Craig yr Aderyn, also known as Bird's Rock,[1] is a hill rising to a height of 258 metres (846 ft) above sea level on the south bank of the River Dysynni near Llanfihangel-y-Pennant in the county of Gwynedd, north-west Wales.

Craig yr Aderyn has been designated as a Site of Special Scientific Interest because of the choughs and other birds that breed there.

[2] Craig yr Aderyn is an isolated hill in the county of Gwynedd, that juts out into the Dysynni Valley.

It rises to a height of 258 metres (846 ft) above sea level on the south bank of the River Dysynni, near Llanfihangel-y-Pennant.

[2] The writer Susan Cooper leads her characters to "Bird Rock" in her book The Grey King from The Dark Is Rising Sequence.