Read gǔ, it is the bull's-eye of an archery target and, by extension, a goal one aims at — as in 中鹄 ('to hit the mark') and 鹄的 ('the target; the objective'). This sense is distinct from the swan reading hú.
The bird radical 鸟 on the right marks the literal meaning in the swan reading — a large water bird. The separate gǔ 'target' sense borrows the same written form.
Supplies the sound. Standalone 告 reads gào; the reading drifted to hú (and gǔ for the target sense). It is the phonetic element, carrying no meaning to the bird.
