First Bad, then Good, and now Ugly - or was it the opposite way round?

Jo Inge Breisjøberget

 

My grandfather, Brede Breisjøberget, was a hunter. He said ”Shoot all the predators - we have to clear up in the weeds. They eat grandma’s chickens”. He just shook his head when the regional game manager, Arne Gabrielsen, in the 1970s announced that predators only took the old and weak. Then the leading wildlife scientist professor Per Wegge and fellow colleagues began to tag small and big game with radio collars. Data showed that the picture is more complex, or is it? Most game animals die because they are killed! First, predators were mean, then they were kind (and just took the old and weak ones), and now – lately - they are mean again. All these views have been prevailing in society at one time or another. Science is evolving but scientists just have fragments of data. They have to interpret their data and always adjust state of the art with the current theoretical and empirical findings. However, science and especially interpretation of science interact with the prevailing political opinions. Things can easily go wrong. We have to be careful and always bring along an element of self-criticism.

Throughout history our agricultural-based society has been in a competitive relationship with predators, and many predators have been reduced in number or made extinct using whatever methods were available at the time. In both Norway and the rest of Europe, the early and common belief was that predators limited their prey. The 1 000 year old Norwegian Gulating law says: “Bears (Ursus arctos) and wolves (Canis lupus) shall in all places be outlaws”. A similar statement can be found in The Frostating law; “No one must trap in the forest of another owner for any game except wolves, foxes (Vulpes vulpes) and otters (Lutra lutra)” (Smedshaug and Reimers, 2002). In 1845 a new hunting law was introduced; “the Law of extermination of predators and protection of game”. It stated that many predator species should be exterminated. Clearly these statements cannot be misunderstood. Both livestock and game were killed by predators, sometimes even humans. The predators were seen as our enemies. If we removed these enemies, our livestock would walk in peace and there would also be more game food on the table for us.

The leading Norwegian forester J.B. Barth surveyed the best Norwegian ptarmigan areas from Fokstua to Kongsvold during a week in July 1868 and reported that the only ptarmigan he observed was one single adult male (Barth, 1891). With the new Hunting law of 1899, the fight against predators was intensified by including more species in the bounty system and the rewards were increased (Smedshaug and Reimers, 2002). Everything with a crooked beak and dogtooth should be killed. Teachers were employed to travel around to learn people more effective ways of hunting predators through the use of traps and poisoned baits (Smedshaug and Reimers, 2002). The public needed to be taught how they could get rid of the troublesome predators.

The hunters and trappers did their job dutifully and got rid of as many predators as they could. Seemingly, this had a positive outcome for the ptarmigan populations. The period 1906 to 1912 is considered the “Golden Age” of ptarmigan hunting in Southern Norway (Pedersen and Karlsen, 2007; Hjeljord, 2008). In one hunting area in Hallingdal, 30 ptarmigan were shot in the autumn of 1900, which is to compare with 905 ptarmigan in the same hunting area in 1907 (Hjeljord, 2008). The ptarmigan population in the winter of 1912-13 was the largest ever measured, and it was concluded that the most obvious reason for this was the intense hunting of predators in the previous years (Smedshaug and Reimers, 2002).

In 1913 there were signs that this may not have been the only side to the story. The ptarmigan populations collapsed in many parts of the country (Smedshaug and Reimers, 2002; Pedersen and Karlsen, 2007; Hjeljord, 2008). How could this be? In a short period of time the ptarmigan populations fell from its highest ever to just a fraction (Dahl, 1924). This decline could not be ascribed to the number of predators, as they were now almost extinct. According to the polar hero Fridtjof Nansen, this was nothing short of a crisis. He started to talk about a national catastrophe. He suggested that the main cause for this was a disease caused by too high population densities. He had heard about “ptarmigan-plague” on his journeys in England and Scotland (Solli, 2002). Inspired by this, he started research in Norway, the first Norwegian ptarmigan research. He engaged Professor August Brinkmann and the The Norwegian Hunting Organisation (NJFF) milieu in Bergen (Smedshaug and Reimers, 2002; Steen, 2004). They found coccidiosis in ptarmigan, and some of the deaths were ascribed to this infestation. Coccidiosis was clearly more prevalent in the densest populations. From this, Professor Brinchmann concluded that the predators only took the weak and sick prey. The predators were an important part of the ecosystem and by removing the weak and sick individuals they prevented disease accumulating in the population.

If the predators were not present, disease would hit the populations (Smedshaug and Reimers, 2002). But most hunters still saw predators as the major threat to their game, and the intense hunting of predators continued up until after World War II. Fresh tracks of Pine marten (Martes martes) were sold to the highest bidder, and the prices for fur reached an all time high. This brought much-needed income and food to the table in the otherwise poor areas of the countryside, especially in the depression period during the 1920s and 1930s.

