Petrochelidon lunifrons

from The Collaborative International Dictionary of English v.0.48

Cliff \Cliff\ (kl[i^]f), n. [AS. clif, cloef; akin to OS. klif,
   D. klif, klip, Icel. klif, Dan. & G. klippe, Sw. klippa;
   perh. orig. a climbing place. See {Climb}.]
   A high, steep rock; a precipice.
   [1913 Webster]

   {Cliff swallow} (Zool.), a North American swallow
      ({Petrochelidon lunifrons}), which builds its nest against
      cliffs; the {eaves swallow}.
      [1913 Webster]