Oamaru Penguin Symposium, 2003
Oamaru, New Zealand, 19-20 June 2003
Comparative diving behaviour of Blue penguins at two NZ locations
Presentation type:
Talk (PowerPoint)
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Authors:
Thomas Mattern
Lloyd Davis
Boris Culik
Dave Houston
Abstract:
A comparative study of foraging ranges during the chick rearing phase of blue penguins (Eudyptula minor) from Motuara Island, Queen Charlotte Sound and Oamaru, North Otago, New Zealand, revealed great differences between both sites (Mattern et al. unpubl. data). Birds from Oamaru travelled much larger distances during one-day trips, whereas birds from Motuara Island stayed within a short range of their breeding colony. To compare diving behaviour, five birds on Motuara Island and six birds at Oamaru were equipped with time-depth recorders (TDRs). Compared with Oamaru, penguins from Motuara Island showed a greater number of dives per trip (mean number of dives 1165 versus 809), dived significantly deeper (mean depth 10.1 versus 6.0 m) and longer (mean dive duration 29.5 versus 22.4 seconds). Comparison of dive parameters suggest that penguins from Motuara Island search for prey at greater depths (depths <26 m) and, thus, increase foraging efforts vertically, while penguins at Oamaru tend to extend foraging efforts horizontally and dive shallower (depths <14 m). These findings correspond well with foraging ranges determined at both sites by Mattern et al. (unpubl. data) using VHF telemetry. The main factors influencing the foraging behaviour of Motuara Island penguins are thought to be prey availability and topographic features of Queen Charlotte Sound, which limit their foraging range on one-day trips. In contrast, Oamaru penguins profit from high abundance of one major prey species close to their breeding colonies. Furthermore, the penguins do not face any obvious environmental constraints (topography) when foraging and can travel large distances on one-day trips.
Oamaru Penguin Symposium, 2005
Oamaru, New Zealand, 21-22 June 2001
Foraging ranges and breeding success of Blue penguin Eudyptula minor at two different locations in New Zealand
Presentation type:
Talk (PowerPoint)
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Online status: RAW
(no narration, slide timing unadjusted)
Authors:
Thomas Mattern
Lloyd Davis
Boris Culik
Dave Houston
Abstract:
Breeding success and foraging ranges of blue penguins from Motuara Island/Marlborough Sounds and Oamaru/North Otago were examined during the breeding season 2000/2001. We examined 64 nests on Motuara Island and 87 nests at Oamaru. Breeding success parameters and chick growth were determined. Breeding success differed significantly between sites. Oamaru penguins raised 1.44 fledged chicks per pair compared with 0.71 on Motuara Island. Breeding failure on Motuara Island was generally related to chick starvation and nest desertions by adults, whereas at Oamaru, predation was the main mortality factor. Differences between the two sites were directly related to adult foraging strategies. We used VHF-telemetry to determine foraging routes and ranges of penguins equipped with streamlined transmitter packs. On Motuara Island we tracked penguins on 11 one-day-trips and five partial long-term trips (>2 days). At Oamaru penguins were tracked on 16 one-day trips and four longterm trips. Differences in foraging patterns between the populations were apparent. Motuara penguins rarely left the Queen Charlotte Sound on one-daytrips, stayed close to the Island (mean foraging range <6 km). Birds leaving the Sound on longterm trips generally stayed away for at least 2 days. Some adults undertook long-term trips during chick rearing. The main factors influencing the foraging behaviour of Motuara Island penguins seemed to be time dependent variations in prey availability and foraging restrictions by topographic features of Queen Charlotte Sound.
6th International Penguin Conference, 2007
Hobart, Tasmania, Australia, 3 - 7 September 2007
Warm-water penguins – Why are Snares penguins doing better than other crested penguin species?
