Little Blue Penguin (Eudyptula minor)
Image from http://animal-unique.blogspot.com/2011/11/little-blue-penguin.html
Found all along the coast of New Zealand and Southern Australia, this dinky little sea bird is the smallest species of penguin, reaching dizzy heights of just 33cm! This species has lovely dusky blue plumage fading into white feather on their bellies. First discovered in 1781 by the naturalist Johann Reinhold Forster, there are today several subspecies identified, although there is a lot of disagreement between taxonomists over exactly how many there should be. Molecular studies have recently shed more light on this controversy, indicating that populations from Australia and the Otago region of the South West Island of New Zealand are possibly a distinct species, called Eudyptula minor novaehollandiae and Eudyptula minor minor respectively.
Fortunately, this species is currently listed as Least Concern by the IUCN, with their population determined to be stable, although scientists have recently noted that certain populations are declining through human disruption and environmental changes.
New Zealand: the evolutionary home of the penguin
For a long time, researchers were unsure where penguin species evolved, but the discovery of fossil records identified New Zealand as the origin of these cute seabirds, specifically the South Island in an area called Waipara. Molecular studies of penguin genomes have shown that penguins evolved from flightless birds 60 to 65 million years ago hailing from the ancient super continent Gondwana. The Little Blue Penguin is part of a family called the Spheniscidae, which contains 18 species of penguins including famous members like the Emperor Penguin, gentoo penguin and the yellow eyed penguin. Their closest relatives are the Procellariiformes, a family of seabirds including the Albatrosses, loons, petrels and frigatebirds.
No one exactly knows what drove the early penguins into the sea, but the most common theory is that food became more abundant in the ocean, driving their evolution into flightless sea birds. Their wings evolved into hydrodynamic flippers, their legs shifted into a more posterior position, allowing them to use their feet as rudders and they developed thick layers of waterproof feathers to protect them from the cold water.
The ancient ancestors of the modern penguins seen today were as tall as humans, based on the fossil records found in New Zealand. (image from https://theusbport.com/zealand-fossils-reveal-details-penguin-evolution/29268)
Habitat and Ecology
The range of the little blue penguin. (image from https://www.penguins-world.com/little-blue-penguin/)
The Little Blue Penguin is endemic to the coastal regions of South Australia and New Zealand and several offshore islands, and there have even been reports of them in Chile and South Africa, although it is likely that these sighting are just rare migrants that have moved outside of their normal range. They inhabit the rocky shores of these regions, utilising several areas like savannahs and scrub forests to nest and rest after days foraging at sea. It is unusual for them to be found in areas unreachable by humans, which is causing issues with human disruption and predation from invasive species like feral cats and dogs. As ground nesters, this makes the species especially at risk from invasive species that will prey on the eggs.
They aren’t fussy feeders, predating mainly on anchovies and sardines but will even eat organisms as small as krill and as large as cephalopods like squid. This generalist diet makes them an important link in the ecosystem, as they keep populations of prey fish down. Although they will snack on many different species, populations will adapt to their local conditions, and differing diets have been identified across their range. This adaptability is encouraging, as species with this trait tend to tolerate climate change and human disruption better than others that struggle to change their ecology so quickly.
This dietary adaptation also causes geographical differences in foraging behaviour and strategies. Across their range, the depth and duration of their dives differ, as well as their foraging strategies. Some of this has been attributed to changes in sea temperature driven by global warming, which is causing shifts in food availability. At one point, this discovery got scientists quite excited, as it was believed the little penguin could be used as an indicator species. This is a species that can indicate changes in the environmental conditions of their habitat, either through metrics like their behaviour or population size. In this case, it was hoped the foraging behaviour and dietary choices of the Little Penguin could indicate fluctuations in temperature and disruptions to the marine food chain. However, the Little Penguin proved to be too adaptable for this, able to change their diets and behaviour however was required to survive, making it impossible to track changes. We can see this as a kind of a positive and a negative: a good sign for penguin survival, but no so great for people trying to track problems in the environment!
All species of penguin are well adapted for their marine lifestyle with a range of adaptations and the Little Blue Penguin is no exception. They have solid bones that act like a diving belt, allowing penguins to maintain a good depth when diving. Their paddle like flippers allow them to propel themselves through the water after fish, their feet are specially designed to act as rudders and their wedge-shaped tails help them clamber up onto land. These specialised adaptations make penguins super-efficient hunters and a vital link in the food chain.
