One of our earlier stars of #BeakoftheWeek, the little penguin, is under the spotlight in todays blog.
Also known as the little blue penguin or fairy penguin, the little penguin is the smallest member of the penguin family Spheniscidae and the only member of its genus. It is 40-45cm in length and weighs around 1kg, with males being larger than females on average and having slightly thicker beaks. Both sexes have metallic, slate-blue plumage on their upper parts and the majority of the head, and white plumage on their underparts. During its annual moult, the little penguin replaces all its feathers simultaneously and so must stay ashore for about 2 weeks as it is not waterproof during this time.
Penguins are flightless birds and their ancestors’ wings evolved into flippers, making them powerful swimmers. Indeed the genus name of the little penguin, Eudyptula, means “good little diver”. The little penguin is a pursuit hunter, foraging for pelagic shoaling fish (in particular the Australian anchovy (Engraulis australis) and southern garfish (Hyporhamphus melanochir)) and cephalopods (e.g. red arrow squid (Nototodarus gouldi)) in the temperate coastal waters of New Zealand and Southern Australia. It can dive to depths of around 50 metres and normally feeds alone or in small groups. The birds return to their colonies after dark, often collecting in a raft with the same individuals out at sea, before coming to shore together.
Breeding colonies can be found along the entire coastline of New Zealand and parts of Southern Australia, such as Victoria, Western Australia, Tasmania, New South Wales and South Australia. The social structure of the little penguin is monogamous during the breeding season and pairs often return to the same nesting site year after year, although the divorce rate is between 18 and 50%. The nesting burrow is excavated into sandy soil at the base of dunes or cliffs, under thick vegetation, in a natural hollow or even under human-built structures such as houses. The nest is lined with plant material. Across their range, little penguins have been recorded breeding throughout the year and have highly variable laying dates. Interestingly, a recently published study suggests that little penguins may be able to fine-tune their reproductive timing with marine productivity patterns (Afán et al. 2015).
Two eggs is the normal clutch size and these are off-white in colour, sometimes with mottled brown markings or spots. Both parents incubate the eggs over a period of 33-37 days. Once they hatch, the chicks are in an altricial state and so need to be tended to and cared for by the adult birds. Chicks become downy, with dark brown down on their upperparts and paler brown and white down below. Young birds may form small crèches with other juveniles and reach independence at 50-55 days old. The average life expectancy of a breeding adult in the wild is approximately 6.5 years, however some particularly long-lived individuals have reached over 20 years in age, with the record being 25 years and 8 months (Dann et al. 2005).
Little penguins have a variety of vocalisations, ranging from trills and braying sounds to low grunts and deep growls to loud squeals and wailing. A ‘bark’ contact call at sea is given. These penguins are particularly noisy after dark at their colonies, which can cause disturbance to residents that have little penguins nesting under their houses. However in many cases, the little penguins relationship with humans is positive. These charismatic birds draw a great deal of attention at specially organised tourist sites. For example, at the Oamaru Blue Penguin Colony and at the Penguin Parade on Philip Island, tourists can observe the penguins returning to their nests after dusk. Volunteers and staff also work to conserve the colonies and their habitat, educate visitors, conduct scientific research and monitor the little penguins. Sir David Attenborough does a great job at describing the penguins on Philip Island in this video.
The little penguin is currently classified under the IUCN red list as ‘Least Concern’ primarily due to its wide range and large population size (unknown, but estimated to be over 1,000,000 individuals in the 1980s). Whilst the population is declining, it is not doing so at a high enough rate to warrant a change of classification to ‘Vulnerable’ at present.
Many colonies are declining as a result of habitat degradation and predation by introduced animals such as domestic dogs, feral cats, stoats (Mustela erminea), ferrets (Mustela furo) and foxes (Vulpes vulpes). Fur seals (Arctocephalus forsteri) are a natural predator of the little penguin and are not thought to be a driving factor of population declines. Little penguins are also killed as a result of oil and plastic pollution, road collisions and entanglement in fishing nets.
On the other hand, populations such as those in Wellington Harbour, Banks Peninsula and the Oamaru Blue Penguin Colony, are increasing as a result of predator control and the provision of safe nesting sites in the form of nest boxes.
There are some good tips on how to help reduce the threats little penguins face on the New Zealand Department of Conservation’s website, including instructions for making your own penguin nest box!
BirdLife International (2012) Eudyptula minor. The IUCN Red List of Threatened Species. Version 2015.2. <www.iucnredlist.org>. Downloaded on 01 July 2015.
BirdLife International (2015) Species factsheet: Eudyptula minor. Downloaded from http://www.birdlife.org on 30/06/2015.
Dann, P., Carron, M., Chambers, B., Chambers, L., Dornom, T., McLaughlin, A., Sharp, B., Talmage, M. E., Thoday, R. & Unthank, S. (2005) Longevity in Little Penguins Eudyptula minor. Marine Ornithology , 33(1): 71–72
Flemming, S.A. (2013) Little penguin. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz
Martínez, I., Christie, D.A., Jutglar, F. & Garcia, E.F.J. 2013. Little Penguin (Eudyptula minor). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.) (2013) Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/52468 on 29 June 2015).
Kowalczyk N.D., Chiaradia A., Preston T.J. & Reina R.D. (2015) Fine-scale dietary changes between the breeding and non-breeding diet of a resident seabird. R. Soc. open sci, 2: 140291. http://dx.doi.org/10.1098/rsos.140291