Tag Archives: behavioural ecology

Clever crows can plan for the future like humans do

Clever crows can plan for the future like humans do

(Markus Boeckle And Professor Nicky Clayton 14 July 2017)

This contrasts with all of the previous studies in future planning, which have focused on naturally occurring behaviour. For example, we know that California scrub jays cache their food according to their future needs. And that bonobos, chimpanzees and orangutans select, transport and save appropriate tools for future needs.

General intelligence

These studies have shown that animals can plan for the future – but they left an important question open for debate. Are animals only able to plan to use abilities that have evolved to give them a specific advantage, or can they flexibly and intelligently apply planning behaviour across various actions? Most critics would say the former, as the animals were tested in naturally occurring behaviours.

But the new research provides the first compelling evidence that animal species can plan for the future using behaviour that doesn’t typically occur in nature. This supports the view that at least some cognitive abilities in animals don’t evolve just in response to specific problems. Instead, it suggests that animals can apply these behaviours flexibly across problems in a similar way to humans.

It seems that, in corvids and apes, intelligence is not a system to solve a predefined set of problems (dedicated intelligence) but rather a computational system to improvise new solutions (improvisational intelligence). But it is still unclear what this cognitive system exactly is and how it evolved.

What’s needed now is neuro-biological evidence of general intelligence in animals. We also need to investigate how flexible and improvisational behaviour evolved. Then we might be able to see how crows’ ability to plan for the future fits in with their broader cognitive powers.

Humans aren’t as unique as we used to think. Not, at least when it comes to making plans for the future. Scientists originally thought humans were the only animals that made plans but, over the past decade, studies on non-human primates and the crow family have challenged this perspective.

For example, we’ve seen that these animals are able to store tools for later use, cache food in places where it will be needed the most, and hide pieces of the sort of food they know will be running low in the future.

In all these studies, the animals had to consider what to do, where to do it and when to prepare for certain specific future events. The latest research shows that ravens can indeed anticipate the “what, where and when” of a future event on the basis of previous experiences. But unlike the previous studies, this work tested the birds in behaviour they don’t normally show in the wild. This provides evidence that they have a much more general ability to plan for the future than previously thought.

Food hoarding is common in members of the crow family (corvids) because they often eat from perishable animal carcasses, which provide lots of food but are only available for a short amount of time. To create a suitable cache of food they need to work out what to store, where to put it and when to do so.

The new study, published in the journal Science, tested the birds outside this naturally occurring behaviour, which may have evolved specifically because it gives crows a survival advantage. Some crow species are known to naturally use tools to retrieve food. So the researchers tested whether the birds could store and retrieve a tool so they could get at their food after a gap of 17 hours – something we wouldn’t expect them to do naturally. The scientists didn’t give the birds a chance to learn this behaviour first but they were still able to instantly select the tool out of a number of unnecessary items.

In another experiment, the researchers taught ravens to select a token from a number of items that they could then exchange for food. Again, the birds then showed that they could plan for the future using this new behaviour. They were able to store this token and then retrieve and use it when they were offered the chance to exchange it for food 17 hours later.

This contrasts with all of the previous studies in future planning, which have focused on naturally occurring behaviour. For example, we know that California scrub jays cache their food according to their future needs. And that bonobos, chimpanzees and orangutans select, transport and save appropriate tools for future needs.

General intelligence

These studies have shown that animals can plan for the future – but they left an important question open for debate. Are animals only able to plan to use abilities that have evolved to give them a specific advantage, or can they flexibly and intelligently apply planning behaviour across various actions? Most critics would say the former, as the animals were tested in naturally occurring behaviours.

But the new research provides the first compelling evidence that animal species can plan for the future using behaviour that doesn’t typically occur in nature. This supports the view that at least some cognitive abilities in animals don’t evolve just in response to specific problems. Instead, it suggests that animals can apply these behaviours flexibly across problems in a similar way to humans.

