Naked Science Forum
Life Sciences => Plant Sciences, Zoology & Evolution => Topic started by: dentstudent on 26/06/2007 08:43:58
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I'm worried about the poor little birds who get blown around in the wind. Is there a high rate of mortality in small birds on windy days? Often the wind seems to be blowing rather faster than they can fly, so do they ever get lost? How do they feed if the wind is blowing for several consecutive days?
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I am sure they must forage low in the shelter of the bushes also don't you think?
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I am sure they must forage low in the shelter of the bushes also don't you think?
Does it not rather depend on what it is they feed on, and where they have built their nest?
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Often the wind seems to be blowing rather faster than they can fly
You talking about Vne or Vmax?
At low altitude, wind speeds can in any case by highly variable, as they are effected by the local topology (including buildings, etc.).
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Often the wind seems to be blowing rather faster than they can fly
You talking about Vne or Vmax?
At low altitude, wind speeds can in any case by highly variable, as they are effected by the local topology (including buildings, etc.).
I'm guessing that the mean wind speed would perhaps have the greater effect rather than individual gusts. But does thier behaviour change at all in the face of storms and wind, and if so, for how long? There aren't so many flying around today because it's raining like a great big wet rainy thing - but they can't stay holed up indefinately. What if it rains like this for a week?
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I am sure they must forage low in the shelter of the bushes also don't you think?
Does it not rather depend on what it is they feed on, and where they have built their nest?
Yes I would agree with that also..Just never thought about it really! LOL
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Laden or unladen?
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I'm guessing that the mean wind speed would perhaps have the greater effect rather than individual gusts. But does thier behaviour change at all in the face of storms and wind, and if so, for how long? There aren't so many flying around today because it's raining like a great big wet rainy thing - but they can't stay holed up indefinately. What if it rains like this for a week?
I have certainly seen birds apparently hovering by flying into wind (birds not usually capable of hovering, but the hover was an abberation caused by the birds forward airspeed matching the windspeed, so the bird had effective zero groundspeed).
Birds are very adept at using local air currents to their advantage - every bit as much as a balloonist or glider pilot must be. Even a yachtsman, although he is constrained to staying at sea level, is going to be acutely aware of the impact that land masses, or even nearby vessels, might have on wind (in racing, they have even been known to steel the wind from a competitor by crossing across his wind, so taking the wind out of his sails).
It is not just about gusts, but uplifts, or using buildings or trees or even hills as windbrakes, or otherwise taking advantage of changes in wind direction caused by these obstacles.