"I hear a bird."
How come there is a macron over the i in "Hontī" when there is only a single bird being heard? Is this a mistake or am I mistaken?
No, it is correct. This is true for all fourth declension words (the ones that have a final vowel -e in the nominative). http://wiki.dothraki.org/High_Valyrian_Noun_Declensions#Fourth_Declension