The epic story of the bison of Białowieża Forest

The story of the European bison is perhaps the textbook example of how humans can both decimate and restore nature.

Europe’s biggest animal once roamed Europe’s vast primeval landscapes from Russia to Spain. But over the past millenium, the expanding human population drove its precipitous decline. People cut down their forests, planted crops on their meadows, and above all, hunted them to the verge of extinction. Only by a stroke of luck were bison saved from oblivion – by Polish kings and later Russian czars, who were rather fond of their value as big game animals. Under their protection the bison held on till the early 20th century, at which point the horrors of war and empire finally wiped them out. Luckily, a few individuals survived in zoological collections. These became the saviours of the species when they were restored to the wild after WW2. Now, some 6000 bison roam European forests once again. This article is an account of this epic history.

What are bison?

Once upon a time there lived seven species of bison, each adapted to different types of habitat across the globe. Only two have survived to the present day: the superficially similar European and American bison, also often called buffalo.

Left: American bison, Right: European bison

The cow-family, of which they are both members, began its evolutionary history some 5-10 million years ago. Since then, this branch of the evolutionary tree has given birth to a diverse array of bison, buffalo and cattle. Interestingly, recent genetic evidence has found that their family tree and relationships are not straightforward – many of the distinct species have interbred with each other, often many millions of years after their ancestors separated into different species. This may catch some people by surprise, considering school-level biology teaches that different species cannot mate with each other to produce fertile offspring. But like many definitions in school level science, this was a simplification that’s not strictly adhered to – as the many bovine hybridisation events prove. These events apparently occurred many times, but did not put the different species back together. Instead we have an especially diverse array of cow-like beasts with rather unexpected relationships, such as the Himalayan yak being recently related to the American bison – which is quite a feat considering they look rather different and live on opposite sides of the world.

A groundbreaking study published last year has suggested this complex evolutionary history also applies to the European bison. 120,000 years ago a male steppe bison mated with a female aurochs, the wild ancestor of modern cattle. This legendary female gave birth to what scientists have amusingly dubbed the Higgs bison, the mysterious ancestor of all modern European bison. Such hybridisation events are rarely successful, as in most cases hybrid animals are less fertile and fit than their parents. But in this case, a brand new species − the European bison − was born. So hardy was this lineage that it outlived both of its ancestors: the steppe bison went extinct more than 11,000 years ago and the last aurochs was shot in 1627.

The Aurochs and European bison were the largest animals of post-glacial Europe (i.e. of the last 11,000 years). By the middle ages both were confined to the primeval forests of eastern Europe. But the bison survived, and the aurochs did not – the last one, a female, was killed 400 years ago in Jaktorów Forest, 40 km from Warsaw. It survives to this day only in its domesticated form – the common farmyard cow.

 

Evolutionary origins aside, insights into the pre-historic lifestyles of European bison have also turned up surprises. Recent radioisotope analysis of fossil bones has shown bison were originally plains animals. Moreover, they likely migrated across European pimeval landscapes in search of food as the seasons changed. This paleoecology of bison may seem counterintuitive, as modern history has known them exclusively as forest dwellers. But this is only because the bison is a refugee species, pushed out of its optimal habitats by human encroachment: few unfarmed plains remain and the landscape is laden with barriers to migration. Thus bison now mainly inhabit forests, a home they seem fairly well adapted to. The only small problem lays in the fact that forests are largely devoid of food in winter. So to help them out, bison have been supplementarily fed hay in winter since at least the 16th century. For the last few centuries bison have used the first heavy snows of winter as a signal to gather into herds around the hay bales left out for them, thus negating their need to migrate to greener pastures.

Some folks validly question whether supplementarily fed bison are truly wild. But with so few bison living in the world, wildlife managers have so far avoided experimenting with the winter food the bison have grown accustomed to. Perhaps bold, future research will determine whether they truly depend on this food, or whether our beloved bison have just become lazy.

