In Decline of the West, Spengler stated that a great statesman should be like a gardener tending to his country with a view to ensuring its “plants” grew up healthy and strong. Sounds quaint and harmless, doesn’t it? But by the time he wrote The Hour of Decision, Spengler was referring to his fellow citizens as “human vermin” and “human insects”. What does a statesman-gardener do with the pests spoiling his garden? The 20th century gave us a detailed answer to this question.
One of those statesman-gardeners was Chairman Mao who apparently took the matter literally in 1958 by declaring “The Four Pests” that were to be completely exterminated under his command: sparrows, rats, mosquitos and flies. The sparrows, apparently, were eating too much wheat and reducing the crop which was making the Great Leap Forward less great than it should have been. Mao ordered the birds to be killed on mass. It’s estimated that the Chinese, who often went around in groups, killed tens of millions of sparrows.
Unbeknownst to Mao, sparrows eat grasshoppers. So, when you get rid of the sparrows you increase the population of grasshoppers. It’s theorised that the main cause of a locust swarm is overpopulation. Whether that’s true or not, it happened in China in the years following 1958. Locust plagues immediately followed the sparrow cull and led to a subsequent famine that killed tens of millions of people. Realising his mistake, Mao took the sparrows off the list of the Four Pests and replaced them with bed bugs. Apparently the list needed to be four items long. The sparrows had probably never really been a problem at all except in the mind of a mad dictator who believed his own propaganda.
But it wasn’t just Mao who believed the propaganda. The only reason so many sparrows could be killed was because many other people believed it too. Nowadays we are familiar with ideas “going viral”. The concept of contagion also reappeared just this week in the context of the financial markets. Apparently, the failure of the Silicon Valley Bank posed a “contagion risk” for the whole banking sector. Just like grasshoppers can state change into locusts and destroy crops, financial institutions and individual account holders can state change into panic-mode and destroy a bank. Perhaps our finance technocrats have not been tending their garden properly.
It’s not just among humans that “information” can go viral. I have a story about “information contagion” that’s based on real-life gardening. Since I like to tell a good gardening yarn, let me share it with you.
The scene of the battle was about three metres from the place where I am currently typing this post. You can see a photo of the view from my computer desk to the left. The desk overlooks a pear tree and, although the contrast in the photo is not great, you should be able to see the enemy in the middle there munching on some pears.
The tree is a Josephine de Malines cultivar, apparently named after the wife of the guy who first cultivated it. I picked it up as a seedling almost ten years ago. I was browsing through a nursery a few days before Christmas and noticed that it was half price. The reason for the discount was probably because planting a tree at that time of year is not ideal as the plant doesn’t have time to root properly which limits its ability to take up water. A few days in a row above 40 degrees, rare but not out of the question in the Melbourne high summer, can kill off a newly planted tree. I took the gamble and it paid off. The tree has grown strongly and now produces hundreds of pears in a good season.
The Josephine had its first really big fruiting season in the autumn of 2020. We all know what else happened that autumn. From mid-March, I began working from home prior to the official corona lockdown. As a result, I spent my day overlooking the pear tree. It was from this position that I was about to do some accidental ornithological research.
Neither the Josephine nor any of the other fruit trees I had planted around the same time had attracted attention from pests before March 2020. In hindsight, I got very lucky. I think of this as the Garden of Eden phase where I had no work to do except pick the fruit and eat it. That was about to change. But the “original sin” was not triggered by a snake and an apple tree but by the Josephine pear and the humble suburban blackbird.
We tend to think of animals as acting entirely by instinct. But even birds have to learn what they can and can’t eat through trial and error. The first time I tried to give tomatoes to my backyard chickens, they turned up their beaks and walked away. But now that they’ve learned how tasty tomatoes are, they will squabble over who gets first bite.
The same goes for blackbirds which, like chickens, are opportunistic eaters. Blackbirds form monogamous pair bonds and the male will usually defend an area of territory. For that reason, in a suburban setting you normally only see a few blackbirds around: the male, the female and any children they are still taking care of. At about one year of age, the younger blackbirds will fly off to start their own family somewhere else. Because of these behavioural patterns and because they have a short lifespan of about 2 years on average, anything a blackbird learns about what is and is not edible is not going to get transmitted to other blackbirds. Information doesn’t “go viral” in the blackbird world.
I suspect it’s for these reasons that, prior to 2020, the couple of blackbirds that were hanging around my yard had shown no interest in the pear tree. Then two things changed. Firstly, the pear tree had a bumper crop in 2020. Secondly, I started free-ranging chickens in the backyard. All fruit trees will normally drop some fruit on the ground before it is ripe. Prior to 2020, I would have picked up any dropped pears and put them in the compost. But now the chickens were around, so I let them eat the fallen pears.
