Great Tits Show How Animals Can Thrive in Cities

Although its name might be unknown (and blush-inducing) to some Americans, the Great Tit is one of the most familiar bird species in Europe and Asia—and one of the most intriguing. The species shows a cognitive capacity that is amazing for a slight bird weighing only 18 grams. It produces false alarms to scare other birds off seed feeders and knocks on kitchen windows to get feeders refilled. On cold winter days Great Tits drum on beehives, whereupon the bees will come walking out, easy prey for the hungry birds. In combination with the bird’s broad food preferences, its cleverness has resulted in an unusual response to urbanization.

By “unusual,” I mean that Great Tits not only get by but thrive. And their success at city living offers some lessons on how we humans can better get along with not just Great Tits but also our other urban animal neighbors.

Urbanization, which involves land development, is an increasing problem for wild animals the world over. Stressors such as pollution, noise, artificial light and the lower-quality food found in cities are considered unhealthy for animals. Studies of urbanization in birds, including my research, are usually designed to elucidate its detrimental effects, with some interesting exceptions. Together with Hannah Watson, a colleague at Lund University in Sweden, I measured levels of corticosterone, or CORT, a common stress hormone in birds, in 188 urban and rural Great Tits. Contrary to expectations, the urban birds had consistently lower levels of CORT than forest birds. This finding is even more remarkable when you consider that urban populations are denser than forest ones, which should increase competition for territories and food and hence ramp up stress.

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Understanding animal cognition is important because of the concern about keeping wild animals in captivity.

Such exceptions may be more common than one would think. Another forest bird, the European Blackbird, a close relative of the American Robin, has successfully colonized suburban habitats in Europe in a similar way as the Great Tit. A study at 10 pairs of urban and rural sites across Europe showed that levels of stress hormones were consistently lower in the urban blackbird populations than in forest ones.

Great Tits belong to the family Paridae and are relatives of North American chickadees but almost twice their size. They are colorful and perky, and they frequently become tame when rewarded with treats. Not surprisingly, they have been the subject of the highest number of scientific studies among all wild birds.

Adaptability has also allowed Great Tits to colonize a habitat that is in stark contrast to an urban one. Originating in the temperate deciduous forests of Eurasia, the little bird is now common in boreal coniferous forests at northern latitudes. The species colonized northern Sweden in the early 1900s during the construction of railroads. Bird feeding has a long tradition in this country, and the rail builders took a liking to the birds, nailing up their leftover pork fat at the entrances to the huts where they slept. As the railroads extended northward, the Great Tits followed. Nowadays they are common in this habitat, but when the cold winter takes hold, they leave the forests and emerge at bird feeders in nearby towns and farms.

Cognition in the Paridae family is interesting, and not only because of the achievements of that single species. In general, members of this family possess the largest relative brain sizes of all small birds. Different species practice one of two entirely different wintering strategies. All American species, such as chickadees, and their close relatives in the Old World, such as Willow and Marsh Tits, are large-scale food hoarders. These species are spatial-memory specialists that store many thousands of food items, all in separate locations, as winter food. The Great and Eurasian Blue Tits, in contrast, do not store food at all. Curious and innovative, they instead obtain food in all possible and seemingly impossible ways, especially from humans.

The cognitive skills of the Great Tit have been important for its successful colonization of new habitats. And understanding animal cognition has become important because of the growing concern about the ethics of keeping wild animals in captivity. Scientists disagree on many questions involving the awareness of animals: Is it justifiable, for example, to keep cognitively advanced animals such as apes and dolphins in captivity for our own entertainment?

The more we learn about animal cognition, the better we will be able to answer such questions. Considering the cognitive ability of a small bird such as the Great Tit, there should be room for much reflection when we think about the confined spaces in zoos where we keep animals that we consider to be even more cognitively advanced.

If you aren’t sold yet on the incredible cognitive skills of the Great Tit, here’s another piece of evidence: they are masters of vocal mimicry. Compared with well-known mimics such as mockingbirds and European Starlings, Great Tits have an ability so rare that it may pass unnoticed. It is the way they use their mimicry that is impressive. Whereas other species mimic with the sole purpose of making their songs more impressive, the Great Tit will mimic other birds only when it might offer some advantage and never in its own song. For example, it may imitate the sounds of almost any other songbird in a neighboring location to expand its own territory. The neighbor bird will then avoid the Great Tit’s range, believing that it is already occupied by a competitor of its own kind.

Great Tits may also strategically mimic a call that warns of predators. The most significant peril for small birds at a feeder is an airborne predator that attacks at high speed, such as a falcon or hawk. When one is nearby, all small birds talk the same language. A high-pitched seeee will make all birds at a feeder take off in panic. In Aesop’s fable about the boy who cried wolf, a shepherd boy gives false alarms by repeatedly screaming, “Wolf!” when there is no wolf present, just to fool the villagers into rushing to his rescue. When a wolf eventually does attack the sheep, no one comes to help because the villagers believe the cry is just another false alarm. The boy did not benefit from his trickery. The clever Great Tit, however, does precisely this, sounding false alarms and actually gaining from it: by scaring the other birds off, the Great Tit gains exclusive access to the feeder.

What can we learn from this? Birds as intelligent as the Great Tit and other urban-survivor species will find food we leave for them and places to make our acquaintance if we give them just a little room to use their smarts.

This is an opinion and analysis article, and the views expressed by the author or authors are not necessarily those of Scientific American.