Presentation type:
Talk (PowerPoint)
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Online status: RAW
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Authors:
Thomas Mattern,Katrin Ludynia,
Dave Houston, Lloyd Davis
Abstract:
The distribution of prey for penguins is often a result of physical oceonographic processes. This is particularily so for penguin species breeding in isolated oceanic areas like sub-Antarctic islands. Snares penguins are primarily planktivorous foragers that find their food in a pelagic environment where prey distribution is a product of currents and frontal systems. During the incubating phase of breeding, Snares penguins have been found to forage at the Subtropical Front which is located some 200 km east of the Snares. However, after the chicks have hatched the penguins' foraging ranges are restricted by nesting duties so that the penguins must find food closer to the island. A possible destination could be to the north of the Snares where a warm current transports nutrient-rich and productive water east towards the Subtropical Front. We examined the foraging and diving behaviour of female Snares penguins during the chick-guard stage using GPS dive loggers and combined geographical and dive data for spatial analysis. The results show a strong correlation of dive behaviour and sea surface temperature and underline the importance of warm water of sub-tropical origin for chick rearing Snares penguins.
Oamaru Penguin Symposium, 2005
Oamaru, New Zealand, 30 June - 1 July 2005
Warm-water penguins – Why are Snares penguins doing better than other crested penguin species?
Presentation type:
Talk (PowerPoint)
Titlepage:
Online status: RAW
(no narration, slide timing unadjusted)
Authors:
Thomas Mattern,Katrin Ludynia,
Dave Houston, Lloyd Davis
Stefan Garthe
Abstract:
Unlike other New Zealand crested penguins, the population of the Snares penguin (Eudyptes robustus) seems to flourish. Its population lies in the order of 30.000 breeding pairs and is believed to be stable. In contrast, other New Zealand crested penguin species are believed to have declined in the past due to changes in the marine environment. This raises the question why any such changes did not have an obvious effect on the Snares penguin. Between 2002 and 2004 we studied the foraging behaviour of Snares penguins during the crucial stages of the breeding season (i.e. late incubation and chick guard stage). We used new GPS dive loggers that record geographic position, dive depth and ambient temperature at set intervals as well as conventional dive loggers. During incubation, males left on long-term trips (mean duration: 11 days) on which they performed deep dives of up to 120m (mean max depth: 55m). Upon return of the males, the females left on shorter foraging trips (mean duration: 6 days), that were marked by shallower diving (mean max depth: 26m). After the chicks had hatched only the females foraged. With few exceptions, all females foraged over the continental shelf north-east of the island (maximum foraging radius: 70km) during which they made many shallow dives (mean max depth: 19m). Foraging movements were linked to the appearance of phytoplankton blooms which indicate high productivity. We conclude that the success of the Snares penguin is rooted in the location of the Snares – west of the subtropical front which acts as a trap for warm and productive surface water coming from the Tasman Sea.
2nd International Bio-logging Science Symposium (Bio-logging II)
St. Andrews, Scotland, 13-16 June 2005
How to get the most (or anything) out of GPS loggers: a case study with Snares Penguins
Presentation type:
Talk (PowerPoint)
Titlepage:
Online status: RAW
(no narration, slide timing unadjusted)
Authors:
Thomas Mattern, Katrin Ludynia,
Lloyd Davis, Stefan Garthe
Dave Houston
Abstract:
The Snares penguin (Eudyptes robustus) breeds only on the Snares Islands, a small archipelago about 200Km south of New Zealand’s South Island. Despite its relative closeness to the mainland, working on the Snares represents a logistical challenge. The Snares are managed as minimum impact islands, which not only limits timing and length of visits but also restricts movements on site. Between 2002 and 2004 we examined the foraging behaviour (foraging range and diving behaviour) of Snares Crested penguins during the late incubation and chick-guard stages. Due to the tempTalk and spatial limitations on the Snares, most of the conventional methods to track penguins (i.e. VHF or satellite telemetry) were inadequate for the proposed research. Instead we relied on newly developed GPS loggers (Earth&Ocean GPS-TDlog) which record geographic position and dive depth/temperature at set intervals. Data quality (i.e. number and tempTalk distribution of fixes during deployment) depended largely on programming of loggers as well as timing and location of deployment. During the work we identified three key issues that have to be considered during deployments of GPS loggers on penguins: (1) reception of GPS devices after power-on, (2) finding adequate GPS logging intervals and (3) limited battery life. Using data recorded on Snares penguins we show the varying degrees of programming-dependent data quality and show how the effect of these issues can be minimized.