It seems that, in corvids and apes, intelligence is not a system to solve a predefined set of problems (dedicated intelligence) but rather a computational system to improvise new solutions (improvisational intelligence). But it is still unclear what this cognitive system exactly is and how it evolved.

What’s needed now is neuro-biological evidence of general intelligence in animals. We also need to investigate how flexible and improvisational behaviour evolved. Then we might be able to see how crows’ ability to plan for the future fits in with their broader cognitive powers.

Lost in translation: To the untrained zebra finch ear, jazzy courtship songs fall flat

(Physorg 10 July 2017)

Zebra finches brought up without their fathers don’t react to the singing of potential suitors in the same way that female birds usually do, hinting that the environment in which the birds are raised can have a determining effect on their behaviour.

The finding, published in the Proceedings of the Royal Society B by McGill researchers, highlights how learning and experience, including developmental auditory experience, can shape how the brain perceives vocal signals.

The research adds to a growing body of evidence underscoring how specific experiences are necessary to shape the developing brain, and how the absence of specific inputs can have long-lasting effects on perception, neural processing, and behaviour.

Songbirds use courtship signals such as song to identify individuals and select a mate.

Zebra finch males each produce a single song, but they perform a “better” version when courting a female. There is accumulating evidence that females choose mates based on how well their potential suitor performs this “improved version”, providing information about his quality, condition and fitness.

Given the importance of being able to judge the subtle difference in the male zebra finches’ song, scientists imagined this skill to be innate within female zebra finches. To test that idea,

Sarah Woolley, professor at McGill’s Department of biology, and graduate student Nancy Chen decided to investigate how developmental exposure to adult male song might affect behavioural responses to song in female zebra finches.

“Because females use song in selecting a mate, we expected that females might have an inherent bias to recognize and prefer high-performance songs”, professor Woolley says.

Surprisingly, they found that a bird’s capacity to distinguish courting versus non-courting singing greatly depends on its upbringing.

Female zebra finches brought up with both of their parents reacted in the “normal” way and preferred the courtship songs of potential suitors. Females reared without their father’s songs didn’t consistently prefer high-performance courtship songs.

In other words, female zebra finches need to hear dad’s singing to help her distinguish which suitor sings best.

“In the wild, females would rarely be raised without a father/tutor,” professor Woolley notes. “That said, it could mean that the environment that birds are raised in will influence song preferences. We already know that male birds can shift their songs to make them easier to hear in noisy, urban environments. Our data could mean that the ability of females to detect those songs may be affected by what they hear when they are young.”

Touchscreen test reveals why some birds are quicker to explore than others

(Science Daily 10 July 2017)

Birds such as parrots and crows have been using touchscreen technology as part of an international research study examining whether the ways in which animals respond to new things influences how eager they are to explore.

The new research, involving scientists from across Europe, looks at how a number of factors affect the speed and frequency with which the birds investigate new objects that they have never seen before.

The study was carried out by researchers from the Messerli Research Institute (University of Veterinary Medicine Vienna) and the University of Vienna in Austria, the Max Planck Institute for Ornithology in Germany and University of Lincoln, UK.

It has generally been assumed that neophobic species (species that do not like new things) have a tendency to explore less than those that do (referred to as neophilic). For example, kea parrots in New Zealand have been known to destroy cars because they are so interested in new things.

The research results reveal that the neotic style of a bird (how neophobic or neophilic an animal is) has an impact on when they choose to explore new objects, but not on their level of exploration. Those who are more neophobic carry out the same amount of exploration, but simply make the approach much later. The results also show that juvenile animals explore more quickly than adults do.

Significantly, the scientists found that individual differences and characteristics seem to be much more important than species-level differences in determining how eager a bird is to explore. This suggests that neotic style is not, as is frequently assumed, a result of the challenges faced by an entire species, but instead appears to differ depending on the individual bird.

As part of the investigation, the parrots and crows were introduced to a touchscreen which revealed two different coloured shapes on a regular basis, and they were trained to understand that choosing one of the shapes (by pecking it) could result in a food reward. The researchers showed each bird 16 pairs of shapes, and throughout the task introduced a few novel stimuli that they had never seen before. The researchers measured how quickly they responded to the new shapes, and at which point in the test they chose to investigate them.