Fact file

Food Predominantly grasses, but also browse on shoots and leaves, consuming up to 32 kg of food in a day. In winter they are supplementarily fed hay.
Lifespan 30 years in captivity, and can live up to 25 years in the wild.
Breeding years Females are fertile between 4 and 20 years old. Males reach sexual maturity by age 4, but fit young males drive away bulls younger than 6 and older than 12 – keeping them well away from females during the rut.
Social structure Females live in mixed-sex groups of on average 12 individuals with other females, their young, and young bulls under 6 years old. Males, especially older ones, are either solitary or form small groups of 2-3 individuals with other males; they join the mixed groups for a short period during the mating season. In winter, bison can form huge herds of several hundred animals at the locations where they are fed.
Hierarchy Mixed groups are headed by an older, experienced female. A cow’s age is a large factor determining dominance, and once elected she can lead her group for several consecutive years (even 10+ years).
Agility Despite their large size they can jump up over 2m high fences and clear 3m wide streams.
Size Bulls are up to 2 m tall, and weigh up to a tonne. Cows are somewhat smaller, weighing up to 600 kg.

 

Modern history

For 120,000 years bison roamed the European plains, surviving ice-ages, giant predators and early human colonists. They inhabited the entire lowlands of Europe, except the UK, Italy and the Iberian peninsula. Modern-man however, put an end to the good times. Over the last thousand years as the human population expanded, the bison range shrank. By the 16th century the Białowieża Primeval Forest and the remote and wild Caucasian mountains had become the bison’s final strongholds.

A unique turn of fate saved the bison of Białowieża Forest. In the late middle-ages, the primeval forest and its animals became protected as the private property of the Polish-Lithuanian royalty. This protection reached its zenith in the mid-16th century, when King Sigismund II August formally passed a law giving Białowieża Forest special status over all other forests and the penalty of death for bison poaching. Though the draconian death penalty was short-lived, protection continued in one form or another till the early 20th century. In a way, Białowieża Forest was protected by some of the world’s first conservation measures.

The kings employed a small army of forest rangers (so-called beaters) to enforce the ban on unsanctioned hunting and logging. This was a prestigious job that uplifted many of the locals out of the peasantry, and was passed down from father to son down the generations. At their maximum there were 300 hundred of them, vigilantly guarding and feeding the bison and protecting the ancient forest from untrammeled exploitation. Despite the near constant state of war from the 16th century on, the forest with its bison survived largely intact.

Strict protection continued until Poland was colonized – ending with the third partition of Poland at the end of the 18th century. Law and order proceeded to break down for a number of years, as Eastern Poland and Białowieża Forest came under the control of the Russian Empire. The new Russian overlords were aware of neither the unique flora and fauna nor of the unusual 400 year-old system of administering the woodland. The guard system was dismantled, Russian army officers poached and logged whatever they could, and the bison reached their lowest ever numbers – just 200 individuals remained alive. The local people determinedly tried to fulfil their duties ‘according to the old custom’, but had been forced into serfdom as the subjects (villeins) of local lords. The future of the forest looked grim.

The locals pleaded for protection of the forest, but try as they might their calls fell on deaf ears. Two czars came and went, before the third Czar Alexander I finally took an interest. In 1803, some 11 years after the forest was annexed by the Russian empire, he decreed the forest be restored to its previous special status. The forest was again protected as a private royal hunting ground and the hunting of bison was outlawed. Though the beaters weren’t restored to their privileged status, they were relieved of their serfdom, allowing them to resume some duties and protective measures. The czars eventually took such a liking to the forest that they built a private palace and railway line. Over the next century the forest retained its integrity and bison numbers grew, up to 600 or so at the outbreak of WW1.

