patrols

n.

a detachment used for security or reconnaissance

the activity of going around or through an area at regular intervals for security purposes

a group that goes through a region at regular intervals for the purpose of security

BOUNDARY PATROLS AND INTERGROUP ENCOUNTERS IN WILD CHIMPANZEES
Who patrols the streets? An international comparative study of plural policing
TRUSTS: Scheduling Randomized Patrols for Fare Inspection in Transit Systems
Congressional Oversight Overlooked: Police Patrols versus Fire Alarms
Learning from Oversight: Fire Alarms and Police Patrols Reconstructed
Plural Policing: The Mixed Economy of Visible Patrols in England and Wales
TRUSTS: Scheduling Randomized Patrols for Fare Inspection in Transit Systems using Game Theory
States of Exception on the Mexico–U.S. Border: Security, “Decisions,” and Civilian Border Patrols
States of Exception on the Mexico–U.S. Border: Security, "Decisions,"and Civilian Border Patrols 
States of Exception on the Mexico–U.S. Border: Security, “Decisions,” and Civilian Border Patrols