Edmonton - A study in the peer-reviewed journal The Wilson Journal of Ornithology to be published in early September (online in late August) shows annual bird mortality in the bitumen tailings ponds of northeastern Alberta - an internationally significant migratory bird corridor - greatly exceeds industry estimates.
The authors investigated three types of data: government-industry reported mortalities; rates of bird deaths at tailings ponds; and rates of landing, oiling, and mortality to quantify annual bird mortality due to exposure to tailings ponds.
For the period 2000 to 2007, reporting by industry indicated a mean annual mortality from tailings pond exposure of 65 birds. The study, entitled "Annual Bird Mortality in the Bitumen Tailings Ponds in Northeastern Alberta," however, indicated an annual mortality in the range of 458 to 5,029 birds - a range deemed conservative because birds found dead represent an unknown fraction of true mortality and data do not include mortalities that occur before spring, between spring and fall migration, and after fall migration. The wide range in the annual mortality estimates is due in large part to spatial and temporal variations in bird mortality rates.
"The ad hoc monitoring by industry, sanctioned by government, cannot address pressing questions whose answers would aid in the conservation of both migratory and resident birds," said Dr. Kevin Timoney of Treeline Ecological Research, one of the study's authors along with Dr. Robert Roncini of Dalhousie University.
Other findings of the study include:
Landing deterrent systems at tailings ponds are only partially effective. The only way to prevent bird deaths is to discontinue the use of tailings ponds.
While tailings ponds, which contain bitumen, polycyclic aromatic hydrocarbons, volatile organic compounds, naphthenic acids, brine, heavy metals, and ammonia, pose the greatest threat in spring when warm effluent-fed tailings ponds provide open water at a time when natural water bodies remain frozen, a high risk of oiling may extend throughout the open water season.
The fate of lightly oiled birds that continue migration, in particular to summer breeding areas, is unknown.
The total number of birds migrating through the region and the total annual bird mortality due to tailings ponds are not known with sufficient scientific rigor.
Data on mortalities during extreme weather events and on the frequency of mass mortality events are lacking.
The study concludes: "Government-overseen monitoring within a statistically valid design, standardized across all facilities, is needed. Systematic monitoring and accurate, timely reporting would provide data useful to all those concerned with bird conservation and management in the tar sands region."