<P> Flying in the V formation has been the subject of study by researchers . The front position is rotated since flying in front consumes the most energy . Canada geese leave the winter grounds more quickly than the summer grounds . Elevated thyroid hormones, such as T and T, have been measured in geese just after a big migration . This is believed because of the long days of flying in migration the thyroid gland sends out more T which help the body cope with the longer journey . The increased T levels are also associated with increased muscle mass (hypertrophy) of the breast muscle, also because of the longer time spent flying . It is believed that the body sends out more T to help the goose's body with this long task by speeding up the metabolism and lowering the temperature at which the muscles work . Also, other studies show levels of stress hormones such as corticosterone rise dramatically in these birds during and after a migration . </P> <P> The lifespan in the wild of geese that survive to adulthood ranges from 10 to 24 years . The British longevity record is held by a specimen tagged as a nestling, which was observed alive at the University of York at the age of 31 . </P> <P> Known predators of eggs and goslings include coyotes, Arctic foxes (Vulpes lagopus), northern raccoons (Procyon lotor), red foxes (Vulpes vulpes), large gulls (Larus species), common ravens (Corvus corax), American crows (Corvus brachyrhynchos), carrion crows (in Europe, Corvus corone) and both brown (Ursus arctos) and American black bears (Ursus americanus). </P> <P> Once they reach adulthood, due to their large size and often aggressive behavior, Canada geese are rarely preyed on, although prior injury may make them more vulnerable to natural predators . Beyond humans, adults can be taken by coyotes and gray wolves (Canis lupus). Avian predators that are known to kill adults, as well as young geese, include snowy owls (Bubo scandiacus), golden eagles (Aquila chrysaetos) and bald eagles (Haliaeetus leucocephalus) and, though rarely on large adult geese, great horned owls (Bubo virginianus), peregrine falcons (Falco peregrinus), and gyrfalcons (Falco rusticolus). Adults are quite vigorous at displacing potential predators from the nest site, with predator prevention usually falling to the larger male of the pair . Males usually attempt to draw attention of approaching predators and toll (mob terrestrial predators without physical contact) often in accompaniment with males of other goose species . Eagles of both species frequently cause geese to fly off en masse from some distance, though in other instances, geese may seem unconcerned at perched bald eagles nearby, seemingly only reacting if the eagle is displaying active hunting behavior . Canada geese are quite wary of humans where they are regularly hunted and killed, but can otherwise become habituated to fearlessness towards humans, especially where they are fed by them . This often leads to the geese becoming overly aggressive towards humans, and large groups of the birds may be considered a nuisance if they are causing persistent issues to humans and other animals in the surrounding area . </P>

Where do canadian geese migrate to in winter from uk