It was recently announced that an estimated 600 million fewer birds are flying around in Europe today than in 1980. But what about in the Netherlands?

An international team of researchers recently examined 378 of the 445 endemic bird species in Europe. They looked at the current size of their populations and how this compares to the population size in 1980. The findings are somewhat shocking; according to the researchers, Europe has lost some 600 million birds in just 40 years. And strikingly enough, especially the populations of common species – such as the well-known house sparrow and starling – have plummeted enormously.

Increase

It naturally raises the question of how representative the findings are for our country. Has the number of birds here also taken a nosedive? Ruud Foppen, professor by special appointment of integrated conservation biology at Radboud University and co-author of the recently published book ‘Appeared or disappeared: more than a century of Dutch breeding birds on the move’can reassure us somewhat. “If we count how many birds there are for each species that occurs here and then compare that with what we saw in the 1950s, we have to conclude that the total number of birds has actually increased in the last 70 years.”

The nuance

That is good news. But it is – unfortunately – not the whole story. “We do see a big difference between habitats, especially what I call the 2D and 3D landscape. With 2D landscape you have to think of open landscape, such as farmland, but also the heaths, raised moors and open dunes. The 3D landscape includes forests, swamps and cities: areas that are more complex and more structured.” And when we zoom in on both types, large and at times dramatic differences become apparent. “For example, we see a huge decline in the 2D landscape, really in the order of millions of birds.” The fact that the total number of birds in the Netherlands is nevertheless still increasing is due to what is happening in the 3D landscape. “There, the number of birds is increasing. To date, that has compensated for the declines that we are seeing, particularly in the agricultural landscape.”

The fact that many birds struggle on farmland is not because it is becoming increasingly rare; Farmland is responsible for about two-thirds of land use in the Netherlands and is therefore still well represented. Farmland is, however, becoming ‘poorer’: it has much less to offer breeding birds than in the past due to economies of scale, intensive use, desiccation, heavy nitrogen load and the use of pesticides.

The gray shrike no longer occurs in the Netherlands. Image: Smudge 9000 (via Wikimedia Commons).

Lost species

And so the number of birds in the Netherlands is subject to major change. But also on a species level it is never boring. In the past century alone, the Netherlands has lost about 12 species. Among them are the hoopoe, the curlew, the gray shrike, hooded crow, dune pipit and crested lark. The exact reasons for their Dutch extinction vary, but are almost always related to the major changes that the Dutch landscape has undergone since 1900. In addition to the impoverishment of farmland, you can also think of degradation of raised bogs and more intensive recreation in dune areas.

The white-tailed eagle has recently been found in the Netherlands. Here you see the first young that crawled out of the egg on Dutch soil. Image: Staatsbosbeheer / Vincent Wigbels (via Wikimedia Commons).

Appeared species

But it’s not just bird species that have disappeared; since 1900 quite a few new species have also appeared. For example, the eagle owl established itself in our country in 1997. The white-tailed eagle followed in 2006, the nun in 2010. And the bee-eater and crane now also feel at home here. In total 49 bird species have been added to the Netherlands since 1900. The exotics – often accidentally introduced species by humans, such as the ring-necked parakeet, house crow and white-fronted goose – are not taken into account for the moment.

If you take stock – 12 species that have disappeared as opposed to 49 that have appeared – one could conclude that bird diversity is fine. But Foppen cautions us to be careful with such conclusions. “If you only look at species, a species that consists of only a few individuals counts just as much as a species that consists of millions of individuals. But from the point of view of diversity, such a species with a handful of individuals is of course not much.” In addition, the way in which species are labeled ‘disappeared’ or ‘appeared’ is also characterized by a slight bias for newcomers. “The process of colonization, the new appearance of a species, usually goes faster than the total disappearance of a species. The distribution area of, for example, the white-tailed eagle has expanded to the west, individuals come this way from the east and settle. And that can go quite quickly. This is not the case with extinction; birds don’t move. There are gaps in the distribution due to, for example, poor breeding success or high mortality. Because this is partly a coincidental process, but also because protective measures are taken to save the last couples, it can take much longer before a species has permanently disappeared from our country.”

According to Foppen, the fact that dozens of species have established themselves in the Netherlands in recent decades can partly be traced to international nature conservation measures. “Particularly Natura 2000, which has led many countries to protect vulnerable areas and reduce the persecution or hunting of animals. You can see that, for example, birds of prey and water birds have reacted very strongly to this and have expanded their habitat further and further. You could see species such as the white-tailed eagle, the osprey and the great egret coming closer and closer this way!” It proves that nature conservation also pays off with regard to birds. “Now you have to conclude that this was partly low-hanging fruit. It concerned bird species that were threatened by a clearly known bottleneck that could easily be solved. In that case, better protection by agreeing not to hunt or prosecute them anymore is of course quite simple. But hey, it worked.” And we’ve got some nice newcomers from it. But the decline of the farmland birds has not been solved. “That requires a large-scale change in land use, actually a large-scale transition. And that’s a lot more difficult. But as long as we don’t make that transition, farmland birds will continue to be very bad.”

bright spot

The fact that birds are currently doing well in urban areas and forests is a ray of hope. But it flickers. “Whereas in the sixties and seventies a lot of work was done to make the city greener, now we see the opposite happening. An enormous fossilization is taking place and that works against birds.” And adverse changes are also in the offing in the wooded areas, especially in the east of the Netherlands. “Poor quality of the trees, mainly caused by the nitrogen problem, threatens the forests in, for example, the Veluwe and Drenthe. There we will see strange scenes in the coming period that will ultimately – in the absence of effective measures and solving the nitrogen problem – lead to the loss of those forests. We are already seeing the first signs of this, as are the consequences for birds.”

Climate change
Land use and changes in it have a huge impact on birds. But climate change also has a – still small – influence on the birds in our country. “For example, we see certain species advancing from the south and surviving here thanks to milder winters.” It is difficult to predict which species will become (further) in difficulty due to climate change or which will settle in the Netherlands due to global warming. “It is not the case that we will soon have a French climate. Instead, climate models predict that our climate will soon be characterized by aspects of, for example, the French, German and English climate.” And with that we can actually compare our future climate with no existing climate. “It’s something very new and we don’t know how species will react to it. But it is clear that something will also change within the bird species and populations.”

What exactly we will find in the Dutch skies in 50 years and in what numbers, Foppen will not comment on that. Because if the professor has learned one thing in recent decades, it is that it is often impossible to predict how bird species and populations will fare in the future. “A lot can change in one birder’s life,” says Foppen. He speaks from experience. “When I watched birds as a boy, the world looked very different from now. If you had predicted then what I see now – when I look around in the same places – I would not have believed you. Take, for example, the greylag shrikes. When I watched birds as a boy, their numbers dropped dramatically and not long after, the species was listed as rare. And now we see that it suddenly recovers and not just a little bit. Or the nightjar, which lives a lot on the heath. All birds on the heath are having a hard time, so it was expected that this species would also have a hard time, but we are now seeing the number of nightjars increasing. Another example: the skylark.” It used to be an easy strain that felt at home everywhere and no one worried about it. “And now the species is rare!” Or the lapwing that started to feel at home in fields in the eighties and was widespread. “The species seemed to have found a new niche after the wet grasslands in which it originally liked to live. But now it appears that the bird can no longer survive in the fields. And strangely enough, no longer in its original habitat, on those wet grasslands.” At the same time, in 2021 Dutch birdwatchers can once again marvel at species whose habitat was only a few decades ago still hundreds of kilometers from the Dutch border and which were never expected to feel at home here. “And so birds continue to surprise us.”