April 16, 2019 Dyer Island Conservation Trust
Why are we designing the perfect artificial African penguin nest?
Before the advent of artificially produced fertiliser, guano was considered a top quality fertiliser rich in nitrogen, phosphorous and
potassium. Guano (an Inca word for a mix of eggshell, feathers, decayed corpses and bird excrement) was scraped from the penguin breeding islands. On Dyer Island, the guano layer was between 4-6m deep. Penguins used to build their nests by burrowing into the thick layers of guano. This “forced removal” from well protected, temperature controlled burrows to open surface nests, exposed the African Penguin to the harsh African heat and occasional flooding. The “open-plan” living arrangement turned their eggs and chicks into an easy meal for predators like gulls & skuas.
At the start of the nest / housing project in 2006, the main aim of the artificial nests was to provide protection from predation. The original nests were manufactured from fibre-glass and although the nests addressed the predation problem, research indicated that the nests became too hot inside. Penguins simply abandoned the nest leaving eggs and chicks behind.
Meeting the housing needs of the African penguin started us on the quest for the perfect penguin penthouse. Research told us that the guano burrows provided the penguins with:
• A constant micro-climate
• High relative humidity
• Buffered temperatures
• Little exposure to the wind
• Shelter from rain & predation
We could therefore reach the following conclusions:
• Temperature inside is the nest most important aspect – material must try to mimic conditions of guano burrows.
• Nest size – must be able to accommodate 1 adult & 2 chicks
• The penguins must be able to defend the access to the nest
• Adequate ventilation
• Ideal temperature: 24 – 26oC
• Humidity: 80 – 90%
The nest team spent 3 months rigorously field- testing 15 different nest prototypes, each equipped with high-precision sensors, to
provide us with information about the microclimate conditions inside the various test nests.
The “winning” nest material is a ceramic based slurry. The interior volume of the nest was based on measurements of wild guano nests. The nest entrance mimics the entrance hole of the old guano burrows. The new style penguin penthouses were revealed to the penguin populations of Bird Island in the Eastern Cape and Dyer Island in the Western Cape in February 2018. Continued environmental monitoring proved that the new design meets all the environmental requirements, but ultimately we need to know
that the penguins will successfully breed and raise their chicks in these newly designed penthouses.
We do not aim to save the African penguin from ex