beach plover
Refers to plovers found on rocky or sandy shores. In everyday use, 千鳥 alone is more common for 'plover'.
A beach plover is scurrying along the water's edge.
Compound of 磯 (iso, 'rocky shore') and 千鳥 (chidori, 'plover'). The exact historical derivation is uncertain, but the spelling is conventionally associated with the meaning.