A condition index for African penguin <i>Spheniscus demersus</i> chicks

Lubbe, Annelize; Underhill, Les G.; Waller, LJ; Veen, Jan

doi:10.2989/1814232x.2014.915232

Cited by 14 publications

(22 citation statements)

References 59 publications

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“…Individual chicks were measured up to five times during the linear phase of their growth (Lubbe et al . ) resulting in several growth increments per chick, and a total of 365 growth rate measurements from 102 chicks. Chick growth increments were calculated for each pair of successive measurements in g/day as:

Growth rate (g/day) = \frac{Mass 2 - Mass 1}{Day 2 - Day 1}

…”

Section: Methodsmentioning

confidence: 99%

Sex allocation and sex‐specific parental investment in an endangered seabird

Spelt

Pichegru

2017

Ibis

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Biased offspring sex ratio is relatively rare in birds and sex allocation can vary with environmental conditions, with the larger and more costly sex, which can be either the male or female depending on species, favoured during high food availability. Sex‐specific parental investment may lead to biased mortality and, coupled with unequal production of one sex, may result in biased adult sex ratio, with potential grave consequences on population stability. The African Penguin Spheniscus demersus, endemic to southern Africa, is an endangered monogamous seabird with bi‐parental care. Female adult African Penguins are smaller, have a higher foraging effort when breeding and higher mortality compared with adult males. In 2015, a year in which environmental conditions were favourable for breeding, African Penguin chick production on Bird Island, Algoa Bay, South Africa, was skewed towards males (1.5 males to 1 female). Males also had higher growth rates and fledging mass than females, with potentially higher post‐fledging survival. Female, but not male, parents had higher foraging effort and lower body condition with increasing number of male chicks in their brood, thereby revealing flexibility in their parental strategy, but also the costs of their investment in their current brood. The combination of male‐biased chick production and higher female mortality, possibly at the juvenile stage as a result of lower parental investment in female chicks, and/or at the adult stage as a result of higher parental investment, may contribute to a biased adult sex ratio (ASR) in this species. While further research during years of contrasting food availability is needed to confirm this trend, populations with male‐skewed ASRs have higher extinction risks and conservation strategies aiming to benefit female African Penguin might need to be developed.

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Growth rate (g/day) = \frac{Mass 2 - Mass 1}{Day 2 - Day 1}

…”

Section: Methodsmentioning

confidence: 99%

Sex allocation and sex‐specific parental investment in an endangered seabird

Spelt

Pichegru

2017

Ibis

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“…Body condition of these chicks was poor (less than Mean − SD) or mediocre (within Mean ± SD) in relation to all chicks admitted to the centre during the same period. In all 8 cases, the values were less than Mean − SD of the parent-reared chicks on Robben Island that fledged in 2004 (the data on which the body condition index was formulated; Lubbe et al 2014). Gross lesions in these 8 cases were varied, with most cases showing some degree of airsacculitis and pneumonia.…”

Section: Resultsmentioning

confidence: 92%

“…Clinical history and necropsy results of African penguin Spheniscus demersus chicks with lesions consistent with herpesvirus on histopathology. Stony Point is at 34°21' 56" S, 18°54' 8" E, Robben Island is at 33°21' 56'' S, 18°21' 58'' E, Dyer Island is at 34°40' 58" S, 19°25' 3" E; BCI: body condition index (calculated following Lubbe et al 2014); EM: electron microscopy; nt: not tested; ni: virus not isolated bilitation in 2010. The PCR tests targeting GaHV-1 and LDV in swabs from penguin chicks in 2010 were all negative, including the sample that was suggestive of herpesvirus.…”

Section: Resultsmentioning

confidence: 99%

“…Here we consider data from African penguins admitted to the Table View facility (33°50' 02 The following data were collected: individual number, date and location of capture, chick stage at admission on a scale from P0 (newly hatched) to P4 (close to Fledging) (Sherley et al 2014), outcome of rehabilitation (release to the wild, death, euthanasia), body mass on admission (floor-standing scale with precision ± 20 g) and head length on admission (measured with a Vernier calliper from the back of the head to the tip of the beak). A body condition index was calculated using a modified Veen index method (BCI4) that uses the head and mass measurements (Lubbe et al 2014).…”

Section: Methodsmentioning

confidence: 99%

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Herpesvirus-like respiratory infection in African penguins Spheniscus demersus admitted to a rehabilitation centre

Parsons¹,

Gous²,

Wilpe³

et al. 2015

Dis. Aquat. Org.