The war changed everything. Overnight the centuries year old protections disappeared. The series of occupying forces ransacked the forest. The Germans invaders instituted what is recognized as the most devastating period in Białowieża Forest’s history – in two and a half years they logged 20% of the forest’s area and killed 600 European bison for sport, meat, hides and horns. Towards the end of the war, a German scientist informed army officers that the European bison was facing imminent extinction, but the retreating German soldiers shot all but nine animals anyway. The last wild bison in the forest was poached a couple of years later, in 1921. This wasn’t quite the last wild bison in the world – this one was killed by poachers in 1927 in the western Caucasus. By that year, fewer than 50 remained, all in zoos. For the next 30 years no bison roamed Europe’s forests.

After the war a breeding programme was soon started in the newly independent Polish state. A few zoo individuals were donated and transported to Białowieża Forest in 1929. The programme was gradually building up towards their release, before war tragically struck again. Sixteen captive animals lived in Białowieża Forest at the outbreak of WW2. By some miracle the forest was spared and they all survived. In the aftermath, Stalin demanded the forest split in half between the USSR and Poland. Fortunately, the village of Białowieża and the breeding centre were awarded to Poland. The breeding and reintroduction programme restarted in earnest and the bison were finally released back into the wild on the Polish side of the forest in 1952. Soon after, they were released on the Belarussian side too. Since then the population has gradually grown, with further populations being set up across Poland and neighbouring countries.

Current status

There now live 6,573 bison in the world, of which 5,500 are free ranging, wild bison. About half of these live in Belarus and Poland, another 1000 live in Russia, and the rest in various other nearby countries. Amazingly, they all descend from just 12 individuals. So far we’ve been lucky, the European bison hasn’t suffered any major problems associated with inbreeding. For a map and details of Poland’s 5 bison population, see another of my recent articles.

A model reintroduction

Now, I’m no expert on wildlife reintroductions, but the resounding success of the European bison’s reintroduction seems to me like a model case study: by looking closely at why this reintroduction succeeded we can perhaps better understand what is required for other reintroductions to be successful.

The first and foremost reason for the reintroduction’s success is undoubtedly the bison’s centuries old public affection: it was and remains a national icon. The importance of this type of democratic mandate for reintroductions cannot be understated. From disincentivizing vigilante killings, to attracting essential resources in the form of public or private funds, everything flows from the public’s acceptance.

Here follows a non-exhaustive list of factors that have supported the bison’s largely harmonious coexistence with humans over the past 65 years – all of which ultimately stem from sufficient monetary resources and public acceptance.

  • A breeding centre exists (almost a century old), which bred the first bison released to the wild. It now maintains a captive population isolated from wild individuals, which acts as an insurance should a calamity ever befall the wild population.
  • There exist governmental compensation and support schemes for farmers who suffer damages.
  • Dedicated rangers support wild herds. Bison that leave their forests are tracked and returned home should they get lost.
  • Diseases in the wild populations are monitored; mitigation measures are put in place.
  • The genetic health of populations is monitored to prevent inbreeding. If necessary new individuals are introduced.
  • Most bison populations are fed hay in winter, which minimises the numbers dying from cold and prevents migrations to neighbouring farmland.
  • The bison forms the focal point of wildlife tourism in all forests it inhabits, bringing in essential tourist money for locals.

It is worth bearing in mind that many of these costly measures were put in place during Poland’s poorest post-war period: which is evidence that for something the public hold dear, money is no object. Obviously, most other species will never gain as much public affection as the European bison, but we can still raise sufficient awareness to obtain democratic mandates for rebuilding nature elsewhere. Recent years have already shown attitudes towards nature are changing rapidly. If this trend continues, our politicians will soon have the public’s backing to restore Europe’s broken ecosystems. The idealist inside me hopes this will happen, so that more of us can enjoy wild landscapes. But idealism aside – if modern society is to have a future, we will have to restore Europe’s vital ecological processes, to prevent our soil being eroded, provide habitat for pollinators, and sequester carbon from the atmosphere. The European bison has proven such feats can be done. So let us use this remarkable story to inspire us to reverse some of the ecological damage of the industrial age.

For other interesting articles on Poland’s wildlife and nature, see my other articles on the wolf or the logging conflict in Białowieża Forest.

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