Industry is vastly underreporting the amount of birds dying because of oil sands operations each year, a new study concludes.

“The self-reported data were internally inconsistent,” reads a report published Tuesday in the Wilson Journal of Ornithology, “and appeared to underestimate actual mortality.”

Energy from the oil sands is difficult to extract. Many operations literally claw bitumen – a viscous substance that needs a lot of upgrading – from the ground.

Waste is collected in massive tailings ponds equivalent to 170 square kilometres. Flocks of migratory birds sometimes land – and die – in these ponds.

Syncrude was recently found guilty for the deaths of 1,600 birds, an incident which gained worldwide attention in 2008.

Birds are dying all the time though, Tuesday's study found, and no credible monitoring system exists to track it.

On average, industry reported 65 bird deaths a year from 2000-2007, the authors calculated. Actual scientific numbers indicated 458 to 5,029 died annually. And even this “represents an unknown fraction of true mortality,” the report reads.

“Government-overseen monitoring within a statistically valid design, standardized across all facilities, is needed,” it said.

Oil sands companies and government officials often clash with the scientific community over environmental impact estimates.

Last week, a report concluded bitumen extraction is releasing cancer-causing heavy metals into the Athabasca River. The Alberta government continues to deny the accuracy of such findings.

One of the authors of the bird mortality report, Kevin Timoney, gained national attention this June. A government scientist apologized for calling Timoney’s previous oil sands research “lies”.

“You did not lie. You did not choose to remove data from your study,” read a letter signed by Dr. Preston McEachern.

The wind-turbine industry also struggles with bird deaths. Between 7,500 and 9,300 die each year at California’s Altamont Pass, one of the United State’s first major renewable energy facilities.

Geoff Dembicki reports for the Tyee.