Drought in the Horn of Africa Delays Migrating Birds

Iturria: Science Daily

ScienceDaily (Dec. 6, 2012) — The catastrophic drought last year in the Horn of Africa affected millions of people but also caused the extremely late arrival into northern Europe of several migratory songbird species, a study published December 6 in Science shows. Details of the migration route was revealed by data collected from small backpacks fitted on birds showing that the delay resulted from an extended stay in the Horn of Africa.

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Thrush nightingale. (Credit: Mikkel W. Kristensen)

The extensive 2011 drought in the Horn of Africa had significant consequences for European songbirds such as thrush nightingale and red-backed shrike. These birds visit northern Europe every spring to mate and take advantage of ample summer food resources.
However, their spring migrating route from southern Africa to northern latitudes passes directly through the Horn of Africa, where the birds stop to feed and refuel for the next stage of their migration.
"Our research was able to couple the birds' delayed arrival in Europe with that stopover in the Horn of Africa. Here they stayed about a week longer in 2011 than in the years before and after 2011. Because of the drought, the birds would have needed longer to feed and gain energy for their onward travel, causing delayed arrival and breeding in Europe. This supports our theory that migrating animals in general are dependent on a series of areas to reach their destination,"says Associate Professor Anders Tøttrup from the Center for Macroecology, Evolution and Climate at the University of Copenhagen.
Data loggers as a backpack
The late spring arrival of European songbirds such asthrush nightingale and red-backed shrike perplexed researchers and bird watchers in 2011.
This mystery was even greater considering these songbirds' tendency to arrive progressively earlier over the last 50 years as climate change has made its impact.
By placing small data loggers on the backs of several birds in the autumn before their migration to Africa, and retrieving them in the spring when the birds returned to Europe, the scientists were able to trace the migration route and stopover sites. These data revealed a delay in the particular stopover in the Horn of Africa. Additionally, it was noted that other migrating birds not passing through the Horn of Africa arrived in Europe at the expected time.
"We have reconstructed 26 migration routes based on data from the small 'data backpacks' weighing just 1 gram. This new technology provides us with a detailed picture of the birds' migration and stopovers. It is brand-new territory to be able to track animals this small over such great distances," says Associate Professor Kasper Thorup from the Center for Macroecology, Evolution and Climate at the University of Copenhagen.
Delayed breeding
The birds' late arrival in 2011 also meant a similarly late breeding year.
"There are no signs of implications on the birds' breeding success and thereby the size of the population. But it is possible that we haven't yet seen the full effect of the delayed year," concludes Anders Tøttrup.
The research was carried out in collaboration with Lund University in Sweden.

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Story Source:
The above story is reprinted from materials provided by University of Copenhagen.

Strategies to Prevent Others from Stealing Food

Iturria: Science Daily

ScienceDaily (Dec. 4, 2012) — In order to prevent other birds from stealing the food they are storing for later, Eurasian jays, a type of corvid, minimizes any auditory hints a potential pilferer may use to steal their cache (food that is buried for later use). The new research was published December 5, in the journal Proceedings of the Royal Society B.

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This is an Eurasian jay. (Credit: Kylie Millar)

Corvids are prolific cachers (or hoarders), burying food such as acorns in several thousand locations over the course of a year. When food becomes scarce during winter and spring, they remember where they buried their caches and retrieve the food items. However, pilfering of caches is commonplace. As a result, they are often trying to minimize other birds stealing their food and maximize the food that they steal.
In the first experiment, the researchers gave the jays options to hide food in substrates which varied in the amount of noise they made (a tray containing noisy gravel and a tray containing quiet sand). The birds' preferences for using these different substrates were tested when they were alone, when they had another bird that could see and hear them and when there was another bird that could hear but could not see them.
The researchers found that if a Eurasian jay is caching and hears but does not see another bird nearby it will hide its cache in the less noisy substrate (for this study, sand rather than gravel). This is presumably done to avoid drawing unwanted attention from potential thieves that might then try to view the location of the cache.
In the second experiment, the scientists measured how many times the subjects vocalised depending on whether they were watching another jay caching, another jay stealing caches that the subject had made themselves, another jay that was not caching or stealing, or an empty compartment that contained no jay.
They found that pilfering birds vocalise less when spying on another bird caching compared to when they are alone. The researchers believe that the jays are quieter in order to prevent their presence becoming known to the caching bird that might otherwise hide their cache elsewhere or stop hiding food.
Rachael Shaw, a PhD student at the University of Cambridge and co-author of the paper, said: "As humans, we understand that other people can hear what we are doing, but there is only limited evidence for this ability in other animals. Our study of Eurasian jays is the first to report that a member of the crow family will suppress acoustic information by vocalising less when spying on another individual that is caching."

