1980 Walter D. Koenig 3 Melanerpes formicivorus Plague (6 April) about 1730, I realized the following: a) there was apparently only 1 intruder still, being vigorously chased by 1 of the residents and just slightly less vigorously by a 2nd. The intruder was a ♀. However, we failed at pinning down who was chasing whom. Ron tried to watch the birds not doing the most chasing and identified 8522, the baby here; however, both the intruder and the chaser- also a ♀ - appeared to be banded. Later, however, Ron identified the most persistent intruder as an ub ♀. We also saw 8521 and 8473. b) It occurred to me, after watching for awhile, to notice that the intruder garricked constantly once she stopped on a limb, but was silent when being chased. Possibly in keeping intruders in the air as much as possible residents 1) maximize the likelihood that the intruders will give up and 2) minimize the displays given by the intruder which would attract other intruders and incite a revolution. c) Throughout this period I was assuming that everyone here was fine and that the intruder was just that- an intruder. However, after I put a net up in the Plague tree and watched some more it became apparent that 1) the adult ♀482 was not here, 2) additional intruders were arriving, and 3) therefore, that persistent ♀ knew, apparently, that there was a vacancy here despite the continued chasing she was