Part 5: Interglacial birds

 

Golden Oriole

The avifauna of the British Isles during the Eemian would have been similar to that of today, with the addition of species now more often found further south in Europe as the climate was slightly warmer. We can imagine as well as the current birds of Britain such species as Golden Oriole, Hoopoe, Serin and Melodious Warbler in the woodlands. Some birds such as House Martins, Swallows and Common Swifts that are strongly associated with human houses as nest sites would have been restricted to their original habitat of cliffs and rocky outcrops, but might have been joined by Red-Rumped Swallow.

Red-Rumped Swallow

Birds today that are associated with farmland, such as most of the finches, Skylark, Grey Partridges and Great Bustard would have been using their original habitat of elephant and large ungulate grazed grasslands, and would probably have been less numerous than in modern times (at least before intensive farming after WWII reduced their numbers)

Black Stork

White storks formerly bred in the UK in historic times and are currently the subject of a reintroduction project. As well as these Black Stork must be a strong possibility as a British breeding species. Unlike the sociable and farmland loving White Stork the Black Stork loves woodland and wetland and has a vast range from Spain across to China, migrating south to Africa and India for the winter. Glossy Ibis is another likely resident, as well as many of the various southern herons that have recently begun colonising Britain in response to climate change. The exception to that would be Cattle Egret – it has finally started breeding in the UK but its current worldwide spread is a result of its adaptation to livestock farming, and without that it would have probably stayed further south.

Western Swamphen

Other specialist marshland and reedbed birds would have included Western Swamphen, Zitting Cisticola, Black-necked Stilt, and Penduline Tit. European Cranes are also known, but they might have been joined by a now extinct, even larger species Grus primigenia. This species has been variously placed as just a large form of the extant Eurasian Crane, but might also have been a second crane species – in many parts of the world multiple cranes species live in similar habitats and in east Asia can be found several large species even today, for example, the Siberian Crane. If it was a real species it might have survived as late as the early Roman period, and remains from Malta suggest it might have been a rare migrant to southern Europe.

Mandarin Ducks

Among ducks Ruddy Shelduck is known to have been present – it now occurs only as a vagrant or escape. The Garganey is a small migratory duck that is a very scarce breeder in Britain and Ireland. It prefers to breed on shallow lakes surrounded by grassland, a habitat that elephants and hippos would have helped create. One remote possibility is Mandarin Duck. Although today they are only native to the Far East, either Mandarin or a closely related species is known from a previous interglacial and presumably became extinct as a result of elimination of habitat by ice advances at some point. Today Mandarin is well established as a feral breeding bird in Oak woodland in England and the Eemian interglacial would have provided a very similar habitat.

Dalmatian Pelican

Dalmatian Pelican sounds like an unlikely species for Britain – it is the largest living pelican and today has a distinctly east European/central Asian distribution, but they had a much wider range even in historic times and are known to have bred at several sites in England up to at least the Bronze Age, so it is quite possible they were at least briefly a British breeding resident during the warmest parts of the Eemian, at least until the climate cooled towards the start of the next glaciation.

Capercaillie

Most of Britain’s grouse species are today associated with the north of the island, especially moorland and pine forest. There would probably have been similar extensive forests of pine and birch in many areas holding the world’s largest grouse, the Western Capercaillie, which in the males is turkey sized. Today these amazing birds are only found in the Highlands, and even there they are a rare and declining reintroduced species, having already gone extinct in the UK once, but we have records from the Mesolithic of Capercaillie as far south as Wales. Also present would have been the ancestors of the modern Red Grouse, an endemic subspecies of the circumpolar Willow Grouse which is confined to the British Isles. When the British and Irish Red Grouse developed its distinctive features is hard to determine, but they can live quite happily in Arctic climates, so they probably survived the heights of the last glaciation in southern England while their current Scottish homes were a mile deep in ice.

Corys Shearwater

Two seabirds in addition to those found today would also have been present. The Great Auk is sadly no longer with us, having become finally extinct less than 200 years ago, but it is known to have bred in at least one island off the coast of Scotland in historic times and would have fed in the offshore and inshore waters around Britain. The other species is happily still with us. Corys Shearwater is only a visitor to the waters around Britain today, but remains found in Welsh caves show that it once also bred here.

