tested,,, passed with flying colors

Well an opportunity did present itself even before i made it to the farm. I have 3 birdhouses that are every year the home to at least 2 finch families.I love to see the laborious finch females flying back and forth bringing food and twigs, and i am rewarded with the wonderful sound of baby finches in the morning, which seems to be the best company for a strong cup of coffee before work. a couple of days ago I saw 3 grackles moving into my yard and at first they only stole from the chicken coop... but the hens would generally scare them off and they did not seem to be bothering anyone else. When i get back from work today i witness a large grackle trying to get into the birdhouse as the adult finch tried to fend him off. They would fly off and then another grackle would try to get in, only to be twarthed by the returning, frantic finch. "oh no" says I, not fair 3 against one... So I loaded a fresh CO2 on the gun and was able to round off the house to the corner near the tree with the bird house. i observed and noticed that the finch was now being harrased into my neighbors yard, and that left the door open for the raiding grackle. I knelt behind a bush, and calculated the target to be about 23 yards away. As the pistol is zeroed at 20 it would be almost dead on. with a loaded hobby on board I adjusted the AO to 25 yards and held steady on the stick under the entrance of the bird house. in an instant the grackle swoops down and lands... though the scope i see him stick his head in the hole, then he feels "the heat" of the scope on his neck and like in slow motion turns to face me... too late, a pellet catches him under the eye and knocks him completely of his perch and into the ground.
I follow with the scope and see him kick up 2, maybe 3 times, and finally exhale...
The finch returns to fend him off but once on the perch, he turns, flies to the roof of the bird house and looks down on the offending bird. I am sure he saw me... and as i came out from behind the bush he sat there, motionless, looking at me with that understanding that he was ok, and that he belonged there, and that the man with the pistol was not a threat...
here is a pic of the offender and the tool used...