The second oil spill in six months has contaminated MacKay Creek in North Vancouver.

Paul Berlinguette was doing a bird count in the area on Sunday morning when he peered over the bridge at First Street and noticed the water looked grey.

"You can see it. And it's different than the last oil spill. It didn't have all the colours in it," he said.

"As we moved up the creek from first walking north toward Marine Drive, it got stinky and we could smell diesel."

BC Hydro says the spill is the result of vandalism to a privately-owned pad mount transformer.

"Since April, several BC Hydro-owned pad mount transformers in North Vancouver have also been deliberately damaged. BC Hydro issued a public warning a few weeks ago about the dangers of this type of act, and the significant safety and environmental risks it poses," the statement said.

North Vancouver RCMP are investigating the incident.

North Vancouver District bylaws require storm drain systems in industrial zones to be outfitted with oil and grit interceptor mechanisms and any infraction can end in a fine of up to $10,000, depending on the severity.

The spill comes six months after more than 49,000 litres of oily water had to be sucked from a storm sewer system near the fish-bearing creek.

Cleanup costs from that spill were expected to run tens of thousands of dollars after crews spent four days cleaning contaminated water out of the storm sewer system.

A sheen of oil can be seen on Mackay Creek in North Vancouver on Feb. 23. (Fiona Wright/North Shore Wetland Partners Society)

Berlinguette, who counts birds monthly in the area with the North Shore Wetland Partners, said the most recent spill did not appear as large as the one last winter.

But he's concerned about the impact of it on the ecosystem.

"In the same spot the month earlier ... we saw a big crawfish in the pond and we've also seen young salmon in the creek," he said.

"We saw nothing alive in the creek on Sunday."