Prickly Knowledge

…Or, at least, it seems to be the case for birds.

I took this picture in Lima during our three week trip in South America and I have had this bird and this picture in the back of my head since 2017. There would be a lot to explore through this picture, the blue church La Recoleta that has been restored since and is no longer blue, or the Estatua de La Libertad gifted by France for the centennial celebration of Peru independence, also restored and given back its torch in 2019. Both could be good entries to the history of Peru and colonization, but having always been fascinated about wildlife, this time, I really wanted to research this little red bird.
At the time, world data subscription was not as broadly accessible as it is now, and I shamefully didn’t search the kind of bird it was when coming back home.

So, let’s remedy that today and find out what kind of bird this one, that put some fire back to a stolen torch, was.
It is a Vermilion Flycatcher, the only kind of flycatcher with bright red coloring. It has a lot of subspecies and some have become species recently through genetic analysis. I won’t be adventuring into finding the right taxonomy for this one, it seems to have given headaches to biologists and bird enthusiasts since Darwin. But if you ever had doubt that a common species still has some mysteries for biologists and ethologists then it is a perfect example. 

In and around Lima, two phenotypes of the Vermilion flycatcher can be observed. This means that, in the same species, individuals can present a certain coloration and some another one. In the case of this little passerine, some of the male have bright red feathers, like the one I remember, and others have few to no red at all with all dark gray feathers. In females, the same gradient can be observed from light gray with a few red feathers on the abdomen to a darker brown with no red. From short mentions in birds database to a podcast, I came across a fascinating thesis on this specific subject by Carl Jonathan Schmitt. 

Since the industrial revolution, biologists have studied a phenomenon called “industrial melanism”. This is referring to the evolution of some insect species that are becoming darker in response to pollution. The repartition of the phenotypes of the Vermilion flycatcher seems to be following this logic, with darker forms being more frequent in the city center than in the suburbs around Lima. In a more gray and polluted environment that are big cities like Lima, it seems logical that natural selection would favor individuals with less bright colors, darker feathers making them less visible to predators. However, Schmitt explains that this phenomenon can not be applied here, mainly because the dark morph was discovered and described by Darwin in 1835 long before Lima became its industrial development. Through study of genetics, spatial repartition and mating pairs, this study tries to explain that color distribution.

While I encourage you to read this relatively short and well written thesis (it is still a scientific paper, be prepared), I will share with you one of the results.
Indeed one of the conclusions is that coastal cloudiness predicts the repartition of the melanic alleles (hence the phenotypes) better than the air pollution. Darker phenotypes are more prevalent in frequently clouded areas (along the coast and city center) than in other parts of Lima. This distribution is not new and it seems to be maintained by the birds preference for same colored mates. Different hypotheses could explain why darker colors can be an evolutionary advantage in dark and humid environments, like for instance heat regulation or pest resistance.

Those readings made me think that I have recently heard about color choices in human clothes (and saw these recent memes about cars being more and more either black or white). I worked in Paris for 7 years, and I have often thought (or heard people say) that, for a “fashionable” city, people were wearing a lot of black, white and dark blue. I think this is the case in most big occidental cities with a lot of corporation and desk jobs. So I wonder if we could do an “industrial melanism” analysis of our modern occidental clothing ? Does the frequency of colors in our closet have changed since the industrial revolution and since the third and fourth industrial revolution ? Social factors would probably be more impactful than the biological and environmental ones but it would still be an interesting thing to study and follow. Maybe, current climatic changes could also have an impact on our wear of dark colors? 

As usual, this picture has sent me on different and interesting paths. The last one I will not explore today, but maybe a future picture will make me do the research in the non less interesting fashion history field !

I am only taking a quick look on the subject, if you want to share your own findings and thoughts, please, comment below !