Morepork Owl (Ninox novaeseelandiae)

Morepork owl

The morepork owl (Ninox novaeseelandiae) also known as the ruru bird, new Zealand owl, little owl, or boobook, is a small brown owl native to New Zealand. It’s also sometimes called kukupa, especially on Stewart Island and Southland by the Māori people.

Ninox novaeseelandiae is an owl native to New Zealand that makes an eerie, guttural sound at night, earning it the nickname morepork or mopoke among New Zealanders. Despite its screeching call, the morepork owl relies on its nearly silent flight to capture prey rather than startling it with a noise like other owls.

New Zealanders know them as Morepork owls, to Australians they’re called ruru birds, but no matter what you call them, the morepork owl (Ninox novaeseelandiae) remains one of the most unique and revered birds in Australia and New Zealand.

Description

Morepork owl

The morepork owl is also known as New Zealand’s biggest endemic owl species. There are two subspecies of the morepork owl, one with smaller wings and shorter tail feathers, found in the southeastern corner of Australia and Tasmania.

The other, larger variety can be found in New Zealand and has a long tail and wings that extend past its feet. These owls are relatively common throughout their habitat but remain largely hidden from view due to their cryptic coloring.

They are mainly nocturnal birds, meaning they fly at night and sleep during the day. They generally nest in tree hollows and use their large flat feet to help them climb. Although these owls live for about 12 years on average, their life expectancy depends on how often they are preyed upon by eagles or cats which will kill them before they reach adulthood.

Morepork owl scientific name

The scientific name of the morepork owl is Ninox novaeseelandiae

Morepork habitat

The Morepork owls are primarily found in forests and the canopy of tall trees, but they can also be found in areas that have a lot of tall grass, such as alongside fences and tracks.

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Morepork size and weight

An adult morepork owl weighs between 140 and 216 grams, which is about 4.9 to 7.6 oz. They are one of the heaviest species of owl in the world with a body size of around 26 to 29 cm or 10.2 to 11.4 inches. They have a wing length of around 18.3 to 22.2 centimeters or 7.2 to 8.7 inches.

Feathers and plumage

Morepork owl

Generally, moreporks are dark brown with pale brown spots on the head and neck, dark brown ear coverts, and buff cheeks, with a pale yellow-white supercilium (eyebrow) and a pale yellow-white supercilium (eyebrow).

In color, the eyes range from yellow to golden yellow. There are buff feathers on the chin and throat with dark brown shafts. With larger markings on the belly, the underparts appear paler overall due to the darker brown feathers and buff and white spots.

A darker brown bar runs along the upper portion of the tail. There is a thin black cutting edge on the cere and bill. There are blackish claws on the feet, which are orange or yellow in color.

It takes more than two years for young moreporks to reach their adult plumage. Young birds have white and fluffy feather tips, resembling those of their nestlings. It is these that wear away over time, and they last longest on the head.

There is more fluff on the head, neck, and underparts. Compared to adults, they have darker plumage and a more greyish brown complexion.

Molting

The molting process starts a few months before when the owl starts eating less to save up energy. They also spend more time sitting out on branches during the day and foraging at night.

After about three months of gathering energy, their feathers start to shed and new ones grow in their place. With fresh feathers come renewed strength, so owls that have molted can go on long hunting excursions without getting tired.

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Once they are done growing, the old feathers are pushed off by the new ones. For most birds, this happens gradually over a period of weeks or months, but some birds (like owls) molt all their feathers in one go! Molting is an important part of being an owl because it ensures they will always be able to fly away from danger if needed.

Nesting behavior

Morepork owls typically nest in cavities but will sometimes use the holes excavated by larger birds. They are fiercely territorial during the breeding season, aggressively defending their territory from intruders who are on the ground like raccoons or possums.

The morepork owl is a relatively small, ground-dwelling bird that lives in the forests of New Zealand. Unlike other species of owls, they are strictly active during the day and they do not roost on tree tops. They prefer forest edges with substantial foliage coverage as well as suburban and agricultural areas near forests or scrublands.

In regions with high population densities and heavy deforestation, the moreporks will nest much closer to urban areas including city parks. These birds are territorial and may defend their territory against others of their own kind if there is enough food available.

To deter potential invaders, they make loud sounds by beating their wings on the sides of trees. However, this behavior can also attract unwanted visitors like hawks so it should be done carefully. Moreporks mate for life and both males and females take turns sitting on the eggs while they incubate them together.

Diet and foraging

Morepork owls live in a variety of habitats, from forests to scrubland, and eat all kinds of invertebrates. Most of their diet is beetles and large bugs, but they also eat other smaller prey such as lizards and spiders.

Sometimes, they will also feed on small birds or even smaller mammals that have fallen out of the trees. This can include opossums and sometimes rats. As for foraging, moreporks are most active at night during the breeding season.

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Morepork owl sound and vocal behavior

Calls are almost exclusively made at night. There is an onomatopoeic call called the ‘more-pork’ that is among the most characteristic and frequently heard. In addition to their repetitive ‘quork-quork’ call, they make a rising ‘quee’ call, often mistaken for the call of a Kiwi, and a short yelping call that sounds like the call of a little owl.

Breeding

Morepork owl

Morepork owls form monogamous bonds that last for a lifetime. Breeding takes place between September and February and they nest in hollow trees. Nests are found in hollow trees, in trees with holes, and occasionally in a tree fork.

A female will typically lay 2 to 3 eggs a month and then tend to them for the duration of their incubation. Their feathers are grayish-white and they hatch helpless. They are nurtured by both parents and fledge by five weeks of age.

Typically, young owls remain with their parents for some time, reaching reproductive maturity at two to three years of age.

Lifespan

The life span of the Morepork owl is typically 5 to 6 years in the wild. In captivity, moreporks can live up to 11 years.

Movements and migration

The Morepork owl mainly inhabits the top of NZ’s North Island and lower areas of the South Island. They only migrate in response to changes in food supply and habitat, but sometimes their migration is forced by predators, such as cats and rats.

These owls like to roost on high branches, making it easier for them to hunt prey below and spot predators coming up from below. The Moreporks roost near other types of birds and do not travel as far as other types of owls.

Diseases and threats

The morepork owl is threatened by habitat destruction, light pollution, human development, and feral cats and rats. It also suffers from its territorial nature which limits the number of mates available for breeding.

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In some cases, invasive species have caused population declines. Moreporks are preyed upon by ferrets, stoats, weasels, and occasionally wild cats.

Morepork owls also suffer at the hands of humans as they are shot on sight due to their sometimes aggressive behavior towards poultry.

Population status

Morepork owl population size is not provided in the IUCN Red List or other sources. Its numbers today remain stable and its status on the IUCN Red List is Least Concern (LC).

Conservation and management

Many conservation efforts for this species focus on clearing vegetation from around their nests, which has been proven to be successful in encouraging nest-building behavior. An alternative and arguably more successful approach has been to limit access to the breeding colonies during the breeding season by removing ground cover so that they cannot set up nests.

At some sites where this method is used, egg numbers have remained constant despite reductions in tree numbers. Ongoing research is being conducted to determine if disturbance at these sites is causing a higher mortality rate than elsewhere or if eggs are being destroyed after laying as a result of increased predation rates.

A third management option is to provide artificial roosts near tree habitats as an alternative nesting site. This option requires regular monitoring and maintenance of the roosts and should only be implemented when natural nesting trees are scarce.