Sunday, January 15, 2012

WATCHER OF THE SKIES: Albatrosses and grebes

As regular CFZ-watchers will know, for some time, Corinna has been doing a column for Animals & Men and a regular segment on On The Track... about out of place birds, rare vagrants, and basically all things feathery and fortean.

Because we live in strange times, there are more and more bird stories that come her way, so she has now moved onto the main CFZ bloggo with a new column with the same name as her aforementioned ones...

Global warming helping endangered wandering albatross





The wandering albatross is an endangered bird which rides on strong winds and spends much of its life on the wing. After analysis of 40 years of data on this bird living on the windy Crozet Islands that lie south of Madagascar has revealed that increased wind speeds courtesy of global warming are giving ‘a lift’ to this endangered species, according to a study reported in Science. The windier conditions over the Southern Ocean are allowing the birds to shorten their time at sea as they can cover feeding grounds quicker, therefore the albatross parents can spend more time on the nest, which in turn makes it easier to rear chicks.


Researchers, led by Henri Weimerskirch of the Centre d'Etudes Biologiques de ChizĂ© in France said: "We aimed to assess whether the foraging performance of albatrosses has changed over the past few decades in relation to wind conditions and to understand the possible consequences of such change on life history (breeding performance and condition).”

The Wandering Albatross (Diomedea exulans) (also known as the Snowy Albatross or White-winged Albatross) was first described by Carolus Linnaeus, in 1758 and has the largest wingspan of any living bird, averaging from 2.51–3.50m (8.2–11.5ft). They have a large pink bill and feet and also have a salt gland situated above the nasal passage which helps desalinate their bodies due to the large quantities of sea water they take in. This excretes a high saline solution through their nose. Pairs mate for life and breed every two years and feed on cephalopods, small fish and crustaceans at night. They also feed on animal refuse floating on the sea, eating so much sometimes that they are unable to fly, causing them to rest helplessly on the water.

Their long wing bones were sought after for tobacco-pipe stems, causing them to be captured by sailors. New Zealand Maoris also used these bones; for flutes, needles, tattoing chisel blades and barns for fishhooks due to their light but very strong composition. In the days of sail and early explorers of the southern seas the wandering albatross could often been seen wheeling in wide circles around the ships it followed, never being seen to land and continuing its flight even in tempestuous weather seemingly tireless. Those of you who have read Coleridge’s The Rime of the Ancient Mariner will be well aware of “the evil fate of him who shot with his cross-bow the ‘bird of good omen’.”

Read more about the study at: http://www.wirralnews.co.uk/wirral-news/local-wirral-news/2012/01/11/merseyside-farmers-help-wild-birds-in-pioneering-new-scheme-80491-30093997/
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Slavonian Grebes – study on their breeding requirements





A report by Louise Smith, Media and Communications Officer at the RSPB, says that stopping the introduction of pike into Scottish lochs may help to ensure the future of one of Scotland’s rarests birds, the Slavonian grebe. A study led by the RSPB and funded partly by Scottish Natural Heritage investigated into what influences breeding Slavonian grebes in choosing certain lochs to raise their young. Those lochs that have pike had fewer small fish, which are a valuable food source for the grebes, whereas moderately sized lochs that have a wealth of small fish such as sticklebacks and minnows, clear water in which to hunt the fish and plenty of nesting habitat were the most suitable. The Slavonian grebe did not begin breeding in the UK until 1908 and its population is still restricted to northern Scotland, showing only 29 breeding pairs remaining according to the latest counts.
Notes from the RSPB include:

“Slavonian grebes are strong swimmers and build their nests in sedge beds. They arrive back in Scotland in March/April and leave in autumn.

Slavonian grebes are best recognised by their colourful summer plumage and trilling calls. Both males and females have golden ear tufts, black faces and deep red eyes.

Around half of the UK population of Slavonian grebes breed at Loch Ruthven. The RSPB has a nature reserve at the eastern end of the loch. In the spring and summer, it is possible to get excellent views of displaying grebes in front of the hide.

The study is titled and authored: Ron W. Summers, Roddy A. Mavor, Sandra Hogg & Ron Harriman 2011 Lake characteristics and their selection by breeding Slavonian grebes Podicpes auritus in Scotland Bird Study 58, 349-356.”
You can find out more on: http://www.rspb.org.uk/media/releases/301721-new-study-reveals-slavonian-grebes-breeding-musthaves

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