Laughing owl

Laughing owl
Live S. a. albifacies specimen photographed between 1889 and 1910

Extinct  (1914)  (IUCN 3.1)[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Strigiformes
Family: Strigidae
Genus: Sceloglaux
Kaup, 1848
Species: S. albifacies
Binomial name
Sceloglaux albifacies
(Gray GR, 1845)
Subspecies
  • S. a. albifacies
    (South Island laughing owl)
  • S. a. rufifacies
    (North Island laughing owl)

The laughing owl (Sceloglaux albifacies), also known as whēkau or the white-faced owl, was an endemic owl of New Zealand. Plentiful when European settlers arrived in New Zealand, a scientific description was published in 1845, but it was largely or completely extinct by 1914. The species belonged to the monotypic genus Sceloglaux ("scoundrel owl", probably because of the mischievous-sounding calls).

Description

S. a. albifacies by John Gerrard Keulemans, drawn after living specimens owned by Walther Rothschild

The laughing owl's plumage was yellowish-brown striped with dark brown. There were white straps on the scapulars, and occasionally the hind neck. Mantle feathers were edged with white. The wings and tail had light brown bars. The tarsus had yellowish to reddish-buff feathers. The facial disc was white behind and below the eyes, fading to grey with brown stripes towards the centre. Some birds were more rufous, with a brown facial disk; this was at first attributed to subspecific differences, but is probably better related to individual variation. There are indications that males were more often of the richly colored morph (e.g. the Linz specimen OÖLM 1941/433). The eyes were very dark orange. Its length was 35.5–40 cm (14-15.7") and wing length 26.4 cm (10.4"), with males being smaller than females. Weight was around 600 grams.

Vocalizations

The call of the laughing owl has been described as "a loud cry made up of a series of dismal shrieks frequently repeated". The species was given its name because of this sound. Other descriptions of the call were: "A peculiar barking noise ... just like the barking of a young dog"; "Precisely the same as two men "cooeying" to each other from a distance"; "A melancholy hooting note", or a high-pitched chattering, only heard when the birds were on the wing and generally on dark and drizzly nights or immediately preceding rain. Various whistling, chuckling and mewing notes were observed from a captive bird.

Buller (1905) mentions the testimony of a correspondent who claimed that laughing owls would be attracted by accordion play. Given that recorded vocalizations are an effective means to attract owls, and given the similarity of a distant accordion's tune to the call of the laughing owl as reported, it is apparent that the method might have worked.

Distribution and subspecies

S. a. rufifacies

In the North Island, specimens of the smaller subspecies rufifacies were allegedly collected from the forest districts of Mount Taranaki/Egmont (1856) and the Wairarapa (1868); the unclear history of the latter and the eventual disappearance of both led to suspicions that the bird may not have occurred on the North Island at all. This theory has been refuted, however, after ample subfossil bones of the species were found in the North Island. Sight records exist from Porirua and Te Karaka; according to Māori tradition, the species last occurred in Te Urewera. In the South Island, the larger subspecies albifacies inhabited low rainfall districts, including Nelson, Canterbury and Otago. They were also found in the central mountains and possibly Fiordland. Specimens of S. a. albifacies were collected from Stewart Island/Rakiura in or around 1881.

Trevor H. Worthy (1997) records 57 body and 17 egg specimens in public collections. He concluded that the only ones of these that may be the missing type of rufifacies were NHMW 50.809 or that of the Universidad de Concepción. Greenway (1967) mentions specimens at Cambridge, Massachusetts (probably Harvard Museum of Natural History) and Edinburgh (Royal Museum) that seem to be missing in Worthy's summary.

Ecology and behaviour

The laughing owl generally occupied rocky, low rainfall areas. It was also found in forest districts on the North Island. Their diet was diverse, encompassing a wide range of prey items, from beetles and weta up to birds and geckos of more than 250 grams, and later on rats and mice. Laughing owls were apparently ground feeders, chasing prey on foot in preference to hunting on the wing. Knowledge on their diet, and how that diet changed over time, is preserved in fossil and sub-fossil deposits of their pellets. These pellets have been a boon to the paleobiological concentrations of otherwise poorly preserved small bones: " Twenty-eight species of bird, a tuatara, 3 frogs, at least 4 geckos, 1 skink, 2 bats, and 2 fish contribute to the species diversity" found in a Gouland Downs roosting site's pellets.[2]

Juvenile S. a. albifacies photographed around 1909

The owls' diet generally reflected the communities of small animals in the area, taking prions (small seabirds) where they lived near colonies, Coenocorypha snipe, kakariki and even large earthworms. Once Pacific rats were introduced to New Zealand and began to reduce the number of native prey items the laughing owl was able to switch to eating them instead. They were still therefore relatively common when European settlers arrived. Being quite large, they were also able to deal with the introduced European rats that had caused the extinction of so much of their prey; however, the stoats introduced to control feral rabbits, and feral cats were too much for the species.

Individuals of a bird louse of the genus Strigiphilus were found to parasitize laughing owls (Pilgrim & Palma, 1982).

Reproduction

Breeding began in September or October. The nests were lined with dried grass and were on bare ground, in rocky ledges, fissures or under boulders. Two white, roundish eggs were laid, measuring 44-51 x 38–43 mm (1.7-2" x 1.5-1.7"). Incubation took 25 days, with the male feeding the female on the nest.

Extinction

Turnaround video of a specimen, Naturalis Biodiversity Center

By 1880, the species was becoming rare, and the last recorded specimen was found dead at Bluecliffs Station in Canterbury, New Zealand on July 5, 1914 (Worthy, 1997). There have been unconfirmed reports since then; the last (unconfirmed) North Island records were in 1925 and 1927, at the Wairaumoana branch of Lake Waikaremoana (St. Paul & McKenzie, 1977; Blackburn, 1982). In his book The Wandering Naturalist, Brian Parkinson describes reports of a laughing owl in the Pakahi near Opotiki in the 1940s. An unidentified bird was heard flying overhead and giving "a most unusual weird cry which might almost be described as maniacal" at Saddle Hill, Fiordland, in February 1956 (Hall-Jones, 1960), and laughing owl egg fragments were apparently found in Canterbury in 1960 (Williams & Harrison, 1972).

Extinction was caused by persecution (mainly for specimens), land use changes, and the introduction of predators such as cats and stoats. It was generally accepted until the late 20th century that the species' disappearance was due to competition by introduced predators for the kiore, or pacific rat, a favorite prey of the laughing owl (an idea originally advanced by Walter Buller). However, since the kiore is itself an introduced animal, the laughing owl originally preyed on small birds, reptiles and bats, and later probably utilized introduced mice as well. Direct predation on this unwary and gentle-natured bird seems much more likely to have caused the species' extinction. A comprehensive review of the species' decline and disappearance is presented by Williams & Harrison (1972).

See also

References

  1. ↑ BirdLife International (2012). "Sceloglaux albifacies". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. ↑ Worthy, 2001

External links

This article is issued from Wikipedia - version of the Monday, May 02, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.