The use of a nutritional supplement to improve egg production in the endangered kakapo

Houston, David C.; McInnes, Kate; Elliott, Graeme; Eason, Daryl; Moorhouse, Ron; Cockrem, John F.

doi:10.1016/j.biocon.2007.04.023

Cited by 33 publications

(35 citation statements)

References 26 publications

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“…Growing evidence suggests that the ecological impacts of food supplementation can depend on the specific nutritional profile of provisioned foods [48,[60][61][62][63][64] and that the energetic content of the food (in joules or calories) does not necessarily constitute an indicator of food quality [61,63]. For example, the availability of essential amino acids [62,65] and vitamins or antioxidants [60] may constrain egg production in birds.…”

Section: Conclusion and Future Prospectsmentioning

confidence: 99%

Reproductive responses of birds to experimental food supplementation: a meta-analysis

et al. 2014

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Introduction: Food availability is an important environmental cue for animals for deciding how much to invest in reproduction, and it ultimately affects population size. The importance of food limitation has been extensively studied in terrestrial vertebrate populations, especially in birds, by experimentally manipulating food supply. However, the factors explaining variation in reproductive decisions in response to food supplementation remain unclear. By performing meta-analyses, we aim to quantify the extent to which supplementary feeding affects several reproductive parameters in birds, and identify the key factors (life-history traits, behavioural factors, environmental factors, and experimental design) that can induce variation in laying date, clutch size and breeding success (i.e., number of fledglings produced) in response to food supplementation. Results: Food supplementation produced variable but mostly positive effects across reproductive parameters in a total of 201 experiments from 82 independent studies. The outcomes of the food effect were modulated by environmental factors, e.g., laying dates advanced more towards low latitudes, and food supplementation appeared not to produce any obvious effect on bird reproduction when the background level of food abundance in the environment was high. Moreover, the increase in clutch size following food addition was more pronounced in birds that cache food, as compared to birds that do not. Supplementation timing was identified as a major cause of variation in breeding success responses. We also document the absence of a detectable food effect on clutch size and breeding success when the target species had poor access to the feed due to competitive interactions with other animals. Conclusions: Our findings indicate that, from the pool of bird species and environments reviewed, extra food is allocated to immediate reproduction in most cases. Our results also support the view that bird species have evolved different life-history strategies to cope with environmental variability in food supply. However, we encourage more research at low latitudes to gain knowledge on how resource allocation in birds changes along a latitudinal gradient. Our results also emphasize the importance of developing experimental designs that minimise competition for the supplemented food and the risk of reproductive bottle-necks due to inappropriate supplementation timings.

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Section: Conclusion and Future Prospectsmentioning

confidence: 99%

Reproductive responses of birds to experimental food supplementation: a meta-analysis

et al. 2014

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“…The response of birds to removal/addition experiments has been described as some species laying to achieve a particular clutch size (indeterminate layer) and others laying a particular number of eggs (determinate layer). Although phylogenetic constraints play a role in the determination of clutch size (Yom-Tov 1987, Postma andvan Noordwijk 2005), the termination of laying has been attributed to (1) extrinsic cues that trigger the cessation of laying (e.g., the tactile stimulation of the brood patch; Haywood 1993a, b), (2) nutrient limitations on egg production (Houston et al 2007), and (3) hormonal and circadian regulation of clutch size (Haywood 1993a, b, Zivkovic et al 2000. If any of these mechanisms play proximate roles in…”

Section: Short Communicationsmentioning

confidence: 99%

Extended Laying Interval of Ultimate Eggs of the Eastern Bluebird

Cooper

Voss

Zivkovic

2009

Condor

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“…The rimu tree undergoes a mast season every 3 or 4 years, during which time kakapos mate and rear young. While the link between kakapo and rimu is well established, the causal link between these two phenomena is unclear and is not simply a matter of additional dietary energy enabling reproduction (17).…”

mentioning

confidence: 99%

Influence of Hand Rearing and Bird Age on the Fecal Microbiota of the Critically Endangered Kakapo

Waite

Eason²,

Taylor

2014

Appl Environ Microbiol

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bThe critically endangered New Zealand parrot, the kakapo, is subject to an intensive management regime aiming to maintain bird health and boost population size. Newly hatched kakapo chicks are subjected to human intervention and are frequently placed in captivity throughout their formative months. Hand rearing greatly reduces mortality among juveniles, but the potential long-term impact on the kakapo gut microbiota is uncertain. To track development of the kakapo gut microbiota, fecal samples from healthy, prefledged juvenile kakapos, as well as from unrelated adults, were analyzed by using 16S rRNA gene amplicon pyrosequencing. Following the original sampling, juvenile kakapos underwent a period of captivity, so further sampling during and after captivity aimed to elucidate the impact of captivity on the juvenile gut microbiota. Variation in the fecal microbiota over a year was also investigated, with resampling of the original juvenile population. Amplicon pyrosequencing revealed a juvenile fecal microbiota enriched with particular lactic acid bacteria compared to the microbiota of adults, although the overall community structure did not differ significantly among kakapos of different ages. The abundance of key operational taxonomic units (OTUs) was correlated with antibiotic treatment and captivity, although the importance of these factors could not be proven unequivocally within the bounds of this study. Finally, the microbial community structure of juvenile and adult kakapos changed over time, reinforcing the need for continual monitoring of the microbiota as part of regular health screening.

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The use of a nutritional supplement to improve egg production in the endangered kakapo

Cited by 33 publications

References 26 publications

Reproductive responses of birds to experimental food supplementation: a meta-analysis

Reproductive responses of birds to experimental food supplementation: a meta-analysis

Extended Laying Interval of Ultimate Eggs of the Eastern Bluebird

Influence of Hand Rearing and Bird Age on the Fecal Microbiota of the Critically Endangered Kakapo

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