Difference between revisions of "Blue Duck" - BirdForum Opus

Latest revision as of 20:19, 27 November 2023

Alternative name: (Maori) Whio

Photo © by martinuk
Manganui o te Ao River, Manawatu-Wanaganui Region, North Island, New Zealand, January 2010

Hymenolaimus malacorhynchos

Identification

Size: 53cm (21in); weight: male 1,000g, female 750g.

Bluish-grey overall plumage
Reddish-chestnut spots on the breast
Yellow eyes
Pale pink bill, with the upper mandible having a thick semi-circular, fleshy 'lip' that overlaps the lower mandible, allowing it to scrape insect larvae off underwater rocks, without causing wear on the bill

Sexes are similar, female is smaller.
Juvenile has less speckling on breast, and has a grey bill and eye.

Showing the fleshy 'lip'
Photo © by the late Rookery
Back country, Hawke's Bay, New Zealand, February 2016

Distribution

New Zealand.

Status

It is classified as a "Nationally Endangered" species, with current populations at about 2,500 individuals and declining. Early causes for the decline, were habitat loss, especially forest clearance for agriculture. Unless the causes for the decline can be remedied, the species is on the track for extinction.

Taxonomy

Subspecies

Two subspecies are recognized^[1].

H. m. hymenolaimus

central and eastern North Island, New Zealand

H. m. malacorhynchos

western South Island, New Zealand

Habitat

Clean, fast flowing, mountain streams, in well-vegetated areas.

Behaviour

A strong swimmer not often seen in flight.

They are usually active during the early morning and late evening, when they are seen standing on rocks, or with head and neck underwater while feeding. During the rest of the day they hide in caves, log-jams or suchlike and some populations have become almost nocturnal.

Breeding

Blue Ducks develop strong pair bonds, and an individual pair will stay on the same stretch of river (approx. 1km long) for many years. They will aggressively defend their territory from other Blue Ducks, Paradise Shelducks and even gulls or shags. The larger male can live for about 12 years, but the smaller female is shorter lived.

Nesting is between August and October, with incubation of 4-9 eggs being done by the female (35 days), while the male stands guard. The down-lined nest of grass and twigs, is built in a scrape in caves, in log jams or under river-side vegetation and consequently often destroyed by spring floods. Breeding success is therefore very variable from year to year.

Diet

The diet includes insect larvae and invertebrates.

Vocalisation

The male's call is high-pitched whistle whio whio, and the female's is a rattling growl.

References

Clements, J. F., T. S. Schulenberg, M. J. Iliff, T. A. Fredericks, J. A. Gerbracht, D. Lepage, S. M. Billerman, B. L. Sullivan, and C. L. Wood. 2022. The eBird/Clements checklist of Birds of the World: v2022. Downloaded from https://www.birds.cornell.edu/clementschecklist/download/
Gill, F, D Donsker, and P Rasmussen (Eds). 2022. IOC World Bird List (v 12.2) DRAFT. Doi 10.14344/IOC.ML.12.2. http://www.worldbirdnames.org/
For more information, see the NZ Department of Conservation website: [1]
Handbook of the Birds of the World Alive (retrieved July 2016)

List of references

Recommended Citation

BirdForum Opus contributors. (2024) Blue Duck. In: BirdForum, the forum for wild birds and birding. Retrieved 21 December 2024 from https://www.birdforum.net/opus/Blue_Duck

