Aboru Aboye Aboshishe,
Someone was posing a question about Osun of lucumi (not Oshun), this connection occurred to me. Osun for traditional Yoruba practitioners lies only within the realm of Ifa, other Orisa priests don't own/consecrate the staff of Osun (though it often looks similar to the staff of Osayin, which is also iron, and also has birds, but is in fact different. Osayin satff usually have only birds, often 16, an Ifa Osun, held only by Ifa diviners, usually has only one (sometimes two) and the conical shaped bells, the whole staff then prepared with medicines).
The bird at the top of an Ifa Osun is referred to as the "bird of Ifa." and is said to invoke the power of the hawk (asa), symbolizing the diviner's ability to address problems expediently and effectively. Now this is where it gets interesting. If as Wande Abimbola notes in his book on Ifa Corpus, one of the main purposes of Ifa is to get in touch with one's Ori, as evidenced in ogunda meji when Ifa says:
Death, disease, loss, paralysis and wickedness
were all staring at Orunmila
they said that one day
they would kill him
Orunmila then set down his divination instruments ready to consult his Ori
Iku, arun, ofo egba, ese
Gbogbo won ni nyo Orunmila wo
Won nwi pe ojo kan
Ni awon o pa a
Ni Orunmila ba gbe oke Iporii re kale
If then the hawk on the top of the Osun is meant to represent the Diviners ability to see, get in contact with Ifa, in this case to understand the wishes of a devotees Ori, it's a quite simple leap to see where the lucumi use Osun to represent Ori (or "crown" as they refer to it) and further to say that Osun "falling" is representative of a message for the aborisa who's Ori/"crown" it looks after. The one big difference is that in the diaspora other Orisa priests took up "preparing" Osun, even though Osun for Traditional Yoruba practitioners is only in the realm of Ifa.