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Story Source:

The above story is reprinted from materials provided by University of Cambridge. The original story is licensed under a Creative Commons Licence.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Rachael C. Shaw and Nicola S. Clayton. Careful cachers and prying pilferers: Eurasian jays (Garrulus glandarius) limit auditory information available to competitors. Proc. R. Soc. B., 2013 280 20122238 DOI: 10.1098/rspb.2012.2238

Hatching Order Influences Birds' Behavior

Iturria: Science Daily

ScienceDaily (Dec. 7, 2012) — The hatching order of birds influences how they behave in adult life according to research from the Lancaster Environment Centre. Dr Ian Hartley and Dr Mark Mainwaring (LEC) are the authors of the study in Animal Behaviour, which looked at how the birds' behaviour was affected by the way their parents cared for them as hatchlings.

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The youngest members of zebra finch broods are more adventurous than their older siblings in adult life. (Credit: Image courtesy of Lancaster University)

They found that the youngest members of zebra finch broods are more adventurous than their older siblings in adult life.
Dr Hartley said that the study showed for the first time that hatching order influences birds' "behavioural repertoires" in adulthood.
Hatching eggs over a period of time, rather than all at once, is known as "hatching asynchrony" and occurs when eggs are incubated as soon as they are laid. For a zebra finch, this means that birds born up to four days apart can share the same nest and must compete for food.
The researchers experimentally controlled hatching synchrony within clutches, so that some clutches hatched simultaneously, while others hatched over a period of days. They then tested the behaviour of over one hundred offspring as adults. They found the youngest birds from asynchronously hatched clutches explored their environment more widely.
They measured how explorative the zebra finches were by recording how many times they visited bird feeders within an unfamiliar test aviary. They found that the youngest offspring in a brood approached the feeders significantly more often than their peers within a 30 minute period.
Researchers wanted to know how the method of rearing affected the behaviour of offspring beyond the nest, once they were living as independent adult birds. The results have implications for understanding how environmental stability might influence behaviours, and how flexible animals might be at coping with environmental change

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Story Source:

The above story is reprinted from materials provided by Lancaster University.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Mark C. Mainwaring, Ian R. Hartley. Hatching asynchrony and offspring sex influence the subsequent exploratory behaviour of zebra finches. Animal Behaviour, 2012; DOI: 10.1016/j.anbehav.2012.10.009

Ecologists shed new light on effects of light pollution on wildlife

Ecologists shed new light on effects of light pollution on wildlife

Iturria: Science Daily

ScienceDaily (Nov. 27, 2012) — Light pollution is often associated with negative effects on wildlife. Now, ecologists have found that by mimicking a perpetual full moon, the gas flares and electrical lighting along Scotland's Forth estuary are helping shorebirds stock up on more food during the winter to fuel their spring migration.

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VHF tracking in front of Grangemouth refinery. (Credit: Copyright Hamish Campbell)

The research is the first to use night-time light data from US military satellites to study animal behaviour.
Coasts and estuaries are among the most rapidly developing areas on Earth. Night-time satellite images of the planet show that except Antarctica, continents are ringed with halos of brightly-lit human development. But coasts are also key wildlife sites. Every year, millions of waterbirds arrive from the Arctic to overwinter on UK coasts, yet scientists remain largely in the dark about how these birds respond to the bright lights of coastal cities and industry.
To shed light on the issue, Dr Ross Dwyer and colleagues from the University of Exeter's Biosciences department investigated how artificial light affected feeding habits of the common redshank in the Forth estuary, one of Scotland's most industrialised coasts. As well as major industry such as Grangemouth oil refinery and Longannet power station, whose lights and gas flares illuminate the intertidal areas at night, the estuary's pristine salt marsh and mudflats are home to hundreds of thousands of migrating birds each winter.
Dr Dwyer measured the amount of artificial light in the Forth estuary at night using satellite images from the US Air Force. Although they have been previously used to study electrical power consumption, this is the first time such US military data has been used in animal behaviour research.
He then worked out how the light affected the birds' foraging behaviour by attaching tiny radio transmitters to the backs of 20 redshanks. The devices monitored the birds' location and contained posture sensors to detect how often the birds put their heads down to feed.
Generally, redshanks need to forage day and night during the winter to find enough food. These birds usually forage by sight during the day, which provides them with the most food, and less efficiently at night by locating prey by touch using their bills.
The study found that artificial light had a major impact on how redshanks searched for food, allowing them to forage more efficiently. At night, birds in brightly-lit areas foraged for longer and foraged by sight, rather than touch, compared with birds under darker night skies.
According to Dr Dwyer, who was based at the University's Cornwall campus at the time of the study: "Artificial light from industrial areas strongly influenced the foraging strategy of our tagged birds. It was as if the 24-hour light emitted from lamps and flares on the Grangemouth oil refinery site created, in effect, a perpetual full moon across the local inter-tidal area which the birds seemed to capitalise on by foraging for longer periods at night and switching to a potentially more effective foraging behaviour to locate prey."
The results contrast with other studies, which have found adverse effects of light pollution on wildlife. Previous research found artificial light caused newly-hatched turtles to head away from the sea, rather than towards it, and caused seabirds such as petrels to collide with lighthouses and other lit structures.
Named for their long bright orange or red legs, the common redshank is a medium-sized shorebird with a greyish brown back and wings in winter, and a black-tipped orange bill. On their wintering sites, the birds patrol estuaries and coastal lagoons feeding on molluscs, worms and crustaceans. Redshanks are generally very wary and nervous birds. Often the first to panic, they give noisy 'teu-hoo' alarm calls, earning them the nickname 'sentinel of the marshes'.
Redshanks are widely distributed, breeding and wintering across temperate Europe and Asia. Although numbers are in decline, the species is widespread and quite plentiful in some regions, and thus not considered a threatened species by the IUCN.

