Tag Archives: health

Storkesæsonen fusede ud i regn, rusk og kulde

(Jan Skriver 6 juli 2017)

Forårets spirende optimisme på storkefronten er afløst af kolde kendsgerninger. Danmark huser i år kun to par hvide storke, der trods en lovende start blot har udsigt til tre flyvefærdige unger

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Ynglesæsonen 2017 for den hvide stork i Nordvesteuropa tegnede i det tidlige forår lovende med storkevenligt trækvejr i landene mod sydøst.

Men den vægelsindede april tippede meteorologisk set til den forkerte side set fra en trækkende storks synsvinkel, og maj blev hverken mild eller sød for de storke, der nåede frem.

Så nu kan en skuffende sæson for den hvide stork i Danmark gøres op.

”Facit bliver 2 ynglepar og 2 enlige fugle. De to storkepar vil tilsammen højst få tre unger på vingerne, selv om der har været masser af æg i rederne hos begge par. Desværre blev det kun til enlige storke i Nørreådalen ved Viborg og ligesådan i Bolderslev i Sønderjylland”, siger Hans Skov, der er Dansk Ornitologisk Forenings (DOF) førende ekspert i storke.

”April blev ganske enkelt en træls måned for trækkende storke på vej mod Nordeuropa. Efter en lovende begyndelse kom kulden med nordenvinden, og den holdt storketrækket tilbage, så vi ikke fik et rykind af mulige ynglefugle på de lokaliteter, hvor der var forventninger om ynglepar”, siger Hans Skov.

Massedød i nordtyske reder

Også maj blev præget af regn, rusk og kulde, hvilket resulterede i, at de etablerede storkepar mistede unger. I Gundsølille ved Roskilde har 7 æg resulteret i 2 unger, som ser ud til at klare sig. Og i Smedager i Sønderjylland endte 5 æg med at blive til kun en unge, som i skrivende stund er cirka tre uger gammel og i dunet dragt. Den skal helst have tørt og gerne lunt vejr de næste uger, hvis den skal blive flyvefærdig.

”Når storkeunger bliver så store, at forældrene ikke længere kan ligge og varme dem i reden, opstår en kritisk periode. Hvis der kommer store mængder af regn, mens det blæser kraftigt, bliver de dunede unger så nedkølede, at de dør af kulde. Det er sket i år i stor stil lige syd for den dansk-tyske grænse i det ellers storkevenlige og føderige Sydslesvig. Her er cirka 40 procent af alle storkeunger døde, fordi vejret har været imod ynglefuglene”, fortæller Hans Skov.

Udsigt til gode år i Nørreådalen

DOF’s storkeekspert, der i fire årtier nøje har fulgt udviklingen i den danske storkebestand, var i april optimistisk på vegne af Nørreådalen ved Viborg, hvor der i 2016 etablerede sig et storkepar, som dog kom for sent i gang til at yngle med succes. Parret etablerede sig sidste år først mod slutningen af juni.

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Hidden feather patterns tell the story of birds

(Richard Banat 5 June 2017)

Shearwaters are migratory marine birds that travel in a figure-of-eight pattern between the coasts of Siberia and Japan to Tasmania.

 

Placing one of the undistinguished grey feathers from a shearwater into the brilliant light of the X-ray fluorescence microscopy beam reveals something unexpected. We see intricately patterned deposits of chemical elements that tell the story of how a feather grows.

Among other findings, the images show strikingly regular bands containing zinc. There are roughly the same number of bands as the estimated number of days of feather growth.

Different from simple feather growth bars, these patterns were not known before our study, published this month.

Like the annual growth rings of trees, birds’ feathers lay down growth bars during their moult. (Moulting is the process of shedding old feathers, making way for new ones to grow.)

While bars simply show growth, the patterns of chemical elements tell us about the bird’s life during the growth period of the feather. They can indicate environmental exposures in a bird population, perhaps before impacts such as illness and death are clear.

We think the zinc banding may be a natural diurnal (daily) time stamp locked up within the feather. If confirmed, it’s a finding that may be applicable for retrospective dating of the occurrence of stressful events – for example, the temporary exposure to environmental contaminants such as heavy metals – during the period when birds grow new feathers.

In addition to zinc, other elements detected in feathers include calcium, bromine, copper and iron, each with its own unique pattern of distribution.

The team, including field researcher Jennifer Lavers, analysed feathers painstakingly sampled from remote locations in Japan, as well as Lord Howe Island and New South Wales, and complemented by feathers from the Australia Museum collection in Sydney.

The bulk of the work investigated feathers from three species of shearwaters who migrate more than 60,000km over open ocean each year, to and from their breeding areas.

Foraging across huge areas, shearwaters are important indicators of environmental health. As described by Nobel Laureate and author Peter Doherty in his book Sentinel Chickens:

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Watching birds near your home is good for your mental health

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(University of Exeter, February 25, 2017)

People living in neighbourhoods with more birds, shrubs and trees are less likely to suffer from depression, anxiety and stress, according to research by academics at the University of Exeter, the British Trust for Ornithology and the University of Queensland.

The study, involving hundreds of people, found benefits for mental health of being able to see birds, shrubs and trees around the home, whether people lived in urban or more leafy suburban neighbourhoods.

The study, which surveyed mental health in over 270 people from different ages, incomes and ethnicities, also found that those who spent less time out of doors than usual in the previous week were more likely to report they were anxious or depressed.

After conducting extensive surveys of the number of birds in the morning and afternoon in Milton Keynes, Bedford and Luton, the study found that lower levels of depression, anxiety and stress were associated with the number of birds people could see in the afternoon. The academics studied afternoon bird numbers — which tend to be lower than birds generally seen in the morning — because are more in keeping with the number of birds that people are likely to see in their neighbourhood on a daily basis.

In the study, common types of birds including blackbirds, robins, blue tits and crows were seen. But the study did not find a relationship between the species of birds and mental health, but rather the number of birds they could see from their windows, in the garden or in their neighbourhood.

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