The blue or little penguin (Eudyptula minor), also known in Maori
as korora, can be found in many places around New Zealand and Southern
Australia and is the world's smallest penguin. They only come ashore
under the cover of darkness and live underground in burrows. Although
quite common, its small size and unusual habits make it rarely seen.
The blue penguin stands just 25 cm tall and weighs a little over 1
kilogram. The plumage is slate-blue with a bright white belly. Juveniles
are indistinguishable from adults. Both sexes are alike, although
the male is a little heavier and usually has a larger bill. There
are several distinct races of blue penguins and some argue that they
should be split up into sub-species. Perhaps the most distinct is
the "white-flippered" penguin of Canterbury, however genetic
tests have shown it not to be as distinct as its plumage would suggest.
The Blue penguin breeds along the entire coastline of New Zealand,
the Chatham Islands, and southern Australia. Blue penguins have also
been reported from Chile (where they are known as Pingüino pequeño
or Pingüino azul and South Africa, but it is unclear whether
these birds were vagrants. Rough estimates (as new colonies continue
to be discovered) of the world population are around 350,000-600,000
animals. The species is not considered endangered, except for the
White-Flippered subspecies found only on Banks Peninsula and nearby
Motunau Island in New Zealand. Blue penguins breed underground in
burrows or natural holes, although they will make use of any man-made
cavity. Near human habitation it is not uncommon to find them nesting
under buildings, stacks of timber or even railway tracks. Artificial
nest boxes are readily adopted.
Blue penguins in New Zealand have rather variable breeding seasons.
The core egg-laying period for most of New Zealand is September to
November, and only one clutch is laid. In good food years, blue penguins
in Otago will egg-lay from May to February, with many pairs raising
two clutches of chicks.Usually two eggs are laid and are incubated
for 36 days, with both parents sharing the incubation and feeding
duties. The chicks are guarded by one parent for the first 2-3 weeks,
after which both parents must go to sea to keep up the supply of fish.
Chick growth is rapid, with adult weight (1000g) being achieved in
4-5 weeks. Chicks usually fledge at 8 weeks and are independent from
then on.Blue penguins usually breed for the first time at 2-3 years
of age. Long term partnerships are the norm, but divorce is not uncommon.
There is a high rate of juvenile mortality, but individuals can reach
up to 25 years of age.Blue penguins are very faithful to their home
site. Chicks will often return to within a few metres of where they
were raised and once settled in an area never move away. A small number
(<1%) of juveniles disperse to other breeding sites.
These birds feed by hunting fish, squid and other small sea animals,
for which they travel and dive quite extensively. They are generally
inshore feeders. The use of dataloggers has provided information of
the diving behaviour of Little Penguins. 50% of their dives go no
deeper than 2 m and the mean diving time is 21 seconds. Yet, they
are able to dive as deep as 20m and remain submerged as long as 60
The species is not considered endangered, except for the White-Flippered
subspecies found only on Banks Peninsula and nearby Motunau Island
in New Zealand. Since the 1960s, the mainland population has declined
by 60-70%; though there has been a small increase on Motunau Island.
But overall Little Penguin populations have been decreasing as well,
with some colonies having been wiped out and other populations continuing
to be at risk. However, new colonies have been established in urban
areas. The greatest threat to Blue Penguin populations has been predation
(including nest predation) from cats, dogs, mustelids, foxes, large
reptiles, and possibly ferrets and stoats. Due to their diminutive
size and the introduction of new predators, some colonies have been
reduced in size by as much as 98% in just a few years, such as the
small Fairy colony on Australia's Middle Island, which was reduced
from 5000 penguins to 100. Because of this threat of colony collapse,
conservationists pioneered an experimental technique using Maremma
Sheepdogs to protect the colony and fend off would-be predators.