Saturday, 17 August 2013

Passerines 5: Azure-Winged Magpie

Asian Azure-Winged Magpie, Bristol
 The only species of the crow family that Bristol currently has in its collection is a bird with (until recently) a rather mysterious distribution. The Azure-Winged Magpie is know from only two parts of the world, the Iberian peninsula in Europe, and eastern Asia, with no known populations in between. This was so confusing a picture that for a long time it was believed that the birds in Spain and Portugal originated very recently as escaped sailors pets, brought back by Spanish or Portugese navigators to the Far East in the 16th or 17th centuries, but it is now known that they are relicts of a much more widely spread population, which diverged from the Asian birds at least a million years ago. The European birds do look somewhat different, being rather smaller and lacking a white end to the tail, but otherwise look and behave the same as the Asian birds. The Bristol zoo birds are the Asian form, Cyanopica cyana. The European birds have been classed as a separate species, C.cooki, but this is not yet on the official lists.

As with most members of the crow family, Azure-Winged Magpies are omnivorous feeders, eating acorns, pine nuts, fruit and various invertebrates, and round picnic sites they will also scavenge for scraps. Unlike many of their larger relatives, they are highly social and semi-colonial nesters, moving around their territory in family groups, Co-operative nesting, with other group members helping with nest building, feeding and caring for young, and even feeding the incubating female, happens frequently, and both other adults and juveniles in the colony may be the helpers.
Japanese Sparrowhawk

Azure-winged magpies build open, cup-shaped nests and usually 5 or 6, occasionally up to 9, eggs. The eggs are incubated solely by the female, and hatch after 15 days. In Spain, they seem to suffer quite high rates of nest predation, but in Japan they have a useful additional way of protecting themselves – they choose to breed near active nests of the Japanese Lesser Sparrohawk, Accipiter gularis. Many birds of prey do not hunt near their nests, but drive off potential nest predators, and this enables some other species to benefit. In the European tundra, Red-Breasted Geese have a similar relationship with Snowy owls and Peregrines.

Another threat Azure-winged Magpies face is brood parasitism. Asian birds are prone to nest parasitism from Common Cuckoos, but they do not seem to attack Iberian birds. In Iberia however they face another potential threat, the Great Spotted Cuckoo Clamator glandarius. This specialises in parasitizing members of the crow family, and in the past it seems to have attacked Azure-Winged Magpies. These have at present though strong nest defenses against the cuckoos, and have high recognition of Great-Spotted cuckoo eggs, which they eject from the nest. At present, the preferred targets for Great Spotted Cuckoos are European Magpies and Hooded Crows instead.
Juvenile Great-Spotted Cuckoo

In captivity, Azure-Winged Magpies (all of the Asian form as far as I am aware) are widely kept and bred. They are straightforward birds to care for, feeding on proprietary pellets with added fruit and live food, especially when feeding young. Bristol breeds them every year, and our colony is currently on show in one of our newer aviaries in the quieter corner of the zoo. As with parrots, one of the main husbandry issues for all members of the crow family is mental stimulation and enrichment. Our colony is in a planted aviary with many corners and potential live food sources to explore, and keeping them as a group is also very beneficial.

In the wild, Azure-Winged Magpies are classified as Least Concern, and in fact in both Europe And Asia the populations seem to be on the increase. The Iberian birds howver do seem to have rather precise habitat requirements, and changes in habitat either as a result of changes in farming practise or climate change may have an adverse affect.

(images taken by myself, also from wikipedia)

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