Interesting ad I found in an old catalogue for tam-o-shanters with feathers

[EagleJCS]

eagle feathers, regardless of colour, are unmistakenly ginormous. All of the noneagle feather ivs seen have been nowhere even half the size of an eagle feather, whether it is intentional to avoid being mistaken for “stolen valor” I know not. But I do think anyone who associates feathers with clan chiefs specials tatus would even at a moment’s glance tell that a feather is not an eagle feather in these cases we speak of. As for the general public, eagle feather or not, a feather is probably just a macaroni!

I'm sure for most people, a feather (of any size/type other than an eagle) on a hat (of any style) is intended purely as decoration.

The reason for my remark at the end of my previous post was that many years ago, a friend was told that they couldn't wear their pheasant tail feathers on their Glengarry (two long narrow, bronze and black striped feathers, worn along the side/edge of the cap rather than standing tall) because they weren't a clan chief. This was by a Highland Games 'official' who threatened to have this friend removed and barred from the event if the said feathers were not removed, even after they were informed of the species.

[Jock Scot]

There is one Clan Chief not far from here, who regularly wears three pheasant tail feathers in his bonnet on official occasions. His reasoning is pheasants are not an endangered species and eagles are.

[Kriegbert]

There is one Clan Chief not far from here, who regularly wears three pheasant tail feathers in his bonnet on official occasions. His reasoning is pheasants are not an endangered species and eagles are.

I recall, the war bonnets used by some indian tribes in america are exclusively collected from fallen feathers for the same reason

[Dr Bee]

Here's the deal - in Scotland at least. If I can paraphrase Gene Hackman in The Royal Tenenbaums "It might not be illegal but it's still frowned upon." Actually some claim that it is illegal here but the tradition is as EagleJCS already stated: 3 feathers for a chief, 2 for a chieftain and 1 for a gentleman granted a coat of arms (probably at the very least knighted). These are the traditional entitlements as they are understood by those in the know. Therefore if anyone else starts feathering their bonnets (regardless of the legal position) they are likely to be frowned upon on the grounds of exhibiting blatant bad taste. Simple solution - if you don't want to be frowned upon, don't do it - unless you are entitled.