Vendée Globe: Un oiseau copilote d'Alessandro Di Benedetto (VIDEO)

Iturria: Vendée Globe

Un oiseau copilote d'Alessandro Di Benedetto ? (VIDEO)

Articles | mardi 27 novembre 2012, 11h14

Alessandro Di Benedetto a reçu la visite d'un oiseau sur Team Plastique pour l'aider à barrer son monocoque.

© Alessandro Di Benedetto / Team Plastique

Alessandro Di Benedetto a un copilote par VendeeGlobeTV

Swans Have Crash Landings and Hip Injuries Are More Common Than Previously Thought

Iturria: Science Daily

ScienceDaily (Nov. 26, 2012) — Despite -- or perhaps because of -- their large size, swans seem particularly prone to injury. Known problems include collisions with cars, lead poisoning due to gunshot wounds or ingested foreign bodies and injuries from fishing hooks. Injuries to the birds' hips, however, are believed to be uncommon. Michaela Gumpenberger and Alexandra Scope of the University of Veterinary Medicine, Vienna now present evidence to suggest that such injuries are more frequent than suspected but are under-recorded because of difficulties in diagnosis. They show that computerized tomography is far better suited to examine the hip joint than classical radiographic methods.

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CT image of a swan's hip: the hip joint on the right is intact, the one on the left is dislocated. (Credit: Vetmeduni Vienna/Diagnostic Imaging)

Their results are published in the journal Avian Pathology.
Diagnosing an injury in a swan is a far from easy undertaking. Not only are swans large, frequently weighing over 10 kg, but they are generally not happy at being handled and thus many of them can only be examined after sedation, which naturally represents a risk. The hip joints of many species of bird are known to be vulnerable to injury but swans are believed to suffer broken hips only rarely. The traditional way of examining the birds' hips relies on radiography but Gumpenberger and Scope now show that computerized tomography (CT) gives more reliable findings.
The researchers examined the hip joints of five swans that had been brought to the Clinic for Avian, Reptile and Fish Medicine of the University of Veterinary Medicine, Vienna because they were unable to stand. Radiographs were taken of three of the birds, while all of them were subjected to CT scans. The results were highly illuminating. Radiography gave indications that one of the swans might have problems with its hip joint but the diagnosis was not conclusive and the other two swans examined seemed to have intact joints. In contrast, CT showed correctly that all five swans had lesions of the hip.
Computerized tomography is thus much better able to identify problems with the hip joint than classical radiographic methods. In addition, it is often less stressful for the animals: imaging can be performed without the need for narcosis by simply placing the bird in a darkened cardboard box and allowing it to sit comfortably, whereas radiography of many species requires their sedation.
It seems, then, that hip problems in swans are more common than previously believed. It is likely that the majority of injuries of this kind arise when the birds attempt to land on hard surfaces, when the landing forces are transmitted through their legs to their hips. Of course, such emergency landings may simply be the result of air turbulence but Gumpenberger notes that "many injured swans are found near roads or railway lines, so it is possible that they misinterpret shiny rails or even concrete road surfaces as being water and thus try to land."

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Story Source:

The above story is reprinted from materials provided by University of Veterinary Medicine -- Vienna.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.

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Journal Reference:

1. Michaela Gumpenberger, Alexandra Scope. Computed tomography of coxofemoral injury in five mute swans (Cygnus olor). Avian Pathology, 2012; 41 (5): 465 DOI: 10.1080/03079457.2012.712205