Many of the thefts appeared to be opportunistic and could have been prevented, he said.
"It's likely we are looking at younger offenders walking around in the early hours of the morning," Mr Osland said.
The young age of many of the offenders was worrying, with some as young as 14 sometimes racking up dozens of charges.
"The age of offenders is getting younger, which ... makes our suspect pool wider, and obviously the risk to them of potentially being disturbed or apprehended by a member of the public who has had a gutful is significant.
"It's not only the impact on the community, but the risk that they're putting themselves in."
Mr Osland urged people to report any type of suspicious activity.
"Police would rather attend and find out there's an innocent explanation rather than miss the opportunity to apprehend the culprit.
"We'd rather be called than not called."