Dr Anna Wilkinson, a specialist in animal cognition from the School of Life Sciences at the University of Lincoln, explained: “Rather than its species, we found that individual differences have a significant impact upon how quickly a bird begins to explore. This is likely to be due to a combination of the bird’s age, its individual position in the social hierarchy, and its own previous experiences.”

The birds that featured in the study were from nine different species of parrots and corvids — also known as the crow family. They were selected to represent different ecological backgrounds so that factors such as the likelihood of pressure from predators could also be taken into account. For example, species originating from islands such as Goffin’s cockatoos and vasa parrots are less likely to face pressure from predators than those such as ravens, jackdaws and African grey parrots, which are much more widely distributed.

As part of the study, researchers worked with Eclectus parrots from the Lincolnshire Wildlife Park to assess their reactions.

The first author of the study, Dr Mark O’Hara from the Messerli Research Institute and the University of Vienna, said: “Our findings allow for a more accurate interpretation of behaviour and the processes which control responses to changes in the environment.”

The full paper, The temporal dependence of exploration on noetic style in birds, is published in Scientific Reports.

Palm cockatoos beat drum like Ringo Starr

(Physorg 28 June 2017; Photo C. Zdenek)

This was slowly acquired over the seven year study by patiently stalking the birds through the rainforest with a video camera.

“Each of 18 male palm cockatoos, known for their shyness and elusiveness, was shown to have its own style or drumming signature,” said Professor Heinsohn.

“Some males were consistently fast, some were slow, while others loved a little flourish at the beginning.

The palm cockatoo drumming is part of the species courtship ritual that involves a lot of calls and movements to attract a mate.
The research is part of a broader study of the palm cockatoo’s conservation needs on Cape York Peninsula where they suffer low breeding success and loss of habitat due to mining activity.

Professor Rob Heinsohn said while songbirds and whales can belt out a musical tune, few species recognise a beat.

But the shy and elusive palm cockatoo, iconic to Cape York Peninsula in far North Queensland, plays the drums and crafts the sticks.

“The large smoky-grey parrots fashion thick sticks from branches, grip them with their feet and bang them on trunks and tree hollows, all the while displaying to females,” said Professor Heinsohn, from the ANU Fenner School of Environment and Society.

“The icing on the cake is that the taps are almost perfectly spaced over very long sequences, just like a human drummer would do when holding a regular beat.”

Professor Heinsohn said the palm cockatoo’s ability to drum has been known for a long time but this is the first research to secure the footage to analyse it.

The trouble with being a handsome bird

(SD, Monash University 28 June 2017; Photo Kaspar Delhey)

Male birds often use brightly colored plumage to be attractive to females. However, such eye-catching trimmings may also attract unwanted attention from predators. Now, a new study led by Monash University has found that showy males indeed perceive themselves to be at a greater risk of predation.

The study’s lead author, PhD student Alex McQueen, from the School of Biological Sciences, studied risk-taking behaviour in Australia’s favourite bird, the superb fairy wren, also known as the blue wren. Every year, male wrens change their color from dull brown to a stunning combination of brilliant azure blue, with contrasting dark-blue and black plumage.

This annual color change makes them a useful study species for measuring the risk of being brightly colored, as the behaviour of the same individual bird can be compared while he is in different colors.

As part of this study, published in the Royal Society Journal Proceedings B, researchers snuck up on unsuspecting fairy-wrens. They then broadcast fairy-wren alarm calls from portable speakers, and observed the behaviour of the birds.

“When birds hear such alarm calls, it tells them there might be a predator nearby,” says Alex. “Whether they ignore the alarm or flee to cover, and the amount of time taken to re-appear from cover, tells us how high they perceive their predation risk to be.

