Tag Archives: animal behaviour

AlpineSwift

These migrating birds fly non-stop for six months

AlpineSwift

All migrating animals, whether they do it by walking, swimming or flying, are nothing less than amazing. The intense energy expenditure most migrating species make to reach breeding grounds or safe, warm areas is absolutely amazing. Even after traveling thousands of miles away from home, animals like the freshwater salmon still know how to make their way back with pinpoint accuracy. The Alpine swift, a swallow-like bird species, is perhaps particularly impressive in its migrating pattern. This remarkable bird leaves its breeding grounds in Switzerland every winter to travel to the warmer shores of west Africa. The birds make this journey in six months, time in which they never stop flying! Actually, there’s very little evidence to suggesting how long they sleep.

Researchers had been suspecting that the Alpine swift was a remarkable migratory bird for some time, however, it was only after scientists at the Swiss Ornithological Institute and the Bern University of Applied Sciences in Burgdorf, Switzerland studied them very closely that the extent of their migratory capabilities surfaced.

Six birds were captured and fitted with a small device that logged acceleration and ambient light during the course of a year-long migration cycle that began and ended in Switzerland. Only three of them were eventually recaptured but this proved enough to reveal how the Alpine swift migrates.

Using data provided by the accelerometer, the researchers could accurately assess when the birds flapped their wings vigorously, when they glided or when they rested. The birds appeared to glide and flap throughout their entire migration across the Sahara Desert and their overwintering period in sub-Saharan West Africa. Apparently, the birds only rested their wings entirely during the breeding season in Switzerland.

“Their activity pattern reveals that they can stay airborne continuously throughout their nonbreeding period in Africa and must be able to recover while airborne,” the team writes in the report. “To date, such long-lasting locomotive activities had been reported only for animals living in the sea.”

Wait a minute? Where do these birds get all their energy – don’t they stop to eat or sleep? Whales and various migrating fish species also travel for months at a time without stopping. These swimming animals feed on the move on marine plankton. Similarly, the Alpine swifts feed mid-flight on an array of tiny bacteria, fungus, seeds, spores and small insects that get caught in air currents.

Observations show that the birds alternate between vigorous flapping and gliding when they rest. Still, the clear lack of significant resting periods suggests that the birds do not need as much sleep to perform their migration as previous research has suggested. It’s worth noting that while some marine migratory animals may swim just as long and continuously as the Alpine swift, the former have the advantage of exploiting buoyancy and thus conserve energy.

“We cannot rule out that the Alpine swifts may interrupt their flight for a few minutes,” the team writes. “Nevertheless, they must be able to accomplish all vital physiological functions in flight over a period of several months.”

I can barely perform them in bed. Well played, Alpine swifts.

The researchers detailed their findings in a paper published in the journal Nature Communications.

animal_power_line

Power lines may be absolutely terryfing animals and disrupt herding

animal_power_line

High voltage power lines aren’t quite the safest places to be around, especially if you’re a large animal or bird and touch two different conductors, thus creating a voltage difference which kills on the spot. Apparently, though, not too many animals wonder near power lines. Roads are known animal traffic disruptors, but even power lines stretched across isolated portions where there aren’t any roads still keep animals away. A possible explanation for this is that the electricity flowing through power lines looks terryfing to them, thus discouraging the animals from coming in the vicinity. If this is found true, it could potentially have important implications from an environmental perspective, as power lines should be designed to cross areas where there’s a low risk of disrupting herding paths and flock patterns.

Power lines may look scary to some humans too, but when some animals gaze them they see something much different. Researchers in Norway and the United Kingdom recently proposed that animals keep away from high voltage cables because of their ability to see ultraviolet light frequencies. This spectrum is totally invisible to humans, hower some animals, especially those that have developed nocturnal vision, can see it. These include critters like birds, rodents and some species of large mammals like raindeer. The scientists write:

“We suggest that in darkness these animals see power lines not as dim, passive structures but, rather, as lines of flickering light stretching across the terrain. This does not explain avoidance by daylight or when lines are not transmitting electricity … but it may be an example of classical conditioning in which the configuration of power lines is associated with events regarded as threatening.”

