Odd Geese Formation: Ornithological input, please

I noted quite a few geese flying overhead the other day, in their traditional V formations, or variations on it, with the pointy part of the V moving first in the direction the flock was flying. Then I noted a new formation, one looking somewhat like the letter Z, with about 7-10 geese in each line. Odd, I thought. But eventually rationalized how it could come about.

Then suddenly, one of the outer lines of birds in the Z peeled away, leaving a more classic V formation intact. But this V formation was flying with the open end of the V pointing in the direction of flight. WTF? I’m used to seeing my geese formations piercing the skies with the needle-tip nose configuration of a super-sonic jet! Not like some great scoop!

So, ornithological dopers, was this a true anomaly? A sign of imminent magnetic pole reversal? Further evidence of global warming? A sign from revelations? Or something that happens all the time that I’ve never noted. Clue me in.

IIRC there’s an advantage in flying behind the shoulder of a bird, but a disadvantage in being directly behind one. If you line up some counters in this way, I think you’d get a V a lot of the time, but occasionally some other lines.

Sound right?

The reason geese fly in a V shape has come up before. Rather than only for aerodynamic reasons, it seems that the reason is the the geese can see the ones in front.

Since geese cant see directly in front it is easier to follow one in front and off to the side. So any goose that joins a formation will follow so that it can see the others lined up to the diagonal.

A V shape satisfies this condition. A ‘scoop’ V also satisfies the condition, but involves a maneuver to be set up, presumably via the // formation.

I suppose that makes sense.

Any special benefit to the last goose in line, who’s got two geese in front of him breaking trail on either side?

And has anyone else noticed geese in the ‘scoop’ V formation?

How long did the formation stay together for?

You would expect that the two leaders would soon drift apart and the connection between the two trails of geese would be lost.

/\ + / --> //

// - / --> /

/ --> \ + /
disclaimer: i’m a chemist not an ornothologist

I couldn’t see how long they lasted, they flew out of my range of discernment of such fine details.

I have not seen the scoop V formation before, but I have a related question.

Background: yesterday I witnessed a mid-air collision between two flocks of geese. A formation of about 10 geese came flying low over my house (towards the south, natch), followed by another formation of 10 maybe 100 yards behind the first. The first group peeled around 180 degrees and came heading right for the second group. As the two groups converged there was much swerving and banking and at least two of the birds collided with each other (and I proceeded to laugh my ass off). The two groups then flew around each other in circles, finally melding into one larger flock which then headed south again in a “V”. Yet another one of nature’s “oopsies” moments that we humans aren’t supposed to see.

My questions: why would the first flock bother to interrupt its journey to wheel around and join the second? Is there any advantage to having a 20-bird formation vs. a 10 bird formation other than safety in numbers?
And, when the two flocks joined, how was it decided who would lead the new super-flock?

BTW here’s a previous thread on the subject. http://boards.straightdope.com/sdmb/showthread.php?threadid=149906

stochastic: I’m guessing they instinctively join up as larger formations have more aerodynamic benefit, more geese that know where they’re going, etc.