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Rehabilitation is an important strategy for the conservation of the Endangered African penguin Spheniscus demersus, and disease has been raised as a concern in the management of the species, both in the wild and in rehabilitation centres. We report 8 cases of herpesvirus-like respiratory infection in African penguin chicks undergoing rehabilitation between 2010 and 2013 at a facility in Cape Town, South Africa. Infection was confirmed through the identification of viral inclusions in the tracheal epithelium and demonstration of particles consistent with herpesvirus by electron microscopy, whereas virus isolation in eggs, serology and PCR testing failed to detect the virus. Only penguin chicks were affected; they were in poor body condition, and in 2 cases infection occurred prior to admission to the rehabilitation centre. The role played by the herpesvirus-like infection in the overall respiratory disease syndrome is uncertain, due to identification of lesions in only a small proportion of the chicks as well as to the occurrence of other concurrent pathological processes. Further studies are advised to characterise the specific virus involved through the development of sensitive diagnostic methods and to clarify the epidemiology and significance of these infections in wild African penguins.

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“…Thus, maximizing release rates could provide conservation benefit in line with the national and international recommendations to reinforce populations and establish techniques for conservation translocations (Ellis, Croxall & Cooper, ; Crawford et al ., ). Until the recent development of a body condition index (BCI), colony managers lacked quantitative criteria to assess whether individual chicks had been abandoned (Lubbe et al ., ; Sherley et al ., ). Instead, abandonment was determined qualitatively (by visual assessment) or chicks were removed en‐masse to minimize disturbance once a high proportion of the adult population had initiated moult (Sherley et al ., ).…”

Section: Introductionmentioning

confidence: 98%

Body condition as a quantitative tool to guide hand‐rearing decisions in an endangered seabird

Morten

Parsons²,

Schwitzer³

et al. 2017

Animal Conservation

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The use of wildlife rehabilitation for conservation is growing, but quantitative criteria are rarely used to guide whether and when to remove animals from the wild. Since 2006, large numbers of African penguin Spheniscus demersus chicks have been abandoned annually when adults enter moult with dependent young still in the nest. As part of conservation initiatives for this endangered species, these chicks were collected and hand reared to fledging age. Post-release survival has been well documented; in this study we develop models to predict survival of individuals during rehabilitation with the aim of improving hand-rearing success and guiding the use of scarce resources. For 1455 chicks abandoned between 2008 and 2013, we assessed whether a chick body condition index (BCI) could predict outcome (death or release) and time spent in rearing. In addition, for a subset of 173 chicks in 2012, we assessed whether BCI at admission influenced chick growth rates during rehabilitation and examined whether the use of additional structural measurements and sex provided additional power to predict outcome. Models predicted an 82.9% (95% confidence interval: 73.3-89.5%) release rate for chicks admitted with a BCI >0, the proposed guideline for removal from colonies. This fell below 50% for BCIs < À1.05; 66% of chicks were admitted with BCIs between these thresholds. Adding bill length to BCI improved the relative model fit, but in both cases onlỹ 70% of rehabilitation outcomes were correctly predicted. Chicks that grew more quickly were more likely to be released and, for those that were released, had lower BCI at admission suggesting compensatory growth. Chicks were generally removed at an appropriate time to ensure successful hand-rearing. However, 32% were admitted in good condition, highlighting the importance of using adaptive management to guide wildlife rehabilitation and the allocation of conservation resources.

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A condition index for African penguin Spheniscus demersus chicks

Cited by 14 publications

References 59 publications

Sex allocation and sex‐specific parental investment in an endangered seabird

Sex allocation and sex‐specific parental investment in an endangered seabird

Herpesvirus-like respiratory infection in African penguins Spheniscus demersus admitted to a rehabilitation centre

Body condition as a quantitative tool to guide hand‐rearing decisions in an endangered seabird

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