Welcome back to the kettling Sandhill Cranes.  

The 7th Sandhill is still out of frame as the others continue their circuit to the  top of the funneling air.  As to the four who tend to stay close to each other, I suspect those may be the females as they are tending to stay close to one another possibly to use the slightly reduce resistance by the use of formation.

I think this may be the only photograph I in which all seven cranes are visible...four down right, one far left and what appear to two males right of center.  Note  the directions in which they are headed.

The females, down right, continue their flight formation continuing  to reduce even more air resistance.

Note the three down right.  They are nearly exactly in the same flight position.  Obviously the best one currently for the job at hand.

 When in doubt of their heading look for the bit of white which is their heads.

Oops  a near mid air collision, center.

The turn is made and off they go higher.

And higher.  Note the further upward angle.

And round the other direction.  Higher.

Two bottom birds and down right bird head right.  The top three  left making the turn.

Then  five using the break in air pressure from the wake of the bird before them angle steeply up, gaining height without much effort.

Four on right leave this kettle loosing a bit of altitude when they leave it and head for the next where the lead male circles at the top of a second vortex of air out of frame.

The last crane finishes this vortex and heads right towards the other cranes who have lost a bit of altitude, as she will, making their way to the next vortex.

Donegal Browne

P.S. Heading out to see what today may bring.