Snares Crested Penguin (Eudyptes robustus)

Species Description

Adult Plumage:

Yellow crest similar to a Fiordland penguin on head, slightly more narrow in females. Back, upper tail, mantle are dark black-brown. Underparts are white. Bases of underparts are hidden, but in fact light grey-brown.

Juvenile Plumage:

Retained until 15 months old, indistinguishable from adult after post-juvenile molt.

Chick Plumage:

Down is short, head, hindneck, sides of neck and upperparts are dark brown. From lower throat, rest of neck, and underparts are a dull white.

Weight - Males:

3 kg

Beak - Males:

5.92 cm

Flipper - Male:

18.30 cm

Weight - Females:

3.88 kg

Beak - Females:

5.25 cm

Flipper - Female:

17.70 cm

Sexual Dimorphism:

Males slightly larger, but overlap of all fields occurs with the exception of bill index number, which is really the only for sure indicator to determine male and female by appearance. Bill depth ratio 27.7:24.2 male to female.

Vocalizations:

Similar to Fiordland penguin, peaks in morning. Generally persistent, loud harsh, and low-pitched, most composed of loud discordant pulsed phrases. Three distinct calls (contact, sexual, and agonistic calls).

Taxonomy

Subspecies:

Distribution

Map references:

Miskelly, C.M., P.M. Sagar, A.J.D. Tennyson, R.P. Scofield. 2001. Birds of the Snares Island. Notornis 48:15-16.

Population over time:

Breeding Biology

Average Arrival date:

09/01

Nest and nest materials:

twigs, bones, vegetation, mud

Egg laying average date:

09/18

Incubation:

31 days

Chick period:

21 days

Fledgling period:

early January to mid-February

Reproductive Success:

0.73chicks/nest

Breeding Cycle

Age at first breeding:

6 years

Maximum lifespan:

22 years

Molt:

24 to 30 days, ending by April 20.

Egg length:

7.2 cm

Egg breadth:

5.5 cm

Incubation period:

33.3 days

Laying eggs again:

N/A

Prey

Prey:

Crustaceans, cephalopods, fish.

Description:

During GPS and stomach flushing, it was found that during dive trips during the incubation phase, males consumed primarily fish (roughly 90%). Females consume mostly krill (55%) on their dives. Diet outside of breeding season poorly known.

Status

IUCN listing:

Vulnerable

Discussion:

Listed as vulnerable due to small geographic range, however populations numbers have remained stable. The islands are currently listed as nature reserves. Landing on islands is by permission only.

Threats

Predators on land of adults:

None

Predators on land of juveniles:

None

Predators on land of eggs, chicks:

skaus (Stercorarius skua)

Predators at sea of adults:

assumed seals

Predators at sea of juveniles:

assumed seals

Predators at sea on fledglings:

assumed seals

Human threats:

Large amount of squid fishing nearby, may be causing food competition.

Climate variation:

No direct evidence, but mentioned by IUCN that climate change may be causing distribution of prey species to change

Analysis:

Continue protection of islands.

Mitigation of threat

Current actions:

The islands are currently listed as nature reserves. Landing on islands is by permission only.

Possible actions:

Climate change prevention to avoid prey range shifting. Minimize harvesting of squid near Snares Island Chain. Continue to make sure no invasive species end up on the island.

References and Comments

Species references:

Houston, D.M. T. Mattern, L.S. Davis. 2004. Foraging ecology of the snares crested penguin. Proceedings of the Oamaru Penguin Symposium. New Zealand Journal of Zoology, 2004, Vol. 31: 121. Marchant and Higgins. 1990. Handbook of Australian, New Zealand, and Antarctic Birds. Volume 1. Oxford University Press: Melbourne. Miskelly, C.M. 1984. Birds of the western chain, Snares Islands. Notornis 31: 209-233 Miskelly, C.M., P.M. Sagar, A.J.D. Tennyson, R.P. Scofield. 2001. Birds of the Snares Island. Notornis 48:15-16. Steonhouse, B. 1971. The Snare Island penguin. Ibis 113:1-7 Warham, J. 1967. Snares Island birds. Notornis 14:122-139. Warham, J. 1974. Snares crested penguin. Royal Society of New Zealand 4:63-108.

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Snares Crested Penguin (Eudyptes robustus)

Penguin Species