Checkpoint Cardinal

Songbird territories are terribly interesting, and it's not easy to figure out where the birds draw the lines.  Something I observed tonight suggests to me that the Northern Cardinals may have drawn a line not through one feeder station, but through two.  I've already seen that rival males tolerated one another on the north side of the house.  And weeks later I saw two males perched on opposite sides of the southeast station.  The whole scene reminded me of Checkpoint Charlie at the old Berlin Wall.  It's fascinating that the birds allow some of the rich harvest to their rivals, and the rest of the season should be quite entertaining!