Justification of Red List Category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be stable, with localised decreases in population size driven by human disturbance and climatic variability, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has now been quantified at under 500,000 breeding adults, not approaching the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The global population size has been quantified for most sites, with current population estimated of 469,760 breeding adults. This is less than the previous Red List assessments that estimated the total population as under 1,000,000 individuals, but was based on non-quantified data. Considering the current estimation, there is an increase of 18% in population size when historic and recent data are compared. However, this increase should be interpreted with caution as it is very likely to be related to improved population survey effort rather than an actual increase in population. For sites with current population estimates, 60% of the sites have an “unknown” trend due to data deficiency. Nevertheless, for the sites where data were available, 51% of sites were stable, 29% deteriorating and 20% improving. Fifteen sites are suspected extinct.
There is an increase of 18% in population size when historic and recent data are compared. For sites with current population estimates, 60% of the sites have an “unknown” trend due to data deficiency. Nevertheless, for the sites where data were available, 51% of sites were stable, 29% deteriorating and 20% improving.
Endemic to Australia and New Zealand. In Australia, the species occurs from Western Australia (Carnac Island) to New South Wales (Broughton Island). The distribution is not continuous, with sections of the southern coast of Australia without occurrence of breeding colonies. In New Zealand, Little Penguins occur from the Chatham Islands to mainland New Zealand, including Stewart Island.
The Little Penguin breeds during the austral autumn to summer months and are the only truly nocturnal penguin species on land; adults always arrive after dusk and leave before dawn (Klomp and Wooller 1991, Chiaradia et al. 2007, Rodríguez et al. 2016). This species is a generalist feeder, with large variability in diet between colonies and even between years at the same colony (Klomp and Wooller 198,; Gales and Pemberton 1990, Cullen et al. 1992, Fraser and Lalas 2004, Chiaradia et al. 2010, 2016). They feed mainly on clupeids, such as anchovy Engraulis sp. and sardines Sardinops sagax, when feeding chicks, but they may also feed on krill Nyctiphanes australis and several species of cephalopods at all stages of breeding (Gales and Pemberton 1990, Cullen et al. 1992, Chiaradia et al. 2016). This variability in diet is also found in their trophic interactions, where penguins can reduce the prey trophic range in response to years of low breeding success (Chiaradia et al. 2010).Little Penguins typically lay two eggs per clutch (Stahel et al. 1987), and up to three clutches over a breeding season (Johannesen et al. 2003). The penguins exhibit six main breeding stages: courtship, pre-laying exodus, pre-laying, incubation, guard and post-guard (Chiaradia and Kerry 1999), followed by moulting and inter-breeding stages (Salton et al. 2015). When feeding chicks, some parents make more foraging trips than their mates. This situation actually represents the norm (72% of cases), rather than the previously expected equal parenting (Saraux et al. 2011). Individuals can also alternate between two consecutive long foraging trips and several shorter ones throughout the chick rearing period (Saraux et al. 2011). Short trips allow for regular food provisioning of chicks (high feeding frequency and larger meals), whereas longer trips are triggered by a parent’s low body mass and therefore the need to replenish its own energy reserves. Little Penguins form groups when crossing the beach to nesting sites, and individuals seem to choose their travelling partners (Daniel et al. 2007). When foraging, some individuals can take advantage of manmade features, like ship channels to aid in their foraging (Preston et al. 2008). Breeding age, ranging from 2 to 18+ years, seems to play a crucial role as well, as middle-aged (8-12 years) penguins are better breeders (Nisbet and Dann 2009), employ more effective foraging strategies (Zimmer et al. 2011) and feed in different locations (Pelletier et al. 2014).
Principle threats to Little Penguins are introduced predators, bycatch, habitat loss through coastal development, oil pollution, mortality through roadkill and human disturbance at breeding colonies (Chiaradia 2013, Dann 2013, Cannell et al. 2016). Additionally, the impact of changing oceanic conditions appears to impact food availability and reproductive success (Voice et al. 2006, Wu et al. 2012).
Introduced predators impact colonies throughout the range to varying extents, with significant mortality occurring particularly from domestic dogs Canis familiaris, but impacts also noted from pigs Sus domesticus, cats Felis catus and Weka Gallirallus australis.
The species is assessed as being moderately at risk from bycatch in gillnets, although data is lacking (Crawford et al. 2017). As such, recreational gillnets in some parts of the range appear to have the potential to cause considerable mortality (Crawford et al. 2017). Some Tasmanian colonies have spatial closures (Lyle et al. 2014), but many have no protection and large numbers of gillnets are registered on the island (Crawford et al. 2017).
An additional challenge for this species is in the fast changing marine and terrestrial environment, particularly the rapidly warming sea of south Australia (Voice et al. 2006, Wu et al. 2012). In southwestern Australia, the warming sea has been associated with poorer breeding including lower fledging success, fewer chicks per pair and a lower mean mass of chicks at fledging (Cannell et al. 2012). Penguins have been also shown to catch less prey in warmer conditions (Carroll et al. 2016). Oceanographic change may lead to a mismatch between plankton and the small pelagic fish that are also penguin prey (Hinder et al. 2013).
On land, increasing terrestrial temperatures in the spring and summer months can cause fatal hyperthermia in both chicks and adults (Cannell et al. 2011, 2012, 2016). This is particularly relevant in those colonies where nesting occurs within the vegetation rather than in burrows, as a result of soft, sandy substrate.
Some of these pressures have been locally offset by a wide range of conservation efforts, such as the case of increasing population size at Phillip Island (Sutherland and Dann 2012), St Kilda (Preston et al. 2010, Preston 2011), Manly (Carlile et al. 2015), Oamaru (Agnew et al. 2016). Sites without strong conservation measures have experienced severe decreases, and many known breeding colonies no longer exist (Dann 1994, Stevenson and Woehler 2007).
Conservation Actions Underway
The species is the subject of on-going Australian and New Zealand long term research programs, with research-lead conservation activities in several sites along the distribution. Many populations of Little Penguins are severely threatened by human disturbance. Sites without strong conservation measures have experienced a severe decrease, but some of these pressures have been offset by a wide range of conservation efforts. Several volunteer and research groups are actively monitoring and protecting sites in Australia and New Zealand.
Conservation Actions Proposed
Continue programs to control invasive fauna and flora species. Increase population survey and monitoring to assess causes of mortality and reduced breeding success in populations throughout the species range. Design and propose MPAs within foraging zone at key sites. Encourage more involvement of community groups and schools on local population awareness and protection. Determine sub-species and/or sub-populations under pressure and with decreasing population that need local protection and tailored conservation status.
Text account compilers
Chiaradia, A., Martin, R., Moreno, R., Ekstrom, J., Butchart, S., Pearmain, L., Wilson, K.
Agnew, P., Wilson, K., Cannell, B., O’Neill, L., Carlile, N., Colombelli-Négrel, D., Chiaradia, A., Woehler, E., Carroll, G., Dann, P., Sutherland, D., Tennyson, A., Garcia Borboroglu , P., Copley, P., Grosser, S., Ramirez, F., Waugh, S., Houston, D., Holmberg, R.
BirdLife International (2019) Species factsheet: Eudyptula minor. Downloaded from http://www.birdlife.org on 14/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 14/10/2019.