Laughing Owl
From Wikipedia, the free encyclopedia
|
 |
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
 Plumage variation in the Laughing Owl
|
||||||||||||||
|
|
||||||||||||||
| Scientific classification | ||||||||||||||
|
||||||||||||||
|
|
||||||||||||||
| Sceloglaux albifacies (Gray GR, 1845) |
||||||||||||||
|
|
||||||||||||||
|
The Laughing Owl (Sceloglaux albifacies), Whēkau or White-faced Owl, was an endemic owl found in New Zealand, but is now extinct. It was plentiful when European settlers arrived in New Zealand in 1840. Specimens were sent to the British Museum where a scientific description was published in 1845. The species belongs to the monotypic genus Sceloglaux ("scoundrel owl", probably because of the mischievous-sounding calls).
[edit] Description
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 35.5-40cm (14-15.7") and wing length 26.4cm (10.4"), with males being smaller than females. Weight was around 600 grams.
[edit] 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 the similarity between an accordion's tune from a distance and descriptions of calls of the Laughing Owl, it is apparent that the method should have worked as it apparently did.
[edit] Distribution and subspecies
In the North Island, specimens of the smaller subspecies rufifacies were allegedly collected from the forest districts of Mount Taranaki or Mount 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 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 in or around 1881.
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.
[edit] Ecology
The Laughing Owl generally occupied rocky, low rainfall areas. It was also found in forest districts on the North Island. Their diet was catholic, 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 research of New Zealand's late Pleistocene and Holocene animal communities, creating 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 (Worthy, 2001)
The owls' diet generally reflected the communities of small animals in the area, taking prions (small seabirds) where they lived near colonies, New Zealand 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).
[edit] Breeding
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.
[edit] Extinction
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. 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[citation needed].
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, 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).
[edit] References
- BirdLife International (2004). Sceloglaux albifacies. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006. Database entry includes justification for why this species is listed as extinct.
- Blackburn, A. (1982): A 1927 record of the Laughing Owl. Notornis 29(1): 191-192. PDF fulltext
- Buller, Walter L. (1905): Supplement to the 'Birds of New Zealand' (2 volumes). Published by the author, London.
- Fuller, Errol (2000): Extinct Birds (2nd ed.). Oxford University Press, Oxford, New York. ISBN 0-19-850837-9
- Greenway, James C., Jr. (1967): Extinct and Vanishing Birds of the World, 2nd edition: 346-348. Dover, New York. QL676.7.G7
- Hall-Jones, John (1960): Rare Fiordland birds. Notornis 8(7): 79. PDF fulltext
- Lewis, Deane P. (2005): The Owl Pages: Laughing Owl Sceloglaux albifacies. Revision as of 2005-04-30.
- Pilgrim, R. L. C. & Palma, R. L. (1982): A list of the chewing lice (Insecta: Mallophaga) from birds in New Zealand. Notornis 29(Supplement): 1-33. PDF fulltext
- St. Paul, R. & McKenzie, H. R. (1977): A bushman's seventeen years of noting birds. Part F (Conclusion of series) - Notes on other native birds. Notornis 24(2): 65–74. PDF fulltext
- Williams, G. R. & Harrison, M. (1972): The Laughing Owl Sceloglaux albifacies (Gray. 1844): A general survey of a near-extinct species. Notornis 19(1): 4-19. PDF fulltext
- Worthy, Trevor H. (1997): A survey of historical Laughing Owl (Sceloglaux albifacies) specimens in museum collections. Notornis 44(4): 241–252. PDF fulltext
- Worthy, Trevor H. (2001): A fossil vertebrate fauna accumulated by laughing owls (Sceloglaux albifacies) on the Gouland Downs, northwest Nelson, South Island. Notornis 48(4): 223-233. PDF fulltext
- Worthy, Trevor H. & Holdaway, Richard N. (2002): The Lost World of the Moa. Indiana University Press, Bloomington. ISBN 0-253-34034-9
