Cape cormorants admitted to the Southern African Foundation for the Conservation of Coastal Birds (SANCCOB) for hand-rearing and rehabilitation in January are being released in groups of 40 to 100 birds according to readiness as determined by the organisation’s release criteria. The chicks were rescued from Robben and Jutten islands in very poor condition, suffering with heat stress and dehydration after being abandoned by their parent birds earlier this year.
The initial rescue operation for the majority of birds from Robben Island was carried out by Robben Island Museum (RIM), SANCCOB, Two Oceans Aquarium and the National Sea Rescue Institute (NSRI) from 12 to 14 January. The rescue intervention was deemed necessary due to their high conservation value. Releases will take place regularly in the weeks ahead, most likely through to May until all birds are back in the wild where they belong.
SANCCOB’s research manager, Dr Katta Ludynia, says, “Researchers suggest a combination of food shortage and extreme heat conditions led to the mass abandonment of Cape cormorant chicks. If the birds were already struggling to find sufficient food due to overall low food availability – their main prey being sardine and anchovy – then the heat will have added to the parent birds choosing to fly off as the heat increases the birds’ demand for energy, i.e. food.” Ludynia adds that a particular disturbance event resulting in the abandonment is unlikely as the abandonment of Cape cormorant chicks on Jutten Island started on exactly the same day.
According to Ludynia, the Department of Environment, Forestry and Fisheries (DEFF) confirmed that there was anchovy along the West Coast in November 2020. This may have triggered the birds to start breeding at this relatively later time in the season because Cape cormorant chicks usually fledge in November and December. Sardine stocks are severely low at the moment and the overall trend of declining food resources is showing in all our seabird species that rely heavily on small pelagic fish (sardine and anchovy), three of them being listed as Endangered by the IUCN.
Since the admission of cormorant chicks to SANCCOB, animal professionals, staff of conservation authorities and members of the public have volunteered their expertise and time to augment SANCCOB’s team of veterinary and rehabilitation specialists. Together, they have provided intensive care, fed the birds and kept their environment clean to get to this point where the rehabilitated birds can be set free. In February, a temporary aviary was built on Robben Island in anticipation of carrying out a soft release process, where release-ready birds are to be contained for 48 hours and fed twice a day before opening the gates for them to slowly integrate with wild cormorants roosting in close proximity. Once released, food is provided near the enclosure for as long as supplementary feeding is required. This is considered the best option as Cape cormorants normally provide extended parental care to their young, even after they have fledged. The time in the aviary will allow the hand-reared birds to familiarise themselves with their new surroundings.
“Conservation is essentially central to Robben Island Museum’s mandate as a museum. Although Robben Island was inscribed a World Heritage Site in 1999 under the category of cultural landscapes, fauna and flora form part of our valuable heritage assets and need to be prudently conserved and sustained at all times. We appreciate our collaboration with SANCCOB as it contributes in bolstering our efforts in managing the Island as an integrated resource,” says Mr Thabo Seshoka, Robben Island Museum’s Head of Heritage and Research.
Preparation to assess release readiness of the birds at the SANCCOB centre includes weighing (desired weight is over 1kg), plumage waterproof testing and general health assessments. Blood tests are also conducted on all birds before released to ensure there are no blood parasites or other blood conditions that could affect their survival. To prevent the birds from associating food provision in the wild with humans, all interactions with the birds for feeding will be conducted in black head-to-toe garments. Supported by Environmental Unit staff of Robben Island Museum, SANCCOB’s Penguin and Seabird Ranger on Robben Island is tasked with observing the birds’ behaviour once released and to monitor their movement.
All birds released from SANCCOB will be equipped with metal rings and a subset will be also individually marked with colour bands for easier identification. Ring resightings can be reported to SAFRING and SANCCOB. SANCCOB encourages the birding community and general public to keep an eye out for ringed Cape cormorants along the Western Cape coastline as birds will move to other locations once having joined the wild flocks. Through extensive post-release monitoring, we will be able to assess how successful intervention has been and learn more about the post-fledging movements of Cape cormorants. This information will be crucial to better protect the species in the future.
Thank you to all who have supported from near and far.
SANCCOB can be contacted at +27 21 557 6155 or email firstname.lastname@example.org.