It’s easy to assume that if we see a bird a lot, it cannot be endangered. Birds like House Sparrow and Starling are still fairly populous and easily seen, yet their decline in population size actually places them in danger.
But because our personal experience tells us there are fewer around, we accept that this is true.
But for other birds that have become more obvious too us, it can be difficult when we are told that the are endangered. Such a bird is the Herring Gull. Mentioned on BBC Springwatch a couple of nights back, I noticed several exclamations of surprise across social media that this could be possibly be endangered. I’m going to try answer.
The populations of urban gulls are nearly all increasing. Depending on where you are this will generally include Herring Gulls, Black-headed Gulls, and Lesser Black-backed Gulls.
The IUCN Red List tells a more complete story. The Red List is a regional list, managed by the International Union for the Conservation of Nature, that looks at population trends of species over time, and identifies how ‘at risk’ species are.
Outside of urban settings, much of the Herring Gull population is now restricted to just ten major sites. Over the past 40 years numbers have roughly halved, from around 270,000 pairs to about 140,000 pairs. This is how we judge the species as threatened.
It might seem easier to just say a species is endangered when numbers get low. After all, 140,000 pairs is over a quarter-of-a-million birds. That’s a healthy population.
But if we think about it for a moment, we can see that decline is a far more valuable measure to use. Because if we wait till a species is down to a few thousand, or a few hundred, it may already be too late. By looking at decline, we can try and identify the causes and address them while there is still a healthy population to work with.
More broadly, its an important concept to be aware of. Our experience, our personal or cultural memories of how nature is, that isn’t necessarily ‘how it should be’. Just because ‘garden birds’ didn’t include so many predators when you were young doesn’t mean increased predator numbers are bad. Predators go where the prey is, and the more inhospitable we make the wider environment, the more all will head for urban settings.