Lammergeier

Among raptors Kestrel and Red Kite are known to have been present, but it would be very surprising if the other birds of prey found in Britain today were not also present. What is not certain is if any of Europe’s vultures visited or bred in this country. In 2020 a vagrant young Lammergeier from the ongoing reintroduction project in the Alps spent several months in the north of England before returning south. It was well able to look after itself by feeding on carrion and roadkill even in 21^st century England, and both Lammergeier and European Gryphon and Cinereous Vultures are quite capable of surviving European winters where plenty of carrion is available, so it is quite possible that they lived in Britain and fed on the kills of Lions and Hyaenas just as their relatives do in Africa today.

Grey Junglefowl

However, one bird in Britain’s woods would have been very surprising – a wild chicken! Today there are four species of Junglefowl, of which the Red Junglefowl is the ancestor of the domesticated bird. However, the genus seems to have possibly originated in Europe and various species are known throughout the Pleistocene, with the form in western Europe identified as Gallus europeaus. Junglefowl all have very distinctive male plumages, but the life appearance of the British species is of course unknown. Today the nearest ecological equivalent would be Common Pheasant, but this is an introduced species originally native no nearer than the Balkans and without the vast number released each year by the hunting fraternity might not even survive long term as a British breeding species.

Bird fossils are always fragile and many species go unrecorded. Amphibians and reptiles have the same problem only more so, and it is to those I will turn next.

Part 4: Predators new and old

 

Spotted hyaena, 20,000 years ago

Europe today is home to a diversity of predators large and small, most of which are either resident in Britain or were at least present in historic times before being extirpated from Britain for being a threat to humans, livestock or just because of destruction of their habitat. However, as well as these there would have been at least two additional species resident in the British Isles during the last interglacial.

Brown Bear

Starting with the largest and heaviest, Brown bears were common and were large compared to modern European bears – perhaps as large as Grizzly bears in the US. They would happily live in both warm and cold climates as the various glaciations came and went, perhaps only temporarily being driven out of Britain at the height of glaciations, when they might be replaces by Polar bears. Brown bears were present in Britain in the post-glacial period, only being finally removed from the British Fauna around 2000 years ago.

Lions painting, Chauvet cave

The Cave Lion is now classed as a separate species to the living Lion, but it was plainly very similar in appearance to them. The main difference is that from cave paintings we know it had a very small or non-existent mane and was much larger. It would have preferred open areas rather than closed woodland, but lived in both Glacial and Interglacial periods – lions are not especially cold-sensitive animals as long as sufficient prey is available. They preferred open country and would have preferred the horses common in colder and drier periods, but would also have taken Red and Fallow deer, Wild Boar, and might even have taken young rhinos and Straight-Tusked Elephants.

Spotted Hyaenas are such a characteristic animal of Africa that it is hard to imagine them living anywhere else, but DNA from European Cave Hyaena remains makes it clear that they were the same species as their living African relatives and interbred with them where their ranges overlapped in the Middle East, although they were a larger subspecies.. They liked to use caves as dens, and the collection of bones that they brought back are a valuable guide to animals living in the area of the den. An adaptable species, they lived in both cold and warm periods. They seem to have preferred lowland open country, with populations of wild horse and wild ass which were their chief prey, and the loss of this habitat following the extinction of the Straight-Tusked Elephant and other large herbivores may have led to their extinction.

Grey Wolf

Definitely subordinate in the carnivore guild to all of these would have been the Wolf. Faced with the other large predators they would have had serious competition – in fact hyaena dens have been found to contain Wolf bones which had been gnawed by hyaenas- so they might well have been more restricted to forested areas where Lions and Hyaenas at least would be at a disadvantage, although Bears would have certainly sometimes robbed them of food as they do today. Today in mainland Europe Wolves are major predators of Beavers, which in turn affects forest structure and watercourse behaviour.

