Subtle but significant segregation in the feeding ecology of sympatric penguins during the critical pre-moult period

Whitehead, T. Otto; Connan, Maëlle; Ropert‐Coudert, Yan; Ryan, Peter G.

doi:10.3354/meps12017

Cited by 18 publications

(24 citation statements)

References 53 publications

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“…Marked sex-dependent differences in the choice of foraging habitat were reported during the pre-moult stage in Macaroni penguins from Crozet and Kerguelen [ 43 ] as well as Rockhopper penguins from Marion Island [ 44 ]. However, stable isotope analyses in Southern Rockhopper penguins from the Falkland Islands (Malvinas) showed that during the pre-moult stage both sexes forage on the same trophic levels indicating common foraging grounds [ 45 ].…”

Section: Discussionmentioning

confidence: 99%

Marathon penguins – Reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period

Mattern

Pütz²,

Borboroglu

et al. 2018

PLoS ONE

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Migratory species often roam vast distances bringing them into contact with diverse conditions and threats that could play significant roles in their population dynamics. This is especially true if long-range travels occur within crucial stages of a species’ annual life-cycle. Crested penguins, for example, usually disperse over several hundreds of kilometres after completing the energetically demanding breeding season and in preparation for the costly annual moult. A basic understanding of crested penguins’ pre-moult dispersal is therefore paramount in order to be able to assess factors affecting individual survival. The Fiordland penguin, or Tawaki, the only crested penguin species breeding on the New Zealand mainland, is currently one of the least studied and rarest penguin species in the world. We successfully satellite tracked the pre-moult dispersal of 17 adult Tawaki from a single colony located in the species’ northern breeding distribution. Over the course of 8–10 weeks the penguins travelled up to 2,500 km away from their breeding colony, covering total swimming distances of up to 6,800 km. During outbound travels all penguins headed south-west within a well-defined corridor before branching out towards two general trip destinations. Birds leaving in late November travelled towards the Subtropical Front some 800 km south of Tasmania, whereas penguins that left in December headed further towards the subantarctic front. Using K-select analysis we examined the influence of oceanographic factors on the penguins’ dispersal. Water depth, surface current velocity and sea level anomalies had the greatest influence on penguin movements at the subantarctic Front, while sea surface temperature and chlorophyll a concentration were key for birds travelling to the subtropical front. We discuss our findings in the light of anthropogenic activities (or lack thereof) in the regions visited by the penguins as well as the potential consequences of Tawaki pre-moult dispersal for the species’ breeding distribution on the New Zealand mainland.

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Section: Discussionmentioning

confidence: 99%

Marathon penguins – Reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period

Mattern

Pütz²,

Borboroglu

et al. 2018

PLoS ONE

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“…The other nine species exhibited intermediate δ 13 C memb , suggesting that during egg formation they gathered nutrients from intermediate waters between the Subtropical Front and Antarctic Polar Front as suggested by tracking data for some of them (Reisinger et al 2018). Wandering albatross females obtained their nutrients at one trophic level above grey-headed albatrosses, and king penguins at a higher trophic level than the two crested penguins, showing similar trophic segregation to the chick-rearing period (Adams and Brown 1989, Hunter and Klages 1989, Cooper et al 1992, Whitehead et al 2017; although fasting by penguins during the last stage of oogenesis (Ancel et al 2013) may influence the isotopic ratios of egg components. We did not explicitly calculate trophic levels in our study but captive studies have estimated trophic discrimination factors between food and egg membrane to be between 3 and 4‰ in seabirds (Polito et al 2009).…”

Section: Isotopic Partitioning By Feedingmentioning

confidence: 78%

“…We did not explicitly calculate trophic levels in our study but captive studies have estimated trophic discrimination factors between food and egg membrane to be between 3 and 4‰ in seabirds (Polito et al 2009). Wandering albatross females obtained their nutrients at one trophic level above grey-headed albatrosses, and king penguins at a higher trophic level than the two crested penguins, showing similar trophic segregation to the chick-rearing period (Adams and Brown 1989, Hunter and Klages 1989, Cooper et al 1992, Whitehead et al 2017; although fasting by penguins during the last stage of oogenesis (Ancel et al 2013) may influence the isotopic ratios of egg components. Interestingly, lesser sheathbills are often found around the colonies of crested penguins either stealing food from the penguins or scavenging from carcasses.…”

