Grackles and Martins - Can they co-exist?

[MartiStupka]

For many years grackles would visit my feeders and clean them out on a daily basis. I discovered that they don't care for safflower seeds, which is what I use in my feeders exclusively, and until this year I haven't seen any in my yard or feeders. The Martins began to arrive mid-January. For the past two weeks I am seeing grackles perched on the top of the owl/hawk barrier that surrounds my 20 compartment Martin house. I now suspect that the grackles are building a nest in the next door neighbor's oleander. I searched the Forum for anything about grackles, and it sounds like the grackles and Martins can live in peaceful coexistence, and not bother each other. I am writing to confirm that this is the case, and if not, if anyone knows of problems between these two groups, and if so, how did you correct?
I have a very small colony that keeps me busy. I've added to it over the 5 years I have been a landlord. The first year was uneventful. In year three, I had my first experience with the dreaded house sparrow, and quickly got over my initial difficulty in destroying them after I experienced the destruction that they cause our beloved Martins. The past two seasons, I have been challenged by the nasty yellow rat snake. I know that snakes have their place in nature, but they just make me anxious. The first experience wiped out a compartment with baby Martins that had just hatched. We then wrapped bird netting around our supposed original pole guard (which is no problem for rat snakes to get past) and caught another one in the netting, and then another enroute to the colony. Last year, our netting looked like a work of art, but the snake was able to slide right over it. I saw something amiss and was able to get the house down and the snake out, but was too late, as the just hatched babies were eaten. We then put up bird netting and while not a pleasant sight to behold, it kept away the rat snake. Then once the snake is caught up in the netting, it can't get out without human intervention. The Martins have started nest building. I don't want unanticipated problems with grackles, if there are any, and would appreciate any information that anyone has about experiences you have had. I do want to also thank everyone who provided input over the past two years about pole guards to keep out snakes. I only see them after the Martins have a couple of nestlings, but given the numbers, they must have a nest nearby. I am vigilant, and I think that I occasionally annoy my neighbors as I monitor my Martins at night with my spotlight. There always seems to be a Martin on guard when I check.

[chickadee]

I have never ever had a grackle bother a martin. I get a little bit of every bird sit up on my caged in rack. it is a nice spot to see around them. but they go their way and don't bother my martins.

[wyatt]

The martins and grackles get along just fine at my site. I have come to appreciate the grackles because they help chase away the owl.

[tonyg]

Didn't know grackles flew at night...

[chickadee]

maybe he meant hawks? they are good alarm birds here. chasing the hawks and letting the martins know when one is around.