Eurasian Lynx

More or less on a par with Wolves in terms of prey size would be the Lynx. Eurasian Lynx like to feed on animals the size of Roe Deer, but would also have taken Red Deer fauns, Wild Boar piglets and smaller prey including various birds.

European Wildcat

Finally there would have been a variety of small carnivorous mammals, including various mustelids, Red Fox and the Wild Cat. These would have preyed on small rodents, birds, and in the case of the Otter fish and amphibians.

This very complex set of predators of all sizes would have interacted with each other in ways that are difficult to determine from this point in time. For example, Lynx readily kill Red Foxes, are vulnerable to Wolves, and lose kills to Brown Bears, which means they have to kill more prey than they need just for themselves. Lynx are primarily forest animals, but in open areas Wolves would have been in the same position with regard to Lions and Hyaenas, perhaps relegating them to a more Jackal-like role. One study of Cave Lion diet showed that the animals studied had preferred to eat Reindeer, but Hyaenas preferred Horses, although they also preyed upon various deer. In Africa today both Lions and Hyaenas sometimes prey on young hippos, but adults are more or less immune to predations as they are such dangerous opponents.

That covers the larger mammals of Eemian Britain,  Next time I will turn to the birds of that period.

Part 3: A diversity of plant eaters

 

Megaloceros

Large animals such as elephants and rhinos would have shaped the landscapes of ancient Britain, but the forests and fields would also have been home to many smaller animals, some of which still survive today, even if not in the UK. Sadly, the most magnificent of these is no longer with us, the gigantic "Irish" Elk. It was given the name from where its remains were first discovered, but its range extended all across Europe and Asia. So recently extinct that we have cave paintings showing its appearance in life, it stood over 2m at the shoulder and was built for speed. Apparently related to the living Fallow Deer (which is an introduced species in the UK), large stags of the Irish elk had antlers over 3.5 m across. It seems to have liked open country, but needed fairly rich and productive grassland to sustain its bulk and huge antler growth. It survived in Russia until as recently as five or six thousand years ago

Elk

.Elk (Moose for American readers) are known but remains are surprisingly uncommon. Moose prefer cooler climates and most of the sites for the Eemian are in southern England, so possibly they preferred the Highlands to the south of Britain. As the largest living deer they would have been important prey animals for the various large carnivores also present in the country at the time.

Persian Fallow Deer

Sharing the woodland and woodland edge habitat would have been the Red and Roe Deer that are the only native deer in Britain today. Joining them would have been Fallow deer, which are mostly in deer parks in this country today having been first introduced by the Romans, with more brought in by the Normans. Today the nearest truly wild Fallow deer are in Southeast Europe.

Ibex

Although remains have not been found, there is a cave painting from Nottinghamshire from 12,000 years ago that appears to show an Ibex. As a mountain animal they seldom fossilise, so it is quite probable they were also found before the last glaciation as well nd survived through it until quite recently. Today various feral or semi-wild domestic Goats fulfil the same function.

Feral goat in Wales

European Bison

Remains of Bison have been retrieved from the North Sea and would probably have been present in open areas. Which species is more difficult to decide, as either the modern European Bison (or its immediate ancestor) or the Steppe Bison, the species ancestral to both the European and American Bison, are possible. Steppe Bison were even larger than their living descendants and had long horizontal horns like those of long-horned domestic cattle rather than the smaller, more vertical horns of modern Bison.

Steppe Bison mummy, Alaska

Wild horses have been part of the British landscape in both glacial and interglacial periods, and would have been present in open habitats. Horses tend to be associated in Ice Age faunas with colder habitats and they might therefore have been commoner in the north of Britain. The spread of forests, and possibly hunting by humans, seems to have resulted in the extinction of wild horse in Britain after the end of the last Ice Age. Modern native horses, even the ancient breeds such as the semi-wild Exmoor pony, are descended from domesticated horses brought to Britain around 4,000 years ago.

