At first I didnt know Bolas didn’t work on Argys..Welp. I went full on psycho, charged head in and shot it 6 times in the head. It was lvl 11 and it got knocked out after 6 shots, But please be careful with T.Arrows as they can easily kill ur Argy since it left him on 68 HP ;-; I tamed another argy later on and it left it on 154 HP. (Lvl 18) so please keep that in mind and don’t go psycho on the poor argy like me. I DO NOT RECOMMENT FACING AN ARGY HEAD ON LIKE MEH! Im just a stupid daredevil ;-; but it is possible, I didn’t take much damage. Just that my armor broke and i almost froze to death. I found a lot of argys’ in the RedWoods. Good Luck!
An argentavis can't fit through a ceiling with one tile missing, but a pteranadon or lymantria can. Build a trap with one corner ceiling missing, aggro the argentavis, fly in one side and out the missing ceiling tile, and land. Dismount, run around, and close the entry door. Tame safely at your leisure.