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<\/a>Image via Wikipedia.<\/p>\nOnce you start looking closely at the great tit (Parus major<\/a>), the cutesy garden-bird image changes drastically. These birds murder competitors, steal food from humans, cheat on their partners, develop local traditions, change their accents, and may even be evolving in response to city life.<\/p>\n Here are 12 science-backed facts about great tits that are considerably stranger than their appearance suggests.<\/p>\n 1. Great tits hunt bats \u2014 and eat their brains<\/p>\n In a Hungarian cave, researchers watched great tits actively search for hibernating common pipistrelle bats<\/a> hiding in rock crevices. The birds dragged the bats out, killed them and ate them. Some carcasses had been stripped of flesh and internal organs \u2014 including the brain.<\/p>\n They seem to do it regularly, it wasn\u2019t an isolated freak occurrence. Researchers directly observed 18 attacks over two winters, while records from the cave stretched back more than a decade. The tits were even attracted to recordings of awakening bats, suggesting they could eavesdrop on the bats\u2019 calls to locate them. When researchers provided the birds with extra food, bat attacks dropped dramatically, suggesting this gruesome behaviour was largely a response to food scarcity<\/a>. The study was published in Biology Letters<\/a>.<\/p>\n 2. They sometimes murder other birds over real estate<\/p>\n Nest cavities are valuable property if you\u2019re a small bird, and great tits are prepared to defend them accordingly. But they don\u2019t just defend, they also attack. Pied flycatchers, which migrate back into Europe in spring, sometimes inspect nest boxes that great tits have already claimed. Sometimes, entering the wrong one can be fatal.<\/p>\n A decade-long study<\/a> found that great tits killed male pied flycatchers during conflicts over nest sites, with mortality reaching 8.9% of male flycatchers in years when the two species\u2019 breeding schedules overlapped and great tit densities were high. The researchers described this rather politely as \u201cfatal competition.\u201d Nature, it turns out, has no reliable real estate agents.<\/p>\n \u00d7<\/p>\n Thank you! One more thing…<\/p>\n Please check your inbox and confirm your subscription.<\/p>\n 3. Great tits have culture \u2014 and they conform to peer pressure<\/p>\n We don\u2019t want to paint a picture of great tits as miniature brutes. They have pretty remarkable cognitive abilities, too. They watch one another, copy successful behaviours and can develop different local traditions. In one remarkable experiment<\/a>, researchers trained just two birds in separate populations to open a puzzle feeder in one of two possible ways.<\/p>\n After the trained birds were released, their techniques spread through their social networks until an average of 75% of the birds knew how to operate the feeders. Even more strikingly, each population overwhelmingly stuck with its own local method, including birds that knew both solutions. The traditions survived into a second generation. The 2015 Nature study called this evidence for both animal culture and social conformity in the wild.<\/p>\n 4. They were a part of Britain\u2019s infamous milk-bottle crime wave<\/p>\n For much of the 20th century, British households had bottles of milk delivered to their doorsteps; in some areas, this is still a common practice. For great tits, it turns out, this creates an irresistible opportunity. They learned<\/a> to break through bottle tops and feast on the fatty cream underneath.<\/p>\n Bottle-opening was first reported in Britain in 1921 and eventually appeared at hundreds of locations. Great tits were among several tit species recorded performing the trick<\/a>. Later analyses suggested the behaviour probably arose independently in several places but then spread rapidly through populations, making the milk-bottle saga one of the classic early examples used in the study of animal social learning.<\/p>\n 5. Some great tits are basically born more unhinged than others<\/p>\n Not all tits are the same. Animal behaviour researchers have studied great tits so extensively that individual birds can be placed along personality-like dimensions. Some are cautious and slow to explore unfamiliar environments. Others charge into new spaces, inspect strange objects and generally behave like the bird equivalent of someone who clicks suspicious email attachments just to see what happens.<\/p>\n Culture plays a part of that, but genetics seems to be important too. In an experiment<\/a> spanning four generations, researchers bred great tits according to how quickly they explored a new environment and estimated a realized heritability of about 54% for early exploratory behaviour. Later work has shown that the genetic contribution can change with age, so \u201cpersonality\u201d is not controlled by a single simple switch. But great tits provide unusually strong evidence that consistent behavioural differences can partly run in families.<\/p>\n 6. The bolder ones get around more<\/p>\n Great tits are socially monogamous: a male and female typically form a pair and raise chicks together. But that doesn\u2019t mean some of them don\u2019t like to \u201cget around\u201d.<\/p>\n Researchers genotyped chicks<\/a> from 164 nests and found that 13% of the nestlings had been fathered by males outside the social pair. Almost half of the broods contained at least one extra-pair chick. Intriguingly, bolder, faster-exploring males fathered more young outside their own nests \u2014 although they also tended to lose more paternity at home. In other words, adventurous males apparently gained more affairs without necessarily ending up with more offspring overall.