Lesser noddy (Anous tenuirostris)

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Lesser noddy fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
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Lesser noddy description

The lesser noddy (Anous tenuirostris) is a small, tropical tern species with dark plumage and a long, slender black bill ^{(2) (3)}. The wings of this seabird are long, narrow and pointed, and its tail is wedge shaped ⁽³⁾.

The adult lesser noddy is largely blackish-brown, with a whitish forehead and crown that shade to a grey-brown neck and cheeks ^{(2) (3) (4) (5)}. Its legs and feet are brownish-black ⁽²⁾. The male and female lesser noddy are similar in appearance ⁽³⁾, but the juvenile is paler brown than the adult ⁽²⁾.

Two subspecies of lesser noddy are recognised, Anous tenuirostris tenuirostris and Anous tenuirostris melanops, with the latter being distinguished by a blackish stripe above its eye that extends onto the lores ⁽²⁾. The lesser noddy has sometimes been considered to be the same species as the black noddy (Anous minutus) ^{(2) (3) (5)}, but is smaller and paler, with pale rather than dark lores, and the pale colour of its head blends more evenly into the darker neck ⁽²⁾. The lesser noddy is also smaller, slimmer and paler than the closely related brown noddy (Anous stolidus) ⁽⁴⁾.

The voice of the lesser noddy has been described as a rattling ‘kaarrk’ ⁽⁴⁾.

Also known as

Australian lesser noddy, sooty noddy.

Synonyms

Sterna tenuirostris.

French

Noddi marianne.

Size

Length: 30 - 34 cm ⁽²⁾

Wingspan: 58 - 63 cm ⁽²⁾

Weight

97 - 120 g ⁽²⁾

Lesser noddy biology

The diet of the lesser noddy consists mainly of small fish and squid ^{(2) (3) (5) (6)}, and this species hunts by flying low over the sea before hovering and dipping down to pick prey from the surface of the water ^{(2) (3) (4)}. Before breeding, adult lesser noddies also eat large quantities of coral fragments from beaches, presumably as a source of calcium for producing eggs ⁽⁶⁾.

The lesser noddy usually breeds between August and October ⁽²⁾, often coming together in large breeding colonies in which nests are densely packed together ^{(2) (5)}. In some areas, egg laying may continue into early December, or even extend to the following April ^{(3) (5) (8)}. The nest of the lesser noddy is built in a tall mangrove tree, or occasionally in a bush, and consists of a bulky platform of seaweed held together with excrement ^{(2) (3) (5)}. Storms can sometimes cause extensive loss of eggs from more exposed nests, and pairs nesting earlier in the season tend to select more sheltered sites ⁽⁸⁾. Nesting colonies of lesser noddies periodically move location as the nesting birds retard tree growth and can even kill the trees ^{(3) (7)}.

The female lesser noddy lays a single egg ^{(2) (3) (8)}, which is incubated for about 34 to 35 days ^{(2) (8)}. The young lesser noddy fledges at about 40 days old ⁽⁸⁾, and individuals are likely to start breeding from about 3 to 4 years old ^{(3) (7)}.

Outside of the breeding season, the lesser noddy remains gregarious, occurring in flocks of up to about 45 individuals and often associating with brown noddies (A. stolidus) ⁽⁶⁾.

Lesser noddy range

The lesser noddy occurs on islands in the tropical and subtropical Indian Ocean ⁽³⁾. The subspecies A. t. tenuirostris breeds in the Seychelles, Mascarene Islands, Mauritius, the Maldives and the Chagos Archipelago ^{(2) (3) (6)}, with possible breeding attempts also occurring in Somalia, and non-breeding birds recorded in Arabia, Madagascar and the eastern African coast ^{(2) (6)}.

The subspecies A. t. melanops, also known as the Australian lesser noddy, breeds only on the Houtman Abrolhos Islands and possibly on Ashmore Reef in Australia ^{(2) (3) (5) (6) (7)}. It has also occasionally been recorded north of the breeding islands, such as on Barrow Island and Webb Island ⁽⁵⁾, but is generally believed to be resident in the breeding areas year-round ^{(3) (5) (6) (7)}.

Lesser noddy habitat

The lesser noddy breeds and roosts in mangroves on oceanic islands, and can also sometimes be seen resting on shingle or sandy beaches ^{(3) (5) (6)}. Its foraging habitat is not well known, but it is likely to forage in inshore areas, around reefs, or out to sea ^{(3) (6)}.