5th International Penguin Conference
Ushuaia, Tierra Del Fuego, Argentina, 6-10 September 2004
Foraging behaviour of Snares penguins - a matter of role allocation during breeding
Presentation type:
Talk (PowerPoint)
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Online status: RAW
(no narration, slide timing unadjusted)
Authors:
Thomas Mattern
Ursula Ellenberg
Dave Houston
Lloyd Davis
Abstract:
The offshore feeding Snares Crested penguin Eudyptes robustus is endemic to the subantarctic Snares Islands some 200km south of New Zealand’s South Island. During breeding, Snares penguins exhibit a distinct gender depended role allocation. After laying both mates stay at the nest for two weeks before the male leaves on a two week foraging trip, after which the female leaves to forage for four to nine days. The return of the female coincides with chick hatching. Until crèching, only the female performs short term trips and feeds the chicks while the male guards nest and offspring. During the breeding seasons 2002 and 2003 we examined foraging behaviour of male and female Snares Crested penguins using time-depth recorders (TDRs) to record dive depths and GPS-dive loggers that recorded depth and a bird’s position. During the 3-day battery life of the GPS devices, three equipped males swam due east of the islands, moved up to 216Km away from the islands and dived on average 320 times per day (max depth: 101m). On three other males, TDRs recorded dive depths for entire foraging trips (10-14d, 294 dives day-1, max depth: 120.5m); data indicate increased dive activities during the second half of the trips. No GPS data was recovered for females on long-term trips, but trip lengths suggests shorter ranges than determined for males. TDR data of two females on long-term trips (duration: 5d) indicate higher foraging effort (612 dives day-1, max depth: 107m). During chick guard, females performed short term trips on which they foraged 40 to 60Km north-east to north-west from the islands, feeding in the productive waters of the Subtropical Front. These trips either lasted overnight (1086 dives trip-1, max depth: 99m) or were daylight trips only (640 dives trip-1, max depth: 82m). Because of incubation routines, male and female Snares penguins exhibit different foraging strategies. While foraging in males is primarily a matter of self-sustenance, females additionally face the responsibility of finding food for the offspring. As a consequence, chick survival depends mainly on the females’ foraging success.
5th International Penguin Conference
Ushuaia, Tierra Del Fuego, Argentina, 6-10 September 2004
Thugs and Bullies – Patterns of aggression in Snares penguins
Presentation type:
Talk (PowerPoint)
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Online status: RAW
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Authors:
Thomas Mattern
Ursula Ellenberg,
Dave Houston
Lloyd Davis
Abstract:
Snares penguins are aggressive birds. While aggression during the early breeding season are often a result of competition for nest sites and mates (e.g. male-male fights) other forms of aggression observed during later stages of breeding are not as easy to comprehend (e.g. random attacks on incubating females). Although the majority of agonistic behaviour occurs in the colonies (intra-colonial aggression) there are also regular cases of extra-colonial aggression that can be described as “beach bullying” or “forest ambushing”. After clutch completion, the number of aggressive events is low as long as the majority of male penguins are still present at their nests. After most of the males have left their incubating partners to forage, the number of attacks directed towards single females increases markedly. During such attacks, single males or pairs attack an incubating female with at times severe pecks and flipper beating – often for no obvious reasons. The incubating females generally do not fight back but assume a defensive position to protect their clutch. Although attacks often have no severe consequences some assaults result in egg loss or nest abandonment. With the return of the males, the rate of aggression recedes in the colonies. Instead single aggressive birds are now increasingly observable at the penguin landing and along the forest paths to the colonies randomly attacking returning females. During the breeding season 2003 we recorded aggressive behaviour in a Snares large penguin colony of approximately 1200 nest. The data show, that an equal number of attacks were staged by breeding and non-breeding birds. However, the severity and duration of the attacks were higher if the aggressor was a non-breeder. Furthermore, breeders often conducted short attacks to steal nest material, whereas attacks by non-breeders had generally no visible outcome. In most cases, the attacked females often got off lightly with loss of nest material at the worst. Nevertheless we found that assaults contribute significantly to egg loss. The lack of obvious gain for the aggressor makes it hard to explain attacks from an ecological viewpoint. In any case, such patterns of aggression have consequences for the Snares penguins’ general breeding behaviour.