So what do these animals see? It’s impossible to undertand how they see it through their own eyes, but using cameras mounted with UV sensing one can get an idea. Basically, they should be seeing random flashing bands filled with flickering balls of light. This means that even in the dark, what to use humans is nothing but pitch black, power lines may look like alterating bands of light that could frighten them. The video below shot from a helicoper hovering over power lines gives you an example.

This suggests that it’s not noise or traffic that discourages animals coming too close, and thus disrupt habitats through the areas crossed by power lines, but something more suble and impernetrable to the human eye. The cables probably interfere with migration routes, breeding grounds, and grazing areas, which could fragment natural habitats and cause herds to shrink, and the ramifications this may pose to local ecosystems are just begining to be understood. For residents in Norway where a 86-mile-long power line through the northern part of the country is planed the research is of immediate interest. Already, local groups have voiced their disapproval of the project citing herding disruption.

The findings were reported in the journal Conservation Biology.

aggressive-dog

Breed not the dominant factor in canine aggressiveness

aggressive-dog

Photo: dogsense.co.uk

It’s always depressing when we hear stories of dogs attacking people, more so when injuries lead to death. As always after such an unfortunate, yet statistically isolated, event there’s always a massive group of people bantering and calling for “something to be done.” In some countries, public pressure can rule death sentences for thousands of dogs. There’s also a general belief that some breeds are more aggressive than others. Is the breed or the dog’s education the dominant factor that makes it aggressive? Is a pit bull more likely to bite you because of its breed or because the owner trained him to behave this way?

In a recent article for Real Clear Science, Rachel Casey a senior lecturer in companion animal behavior and welfare at University of Bristol, details her team’s findings recently reported in a paper published in journal Applied Animal Behaviour.

Bad, bad dog!

Some 4,000 dog owners were surveyed regarding their pet’s aggressive behaviour, like incidents of growling, lunging, barking and biting. Occurrence of these stances was assessed in three distinct situations: towards family members; towards unfamiliar people entering the house; towards unfamiliar people outside the house. Characteristics for both owner (i.e. age) and dog (i.e. breed) were recorded.

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Their findings show that dogs generally tend not to show aggressiveness in more than one of the three situations. Thus, a dog that might be aggressive to family members, won’t be aggressive towards outsides and vice versa. This suggests that some dogs aren’t by default vicious or friendly to the bone in all situations.

Casey outlines in her article that it’s important for people to understand that any dog can turn aggressive given the right circumstances. This is no reason to marginalize canines, however. Instead, being conscious about it may help people avoid stumbling into false assumption traps.

The study compared breed groups in each situation with a reference category of cross-breeds. No difference in aggressiveness was observed in a family setting between pure breeds and cross-breeds. For aggression toward unfamiliar people, gundogs (hounds, retrievers and pointers) had a reduced risk compared to cross-breeds, and pastoral or herding dogs (for example German shepherd dogs) had an increased risk specifically when outside the house.

Measuring behaviour, instead of skull size

The difference was no more than 10%, however, between aggressive and non-aggressive dogs. Different breeds vary in behaviour, and any dog owner or knowledgeable person can attest this fact. The limited research carried out in this respect, however, so far shows that in evaluating aggression risk for an individual dog, there are more important factors to consider than its breed.

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 Even so, considering all dogs are more or less equal in their innate aggressiveness and this behavior is most heavily dependent on its environment (owner), are some of the existing policies that ban certain large breeds warranted? The idea is that a nutcase owner might turn his dog into a munching machine whether its a chihuahua or a rottweiler. The key difference is that the latter has the power to rip you to shreds. Casey claims there is no hard evidence suggesting this practice works, reducing the number of injuries.

“Policy should instead focus on the factors that influence the risk of aggression in the first place. Most people object when governments take the approach of banning things – imagine the cries of “nanny state” if fast cars were banned from the roads on account of their greater likelihood of causing injury than less powerful vehicles if driven irresponsibly. In reality, society takes the approach of reducing the risk posed by all drivers, regardless of what car they drive,” says Casey.

“Every new driver is given a thorough education, which is bench-marked by a standard theoretical and practical driving test. We have well-established, and largely accepted, codes of practice that govern drivers’ behaviour to reduce accident risk, and laws to enforce them. It would make sense to take the same approach for reducing aggression towards humans in dogs,” she continued.