What I didn’t count on was that the blackbirds would see what the chickens were doing and join in the fun. Here we have an example of cross species information contagion; also known as learning. The blackbirds had learned from the chickens that the pears on the ground could be eaten. Later on, I would see the same thing happen as the New Holland Honeyeaters joined the party and began eating the pears for the first time too.
Initially, I wasn’t too bothered about the blackbirds eating the fruit on the ground. But, unlike chickens, blackbirds can fly and that means they can fly up into the tree and eat the fruit that was still ripening. I wondered how long it would take the blackbirds to look above their heads and realise that the fruit in the tree was the same as the fruit on the ground.
Surprisingly, it took them a full 3 weeks to figure it out. By now we were into the first week of April which is exactly when the Josephine pears start to be ripe for picking. Because I hadn’t had any trouble with pests prior to this, I didn’t own any bird netting. And because it was lockdown, getting a hold of some netting was not going to be easy. What to do?
Fortunately, blackbirds are easily scared. In fact, they’re more chicken than chickens. I realised that by giving just a single loud clap of my hands I could scare them away from the pear tree. This is not a pest deterrent method I would recommend but I had nothing better to do at the time given we were in lockdown. I decided to turn the whole thing into an experiment. Could I “teach” the blackbirds to stop trying to get pears? After all, if a blackbird keeps flying into the tree but gets scared away before it can eat anything, you would think that after a while it would just give up.
The answer to this particular ornithological experiment was that, no, the blackbirds did not give up. I was unable to “teach” them and so I spent the whole month of April and early May shooing them away from the tree. Fortunately, this was not such a big effort because there were only three blackbirds and the whole thing was a welcome diversion from the madness of the world at that time. Plus, it meant I got to eat most of the pears on the tree. Yum!
Ironically, the blackbirds had become almost as singled-minded as we humans. They had become obsessed with the pears. Such behaviour is not uncommon in birds. Even chickens, who are normally very passive and easy going, can pursue a goal with determination and vigour once they set their mind on it. We humans are no different, of course. How do you know when is the right time to give up on a goal? Normally, it’s when the pain has been greater than the pleasure for a long enough time period. But there was no pain for the blackbird in my experiment, only frustrated ambition. Meanwhile, those juicy pears were just sitting there on the tree unprotected. So, the blackbird kept trying.
Obviously, it’s impossible to know exactly what goes on in a blackbird’s head. But I suspect blackbirds operate almost entirely on instinct. They hear a loud clap and they fly away. What they don’t seem to do is form an idea about the intent of the human who is doing the clapping. In this respect, they are not as smart as chickens. Chickens can learn to read whether you’re in a good mood and likely to give them some tasty kitchen scraps or whether the fact that they’ve just dug up half your veggie garden looking for worms might have put you in a bad mood. They have an understanding of human intent.
The same goes for the second “pest” which first showed up in my garden in 2021; the aforementioned rainbow lorikeets. Like chickens, they have an understanding of human intent and they take appropriate measures like hiding from said human on the other side the tree and trying to keep quiet so the human doesn’t know they’re there. But it’s their sociability that’s the real problem and which qualitatively differentiates lorikeets from blackbirds as a pest.
As I mentioned above, there’s only ever a few blackbirds in a given area because the male blackbird will chase away others who happen to stray onto his turf. Information cannot “go viral” among blackbirds for this reason. What’s more, even if I had let the three blackbirds in my backyard eat as many pears off the tree as they wanted, I still would have got some pears for myself because fruit is just one food source for a blackbird and, from my subsequent observations, they only eat about one pear per day if given free rein to do so. Thus, I never had to fear “contagion” on the part of the blackbirds.
The same is not true of rainbow lorikeets. Lorikeets are not territorial or competitive when it comes to food. On the contrary, once a couple of lorikeets have found a food source, other lorikeets will show up to join in the fun. Lorikeets travel in packs over large distances (up to 50 kilometres from their roosting site). This means you can come home one day and find a hundred lorikeets in a tree. Also, lorikeets spend most of the day eating and, unlike blackbirds, they are specially adapted for eating fruit and can get to hard-to-reach fruit by hanging upside down.
What all this means is that information can “go viral” among the lorikeet population. A backyard pear tree becomes the hit of the week and even a tree that produces hundreds of fruit can be totally stripped in a day by a pack of lorikeets that have flown from many kilometres away to have a giant pear party. What’s more, lorikeets live up to 20 years on average and they remember where food is which means that, once they’ve found a fruit tree, they will return the following year and the year after that. By contrast, because of its short life span, the blackbird is likely to have died by the next fruiting season and taken its knowledge about how to eat pears with it.
Are humans more like blackbirds or more like lorikeets? It seems that we can be either. The Chinese and Japanese behaved more like blackbirds when they closed off their borders to foreigners in the 17th century. The ancient Greeks had a similar insular mentality. But these days we live in a lorikeet world where information can travel over long distances and is readily shared. The result is that we behave more like lorikeets. So, it’s not a surprise that our politician-gardeners are terrified of contagion.