Sunday, 12 June 2011

Bristol Waterfowl 6: Wild Goose chase

One of the most beautiful geese in the world is unfortunately also one of the rarest. The Red-breasted Goose Branta ruficollis is currently estimated to have a population of around 35,000 in the wild; perhaps half what it was only 10 years ago, when it was already the rarest in the genus aside from the far more famous Nene Branta sandvicensis.

As with most of its relatives, the Red-breasted Goose breeds in the Arctic, with the main breeding areas on the Tamyr peninsula in Siberia and neighbouring parts of the tundra. They winter much further south, and in the past enough seem to have reached the Nile delta for them to feature on ancient Egyptian wall paintings. Today they winter mainly on a few small areas on the Black Sea coast, mainly in Bulgaria and Romania. Unfortunately agricultural development and hunting, both by locals and increasing numbers of visiting hunting tourists, have an impact on the populations.

The other problem they face is on their breeding grounds. As a very small goose (mallard-size or even less) they are prime prey when nesting, especially to Arctic Foxes. As a precaution against this, they have an unusual relationship with birds of prey, often nesting within 20m of Snowy Owl or Peregrine Falcon nests. This is not as odd as it seems – raptors tend not to hunt close to their nests but vigorously defend their young, so the goose gets a free security guard. While some goslings may fall prey to raptors, especially in good lemming years the owls and falcons will tend to focus on those, enabling a large family of goslings (the usual clutch is 6-7 eggs) to be raised. A decline in peregrines on the Tamyr peninsula has been matched by a similar decline in goose numbers, probably as a result of reduced fledging success.

As with other geese, Red-breasted Geese are grazers, feeding mainly on land on grasses and herbs. In the winter they may frequent farmland, especially winter wheat, often in the company of other geese. Although they are a protected species, it is in this situation that they are most vulnerable to hunting – they can look very similar to Brent geese in the distance, especially in poor light, and Brent are a legal quarry species.

In the UK, Red-breasted Geese are a very rare winter visitor, and probably always have been, although there is a report of a sub-fossil specimen dated at around 130,000 b.p. from a site in Essex in south-east England. It is most likely, as the site is a warm interglacial one, that this too represents a wintering rather than a breeding bird.

Red-breasted geese are not very prolific in captivity, although some are bred every year, and the reason for this may well be day length. As an extreme high-Arctic specialist, Red-breasted Geese will usually conduct their breeding season in continuous daylight, and the longer nights at most of the zoos and wildfowl collections where they are kept at lower latitudes may disrupt their breeding rhythm. Feeding and care is as for other geese – essentially a suitable shallow pool and an area for grazing that is predator-free. They seem to nest in loose colonies, so having several pairs in the same enclosure may also be an advantage.

For more on the conservation of Red-breasted geese, check out the Wildfowl and Wetland Trust website here:

At Bristol, we currently have only a solitary male, which can be seen in the Camargue exhibit by the entrance. Although they do not currently winter as far west as the Camargue, the wintering habitat is somewhat similar. The zoo does not have any current plans to expand the breeding of Red-breasted Geese, concentrating instead on two other species of waterfowl, Mellers’ Duck and Marbled Teal.

Next week: the ferocious Anas melleri!

(images from wikipedia)

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