A ground-breaking new study published in the Journal of Animal Ecology, which used hundreds of reared pheasant chicks as the model, could have invaluable implications for important wildlife reintroduction programmes in the future.
This new research, which formed part of a PhD study by Dr Mark Whiteside, identified that the provision of a more naturalistic diet to very young chicks in captivity, in the form of mixed seed and live meal worms, will help to make a considerable difference to their survival once released into the wild compared to pheasants reared with standard chick pellets.
The three-year study was initiated and supported by the Game & Wildlife Conservation Trust (GWCT) and carried out by Dr Whiteside from the Centre for Research in Animal Behaviour at the University of Exeter. Both the GWCT and Exeter University co-funded this important study.
Mark Whiteside explains why this important study has wide-ranging benefits, “Captive-reared animals released as a part of a reintroduction or restocking programme typically differ from their wild counterparts in their behavioural and physiological characteristics, which can lead to high levels of mortality. Pheasant rearing offers an excellent model system to help identify how we can manipulate early rearing conditions to promote the development of important survival traits once released into the wild.”
Dr Rufus Sage, the GWCT’s head of lowland gamebird research who co-supervised the study said, “Our objective was to improve the fitness of the birds and enable them to adapt more successfully to free-range life before and during the shooting season. Most wild animals learn vital life-skills from their parents but reared birds do not have the same opportunity to develop survival techniques such as feeding from adults. This is a particularly important study as it has very positive implications for pheasant welfare, economics and ecology in the future and can be potentially applied to other species that are captive-reared.”
The study involved rearing 1,800 pheasants (Phasianus colchicus) from one day old for seven weeks under conditions similar to those used by commercial breeders after which the birds were released into the wild. In year one, 900 pheasants were divided into groups with each group being reared with different diets including commercial chick crumb, crumb plus 1% live mealworm or crumb plus 5% mixed seed.
In year two, a further 900 pheasants were divided into two groups, following a similar treatment. In both years the commercial chick crumb acted as a control treatment, while the diet of those with live prey and mixed seeds and fruits mimicked a more naturalistic diet.
Whilst the birds were under captive rearing conditions, various experiments were carried out to measure the bird’s potential survival skills. In one trial Mark presented 117 chicks, aged four-weeks with a tethered cricket to measure the birds observation and food handling skills. The chicks were randomly chosen from each treatment (mealworm – 39, mixed seed – 39 and control – 39), and the results of this test were striking.
The birds that were fed mealworms were twice as quick at catching and eating the tethered crickets after detection as the other birds. This more efficient foraging strategy had consequences after the birds were release into the wild, with birds reared with a more natural diet foraging for less time and being more vigilant than birds reared with standard chick crumb.
Mark Whiteside explains why this study has important implications, “Released pheasants face three distinct threats post-release. They are more vulnerable to predation than wild birds; they are unable to maintain body condition because of poor foraging efficiency; and finally, the birds could become dependent on supplementary feeding, which is often withdrawn in the spring and the birds are often unable to make the transition to a more natural diet.
“Pheasants typically forage in the open and are therefore at risk to aerial predators. Adopting a more efficient foraging strategy means that a bird will obtain enough food for survival whilst spending less time exposed to predation.”
Another interesting discovery from the study is that the birds that were fed on a more naturalistic diet had a five per cent smaller gut. This is quite significant as smaller gut suggests that they are better able to cope with a high energy diet. A lighter bird may have increased flight efficiency and therefore a better ability to avoid predators.
Professor Joah Madden from the Pheasant Ecology and Cognition group at the University of Exeter, who also co-supervised the study adds, “Poor survival is such a common problem in released pheasants, and other animals that are captive reared for release into the wild, that many programmes simply release larger and larger numbers. Having the ability to acquire and assimilate food from the wild produces a more adaptive diet and foraging strategy resulting in a subsequent improvement in survival. Ultimately, this means that wastage is reduced and fewer pheasants need to be released each year, whilst still maintaining an economically viable level for shooting.”
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Photocaption: Photocredit: Martin Clay. Live pheasant chicks on the GWCT Game Fair stand adjacent to the main arena, will help to illustrate the science behind a new three-year project that aimed to see whether simple techniques introduced early in a reared pheasant’s life helps to increase their survival once released.
Notes to editors:
To explain the science behind this fascinating new study, Dr Whiteside and Professor Madden will be on hand at the Game & Wildlife Conservation Trust’s stand at the CLA Game Fair being held at Harewood House, Yorkshire on Friday 31st July to Sunday 2nd July. Mark will be using a group of live pheasant chicks to explain the science and to give an update on the research, which he has extended to investigate important perching and roosting behaviour, which also adds to their survival rate in the wild.
Dr Whiteside’s published paper Diet complexity in early life affects survival in released pheasants by altering foraging efficiency, food choice, handling skills and gut morphology is published in the Journal of Animal Ecology and is co-authored by Dr Rufus Sage from the GWCT and Prof Joah Madden, from the Centre for Research in Animal Behaviour, Psychology, University of Exeter. Follow our work @MarkAWhiteside, @pec_exeter, and @Gameandwildlife.
The Game & Wildlife Conservation Trust (GWCT) – providing research-led conservation for a thriving countryside. The GWCT is an independent wildlife conservation charity which has carried out scientific research into Britain’s game and wildlife since the 1930s. We advise farmers and landowners on improving wildlife habitats and we lobby for agricultural and conservation policies based on science. We employ 22 post-doctoral scientists and 50 other research staff with expertise in areas such as birds, insects, mammals, farming, fish and statistics. We undertake our own research as well as projects funded by contract and grant-aid from Government and private bodies. The Trust is also responsible for a number of Government Biodiversity Action Plan species and is lead partner for grey partridge and joint lead partner for brown hare and black grouse. For Information, contact: Morag Walker – Head of Media, Telephone – direct-dial: 01425-651000. Mobile – 07736-124097 www.gwct.org.uk