From the Hebrew name יִתְרוֹ (Yitro), which was derived from the Hebrew word יֶתֶר (yeter) meaning “abundance”. According to the Old Testament, Jethro was a Midianite priest who sheltered Moses when he fled Egypt. He was the father of Zipporah, who became Moses’s wife. A famous bearer of the name was Jethro Tull (1674-1741), an English inventor and agriculturist.
From the name of the bird, from Old English finc. It was used by Harper Lee for the surname of lawyer Atticus Finch and his children in her novel To Kill a Mockingbird (1960).