Unexpected wildlife visitors to the UK

By James Hanlon

Published: Tuesday, 01 February 2022 at 12:00 am

Vagrancy is a term used to describe the behaviour of an animal that appears outside of its normal range or migration route. This can be caused by a number of factors, including weather conditions while navigating. Our expert guide to wildlife vagrants in the UK reveals which species have turned up and when, and what happened to them next.

Birders and other naturalists may twitch these vagrant species and travel to see them, sometimes across very long distances, particularly when the animal is an especially rare sighting for the UK (usually described as a “mega” by twitchers).

Long-toed stint (Calidris subminuta)

Location: Yorkshire, England.

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A long-toed stint in Japan. © Chisato Yonemochi/Aflo/Getty

The appearance of a rare vagrant bird in the UK tends to attract a lot of attention, especially among the birding community. Sometimes thousands of ‘twitchers’ will make the trip to the spot where such a bird has turned up (or ‘flock to it’ as almost every press journalist inevitably quips whenever it happens).

Just such an event occurred in October 2021 when a long-toed stint appeared at St Aidan’s RSPB reserve near Leeds. This diminutive, sparrow-sized wading bird breeds across Siberia and winters in South-East Asia and Australia. The species has only been confirmed in the UK twice before: in Cornwall in 1970 and Cleveland in 1982 (another was seen in Ireland in 1996). Needless to say, it was hugely popular during its week-long stay, with thousands of visitors arriving to study its features (which, as the name suggests, include long toes).

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Long-toed stint in Yorkshire, UK. © Trevor Woodland

Where the bird went next remains a mystery, though incredibly it seems a second individual (showing juvenile features) was seen a few weeks later in Cumbria. Long-distance vagrancy in birds is not fully understood, but it is expected: thousands of lost Siberian birds arrive in north-west Europe every autumn, especially following periods of favourable weather conditions, such as high-pressure areas dragging in easterly winds from Asia.

Some Siberian species occur here in such numbers that they’re considered merely scarce migrants rather than vagrants and, in a couple of species, entirely new migratory routes, as well as wintering areas in Europe and Africa, have recently been discovered, attributed to such pioneers.

Snowy owl (Bubo scandiacus)

Location: St Kilda, Scotland.

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Snedge the snowy owl has taken up residence on St Kilda, Scotland. © Craig Nisbet

There can be few rare visitors to Britain as recognisable and charismatic as the snowy owl. A species familiar to so many from the Harry Potter films, it has a circumpolar distribution and its reliance on Arctic lemmings, an unpredictable prey species with fluctuating populations, can result in rather nomadic behaviour. Good lemming years can produce snowy owl irruptions further south than usual, particularly in North America.

Fossil records show that during our glaciated past, the species bred in Britain and more recently nested on the Shetland isle of Fetlar for eight years from 1967. Progeny from the single pair hung around for years but no further breeding occurred and the last few resident birds were seen there in the 1980s.

Today, there is likely to be around one to three individuals in Britain and Ireland at large at any one time. They may stay for months or even years and prefer isolated upland areas, with the Northern and Western Isles favoured, as well as the Cairngorm Mountains and the remote archipelago of St Kilda, where a snowy owl called Snedge has been present almost continuously since at least 2018. She feeds almost exclusively on the endemic St Kilda mouse population.

Oleander hawk-moth (Daphnis nerii)

Location: Swindon, England.

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Oleander hawkmoth. © James Hanlon

Garden light traps for attracting and holding moths have surged in popularity in recent years as enthusiasts realise that the right equipment can reveal a wealth of wildlife on their doorsteps. The number of species that can potentially be caught runs into the thousands and includes plenty of rare migrants from the continent and North Africa. On a warm, muggy night there is every chance of catching something good among the commoner species.

One lucky Wiltshire resident caught this oleander hawkmoth in October 2021 in his garden just outside of Swindon. It ticks the main popularity boxes of big, rare and beautiful, and is consequently something of a holy grail for ‘moth-ers’.

Mainly an African and Asian species, the oleander hawk migrates to Spain and other parts of Southern Europe in the summer, and is almost annual in the UK (there aren’t records for every year), mainly along the south coast, with typically one or two records a year nationally and, very occasionally, low double figures during mini influxes.

There are around 115 records to date but the species is widely kept in captivity with releases and escapees likely to account for a fair proportion of these. The origin of this rather small individual cannot be known for sure but it turned up during optimal weather conditions for moth immigration from Spain and Northwest Africa so can perhaps be given the benefit of the doubt as a likely wild vagrant.

The caterpillars of this species, of which there are no verified reports in the UK, can be found on a number of food plants and are immune to the toxins of the oleander plant that gives the species its name.

Walrus (Odobenus rosmarus)

Location: Tenby, Wales, then Isles of Scilly, England.

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Wally, an immature male walrus, on the lifeboat ramp in Tenby, Pembrokeshire, Wales. © Carl Corbridge/Alamy

Chances are, you will have heard of 2021’s young celebrity walrus, with the national press covering its every move (and rather irritatingly naming it Wally – the same name likely given to every vagrant walrus in the UK).

The iconic Arctic creature was first spotted in Ireland, before heading to Wales, enjoying a protracted stay of several weeks in Tenby, where it gave the local tourist economy a much-needed post-lockdown boost. But as the souvenir mugs and tea towels were flying off the shelves, the star left his favoured lifeboat slipway and headed to the French Atlantic coast via Cornwall.

He next turned up in northern Spain, before heading back north. Finding the Isles of Scilly to his liking, he was greeted with a similar reception to that in Wales, but his habit of hauling out onto small boats (some of which he capsized) soon landed him in trouble. A local residents’ committee was formed, and meetings held, but a purpose-built pontoon fortunately resolved the issue.

But soon he returned to the Irish coast where a similar situation unfurled, the issues again resolved with a hastily made pontoon. Next stop was Iceland but by then a second lost walrus, this time a female called Freya, had appeared in Germany before making her way over to Shetland. Vagrant walruses in north-west Europe are nothing new, but multiples like this will only fuel the climate emergency debate.

Sei whale (Balaenoptera borealis)

Location: Firth of Forth, Scotland.

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Sei whale. © Erica Linklater-McLennan

Britain and Ireland are both geographically well placed for a range of unusual cetacean sightings – typically deep-water species that have wandered from the whale migration routes running along the continental shelf in the north-east Atlantic.

Several such sightings were made in 2021 from the Firth of Forth, where the star attraction was a sei whale seen over much of the spring and summer after it was first filmed at close range near to the Forth Road Bridge. The third largest whale on the planet, following the blue and the similar, but more regularly seen, fin whale, this poorly studied and globally rare species is also one of the fastest cetaceans.

Sei whales are rare in British waters, particularly near the coast, but may also be under-recorded due to their similarity to the fin whale. The two can be separated by the dorsal fin shape, but this can be difficult to determine at sea.

The Scottish visitor could be surprisingly unpredictable and elusive, to the frustration of many onlookers, some of whom waited days for a sighting. Its conspicuous 3m-high blow allowed it to be tracked distantly from shore at times, but the whale covered a large area, often swimming 2-3km between breaths
and keeping a generally low profile, with no breaching reported and characteristic minimal surface disturbance when feeding.

After spending about four months in the Firth of Forth, the whale – believed to be healthy and well fed – seems to have swum back out and followed the coastline north, with two subsequent sightings made from St Andrews and near Montrose.