New Zealand dotterel

Charadrius obscurus Gmelin, 1789

Order: Charadriiformes

Family: Charadriidae

New Zealand status: Endemic

Conservation status: Nationally Vulnerable

Other names: red-breasted dotterel, tūturiwhatu, tuturiwhatu, tuturiwhatu pukunui, rako, red-breasted plover, New Zealand plover

Geographical variation: Two subspecies, both extant: northern New Zealand dotterel C. o. aquilonius (Threatened/Nationally Vulnerable); southern New Zealand dotterel C. o. obscurus (Threatened/Nationally Critical).

New Zealand dotterel. Northern subspecies adult in breeding plumage. Te Puru, October 2009. Image © Tony Whitehead by Tony Whitehead Tony Whiteheadwww.wildlight.co.nz

New Zealand dotterel. Northern subspecies adult in breeding plumage. Te Puru, October 2009. Image © Tony Whitehead by Tony Whitehead Tony Whiteheadwww.wildlight.co.nz

The New Zealand dotterel is a familiar bird of sandy east coast beaches in the northern North Island, but is sparsely distributed around much of the rest of the country. There are two widely separated subspecies: the northern New Zealand dotterel is more numerous, and breeds around the North Island; the southern New Zealand dotterel was formerly widespread in the South Island, and now breeds only on Stewart Island. Southern New Zealand dotterels are larger, heavier, and darker than northern New Zealand dotterels.

Coastal development and human recreational activities on beaches are having a growing impact on the northern subspecies; dotterels are often described as ‘appealing’, and local communities are increasingly championing them – providing advocacy and organising protection programmes to improve breeding success.

Identification

The New Zealand dotterel is a heavily-built plover, and is the largest species in the genus Charadrius (c.31 species). The upperparts are brown, darker in the southern subspecies, and the underparts are  off-white in autumn-early winter, becoming orange-red (also darker in southern birds) from about May onwards. The depth and extent of red colour varies individually and seasonally, but males are generally darker than females. The bill is heavy and black, and the legs mid-grey. First-winter birds have pure white underparts, with legs yellowish to pale grey.

Voice: the common call is a sharp chip, often heard before the bird is seen. The call indicates alertness, with the rate increasing as the perceived threat level rises. The same call is also used to maintain contact. A high-pitched tseep is used to warn chicks to stay hidden. A long rattling churr is used when chasing intruders. A sharp werr-wit is used during territory boundary disputes.

Similar species: occasional confusion with eclipse or juvenile banded dotterel, but New Zealand dotterel is much larger, and bill heavier. Juvenile or eclipse New Zealand dotterel is similar to eclipse greater sand plover (rare in New Zealand) but that has slimmer body, longer legs, and the head appears larger in proportion to the body.

Distribution and habitat

New Zealand dotterels are found on or near the coast around much of the North Island. They are sparse on the west coast from about Taharoa north to North Cape, and there are a few isolated pairs in Taranaki. The bulk of the population is on the east coast between North Cape and East Cape. It has spread south of East Cape since 1990, but is still thinly spread in that area. In 2012, a pair bred at Riversdale (northern Wairarapa), the most southerly breeding record for the subspecies.

New Zealand dotterels were previously throughout the South Island, breeding inland and wintering on the coast. Breeding is now confined to Stewart Island. Most birds winter on the island, but one flock is at Awarua Bay, Southland. A few juveniles wander the South Island coast, and are frequently recorded as far north as Farewell Spit, with one bird travelling as far as Auckland, before returning to Stewart Island.

There are major differences in breeding habitat between the two subspecies. Northern birds mainly breed on sandy beaches and sandspits, some on shell banks in harbours, a few on gravel beaches. On beaches, they are usually clustered around stream-mouths. In urban areas (particularly Auckland) they often breed a short distance inland on short grass (golf courses, motorway verges, beside airport runways) or on bare ground (building sites, quarries). Southern birds breed on exposed subalpine herbfields and rocky areas above the tree-line on Stewart Island, but are coastal during the non-breeding season, feeding on inter-tidal mudflats and beaches.

Population

A total of 2175 northern New Zealand dotterels was counted in the 2011 breeding-season census.

Southern New Zealand dotterels reached a low of 62 birds in 1992, but they have responded well to management, and the post-breeding population has fluctuated between 240 and 290 birds since 2005.

Threats and conservation

Breeding success of Northern New Zealand dotterels is usually low at unmanaged sites. The main threats are loss of eggs and chicks to mammalian and avian predators, disturbance from human activities on beaches, loss of nests to big tides, and loss or degradation of habitat from development. Protection programmes began in the 1980s, and normally include predator control, fencing of nesting areas, appointment of wardens to reduce disturbance, and advocacy. About 20-25% of the population is now managed, but effort and success vary between sites and years. The subspecies is conservation dependent – stable or declining where unmanaged, increasing where managed.

Southern New Zealand dotterels were extirpated from the South Island by about 1900 following introduction of stoats and other mustelids. There was a rapid decline of the relict population on Stewart Island from the 1950s due to predation of adults by cats (and possibly rats). Males incubate at night, and are more vulnerable; a severe gender bias developed, with female-female pairs forming. The population was reduced to 18 male-female pairs by 1992, when cat and rat control was initiated. The population has since recovered, but its breeding range remains confined to Stewart Island, and it is conservation dependent.

