I understand that human memory champions do the same in terms of using locations as a crutch for memory, with their memory palaces and so on. They build themselves spatial pictures and clues. So this bird has a memory as good as human memory champions? As for keeping track of where they hid things by noting where they were in relation to other things; isn't that what humans do? If you removed all landmarks, buildings and everything from my city and replaced it with a flat, featureless plain, I would not be able to identify the location of my house. I find my house by looking at other things to work out which way to walk.
Anyway, I'll stop here because we're both using unprovable axioms as our basis. I suggest that human intelligence is very specialised and that we struggle to even see other specialised intelligence, so limited are we in our thinking. You suggest that humans have a wide ranging general intelligence (poorly defined as that concept is), superior to all others? Neither of us can disprove an axiom, although we can both spend all day suggesting things that creature A can do that creature B cannot.
The test you suggest does strike me as very human focussed; reminds me of tests showing that some creatures can't remember faces based on showing them human faces. Turns out that humans are really good at human faces, and some other animals are really good at other kinds of faces.
I do appreciate your civil tone, though. You did come across as a sealion at the start (which is why I ignored you), but that turned out to be a misread on my part.
And no, a real feat of memory can easily be measured and proven. The subject modifies a large list of items (e.g. seed in knothole), then later retrieves said item exactly once. That would be real evidence.