Post-Release Survival Program
Description of Program
A critical knowledge gap in understanding the overall effects of oil in wildlife is, should they be successfully rehabilitated and released, what is their long-term survival and whether they return to normal biological function. Several reports in the literature suggest that oiled and rehabilitated animals survive on the order of days, not months or years. Other reports show examples of birds surviving decades after being cared for during an oil spill event.
To address this issue, beginning in 1995, up to $250,000 has been allocated within the OWCN budget to support specific studies on the post-release survival of rehabilitated oiled wildlife. This program is crucial not only to determine that treated animals survive after release, but also that protocols are improved based upon the success of the animals in their natural environment. These funds are used on a spill-by-spill basis at the discretion of the OWCN Director, and are dependent upon the spill, impacts on wildlife, and scope of rehabilitation effort. Post-release survival studies are collaborative efforts between OWCN and/or OSPR staff and can be initiated only for spills within California and for spills in which the OWCN is the managing wildlife response entity.
Overview of Findings
Thus far, two post-release projects have been initiated: one evaluating the success of oiled bird rehabilitation by following Western gulls after the Torch/Platform Irene spill off the central coast, and one evaluating post-rehabilitation survival of common murres after the 1999 Stuyvesant oil spill in northern California. Each project used radiotelemetry devices attached to rehabilitated and control birds and followed animals after release. In each study, findings suggested that overall success (as determined by survival) was better than determined prior to the development of the OWCN and other spill responses around the world.