The following example is from a hunting area in Setesdalen in Southern Norway: “From 1919 to 1924 in my hunting grounds in Rysstadheiene… in 10 km2, I trapped and shot: 14 foxes, 19 ermines (Mustela ermine), 6 eagles, 39 gyrfalcons (Falco rusticolus), 71 Eurasian eagle-owls (Bubo bubo), 19 goshawks (Accipiter gentilis), 3 Eurasian sparrowhawks (Accipiter nisus), 9 kestrels (Falco tinnunculus), 3 snowy owls (Bubo scandiacus), 10 tawny owls (Strix aluco), 24 ravens (Corvus corax), 14 hooded crows (Corvus cornix)” (Hjeljord, 1981; Hjeljord, 2008). What we hunters would have called a “mixed bag”! Unfortunately, it didn’t have the assumed effect. In the hunting ground where four hunters normally shot 300-500 ptarmigan they could now only shoot 23 with “huge effort”. And the conclusion: ”…trapping predators has been meaningless! It shows that nature regulates the predators itself. It is diseases and epidemics, and to some extent migration, which wipe out the grouse populations” (Hjeljord, 1981; Hjeljord, 2008). Now we have had three theories about the decline of the grouse populations: predation, diseases and migration.

There were discussions of protecting game birds against hunting because of the collapse in the grouse populations around 1923/24. By a Royal resolution (24th of July 1925), Capercaillie (Tetrao urogallus) and Black Grouse (Tetra tetrix) were to be protected in the County of Nordland. Immediately prior to this, there was a rise in the grouse population, and subsequently in 1926 there was a marked increase. This continued until 1929, when NJFF announced that this year was a special year in the history of grouse (Hjeljord, 2008). Unfortunately, there has been a continuous decrease in the populations since then. Over the past 50 years, there have been a few isolated good years, but the populations of Capercaillie and Black grouse remain low even today (Hjeljord, 2008). In the 1930s there were many articles on the causes of the “bad” years and the low population of birds. They concluded that this could not be assigned to predators alone. Dead birds were found, and there were new theories regarding disease and emigration (Hjeljord, 2008). Despite these theories being published and well known, intense persecution of predators continued. The hunters could observe by themselves that foxes still ate “their” hens.

Early in the 1940s, the image of the bad-predator began to fall to pieces with Errington’s hypothesis. The American scientist Paul Errington studied muskrats (Ondatra zibethicus) and found that these predators only took individuals that would have died anyway- what he labeled a “doomed surplus” (Errington, 1967). Errington found that every muskrat defended a territory. When a territorial muskrat died, it was replaced by an individual from the surplus population. If you removed a muskrat from the surplus population, it didn’t affect the resident breeding population. As long as you just killed the surplus individuals, then hunting didn’t have any negative effects on the population size of reproductive muskrats. Therefore, the predators were a “Health Police”, which we were mutually dependent upon. This was later confirmed by Professor Yngvar Hagen’s excellent work in the 1940s. Hagen found an interaction between rodents, predators and grouse. When the rodent populations peaked, the grouse escaped predation. And when the rodent population crashed again, the predators looked for alternative prey - grouse. Hagen also discovered that kestrels ate rodents and not grouse chicks, so why shoot them? (Hagen, 1952). A fourth theory emerged because of Hagens discoveries; the role of the small-rodent cycles and the alternative prey thesis. This theory has been and is still the prevailing view among many hunters, managers and scientists to explain variations in grouse and ptarmigan.

The picture was changing. During the 1960s and 1970s, especially the non-hunting public saw predators as good and kind. In Scotland, grouse were in good numbers, and the birds that died were a doomed surplus (Watson and Moss, 2008). This has also been the basis of Scandinavia’s recent harvesting philosophy. We are hunting mainly the doomed surplus, but is there really such a thing in nature? In Scotland they did not have to assess the influence of predators in their harvesting strategy. These were more or less extinct due to the intense efforts of game keepers. Errington’s hypothesis dealt with territorial species. Environmentalism gained support. The bounty systems were rejected, and predators were instead labeled sacred, and protected by law. We created new national parks, established the Ministry of Environment and stricter hunting regulations came into effect. Despite all this, hunters would still experience foxes taking their small game. A dead grouse hen will never lay eggs!

