Green’s Dictionary of Slang

eagle n.4

(N.Z. prison)
[senses 2, 3 from war movie The Eagle Has Landed (1976)]

the chief officer.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] 64/1: eagle, the n. 2 the head prison officer on duty, the IC. the eagle’s flying! 'Watch out! The head officer is on the prowl.

In phrases

eagle has landed (phr.)

1. a visitor has arrived.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] 64/1: eagle has landed, the 1 an indication that an inmate’s visit has arrived.

2. something awaited has arrived, e.g. a consignment of contraband.

[NZ]D. Looser Boobslang [U. Canterbury D.Phil. thesis] 64/1: eagle has landed, the2 an indication that something much anticipated has arrived, e.g. some drugs have been delivered .