Bird in flight: IFR to VFR

A lone bird is caught in flight headed west on a cold December morning. Northwest winds were scouring out morning fog and the remnants of the fog was now on the verge of forming Cumulus clouds. Just a couple of of hours earlier dense fog shrouded the landscape. In aviation terminology pilots had to follow Instrument Flight Rules (IFR). As the fog dissipated conditions improved to VFR (Visual Flight Rules). We don’t see many birds flying during episodes of dense fog. On this morning temperatures were in the teens as drier air mixed out the moist air and dissipated the fog and birds once again took to the air.