scoticus… nearly there.

Given time, especially if the English Channel widens with progressing climate change, more endemic species will evolve in the UK – just not in any of our lifetimes.