Perhaps relevant, I recall reading about an experiment with homing pigeons in England, results of which may be relevant here.

When released the first time, tens of miles from home, the pigeons flew back fairly directly, using whatever means birds have to navigate back to home.

The second time they were released, the birds followed a major road for much of the way back.  Not as direct, but apparently it didn't take as much concentration or energy, or something.  For whatever reason, it was preferable to the pigeons to take advantage of a visual "map" rather than to use the natural abilities that would have gotten them home if there were no long physical markings on the ground.  

Maybe this is why the crows are following what sounds like a physical marking on the ground (transmission lines?)?  Just speculating....

Tom Grahame

On Nov 22, 2011, at 12:49 PM, James Meyers wrote:

> Each year as autumn progresses into winter I find it fascinating to observe huge numbers of Crows in daily flights along well established flight lines.  At Cromwell Valley Park one such flight line has been consistent for years.  Most days, beginning in mid-afternoon and continuing until dusk, thousands-perhaps tens of thousands- of Crows can be seen flying in a SSW direction along the BGE power line ridge.  Many times I have noticed that they reach a particular point along the ridge and then turn due south.  I believe they then merge with another flight line of Crows which follow Perring Parkway south.
> 
>  I seem to recall yet another flight line in the Owings Mills area heading south along the Riesterstown Rd./Liberty Rd. corridor. 
> Has anyone seen these flight lines or know of any others in the Baltimore area?  Does anyone know where these huge numbers end up roosting each night? 
> 
> This coming Thanksgiving weekend I plan on trying to get a rough count of the Cromwell Valley flight line Crows.  I will post my results on here on MDOSPREY for those interested.
> 
> Jim Meyers
> Cromwell Valley Park HawkWatch
> Parkville Md 
> 
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