Lesser noddy status

The lesser noddy is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Lesser noddy threats

The lesser noddy has a large population that is believed to be stable, and is not currently considered to be at risk of extinction ⁽⁶⁾. In Australia, mining of guano in the 19th and early 20th centuries, and the taking of eggs, chicks and adults as food, is likely to have caused the disappearance of this species from Pelsaert Island, one of the islands in the Houtman Abrolhos group ^{(3) (5) (6) (7)}. However, the colonies on this island have since re-established themselves ^{(3) (7)}.

Today, the main threats to the lesser noddy in Australia are the destructive effects of cyclones and pollution from oil spills ⁽⁵⁾. As this seabird has a very limited breeding range, sea level rise associated with climate change could also potentially have a negative effect on the mangroves in which it breeds, while its food supplies may be affected by commercial fishing ^{(3) (5) (7)}.

On Wooded Island, one of the Houtman Abrolhos islands, the lesser noddy colony is contracting as an expanding population of large pied cormorants (Phalacrocorax varius) is killing the mangroves in which the lesser noddy nests. However, it should be possible for the lesser noddies to move to unused habitat elsewhere on the Houtman Abrolhos islands ⁽⁷⁾. In other parts of its range, the lesser noddy may be affected by habitat loss on its breeding islands, while introduced species could potentially present a threat in some locations ⁽⁶⁾.

Lesser noddy conservation

In Australia, the Australian lesser noddy (A. t. melanops) is listed as ‘Endangered’ as it occupies a tiny area and is believed to be undergoing a decline in its population and in the quality of its habitat ⁽⁷⁾.

A recovery plan for Australian seabirds recommends a number of conservation actions for the lesser noddy in its Australian range. These include confirming its existence at Ashmore Reef, continuing to control introduced animals and plants on its breeding islands, and preventing further introductions of non-native species ⁽³⁾. The monitoring and management of the lesser noddy on its breeding islands in the Houtman Abrolhos group should also be continued ^{(3) (7)}. In addition, further information is needed on the potential effects of commercial fishing on the lesser noddy and its prey ⁽⁷⁾.

No specific conservation measures are currently known to be in place for the lesser noddy in other parts of its range.

Find out more

Find out more about the lesser noddy and its conservation:

• BirdLife International - Lesser noddy:
  http://www.birdlife.org/datazone/speciesfactsheet.php?id=3296

More information on conservation in Australia:

• BirdLife Australia:
  http://www.birdlife.org.au/
• Australian Wildlife Conservancy:
  http://www.australianwildlife.org/
• Australian Conservation Foundation:
  http://www.acfonline.org.au/

Authentication

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Glossary

Guano

Accumulated droppings found where large colonies of animals such as seals, bats or birds occur; it is rich in plant nutrients.

Incubate

To keep eggs warm so that development is possible.

Lores

The space between a bird’s bill and eyes.

Subspecies

A population usually restricted to a geographical area that differs from other populations of the same species, but not to the extent of being classified as a separate species.

References

1. IUCN Red List (August, 2012)
   http://www.iucnredlist.org/
2. del Hoyo, J., Elliott, A. and Sargatal, J. (1996) Handbook of the Birds of the World. Volume 3: Hoatzin to Auks. Lynx Edicions, Barcelona.
3. Department of the Environment and Heritage (2005) Population Status and Threats to Ten Seabird Species Listed as Threatened Under the Environment Protection and Biodiversity Conservation Act 1999. Department of the Environment and Heritage, Australian Government, Canberra. Available at:
   http://www.environment.gov.au/biodiversity/threatened/publications/pubs/seabirds-issues.pdf
4. Harrison, J. (2011) A Field Guide to the Birds of Sri Lanka. Oxford University Press, Oxford.
5. Australian Government - Department of Sustainability, Environment, Water, Population and Communities (2012) Anous tenuirostris melanops. In: Species Profile and Threats Database. Department of Sustainability, Environment, Water, Population and Communities, Canberra. Available at:
   http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=26000
6. BirdLife International (September, 2012)
   http://www.birdlife.org/datazone/speciesfactsheet.php?id=3296
7. Garnett, S.T., Szabo, J.K. and Dutson, G. (2011) The Action Plan for Australian Birds 2010. CSIRO Publishing, Collingwood, Australia.
8. Surman, C.A. and Wooller, R.D. (1995) The breeding biology of the lesser noddy on Pelsaert Island, Western Australia. Emu, 95: 47-53.