The African penguin Passive Integrated Transponder (PIT) Project encompasses the marking of birds to assess long-term survival and seabirds’ movements between different colonies. Marking enables identification of seabirds at the nest site, which assists with breeding success studies. African penguins were historically marked with metal flipper bands, after the Treasure oil spill in 2000, over 17,000 de-oiled African penguins were marked with flipper bands and much of what we know today about the species survival and movements is based on resighting data. For SANCCOB, it is very important to be able to “follow” seabirds that have undergone rehabilitation or hand reared as eggs/chicks to assess the effectiveness of the artificial hand rearing and rehabilitation processes.
Unfortunately, the use of metal flipper bands was shown to have negative effects in other penguin species and the use of these bands was discontinued in South Africa in the early 2000s. Several other methods were trialled, such as silicone flipper bands and individual’s spot pattern recognition. The use of Passive Integrated Transponders (PIT, also called RFID) was selected as the most effective method of marking African penguins. These subcutaneous transponders or microchips are the same as those used in domestic dogs and cats and are inserted under the penguin’s skin. These transponders carry a unique sequence of numbers which provide opportunities to re-encounter marked individuals when coming ashore at seabird colonies as the PIT can be read either using hand-held readers or ground readers which are installed at entry points to the colonies.
Saving and Tracking Seabirds
Since 2013, more than 10,000 African penguins have been marked with PIT, both in wild colonies and as released seabirds from rehabilitation centres in South Africa. All African penguins released from SANCCOB, including hand-reared chicks and other seabirds that were rehabilitated due to injuries, oiling or emaciation, are marked with transponders in addition to fledglings and breeding adults in the wild seabird colonies. SANCCOB Penguin & Seabird Rangers along with conservation authorities' staff are equipped with hand-held readers and encounter marked birds on a weekly basis during their nest check monitoring, thus also obtaining valuable information on the breeding status of these individuals.
Due to the generous funding from the American Zoos & Aquariums (AZA) SAFE programme, 11 ground readers have been installed in 6 of the main seabird breeding colonies in South Africa. These remote readers are placed along main pathways into the colonies and marked penguins walk over a long cable antenna when leaving the colony to go to sea and when returning to attend to their eggs and chicks in the colony. The data from these readers is regularly downloaded and has provided an interesting insight into the penguins’ behaviour. The detection of marked birds allows us to assess their survival probability using mark-recapture models. It is possible to compare the survival probability of wild penguins, both chicks and adults, to those rehabilitated and hand reared at SANCCOB. Initial analyses have shown that the chicks hand reared at SANCCOB have the same chance of survival during their few first years at sea compared to chicks raised by their parents in the wild. This finding is crucial for SANCCOB as it shows that the Chick Bolstering Project contributes to the bolstering of the wild population and that this conservation intervention plays a significant role in conserving this endangered species. Despite a slightly reduced survival probability in rehabilitated adults compared to breeding adults in the wild, the calculated rates are still within the range of what is observed in wild colonies. Adult African penguins rehabilitated at SANCCOB have often endured severe injuries, pollution or malnutrition and undergone extensive rehabilitation. Therefore, a slightly lower survival rate is expected, however initial studies confirm that the release of these penguins back into the wild also plays an important role in saving this species from extinction.
Market with PIT
Marked birds can tell us a lot more than just their survival rates. We are now discovering that they penguins visit several colonies before eventually deciding on where to breed. The transponder data has also revealed that many penguins chose a different colony to breed that was different to where they hatched and fledged. This is most likely linked to breeding sites with good food availability rather than returning to their natal colony.
To obtain further data on body condition, ground readers at Stony Point colony in Betty’s Bay and St Croix Island in Algoa Bay have been linked to a weighbridge in a joint project with BirdLife South Africa. Through this African Penguin Monitoring System (APMS), we can monitor how long penguins stay at sea foraging and how much food their bring back to their chicks as the penguins walk over the weighbridge as they exit the colony and, on their return, thus getting an idea of the food availability around the breeding colony. Data from GPS tracking studies have shown how far penguins travel in a certain amount of time when foraging, assessing important foraging areas. This information is used to inform government on an adaptive management framework, and in particular, an ecosystem approach to fisheries.