Data collected following the 2011 M/V Rena spill in New Zealand document recovery of a population of endangered dotterels after pre-emptive capture and management, and normal behavior in little blue penguins released after cleaning and rehabilitation.
When the M/V Rena ran aground in 2011, one immediate concern was the threat of oil hitting the beaches used by a local population of endangered New Zealand dotterel. The difficult decision was made to bring half the birds into captivity to prevent them being oiled. Why only half the population? Captive care of adult dotterels had never been attempted so there were risks that the species would not do well under these conditions.
Of 60 birds taken into care, 54 were successfully returned to the wild. The other six died of illness related to stress. And, although most of the birds survived, it became clear that the health of this species worsens as time in care increases. In addition to reacting to the presence of people, the birds exhibited a high degree of territoriality, as the spill occurred during breeding season. Given that the birds did not adjust well to the captive situation, in future priority may be given to protecting and cleaning nesting beaches so the birds can be returned to the wild more quickly, thus lowering the risk of secondary health problems.
Post release monitoring showed that the dotterel population was once again stable two years after the spill, after a slight reduction in numbers the first year after release. A manual for captive care, and recommendations for improving procedures should a future pre-emptive capture be necessary, have been developed.
The second paper regarding the response to oiled wildlife looks at behavioural parameters of little blue or fairy penguins after release back to the wild. 383 birds were returned to the wild after cleaning and rehabilitation. From previous spills around the world, it is known that penguins adapt better than many species to the cleaning and rehabilitation process, resulting in high survival rates to release.
Post-release monitoring also finds long-term survival and reproduction is better in these species than for some seabirds such as guillemots and scoters. The study of little blue penguins released after the M/V Rena spill looked further into foraging and diving behaviour of released birds. Researchers found no difference in these activities between oiled, rehabilitated penguins and penguins unaffected by the spill. This paper adds further evidence of the value of rehabilitation of oiled wildlife.
Chilvers, BL, et al. 2015. Diving behavior of wildlife impacted by an oil spill: A clean-up and rehabilitation success?. Marine Pollution Bulletin.(in press). doi:10.1016/j.marpolbul.2015.09.019. Accessed online November 2015
Gartrell, BD, et al. 2013. Captive husbandry and veterinary care of northern New Zealand dotterels (Charadrius obscurus aquilonius) during the CV Rena oil-spill response. Wildlife Research. (40) 624-632. doi.org/10.1071/WR13120. Accessed online November 2015
(Note: Photo credit- Rumpleteaser/Flickr)