“We found that fairy-wrens were more cautious while they were bright blue: they fled more often in response to alarm calls, and took longer to re-emerge from hiding. They also spent more time in cover, and more time scanning their surroundings.”

Alex’s supervisor, Associate Professor Anne Peters said an interesting observation was that brown fairy-wrens appeared to take advantage of the risks faced by blue males.

Fairy-wrens go about in social groups, often made up of individuals in different plumage colors.

“When a blue male was nearby, fairy-wrens spent less time hiding in cover after fleeing in response to alarm calls, and devoted less time to keeping a look-out,” Associate Professor Peters said.

“This could be because the dull brown wrens view blue males as a colorful decoy that reduces their own risk, or because blue males are more vigilant, allowing the brown wrens to drop their guard.”

The study, which was done in collaboration with Professor Rob Magrath from the Australian National University (ANU), shows that fairy-wrens perceive themselves to be at higher risk when they display their bright blue plumage, and adjust their behaviour accordingly.

Högsta hönset – en personlighetsfråga?

gammalsvensk_dvärghöna.jpg

(Marie Mattsson 11 juni 2017; Foto Anna Favati)

Länge har det funnits evolutionära modeller som bygger på att djur är optimalt anpassade som konsekvens av det naturliga urvalet. Men djurindivider kan ha olika personligheter och därmed kan deras beteende ibland te sig icke-optimalt. I flera svenska studier har forskare försökt reda ut hur och varför djur har personlighet med hjälp av gammalsvenska dvärghöns.

Forskning kring att djur har personlighet är något relativt nytt. Med personlighet hos djur menar man att individer beter sig olika varandra, men relativt lika sig själva över tid och i olika situationer. Trots tidiga observationer av att individer kan skilja sig åt i beteenden, började personlighetsforskning hos djur först i början på 2000-talet.

Hur ser då personlighet hos ett djur ut? Hanne Løvlie är etolog vid Linköpings universitet och har forskat mycket på höns och dess vilda anfader djungelhönset.

– Att djur har olika personlighet är något som ifrågasätter idén att djurs beteenden är optimala då det kan leda till att till exempel en tuff individ är tuff också när det kan vara farligt, och en feg individ kan vara feg när det istället kanske kan löna sig att vara tuffare, berättar Hanne Løvlie.

Olika personlighetstyper kan ha olika överlevnadsstrategier

Precis som hos människan utvecklas djurens personlighet genom både arv och miljö. De flesta djur lär sig hur de ska reagera på olika saker, men de har inte obegränsat med energi, tid och kapacitet, och måste därför göra avvägningar. För ett djur kan responsen inför en situation vara en fråga om liv eller död.

–  Personligheter kan även hittas hos ryggradslösa djur. En av de allra första studierna av djurs personlighet gjordes faktiskt på spindlar. Där kunde man se att beteenderesponserna skilde sig mellan olika individer, vissa var onödigt aggressiva när aggression inte behövdes. Responser behöver inte vara antingen eller, det kan finnas flera steg på skalan mellantvå extrema sätt att reagera, säger Hanne Løvlie.

Variation i personligheter kan vara olika strategier som påverkar till exempel överlevnad. Det har gjorts studier med bland annat talgoxe där man sett att vissa personligheter överlever bra under vissa förhållanden, medan andra personligheter fungerar bättre i andra situationer. Ett utforskande och risktagande karaktärsdrag hos en hane kommer exempelvis till nytta efter en vinter med gott om mat då det sedan blir hård konkurrens om häckningsrevir, medan en mer passiv hane sparar energi och kan ha en större chans att överleva under vintrar då det istället är ont om mat.

Höns är bra forskningsobjekt

Tillsammans har Anna Favati, doktorand i etologi vid Stockholms universitet, och Hanne Løvlie har gjort flera studier på hönsrasen gammalsvensk dvärghöna, en nära släkting till röd djungelhöna som är ursprunget till de flesta tamhönsarter. Dvärghöns lämpar sig bra för den här sortens forskning eftersom de inte är så hårt avlade utan beter sig som den ursprungliga hönset.

