“Not all alpacas have this guard quality – generally it’s grumpy, old, castrated men and they need to be in pairs or groups. They are communal animals so they don’t do well on their own.”Tom described the moment the alpacas were introduced to the birds as “like a mexican stand-off”.“We backed the trailer into the turkey range and let the tailgate down and the alpacas came galloping out and then they stood still, frozen staring at the turkeys while the turkeys just stared back.“But then they sort of acknowledged each other and now they co-exist pretty happily with the turkeys.”The grass-eating animals react aggressively to foxes because in their native South America, wild foxes will try to kill unguarded baby alpacas.Tom said he has also noticed there have been less damaged birds – sold as ‘downgrades’ – since the alpacas arrived.He said: “If we get a fox attack, turkeys are killed but the rest of them are scared and they jump on top of each other and scratch each other – which damages their skin. But since introducing the alpacas, our downgrades this year are significantly less than usual too.”Copas Turkeys start planning for the Christmas demand in February.The birds roam around on the farm until they are 26 weeks old when they are slaughtered, hand plucked and hung up for a length of their time – which improves their flavour.The farm charges £14 per kg but Mr Copas says the cost of rearing the birds is reflected in the price.He told the BBC: “We spend more on feed than would be the case for supermarket birds that are typically slaughtered at 16 or 18 weeks.” Owner Tom Copas said their farm manager first became interested in the idea when he heard about alpacas’ strong guard qualities.After the fox attack, which cost the Copas Turkeys around £27,000 in retail value, the business owners tried more powerful electric fences and a range of other tactics but the problem did not go away.“We thought we would try and alpacas and I spent a couple of days calling around the alpaca world trying to find out more about what I needed and where I would find them,” said Tom.“Eventually I found a lovely lady in Gloucester who had some alpacas she couldn’t keep any more so we offered them a good home.” The herd of 10 alpacas are in charge of protecting a gang of 24,000 free-range turkeys Credit:Copas Turkeys Alpacas are used all over the world to deter wild dogs and coyotesCredit: Copas Turkeys
Linking extreme interannual changes in prey availability to foraging behaviour and breeding investment in a marine predator, the macaroni penguin
Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and breeding investment of macaroni penguins Eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. When prey availability was low, foraging trips were significantly longer and extended overnight. Birds also foraged farther from the colony, potentially in order to reach more distant foraging grounds and allow for increased search times. These extended foraging trips were also linked to a marked decrease in fledgling weights, most likely associated with reduced rates of provisioning. Furthermore, by comparing our results with previous work on this population, it appears that lowered first-year survival rates associated, at least partially, with fledging masses were also evident for this cohort. This study integrates a unique set of prey density, predator behaviour and predator breeding investment data to highlight a possible behavioural mechanism linking perturbations in prey availability to population demography.