Climate change chickens have come home to roost
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Cape Town - Climate change does not only have an impact in the lives of humans but seabirds too.
Leiden conservation scientist at the Southern African Foundation for the Conservation of Coastal Birds (Sanccob), Lauren Waller said heavy rain can cause flooding of nests, causing eggs to die or wash away chicks to drown.
“Wave surges can also wash away nests causing egg and chick mortality. African penguin chicks are susceptible to mortality through hypothermia.
“When they are small chicks, they do not have the fully grown feathers yet, but rather downy feathers that are not waterproof.
“When it rains, they get completely wet through, unlike the feathers they have when they are a full grown chick about to fledge which are waterproof. A combination of heavy rain and strong, cold winds, can cause mortality from hypothermia. On extremely hot days, chicks can overheat and die from hyperthermia,” she said.
Seabirds have a layer of warm downy feathers that helps retain heat.
Waller said the structure of the feathers in seabirds allow them to stay waterproof and thus warm when they feed in the cold waters.
“They are tightly backed and overlap to provide waterproofing and warmth. Chicks huddle together, especially penguin chicks. Many penguins have black backs to help absorb the heat.
”Birds also fluff their feathers to trap air between their feathers and bodies, creating a layer of insulation. They reduce the area exposed to the cold by taking their heads under their wings,” she said.
Like many animals, seabirds play an important role to the environment and the health of marine ecosystems.
“Through their guano, they are a supplier of nutrients to land masses and adjacent coastal areas since, consuming biomass that is the same order of magnitude as that of global fisheries.
”This guano influences the functioning of island ecosystems and adjacent marine ecosystems such as promoting the growth of algae which in turn influences the structure of intertidal communities.
“This in turn influences the population sizes of some shorebird species.
”They can indicate what the status or availability of fish stocks are; if oiling events have taken place, or oil leaking from a sunken container; indicate impacts of climate and environmental change; can indicate the impact of marine plastics and how they are travelling in food chains,” she added.