Wandering animals and where to find them. The return of wildlife to the city

A puma (Puma concolor) roams undisturbed in the deserted center of Santiago de Chile, coyotes (Canis latrans) seek food in the streets of San Francisco, while in Wales goats from the Great Orme promontory nature park walk the streets of the town of Llandudno. Also in our country, there is a continuous succession of "wild" sightings in the city centre: dolphins (Tursiops truncatus) at the port of Trieste, a porcupine (Histrix cristata) in a central square in La Spezia, roe deer (Capreolus capreolus) and wild boars (Sus scrofa) free to roam the streets. Many of the sightings witnessed on social media these days have turned out to be fake: either because they happened in another place or because they happened at another time. Others are authentic, but took place before the lockdown. In cities like Genoa, for example, the presence of wild boars is by no means an exception. 

The image of wild nature returning and taking up its spaces is evocative and consolatory. It satisfies us of that need for the "extraordinary" that we yearn so much from our windows today. These "visits" seem to tell of how our absence makes it possible to return to our origins with a bucolic flavour, but the reality is a little more complex and the reasons why animals approach inhabited centres may have very different reasons. The Planet is far from lacking our presence and the wild animals have not actually arrived from so far away. So where were they before? Or perhaps the more correct question is, "where were we?" 

Distracted by the frenzy of our lives, we did not notice their presence not far from our homes and we didn't have time to observe those animals that actually live in our cities all year round. Scientists call these species synanthropic and they have adapted perfectly to the urban environment, by taking advantage of their congenial characteristics and with no need to go back to the wilderness. A typical case is the blackbird (Turdus merula), whose natural habitat is represented by forests but which, already in the 19th century, began to haunt the city spaces of northern Europe. Its maximum expansion occurred in the last century together with domestic pigeon (Columba livia) and sparrows.

It is called urbanization and it is the phenomenon, known for decades, that some wild animals can occupy urban centres. It particularly concerns species with a marked ecological ductility such as hedgehogs (Erinaceus europaeus), foxes (Vulpes vulpes) and numerous species of birds, and includes not only "urban" species, but also those species that can exploit artificial environments for some of their daily activities or at certain stages of life. In fact, contrary to common belief, cities can be suitable for survival and often represent real "surrogates" of natural environments. A famous example is the peregrine falcon (Falco peregrinus) which nests on the Pirellone in Milan. 

Urban centres offer many hiding places, have milder temperatures thanks to heating systems and concrete, provide easy food (like waste) and the hours of daylight are longer. To all this we must add that many species in recent decades are recovering, thanks to the laws for the protection of fauna (Law 157/92; Directive 92/43/EEC; Directive 2009/147/EC) and, with inexorably advancing urbanization, the result has been the interpenetration between "wild" and "urban". 

We are accustomed to conceiving our cities as "biologically deserted" environments, yet they can instead be considered real "urban ecosystems" which, unlike natural ones (like a forest for example), are not autonomous but depend on the resources of the countryside. 
The boundaries of cities themselves are blurred – since the Second World War, uncontrolled (and disorderly) urban growth has led to the overlap between the urban and natural environment, leading to what would be more correct to define an "urban gradient" rather than a real border (Tomasinelli 2014). Under these conditions, the chance of "wild encounters" increases and, among the enlarged meshes of these blurred boundaries, we may come across an animal that has lost its compass – especially if its range, the area where a particular species lives, is wide and has been fragmented by the expansion of our cities.

This fragmentation has led to the interruption of the connections between the different areas, which is fundamental especially for those species that use large areas, in particular, predators and large mammals. This forces the species to distribute themselves in a discontinuous way with respect to the environmental potential and roads, railways, inhabited areas become barriers, or rather "filters", capable of significantly influence their distribution. To make it possible for them to pass from one area to another, if there are anthropic barriers, real "motorways of nature" have been created, capable of overcoming these obstacles. Throughout the world today there are ecological corridors, i.e. areas for the restoration of interconnected habitats, which allow the movement of fauna. 

It is therefore not that exceptional to have these type of encounters and specifically during the past weeks of lockdown is even more likely given the relaxation of our "disturbance". Indeed, the reduced presence of cars and the reduction of noise, allow our neighbours more freedom to explore the urban areas, extending their movements patterns and influencing the times at which they approach the city centres. 

To us two months of social isolation seem endless, but nature has a very different time perception, making two months not enough for a real rewilding process. It is very likely that when we will go back to our daily lives, the positive effects of this stop (as we have seen, even the reduction of some pollutants in the atmosphere) may well not last that long. However, we can only hope that the considerations that we have been forced to come up with will leave a mark within ourselves, leading us to rediscover the advantages of slowness and respect for nature, of which we represent only a very small part.

References
A. Mustoni, F. Zibordi, M. Cavedon, M. Armanini. I Grandi Mammiferi in Trentino: corrodoi faunistici e investimenti stradali. Gruppo di Ricerca e Conservazione dell’Orso Bruno, s.d.
F. Tomasinelli. Vado a vivere in città. Gavi (Alessandria): Piviere Edizioni, 2014.