Despite being a blush-worthy moniker, at least for Americans, the great tit is one of the birds most familiar to people in Europe and Asia. And it’s among the most intriguing. The species shows a cognitive capacity that is amazing for a slight bird weighing only 18 grams. They produce false alarms to scare other birds off bird feeders, and they knock on kitchen windows to get seeds refilled. On cold winter days, they drum on bee hives, whereupon the bees will then come walking out, easy prey for the hungry birds. In combination with its broad food preferences the great tit’s cleverness has resulted in an unusual response to urbanization.
By that, I mean they do not only get by, but they thrive. And their success at city living offers some lessons on how we can better get along with not just great tits, but 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 worse feed found in cities are considered unhealthy for animals. In this spirit, studies of urbanization in birds, including my research, are usually designed to elucidate its detrimental effects.
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With some interesting exceptions. Together with a colleague at Lund University, Hannah Watson, I measured levels of a common stress hormone in birds, corticosterone, or CORT, in 188 urban and rural great tits. Contrary to expectations, the urban birds had consistently lower levels than forest birds. This is even more remarkable as urban populations are denser than forest ones, which should increase competition for territories and food and hence increase stress.
Such exceptions may be more common than one would believe. 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 stress hormone levels are consistently lower in the urban blackbird populations than in forest ones.
For Americans, “great tit” may sound provocative. For Europeans, however, this is the wild bird with which people are most likely to have formed a personal relationship. Belonging to the family Paridae, it is a relative of the American chickadees but almost twice their size. It is colorful and perky, and frequently becomes hand-tamed when rewarded with treats. Not surprisingly, it has been subject to the highest number of scientific studies of all wild birds.
Adaptability has also allowed great tits to colonize a habitat that is in stark contrast to an urban one. Originating from 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 pork fat leftovers 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 not interesting 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 blue tits, on the other hand, do not store food at all. They are instead curious and innovative, obtaining 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. Understanding animal cognition, however, has become important also for its own sake.
Scientists now 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 in a small bird such as the great tit, there should be room for much reflection when we think about the confined spaces where we keep animals that we consider to be even more cognitively advanced, in zoos.
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, thrashers and European starlings, the great tit’s mimicking is so rare that it may pass unnoticed. It is the way they use their mimicry that is impressive. While the species above 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 passerine in a neighboring territory to expand its own territory. The neighbor bird will then avoid the great tit’s territory, believing that it is already occupied by a competitor of its own kind.
The crying wolf call of great tits belongs in this box of tricks. The most dangerous peril for small birds at a feeder comes from an airborne predator that attacks in high speed, for example a falcon or hawk. On such occasions, 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 famous fable, 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 attacks the sheep, no one comes to help as it is believed that this is just another false alarm. Hence, the boy did not get away with false alarming. This clever bird, however, does precisely this, sounding false alarms and gaining from it.
What can we learn from this? Birds as clever 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 way 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.