Section: Isotopic Partitioning By Feedingmentioning

confidence: 96%

Multidimensional stable isotope analysis illuminates resource partitioning in a sub‐Antarctic island bird community

et al. 2019

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A central theme in community ecology is understanding how similar species co-exist and how their interactions may evolve in the context of climate change. Most studies of resource partitioning among central place foragers, particularly birds, focus on the offspring-rearing period, when they are accessible, but breeding success may be determined earlier and little is known about how such species partition resources at the onset of breeding. We used a non-invasive approach to evaluate resource partitioning in co-existing females at a sub-Antarctic island during their pre-laying periods. Three hypotheses were tested using carbon, nitrogen and oxygen stable isotope ratios measured in shells and membranes of hatched eggs as ecological tracers: 1) resource partitioning by geographic location and trophic level will exist among the 12 bird species and will be enhanced within taxonomic groups; 2) given the absence of strong oxygen gradients in the Southern Ocean we will not detect spatial structuring based on oxygen isotopes, but differences will exist between resident and oceanic species as the former may use meteoric water; 3) capital and income breeder strategies can be differentiated using stable isotopes of egg remains.Two and three dimensional isotopic data showed resource partitioning among species. As predicted, segregation was evident within the four main taxonomic groups: penguins, albatrosses, burrowing petrels and giant petrels. Unexpectedly, oxygen isotopes revealed widespread use of meteoric water among a suite of sub-Antarctic birds. Stable isotopes allowed us to identify females of most species as income breeders at the onset of breeding, with the exception of the females of the two crested penguin exhibiting a mix of income and capital resources use. Multidimensional isotopic analyses revealed that resource partitioning exists at multiple stages of the annual cycle in ways likely to be important under global change, exhibiting wide potential for ecosystem analysis.

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“…Marked sex-dependent differences in the choice of foraging habitat were reported during the premoult stage in Macaroni penguins from Crozet and Kerguelen [41] as well as Rockhopper penguins from Marion Island [42]. However, stable isotope analyses in Southern Rockhopper penguins from the Falkland Islands (Malvinas) showed that during the pre-moult stage both sexes forage on the same trophic levels indicating common foraging grounds [43].…”

Section: Spatial Segregation Of Trip Destinationsmentioning

confidence: 99%

Marathon penguins – reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period

Mattern

Pütz²,

Borboroglu

et al. 2018

Preprint

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19Migratory species often roam vast distances bringing them into contact with diverse conditions and 20 threats that could play significant roles in their population dynamics. This is especially true if long-21 range travels occur within crucial stages of a species' annual life-cycle. Crested penguins, for 22 example, usually disperse over several hundreds of kilometres after completing of the energetically 23 demanding breeding season and in preparation for the costly annual moult. A basic understanding 24 of crested penguins' pre-moult dispersal is therefore paramount in order to be able to assess factors 25 affecting individual survival. The Fiordland penguin / tawaki, the only crested penguin species 26 breeding on the New Zealand mainland, is currently one of the least studied and rarest penguin 27 species in the world. We successfully satellite tracked the pre-moult dispersal of 17 adult Tawaki 28 from a single colony located in the species' northern breeding distribution. Over the course of 8-10 29 weeks the penguins travelled up to 2,500 km away from their breeding colony, covering total 30 swimming distances of up to 6,800 km. During outbound travels all penguins headed south-west 31 within a well-defined corridor before branching out towards two general trip destinations. Birds 32 leaving in late November travelled towards the Subtropical Front some 800 km south of Tasmania, 33 whereas penguins that left in December headed further towards the subantarctic front. Using K-34 select analysis we examined the influence of oceanographic factors on the penguins' dispersal. 35Water depth, surface current velocity and sea level anomalies had the greatest influence on penguin 36 movements at the subantarctic Front, while sea surface temperature, chlorophyll a concentration 37 were key for birds travelling to the subtropical front. We discuss our findings in the light of 38 anthropogenic activities (or lack thereof) in the regions visited by the penguins as well as the 39 potential consequences of Tawaki pre-moult dispersal for the species' breeding distribution on the 40 New Zealand mainland. 41PeerJ Preprints | https://doi.org/10.7287/peerj.preprints.26527v1 | CC BY 4.0 Open Access |

show abstract

Subtle but significant segregation in the feeding ecology of sympatric penguins during the critical pre-moult period

Cited by 18 publications

References 53 publications

Marathon penguins – Reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period

Marathon penguins – Reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period

Multidimensional stable isotope analysis illuminates resource partitioning in a sub‐Antarctic island bird community

Marathon penguins – reasons and consequences of long-range dispersal in Fiordland penguins / Tawaki during the pre-moult period

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