–  Hönsen i studierna är tama vilket gör dem lätta att observera, samtidigt som de ger relevant information eftersom de är nära ursprunget i sitt beteende, berättar Anna Favati.

Höns är en grupplevande art, som under naturliga omständigheter lever i grupper med ett par tuppar och något fler hönor. De bildar inte par, utan båda könen har många sexuella partners, och för tupparnas del leder det till hög konkurrens om hönorna. Både tuppar och hönor bildar tydliga dominanshierarkier. Det är som en trappstege där de högst upp har främst tillgång till resurser som exempelvis mat eller, i hanarnas fall parningar. När den sociala ordningen väl är upprättad behöver tupparna oftast inte slåss mer, utan hackordningen blir stabil och leder till att det är få onödiga slagsmål och konflikter.

Vad kom först; hönan eller ägget?

Man vet att det finns ett samband mellan dvärghönsens personlighet och rang, men hur kommer det sig? I en av studierna så tittade man på om det finns ett samband mellan hierarki och personlighet hos höns. Individer beter sig olika beroende på var de befinner sig i rangordningen, men har en viss individ större chans att stå högt i rang på grund av sin personlighet eller har den fått personligheten tack vare sin position i hierarkin? För att undersöka kopplingen mellan personlighet och rang började forskarna med att kategorisera tupparnas personlighet genom att titta på hur de reagerar i olika situationer.

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Genetic differences across species guide vocal learning in juvenile songbirds

songbird

(Physorg 12 June 2017)

Juvenile birds discriminate and selectively learn their own species’ songs even when primarily exposed to the songs of other species, but the underlying mechanism has remained unknown. A new study, by researchers at Uppsala University, shows that song discrimination arises due to genetic differences between species, rather than early learning or other mechanisms. The results are published in Nature Ecology & Evolution.

Songbirds are our primary animal model for studying the behavioral and neural basis of vocal learning and memory formation in general. The tremendous variety in the songs of birds delights ornithologists and fascinates evolutionary biologists as a marker of species diversity. Explaining how species differences in song are maintained is a challenge because birds typically learn their songs by imprinting on songs heard when they were juveniles. What prevents juveniles from imprinting on the songs from a wide-variety of other species in their environment? When exposed to a mixture of different songs from their own and other species, juvenile songbirds discriminate and selectively learn songs typical of their own species, which suggests a remarkable fine-tuning of sound perception during the earliest stages of development. Despite the importance of these findings for our understanding of the vocal learning process, the mechanism underlying early song discrimination has remained unknown.

A new study by researchers from Uppsala University in Sweden resolves this mystery by first demonstrating that juvenile pied and collared flycatchers from the wild discriminate their own species’ songs before they’ve left the nest. Nestling flycatchers as young as 10 days old look at the sound source and produce more begging calls during experimental playbacks of their own species’ songs than to playbacks of the other species’ songs, demonstrating that song discrimination develops incredibly early in these two species. Next, the researchers swapped developing eggs from the nests of each species so that they were raised completely by parents from the other species. These nestlings also discriminated in favor of their own species’ songs, despite having no experience with their own species, demonstrating that song discrimination is not a result of early learning. Finally, to definitively show that genetic differences between species underlie discrimination, the researchers showed that hybrid nestlings formed as a result of matings between parents from each species discriminate in favor of the songs of one of the species, the pied flycatcher. Taken together, these results show that song discrimination has a genetic basis.

‘Song differences across species are vital for birds to choose appropriate mates and negotiate complex social interactions. A genetic basis for song discrimination in early life may help explain how song differences are maintained in a noisy, diverse world’, says David Wheatcroft, researcher at the Department of Ecology and Genetics at Uppsala University and co-author of the study.

The song learning process in birds and the language learning process share remarkable behavioral and neural parallels. One of the longest standing problems has been to determine how the brain encodes the vocal memories that underlie learning. The results of this study suggest that this process begins with a genetic blueprint expressed early in life.