Note the unusual readings: 鹄 normally reads hú (swan), but in 鹄的 it reads gǔ - an old archery term. 的 here reads dì, the same dì as in 目的 (mùdì - purpose), not the everyday particle de.
register
Literary and somewhat archaic. In modern Chinese, 目标 (mùbiāo) or 靶心 (bǎxīn - bullseye) are far more common. You'll see 鹄的 mainly in classical-flavored writing or formal essays.