The future of the Little Blue Penguin
Although this species is listed as least concern by the IUCN, some of their populations are seriously threatened by a combination of invasive species and human disturbance. Feral cats and dogs are a particular issue as they can attack the penguins and their nests on the ground. Penguins may be speedsters in the water, but they are clumsy on land and certainly aren’t graceful enough to outrun predators on land. Human coastal developments and roads are a big threat to the penguins, with disruption to nesting grounds and increasing mortality from cars. Unfortunately, the penguins aren’t entirely safe in the ocean either. In the past they have been the victims of major oil spills around the New Zealand coast and fall prey to deadly gillnets, rows of nets anchored to the seabed to catch fish that have horrendous impacts on many species of marine life. Reduction of their fish and plankton prey has also been recorded in recent years, attributed to both overfishing and climate change affecting food webs in the sea.
Climate changes may be having a particular effect on this species. In a study that looked at 3 years of sea surface temperature data and numbers of chicks born, researchers found that higher sea surface temperatures in April and May, just before the breeding season, resulted in decreased breeding success, with fewer chicks. Those chicks that were born were also found to be a lot lighter than chicks in cooler years. The reasons for these changes weren’t clear, but its likely that climatic fluctuations are making it harder for penguins to find food, reducing the time and energy they have for breeding. With less food, the penguins may not have enough energy to breed at all, and if they do and a chick is successfully born, they won’t have sufficient food and so will be lighter and smaller, as seen in the study mentioned above. Other studies have found increased temperatures also caused increased chick death, especially in areas that are more exposed with less tree or shrub cover.
Further studies on the Little Blue Penguins in New Zealand have found that human induced trauma is the most common cause of death for this species. In particular the researchers found that water sports like speed boats and jet skis were the biggest issue. Starvation was found to be the second cause of mortality.
Although issues with climate change and preventing increasing temperatures are a lot more complicated to deal with, there are some easy changes that can be implemented to help these charismatic little sea birds. For instance, researchers from the paper mentioned before have suggested introducing speed restrictions on boats and jet skis in the waters around penguin nesting areas. In many places, people are encouraged to keep pets on leashes when walking near nesting colonies, and to keep away from burrows the penguins use. In New Zealand, the environmental organisation Conservation Volunteers work to restore coastal habitat, build and install nest boxes, patrol breeding areas and run many educational workshops. Fortunately, several large populations of the Little Blue Penguins are currently found in Marine Park Protected Areas, giving them legal protection. In New South Wales, the population there is officially recognised as endangered, and the local government have imposed several building restrictions on local landowners, preventing loss of vital penguin nesting habitat. In areas where large nesting colonies can be found, invasive species controls are in place, particularly for rats and fast growing, invasive weeds.
https://conservationvolunteers.co.nz/
- Conservation volunteers work on a wide range of vital conservation initiatives across New Zealand, including activities to help the Little Blue Penguin. If you live in New Zealand, you can get involved in their range of projects and have a real impact! They also provide a lot of useful tips on their website if you don’t have time to volunteer but still want to help nature.
Awesome videos!
References
Banks, J.C. Mitchell, A.D. Waas, J.R. and Paterson, A.M. (2002) ‘An unexpected pattern of molecular divergence within the Blue Penguin (Eudyptula minor) complex’ The Ornithological Society of New Zealand, 49, pp 29-38
Cannell, B.L. Campbell, K. Fitzgerald, L. Lewis, J.A. Baran, I.J. and Stephens, N.S. (2016) ‘Anthropogenic trauma is the most prevalent cause of mortality in Little Penguins, Eudyptula minor, in Perth, Western Australia.’ Emu, 116
Cannell, B. Chambers, L. Wooller, R. and Bradley, J.S. (2012) ‘Poorer breeding by little penguins near Perth, Western Australia is correlated with above average sea surface temperatures and a stronger than Leeuwin current’ Marine and Freshwater Research
Chilvers, L. (2019) ‘Variability of Little Blue Penguin (Eudyptula minor) diving behaviour across New Zealand.’ New Zealand Journal of Ecology, 43(2)
https://www.iucnredlist.org/species/22697805/202126091
https://www.penguinfoundation.org.au/
Mayr, G. De Pietri, V.L. Love, L. Mannering, A.A. Bevitt, J.J. and Scofield, R.P. (2020) ‘First complete wing of a stem group of Sphenisciform from the Paleocene of New Zealand sheds light on the evolution of the penguin flipper’ Diversity, 12(2)
Stahel, C.D. and Nicol, S.C. (1982) ‘Temperature regulation of the little blue penguin in air and water’ Journal of Comparative Physiology, 148, pp 93-100