Breeding

New Zealand dotterels breed in monogamous pairs, and vigorously defend territories against other dotterels. The nests of northern New Zealand dotterels are simple scrapes in the substrate, sometimes sparsely lined or decorated, often with a marker of driftwood or vegetation. Three eggs are laid, usually from August or September, and are replaced if lost. Incubation usually takes 28-30 days; the fledging period is variable, but averages about 6 weeks. Double-brooding has been recorded but is not common.

Nests of southern New Zealand dotterels are usually hollows in cushion plants or between rocks; they are extensively lined, commonly with tussock tillers. They typically nest later then northern birds, from October. Incubation and fledging times not well known; limited data suggest these are similar to those of the northern subspecies.

Behaviour and ecology

Both subspecies form post-breeding flocks, typically at large estuaries. They gather from January, and numbers peak in March. Some northern birds move back to breeding sites from May, with all gone by August. Flocks of the southern subspecies stay together throughout winter.

New Zealand dotterels undertake distraction displays to lead intruders away from nests and chicks; include ‘rat-runs’ and injury-feigning. Small chicks crouch and ‘freeze’ when danger threatens; older chicks typically run to the nearest cover and hide. Juveniles often wander widely before settling to breed. Once established on a territory, they are usually faithful to breeding and flock sites, moving predictably between them. Mate-fidelity is high, but divorces have been recorded.

Food

New Zealand dotterels consume a wide range of suitably-sized marine, littoral, and terrestrial invertebrates, and occasionally small fish. Sandhoppers are a common prey item on beaches, and small mussels are taken from rocks. Small crabs and annelid worms are among prey on estuaries; on grass, crickets, flies, beetles, and earthworms have been recorded. Most prey is live, but recently-dead items are occasionally scavenged.

Websites

http://www.doc.govt.nz/conservation/native-animals/birds/sea-and-shore-birds/nz-dotterel-tuturiwhatu/

http://www.nzbirds.com/birds/nzdotterel.html

http://www.arkive.org/new-zealand-dotterel/charadrius-obscurus/

References

Dowding, J.E. 1994. Morphometrics and ecology of the New Zealand dotterel (Charadrius obscurus), with a description of a new subspecies. Notornis 41: 221-233.

Dowding, J.E.; Davis, A.M. 2007. New Zealand dotterel (Charadrius obscurus) recovery plan, 2004-2014. Threatened Species Recovery Plan 58. Department of Conservation, Wellington. http://www.doc.govt.nz/documents/science-and-technical/tsrp58.pdf

Dowding, J.E.; Moore, S.J. 2006. Habitat networks of indigenous shorebirds in New Zealand. Science for Conservation 261. Department of Conservation, Wellington.

Dowding, J.E.; Murphy, E.C. 2001. The impact of predation by introduced mammals on endemic shorebirds in New Zealand: a conservation perspective. Biological Conservation 99: 47-64.

Marchant, S.; Higgins, P.J. (eds) 1993. Handbook of Australian, New Zealand and Antarctic birds. Vol. 2, raptors to lapwings. Oxford University Press, Melbourne.

Pye, D.A.; Dowding, J.E. 2002. Nesting period of the northern New Zealand dotterel (Charadrius obscurus aquilonius). Notornis 49: 259-260.

Recommended citation

Dowding, J.E. 2013. New Zealand dotterel. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz

New Zealand dotterel

Breeding season
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Egg laying dates
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun

Northern New Zealand dotterel

Social structure
monogamous
Breeding season
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Nest type
scrape
Nest description
Nest is a scrape in sand or soil which may be decorated with shells, occasionally sparsely lined.
Nest height (mean)
0.00 m
Clutch size (mean)
2-3
Clutch size (min)
2
Clutch size (max)
3
Mean egg dimensions (length)
44.00 mm
Mean egg dimensions (width)
31.00 mm
Egg colour
Background pale coffee, with dark brown/black spots and splotches, normally evenly spread, occasionally concentrated at the blunt end.
Egg laying dates
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Interval between eggs in a clutch
2-4 days
Incubation behaviour
shared
Incubation length (mean)
28-30 days
Incubation length (min)
27days
Incubation length (max)
33days
Nestling type
precocial
Nestling period (mean)
Less than 24 hours
Age at fledging (mean)
35-50 days
Age at independence (mean)
Some leave after fledging and some leave family groups after 1-2 months
Age at first breeding (typical)
2 years
Age at first breeding (min)
1years
Maximum longevity
32 years minimum
Maximum dispersal
850 km round trip

Southern New Zealand dotterel

Social structure
monogamous
Breeding season
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Nest type
scrape
Nest description
Depression in cushion plants lined with dried tussock.
Nest height (mean)
0.00 m
Clutch size (mean)
2-3
Clutch size (min)
2
Clutch size (max)
3
Mean egg dimensions (length)
46.00 mm
Mean egg dimensions (width)
33.00 mm
Egg colour
Pale coffee-olive background slightly darker than Northern eggs, with dark brown/black blotchers and spots
Egg laying dates
  • Jul
  • Aug
  • Sep
  • Oct
  • Nov
  • Dec
  • Jan
  • Feb
  • Mar
  • Apr
  • May
  • Jun
Interval between eggs in a clutch
Unknown
Incubation behaviour
shared
Incubation length (mean)
Unknown but probably similar to Northern subspecies
Nestling type
precocial
Nestling period (mean)
Unknown
Age at fledging (mean)
Unknoqn
Age at independence (mean)
Unknown
Age at first breeding (typical)
2-3 years
Maximum longevity
21 years minimum
Maximum dispersal
Round trip 2,500 km