How do you attract woodpeckers to an upside down house suet feeder?. I recently replaced a cage suet feeder to an upside down feeder as a result of blackbirds & grackles taking over it and devouring the feed.
Since you mention Grackles I assume you live in the US. This is mainly a UK site so I'm not sure whether we can help.
Where abouts do you live in the US. Do you get woodpeckers in the vicinity and what species. From webcams that I've watched in the northeast of the US the most frequent visitors seem to be Downy and Hairy Woodpeckers. They seem to prefer vertical log type feeders which simulate a more usual way of feeding. SEE HERE. I'm not familiar with upside down feeders so I don't know how effective they would be.
Sorry not much help.
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Tony
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I've only seen the Cornell feeders webcam (New York State I think), but a 3rd species Striated (possibly!) also uses the vertical log feeder