External Links

Search for photos of Blue Duck in the gallery

GSearch checked for 2020 platform.1

@@ Line 1: / Line 1: @@
-[[Category:Hymenolaimus]]
+'''Alternative name: (Maori) Whio'''
+[[Image:IMG 7991 blue duck 1 cr sm.jpg|thumb|550px|right|Photo &copy; by {{user|martinuk|martinuk}}<br/>Manganui o te Ao River, Manawatu-Wanaganui Region, North Island, [[New Zealand]], January 2010]]
 ;[[:Category:Hymenolaimus|Hymenolaimus]] malacorhynchos
-[[Image:Blue_Duck.jpg|thumb|550px|right|Photo by Moa<br/>Location: Cedar Flats Track, Hokitika, West Coast of South Island, New Zealand]]
-Also known by it's Maori name: '''Whio'''
 ==Identification==
-Size: 53cm (21in); weight: male 1,000g, female 750g.<br/>Sexes are similar, female is smaller.  Overall colour is blue-grey with reddish-chestnut spots on the breast.  Eyes are yellow; bill pale pink, with the upper mandible having a thick semi-circular, fleshy 'lip' that overlaps the lower mandible, allowing it to scrape insect larvae off underwater rocks, without causing wear on the bill.
+Size: 53cm (21in); weight: male 1,000g, female 750g.<br/>
+*Bluish-grey overall plumage
+*Reddish-chestnut spots on the breast
+*Yellow eyes
+*Pale pink bill, with the upper [[Dictionary_M-O#M|mandible]] having a thick semi-circular, fleshy 'lip' that overlaps the lower mandible, allowing it to scrape insect larvae off underwater rocks, without causing wear on the bill<br />
+Sexes are similar, female is smaller.<br />
+Juvenile has less speckling on breast, and has a grey bill and eye.
+[[Image:IMG 1465a.JPG|thumb|350px|right|Showing the fleshy 'lip'<br />Photo &copy; by the late '''[http://www.birdforum.net/gallery/showgallery.php/ppuser/67980/cat/500 Rookery]'''<br />Back country, Hawke's Bay, [[New Zealand]], February 2016]]
 ==Distribution==
-A threatened endemic to New Zealand.  It is classified as a "Nationally Endangered" species, with current populations at about 2,500 individuals and declining.  Early causes for the decline, were habitat loss, especially forest clearance for agriculture.  Unless the causes for the decline can be remedied, the species is on the track for extinction.
+[[New Zealand]].
+====Status====
+It is classified as a "Nationally Endangered" species, with current populations at about 2,500 individuals and declining. Early causes for the decline, were habitat loss, especially forest clearance for agriculture. Unless the causes for the decline can be remedied, the species is on the track for extinction.
 ==Taxonomy==
-The Blue Duck (''Hymenolaimus malacorhynchus'') is a member of the duck, goose and swan family Anatidae.  It is the only member of the genus Hymenolaimus, placed in the shelduck subfamily Tadorninae [citation needed] after previously being considered part of the paraphyletic "perching duck" assemblage. The Māori name is whio, which is an onomatopoetic rendition of the males' call.  It is a unusual waterfowl species, being the only member of it's genus, with no close relative anywhere in the world.  It is believed to have appeared early in the evolutionary history of New Zealand, this isolation having resulted in some unique behavioural and anatomical features.
+====Subspecies====
+Two subspecies are recognized<sup>[[#References|[1]]]</sup>.
-==Voice==
+*''H. m. hymenolaimus''
-The male's call is an aspirated whistle, and the female's is a rattling growl.
+:*central and eastern North Island, New Zealand
+*''H. m. malacorhynchos''
+:*western South Island, New Zealand
 ==Habitat==
-It is a rare duck, holding territories on clean, fast flowing, bouldery streams, in the forested upper catchment areas of New Zealand rivers.
+Clean, fast flowing, mountain streams, in well-vegetated areas.
+==Behaviour==
+A strong swimmer not often seen in flight.
-==Behaviour==
+They are usually active during the early morning and late evening, when they are seen standing on rocks, or with head and neck underwater while feeding. During the rest of the day they hide in caves, log-jams or suchlike and some populations have become almost nocturnal.
-It is a powerful swimmer even in white water, but is reluctant to fly.  It is difficult to find, but not particularly wary when located.  Blue Ducks develop strong pair bonds, and an individual pair will stay on the same stretch of river (approx. 1km long) for many years.  They will aggressively defend their territory from other Blue Ducks, Paradise Ducks and even gulls or shags.  The larger male can live for about 12 years, but the smaller female is shorter lived.  Nesting is between August and October, with incubation of 4-9 eggs being done by the female (35 days), while the male stands guard.  The down-lined nest of grass and twigs, is built in a scrape in caves, in log jams or under river-side vegetation and consequently often destroyed by spring floods.  Breeding success is therefore very variable from year to year.  They are usually active during the early morning and late evening, when they are seen standing on rocks, or with head and neck underwater while feeding.  During the rest of the day they hide in caves, log-jams or suchlike and some populations have become almost nocturnal.  The male's call is a high-pitched whistled ''whio whio'', whereas the female makes a guttural rattle.
+====Breeding====
+Blue Ducks develop strong pair bonds, and an individual pair will stay on the same stretch of river (approx. 1km long) for many years. They will aggressively defend their territory from other Blue Ducks, [[Paradise Shelduck]]s and even gulls or shags. The larger male can live for about 12 years, but the smaller female is shorter lived.
+Nesting is between August and October, with incubation of 4-9 eggs being done by the female (35 days), while the male stands guard. The down-lined nest of grass and twigs, is built in a scrape in caves, in log jams or under river-side vegetation and consequently often destroyed by spring floods. Breeding success is therefore very variable from year to year.
+====Diet====
+The diet includes insect larvae and invertebrates.
+====Vocalisation====
+The male's call is high-pitched whistle ''whio whio'', and the female's is a rattling growl.
+==References==
+#{{Ref-Clements6thOct22}}#{{Ref-GillDonskerRasmussen22V12.2}}#For more information, see the NZ Department of Conservation website: [http://www.doc.govt.nz/templates/podcover.aspx?id=33059]
+#Handbook of the Birds of the World Alive (retrieved July 2016)
+{{ref}}
 ==External Links==
-For more information, see the NZ Department of Conservation website: [http://www.doc.govt.nz/templates/podcover.aspx?id=33059]
+{{GSearch|"Hymenolaimus malacorhynchos" {{!}} "Blue Duck" {{!}} "Whio"}}
-{{GSearch|Hymenolaimus+malacorhynchos}}
+{{GS-checked}}1
-[[Category:Birds]]
+<br />
+<br />
+[[Category:Birds]][[Category:Hymenolaimus]]