Oamaru Penguin Symposium, 2008
Oamaru, New Zealand, 26-27 June 2008
The tip of the iceberg? The decline of Stewart Island Yellow-eyed penguins indicates serious problems at sea
Presentation type:
Talk (PowerPoint)
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Online status: RAW
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Authors:
Thomas Mattern
Abstract:
The numbers of the endangered Yellow-eyed penguin on breeding along Stewart Island’s north eastern coastline have declined dramatically. Poor breeding outcome observed in the past five years suggest that recruitment is insufficient to sustain the population. On adjacent Codfish Island, penguins seem to be faring reasonably well – breeding outcome is comparable to monitored mainland sites and the local population appears to be stable. That success and failure of local penguin populations occurs on such a small spatial scale suggests that global changes are unlikely to play a significant role in the Stewart Island penguins’ demise. Foraging and diet research conducted between 2004 and 2006 found strong evidence for localised sea based problems. Foraging grounds of penguins from both islands were spatially distinct, individual foraging ranges and diving behaviour revealed greater flexibility and performance in Codfish Island penguins. Diet composition also differed significantly with Codfish Island penguins feeding on a greater variety of prey species that were also of better quality. As a primarily benthic forager, the Yellow-eyed penguin depends on an intact benthic ecosystem. Stewart Island penguins forage primarily in areas that are commercially dredged for oysters. In this light, it seems likely that the degradation of the benthic habitat associated with dredging is limiting viable foraging habitat and prey diversity for Stewart Island penguins. Since Yellow-eyed penguins are at the top of the benthic food web their rapid decline in the past few years suggest that far more is at stake than the fate of a single species of penguin. Foveaux Straits’ unique biogenic reefs off Stewart Island must also be disappearing at an alarming rate.
6th International Penguin Conference, 2007
Hobart, Tasmania, Australia, 3 - 7 September 2007
Decline for a Delicacy: Are decreasing numbers of Yellow-eyed penguins on Stewart Island a result of commercial oyster dredging?
Presentation type:
Poster
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Authors:
Thomas Mattern
Ursula Ellenberg
Lloyd Davis
Abstract:
Yellow-eyed penguins are inshore foragers that often tend to forage repeatedly at discrete, individual sites on seperate foraging trips and across different years. This behaviour seems to be facilitated by a predominantly benthic foraging behaviour that allows the penguins to exploit distinct patches of diverse epibenthic communities. Overall, this foraging strategy suggests a considerable degree of specialisation and raises the question whether the behavioural flexibility to react on changing food situations, generally apparent in other penguins, might have been compromised in Yellow-eyed penguins. To examine the plasticity in the penguins' at-sea behaviour we studied foraging patterns of Yellow-eyed penguins breeding on Stewart Island and adjacent Codfish Island using GPS dive loggers. In comparison to Codfish birds, penguins from Stewart Island regularily exhibit a low reproductive outcome which suggested sub-optimal feeding conditions. Consequently it was expected that the Stewart Island birds would forage harder (e.g. greater foraging ranges, higher dive effort) than their conspecifics on Codfish Island. However, even though their chicks were dying of starvation, Stewart Island birds performed much shorter trips and foraged much closer to their nest sites than the more successful Codfish Island birds. We discuss this paradoxical situation and present likely explanations for this phenomenon.