Exmoor Pony

In the wooded areas a key prey animal and ecosystem engineer would have been Wild Boar. These both distribute seeds, excavate the forest floor and constitute a key prey species for the various large predators that would also have been present. In Britain today the European Robin is associated with gardeners as it looks for worms as they dig their gardens. In the human-free world of Eemian Britain, they would have followed the Wild Boar for the same reason. As a woodland animal, during major ice advances they would have been greatly restricted in Europe to around the Mediterranean. Although Wild Boar became extinct in Britain a few hundred years ago, escapes from boar farms mean that several woodlands in Britain now once more hold them. However, lack of predators other than humans means that they cause a great deal of disturbance and as they can host serious diseases of pigs the pork industry does not like this situation at all.

Wild Boar

One animal common today that would definitely not have been present is the rabbit. During the Pleistocene rabbits of the modern species have been around at least half a million years, but they never naturally moved north of the Iberian peninsula and southern France and Italy.

All these herbivores would have sustained a large variety of predators and scavengers, and I will look at those next time.

Part 2: Ecosystem Engineers

 

Last time I started to outline the kind of animals that lived in the UK before the last Ice Age, which we can consider a baseline of what would have lived in this country when the climate last resembled that of today. Most people are familiar with the Woolly Mammoth and other ice age fauna, which in warm periods have been confined to the high Arctic and dry grasslands in central Asia. South of them and in western Europe would have been animals that preferred woodland and warmer open country. Starting with the largest, the undoubted major influence on the habitats of Britain would have been elephants.

Seriously. The Straight-Tusked Elephant survived until only 30,000 years ago and lived in the temperate forest belt across the whole of Europe and Asia as far as Japan. Closely related to, but even larger than, the living African elephants, it would have opened up the forests, pushing over and eating trees, and creating a more parkland or open grassland habitat for other animals. This would have increased the variety of forest types – closed-canopy forest would not have been the only kind of woodland to be found, instead a mosaic of open grassland, small clearings and scrub would also have been found, with dense woodland perhaps more confined to steeper slopes where elephants found the going harder.

Narrow-Nosed Rhino

In addition to elephants, another surprising addition would have been rhinoceros. In fact, two species of temperate-climate rhino would have been found in the UK or northern Europe, the open country Narrow-nosed Rhino and the more forest loving Merck’s Rhinoceros.

Merck's Rhinoceros

 Both of these were large even for rhinos, as large as the Indian One-Horned Rhinoceros. Today their closest living relative is the Critically Endangered Sumatran Rhino, which has a total surviving population as low as 80 individuals.

Sumatran Rhino

 Although not as extensive an engineer of woodlands as elephants, they would still have created trails in the woodlands and affected the structure of grasslands by grazing. Another effect would have come about from most rhinoceros’ habits of using large dung piles for marking territory and social communication – the dung beetles and other insects these would attract would certainly have affected foraging by many bats, especially those that prefer beetles or gleaning from foliage along forest trails such as the Brown Long-Eared Bat.

Brown Long-Eared Bat

Perhaps the most unexpected animal of all to find in Britain though would have been the hippopotamus. Not just closely related, but the very same species to live in Africa’s rivers today, hippos only became extinct in Europe at the close of the last Ice Age when an unusually cold period even for an Ice Age eliminated the last populations in Spain and southern France. 

River Hippo

 In Africa they tend to create trampled grasslands up to 1km from the river, which would have impacted other animals in the waterways and coming down to drink. However, shallower rivers and streams would have been avoided, which would have left room for the last of the ecosystem engineers for this post, and the only one which so far has been reintroduced to the UK, the European Beaver.

Eurasian Beaver

Although a distinct species to the beavers of North America, their habits are identical and they would have greatly impacted wet woodlands, forest streams and the general hydrology of the land. This in turn would have affected fish, amphibians, waterside animals like the Water Vole and Otter, and their activities would have affected forest type and availability of nest sites for many birds.

Beaver dam, Scotland

Beavers have only been reintroduced to the UK in recent years but they are already having a big effect on how conservation of wetland and other areas is managed, although their impact on drainage of farmland and feeding on maize crops close to water has caused some issues. They are now starting to spread through the countryside away from the known sites, and recently they showed up at Longleat wildlife park under their own volition. As Longleat is one of the few collections in the UK to hold hippos, this means that England is now the only place on earth where hippos and beavers share the same waterways as they did in the Eemian.