** Reply to note from Michael P.

> And nothing is spookier than seeing a southbound, tightly-compacted ball of
> white birds maybe a couple of thousand feet up over Georgia Strait in
> September or October and have them resolve in the telescope as hundreds of
> Bonaparte's Gulls as jammed together in unison flight as the densest flock
> of shorebirds.

And which should be easily seen by C-band weather radars if they are in a tight
ball. Could be some useful bird migration info gained by the planned construction of
Doppler radars around BC the next few years (if the project isn't scrapped, that
is). Note that satellite transmitters do not show elevation of migrating birds; only
radar, aircraft obs., sharp-eyed land-based obs., etc can do this.

> So I think the feeling of anomaly at seeing these gulls at high altitude is
> essentially seeing them out of the familiar context of a low-altitude
> shore-edge/field/offshore scavenger wintering on non-breeding territory
> rather than a migrant between destinations and unconsciously expecting the
> behavior of the former phase.

Agreed. There are many holes in our knowledge of bird migration to fill in.
Migration altitude is only one of them.

- Jack



Jack Bowling
Prince George, BC
jcbowling at mindlink.bc.ca