Annual Yellow-eyed penguin Symposium 2006
Dunedin, New Zealand, August 2006
Starving chicks, short foraging ranges - the Stewart Island Paradox
Presentation type:
Talk (PowerPoint)
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Online status: RAW
(no narration, slide timing unadjusted)
Authors:
Thomas Mattern
Ursula Ellenberg
Lloyd Davis
Abstract:
none
Oamaru Penguin Symposium, 2005
Oamaru, New Zealand, 30 June - 1 July 2005
Fish and Chips? Indications for substantial fisheries interaction of Yellow-eyed penguins (Megadyptes antipodes)
Presentation type:
Talk (PowerPoint)
Titlepage:
Online status: RAW
(no narration, slide timing unadjusted)
Authors:
Thomas Mattern
Ursula Ellenberg
Dave Houston
Lloyd Davis
Abstract:
In November and December 2004, a bacterial infection caused high Yellow-eyed penguin chick mortality along the Otago coast. In order to examine whether sea-based factors (e.g. prey scarcity) might have contributed to the disease, the foraging behaviour of adult penguins was studied using GPS dive loggers. Loggers were fitted to penguins from three different sites: the Boulder Beach complex and Penguin Place on the Otago peninsula, and at Bushy Beach, Oamaru. Although basic foraging parameters did not differ from what was known from previous studies, most of the penguins from the Boulder Beach complex exhibited unusual linear foraging patterns that were probably a result of interactions with fisheries. On their trips, the penguins spent up to 94% of their foraging time swimming along straight lines for up to 9.6km (mean 3.3km). These lines were not only parallel to the coast but also parallel to each other. Astoundingly, the penguins navigated along the lines with extreme accuracy, having a mean horizontal deviation from an ideal straight line course of 37m. In order to maintain such accurate navigation in open water, the penguins need cues. Considering the scale of the lines and the accuracy of navigation, it seems unlikely that the birds used natural features but rather man-made cues. These could be fishing vessels but it seems more likely that dredge marks from bottom trawls are used as linear guides. It is unclear whether the penguins commonly employ such foraging strategies or if these were a product of unusual circumstances.
Annual Yellow-eyed penguin Symposium 2004
Dunedin, New Zealand, August 2004
The Bottom Lines - Foraging patterns of Yellow-eyed penguins
Presentation type:
Talk (PowerPoint)
Titlepage:
Online status: RAW
(no narration, slide timing unadjusted)
Authors:
Thomas Mattern
Dave Houston
Ursula Ellenberg
Lloyd Davis
Abstract:
none
5th International Penguin Conference
Ushuaia, Tierra Del Fuego, Argentina, 6-10 September 2004
Humboldt penguin census on Isla Chañaral, Chile: recent increase or past underestimate of Penguin numbers?
Presentation type:
Poster
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Authors:
Thomas Mattern
Ursula Ellenberg
Guillermo Luna Jorquera
Lloyd Davis
Abstract:
While Isla Chañaral (29°02’S) in Chile has long been recognized as one of the most important breeding islands for the Humboldt penguin, its population size reportedly never exceeded 3,500 breeding individuals in the last two decades. However, in 2002 a one-day survey found that the population size on Isla Chañaral may be considerably higher than that and may even exceed the world population estimate for the species (3,300 - 12,000 birds). Between 9 and 14 February 2003 we conducted a population census on Isla Chañaral to determine the number of Humboldt penguins present on the island. Two different census methods were used to assess the population size. Terrestrial or surface counts were used to survey penguins on open plains or beaches. Small area surveys of randomly established counting quadrates were conducted to assess the number of penguins inside nests as well as total number of nests. Results from small area surveys were extrapolated using surface size ratios of counting quadrates vs. entire nesting sectors. From the surface counts and small area surveys we determined that approximately 22,000 adult Humboldt penguins, 3,600 chicks and 117 juveniles were present on the island during the survey. The results were higher than any previously published population estimate, which range from 146 to 6,000 individuals. We conclude that natural processes alone cannot account for a population increase of this magnitude. Furthermore, our results correspond well with recent publications that suggest that Humboldt penguin numbers might have been underestimated in the past due to inconsistent census methods. We are concerned about the current protection status of the island in light of its fragility and importance as the premier breeding location of the Humboldt penguin along its entire distributional range.
XXII Congreso de Ciencias del Mar
Valdivia, Chile, 28-31 May 2002
¿Pingüinos tímidos? - Impacto de la perturbación humana en el pingüino de Humboldt
The most timid of all? Impact of human disturbance on Humboldt Penguins
Presentation type:
Poster
Preview:
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Authors:
Ursula Ellenberg
Guillermo Luna Jorquera
Abstract:
none