<\/p>\n 7. They pick up accents from other tits<\/p>\n Raise a great tit with blue<\/a> tits and it can pick up the wrong accent. To see just how much social upbringing matters, researchers performed an extraordinary experiment in Norway<\/a>: they moved great tit and blue tit chicks into nests belonging to the other species and allowed them to grow up with foster parents.<\/p>\n The effect on male great tits was substantial. Their adult songs became intermediate between normal great tit and blue tit songs, changing in repertoire, timing and frequency. Several even started producing trilled song types normally associated with blue tits. Great tits, it seems, can grow up sounding conspicuously like the birds that raised them.<\/p>\n 8. City tits have their own dialect<\/p>\n Given how cultural they are, and how they can even pick up dialects form other species, it shouldn\u2019t come as a surprise that they can also adapt their own dialects. A great tit trying to impress a mate beside a busy road faces a basic communications problem: traffic is loud. Because much urban noise occurs at relatively low frequencies, low-pitched components of birdsong can simply disappear into the background.<\/p>\n When researchers compared<\/a> great tits from 10 European cities, including London, Paris, Amsterdam and Prague, the urban birds consistently sang with higher minimum frequencies than nearby forest birds. Their songs were also shorter and delivered faster. Other experiments have supported the idea that higher-frequency songs can be easier to detect through urban noise. City birds<\/a> haven\u2019t stopped singing; they\u2019ve changed the pitch.<\/p>\n 9. Cities are literally draining the colour out of them<\/p>\n You\u2019re probably starting to see the pattern here: cities are changing great tits. One of the great tit\u2019s defining features is its bright yellow belly, coloured partly by carotenoid pigments obtained through its diet. But if you compare city birds with their woodland cousins, something odd emerges: urban great tits tend to look paler and less intensely yellow.<\/p>\n A 2023 study combined<\/a> observations from populations across Europe, an experiment in Sweden and a meta-analysis of previous research. It found consistent evidence for what scientists wonderfully call \u201curban dullness.\u201d The differences appear to arise largely from environmental conditions<\/a> experienced after the birds leave the nest rather than simply from cities containing genetically drabber birds. Even great tits, apparently, become washed out by metropolitan life.<\/p>\n 10. One tiny artificial light can wreck half their night\u2019s sleep<\/p>\n Oh yeah, did we mention that cities are affecting great tits? Turns out, humans aren\u2019t the only animals whose sleep is being ruined by artificial lighting. Researchers studying wild female great tits placed a small LED inside nest boxes during the breeding season. The illumination was just 1.6 lux \u2014 dim by human indoor-lighting standards.<\/p>\n But for the birds, the effect was enormous<\/a>. Under the artificial light, females fell asleep about 95 minutes later, woke around 74 minutes earlier, and slept roughly 56% less than on the previous dark night. The following night, after darkness returned, they slept more than usual, suggesting a rebound after sleep loss. So yes: great tits<\/a> can apparently experience the bird equivalent of staying up all night staring at a screen and regretting it the next morning.<\/p>\n 11. Natural selection seems to care about the size of their little black necktie<\/p>\n Male great tits have a black stripe running down their chest and belly, usually called a \u201ctie.\u201d It isn\u2019t merely decorative. The ornament has been linked to social signalling and mate choice, and its size varies considerably between males.<\/p>\n But here\u2019s the strange part: the direction of natural selection<\/a> on tie size may reverse depending on where the bird lives. Researchers followed male great tits in Barcelona<\/a> and a nearby forest for 17 years. In the forest, males with larger black ties had better survival prospects. In the city, the opposite pattern emerged: smaller-tied males survived better. The researchers suggested that different personality traits<\/a> associated with the ornament might be favoured in different environments.<\/p>\n 12. They can rearrange their song repertoire in a week because somebody annoyed them<\/p>\n In one experiment, researchers played territorial male<\/a> great tits recordings designed to simulate another male singing nearby. Birds exposed to an unfamiliar song showed a remarkable turnover in the songs they actually used: over roughly one week, some song types disappeared from their active repertoire while others appeared. <\/p>\n The total number of songs remained fairly stable, and the birds weren\u2019t simply copying the intruder \u2014 none of the apparently new songs accurately reproduced the unfamiliar recording. The researchers argued that a social challenge could cause great tits to rapidly reorganize which songs they pull out of their musical arsenal.<\/p>\n So, the next time you see a great tit bouncing harmlessly around a garden feeder, remember what you\u2019re actually looking at.<\/p>\n A culturally conformist, milk-stealing, genetically promiscuous, accent-changing, rapidly evolving songbird that occasionally locates sleeping bats by sound, drags them from their hiding places and eats their brains.<\/p>\n Christmas cards really undersold them.<\/p>\n<\/a>Image in Creative Commons.<\/p>\n<\/a>Image via Wikipedia.<\/p>\n<\/a>Great tit postcard. Image in Creative Commons.<\/p>\n<\/a>A great tit in Bulgaria. <\/p>\n