Go Back   Steve's Digicams Forums > Digital SLR and Interchangeable Lens Cameras > Pentax / Samsung dSLR, K Mount Mirrorless

Reply
 
Thread Tools Search this Thread
Old Oct 12, 2009, 12:35 AM   #11
Senior Member
 
bilybianca's Avatar
 
Join Date: Nov 2005
Location: Hassleholm, Sweden
Posts: 3,435
Default

Thanks all for the nice comments!
And thanks Penolta for sharing another slice of your vast knowledge on about everything nature-related. One of the things that makes this forum so worthwile!
SharpShotGal, I can see a dolphin in #1 and a portrait of my dog in #3.
Keith, the birds were quite high, but it also true that this lens is a joy to use. Here is a 100% crop of #1, I think it's amazing to see so much detail in these tiny specks:

Kjell
Attached Images
 
bilybianca is offline   Reply With Quote
Old Oct 12, 2009, 1:32 AM   #12
Senior Member
 
penolta's Avatar
 
Join Date: Apr 2007
Location: California USA
Posts: 5,206
Default

SharpShotGal, that is a nice thought, but any art is in our own perceptions -- there is neither art nor secret in these formations, only a way to save energy in a long, exhausting flight, but there is order in nature -- it's all a matter of aerodynamics.

When birds fly in v-formations or in echelons (diagonal lines), each is deriving lift from a wing-tip vortex of the bird in front, as shown in the first and third photos. If you look carefully in the enlargement that Kjell so thoughtfully provided, you can see that each bird is positioned off one wing of the bird in front of it - all except the leader in each group, who works the hardest "breaking trail" - this is more tiring, and so the lead will change periodically (at least this is the case with geese, and I imagine also with these cranes). In the middle picture there are no such formations because the birds are riding a thermal - soaring around within one of the bubbles within a column of rising warm air (like the lines of bubbles forming on the bottom of a pot of simmering water) - they don't have to flap, but move with the bubble as the column is displaced by the wind - another means of saving energy, commonly used by hawks in their migrations over the Great Plains, where there are no north-south trending mountain ranges to provide orographic uplift caused by wind moving upwards as it flows over them.
__________________
.
.
If life brings you lemons, you can make lemonade.

Last edited by penolta; Oct 12, 2009 at 1:35 AM.
penolta is offline   Reply With Quote
Old Oct 12, 2009, 6:35 AM   #13
Senior Member
 
mole's Avatar
 
Join Date: Mar 2009
Posts: 8,522
Default

Great photos Kjell - offering all of us much food for thought. Have a great & safe trip!

Penolta - thanks for the detailed explanation!
mole is offline   Reply With Quote
Old Oct 12, 2009, 4:08 PM   #14
Junior Member
 
Alpo's Avatar
 
Join Date: Nov 2007
Posts: 27
Default

Kjell, amazing shots!

Is the start of the migration realy that specific in time? Does it happen on one specific day in your area or does it happen over say a week or two (for the same specie of cranes)?

Glad that you've passed summer this way.

Travel well.

AL
Alpo is offline   Reply With Quote
Old Oct 12, 2009, 5:31 PM   #15
Senior Member
 
bilybianca's Avatar
 
Join Date: Nov 2005
Location: Hassleholm, Sweden
Posts: 3,435
Default

Quote:
Originally Posted by Alpo View Post
Kjell, amazing shots!

Is the start of the migration realy that specific in time? Does it happen on one specific day in your area or does it happen over say a week or two (for the same specie of cranes)?

AL
Well, it's not that specific, but nearly. First the breeding pairs sneak away long before the young ones. Then the youngsters gather in their thousands in remote wetlands and await the right weather conditions, so when they finally go they more or less leave at the same time. Next thing is that you have to be outdoors to observe them, that is on a sunny day after working hours or in the weekend. Some years I miss them totally, most years I see them for a day or two, but then in huge numbers.
We only have one species, the Eurasian crane, Grus grus.

Kjell
bilybianca is offline   Reply With Quote
Old Oct 12, 2009, 5:40 PM   #16
Senior Member
 
Join Date: Feb 2005
Location: East Central Vermont
Posts: 1,890
Default

Great pics, Kjell, and a very interesting thread. I learn a lot from everyone on this forum! I've seen quite a few Canada Geese flying south over the last few weeks, but as yet, I've not seen any Snow Geese. I'm sure they're also passing through our area; I just havent seen them.
mtnman is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 4:31 PM.