Towards the end of the 1970s and beginning of the 1980s, people became alarmed by the decreasing population of capercaillie in South Norway (Wegge 1978). Would our capercaillie populations disappear? Luckily, this concern raised money for further research. The research concluded that capercaillie were taken by predators! Some years as much as 90% of the capercaillie eggs could be taken by predators (Wegge and Storaas, 1990). So, were the predators so sacred after all?

However, the focus was also on fragmentation and changes in habitats, and on the interplay between habitat change, predator density and game production. Humans had major impacts on the landscape; clearcuts, fragmentation of old forest, intense grazing of sheep in the mountains. Clearcutting affected leks and acid rain might also affect the grouse. If the negative tendency continued, it would definitely lead to a crisis in the capercaillie population. In the late 1990s we were reminded of another human factor; hunting. A research project had shown that, in many cases, hunting led to additional (additive) mortality of Willow ptarmigan (Lagopus mutus) (Pedersen et al. 1999). Until then we believed that hunting took less than 10 % of the population (Gabrielsen, 1961; Myrberget, 1974) in accordance with the “doomed surplus” theory. The focus in management therefore took yet another turn and aimed at the hunters. Hunters and managers now had to take hunting pressure into account as well.

In the autumn of 2007 there were plenty of capercaillie and black grouse in parts of Eastern Norway. Why did we see such large populations that year? The line census monitoring didn’t catch the initial growth in the populations the year before. It was simply very difficult to predict this increase. In 2007 we had a lot of rodents in these areas. This was the first “rodent-year” since 2002. This was in accordance with the alternative prey hypothesis. But still, we did not foresee this. Another possible explanation was that we failed to include the whole picture in our understanding. We tend to focus on one area and one theory and create our hypotheses and test them in the same area. By doing so, we might often fail to see the whole truth. As this story shows, this has been the case throughout the years and we will probably also continue to make wrong conclusions in the future.

Nature is complicated. We only know fragments of what is going on. In the last 30 years there has been a lot of research on small game population dynamics. Better ways of analyzing data and new research technology like GPS transmitters have revolutionized our understanding of these complexities. We now know that there are more factors than predation involved; diseases, changes in habitat, alternative prey, weather, hunting and so forth. We have to take into account the interaction of all these factors over time. Still we tend to interpret our data in accordance with what people or scientists presently believe. Grandpa Breisjøberget was living on his farm in the forest and did not know much about the scientists’ knowledge, beliefs nor about dominating political views. But he nonetheless saw that the goshawk killed grandma’s young and healthy hens. What is the lesson I want to bring forward? Scientists should be humble and look critically at their data, and also be reflective on the biases and preconceptions they bring along. It is dangerous to fully trust the present way of thinking and interpret all observations within the frames of the current theory. Listen again to grandpa Breisjøberget, he may have had a good point, after all.

References

Barth, J.B. 1891. Erfaringer fra jagten paa det mindre vildt i Norge. H. Aschehoug & Co’s Forlag, Kristiania.

Dahl, K. 1924. Norges Jeger og Fiskerforbunds Tidsskrift 53: 169-189.

Errington, P.L. 1946. Predation and vertebrate populations. Quart. Rev. Biol., 21: 221-245.

Gabrielsen, A. 1961. Vilt og jakt. En innføring i viltstell. Johan Grundt Tanum forlag, Oslo.

Hagen, Y. 1952. Rovfuglene og viltpleien. Gyldendal, Oslo.

Hjeljord, O. 1980. Viltbiologi. Landbruksforlaget, Oslo.

Hjeljord, O. 2008. Viltet. Biologi og forvaltning. Tun forlag, Oslo.

Myrberget, S. 1974. Viltøkologi. Universitetsforlaget, Oslo.

Pedersen, H.C. & Karlsen, D.H. 2007. Alt om rypa. Tun forlag, Oslo.

Pedersen, H.C., Steen,H, Kastdalen, L., Svendsen, W. & Brøseth, H. 1999. Betydningen av jakt på lirypebestander. Framdriftsrapport 1996-1998. NINA oppdragsmelding 578: 1-43.

Smedshaug, C.A & Reimers, E. 2002. Småvilt og rovvilt. Landbruksforlaget: 8-13.

Solli, S. 2002. Jegeren Fridtjof Nansen. Gyldendal forlag, Oslo.

Steen, J.B. 2004. Ryper og rypejegere. Gyldendal forlag, Oslo.

Watson, A & Moss, R. 2008. Grouse. Harper Collins, UK.

Wegge, P. 1978. Proceedings of the first international symposium on Grouse. World Pheasant Association, Inverness.

Wegge, P. & T. Storaas. 1990. Nest loss in capercaillie and black grouse in relation to the small rodent cycle in south east Norway. – Oecologia 82:527-530.