Saturday, 28 August 2010

Bristol Parrots 1: Killer Clowns

“Clowns of the Snowline” is the commonest description of the first species in Bristol’s parrot collection that I am going to write about, the Kea, Nestor notabilis. It is appropriate that I start with this species, as it represents the earliest branch on the family tree of living parrots, together with some other New Zealand species, the Weka Nestor meridionalis, and the famous Kakapo, Strigops habrotila. These make up the family Nestoridae, together with the extinct Norfolk Island Kaka Nestor productus (extinct 1851). A fourth form of Nestor, the extinct Chatham Island Kaka, is not certainly a separate species and has not been scientifically described. Wekas are very similar to Keas, but are lowland rather than mountain birds.

Although not as aberrant as the Kakapo, the Kea has its own unique characteristics as a result of its adaptation to life above the treeline. Today it is only found in the South Island in the Southern Alps, although there are fossil remains from the North island from the end of the last glaciation – it is unclear when this population died out, but they were gone before European settlement.

Traditionally, all parrots have been placed in the same family Psitaccidae, but this does not reflect their relationships. As well as the Nestoridae, the Cockatoos are usually placed in a separate family Cacatuidae, with the other parrots being retained in Psitaccidae. The Brush-tongued parrots or Lories are however very distinctive, and they are also often placed in a separate family these days. We have representatives of most of the major groups at Bristol, though unfortunately our Red-Vented Cockatoos are not on show at the moment.

Most people have a fairly standard picture of the typical parrot – noisy, sociable, intelligent, monogamous, forest dwelling, and vegetarian. As with most stereotypes, this has a fair amount of truth, but is far from universal, hence the title of this post.

Whilst its cousin the Kaka is a fairly typical forest parrot, the Kea, as a result of its colder environment, has a strong appetite for high energy foods, especially animal fats. Where their range overlaps seabird colonies they will raid shearwater nests for the oil-rich chicks (a risky business – the chicks protect themselves with projectile vomiting of fish oil), As well as animal food, Keas eat fruits, leaves, buds, and will dig in the ground using their long curved beaks for roots and insect larvae. Unfortunately for them they will also attack sheep for the fat on their backs. This has been filmed, so it is not just a farmer’s story. When this became known, a bounty was placed on their heads and at least 150,000 were killed before the bounty was lifted.

Keas are also unpopular with skiers. They are extremely curious, and are very fond of ripping the trim off cars when holiday makers visit ski resorts in their range. I am told that special insurance is needed if you are taking your car into Kea territory – perhaps a reader could confirm this?

Like most parrots, Keas are hole nesters, but with few trees in their habitat they have taken to using holes dug into slopes or under boulders. The entrance tunnel can in some cases be 6m long. The eggs (2 to 4) are white, as with most parrots, hatch after 21 days. Keas are attentive parents, but there is a high mortality among young birds in their first year. Once they have reached their first anniversary, they are long lived, with over 50 years being recorded in captivity. Although usually monogamous, there is one account that suggests they are polygamous, but as females and subadults are very similar this may be a misinterpretation.

Today the population is at most 15,000 birds, probably much less, and the population is declining as a result of continuing persecution and introduced mammals either attacking chicks in their nests or competing with adult birds for food, especially in the winter. Research on their conservation needs is ongoing.

Bristol has a successful breeding group of Keas, which have produced one or two young at least every other year. Captive parrots need a lot of mental stimulation (one reason that pet parrots are not a good idea) – in terms of their psychological requirements it is comparable to looking after a monkey, or even one of the great apes. Even the less curious and intelligent of the parrot family have a level of intelligence comparable to that of a dog, and Keas are well up the scale of avian intelligence. To keep them happy we have multiple cage furniture in their aviary, which is changed regularly as they destroy it, and also a water feature in the form of a waterfall. They use this to make up their own games – I saw one picking up a stick, flying to the top of the waterfall to drop it in, then following it all the way down to the bottom pool before fishing it out and starting again.

The presence of multiple birds (mostly previous years’ offspring) also provides much stimulation – parrots are often kept only in pairs but in the wild most are flock birds which only split up into pairs during the breeding season, with the adults and any new young rejoining the flock later in the year. Experience has shown us that several of our parrot species will happily tolerate young from previous years in their aviary even while they are nesting, although an unrelated pair breeding at the same time would be a different matter.

Despite all this, Keas are rare in zoos, with ISIS listing 113 in Europe and another 29 in the US, of which Bristol has 6. There are also some in private hands as a result of birds being exported before the pest control bounty was lifted in the 70’s. The only Wekas in captivity outside new Zealand are in Stuttgart zoo, which has 4.

For more information on these wonderful birds, look at the Kea conservation website here:

Images from Wikipedia or taken at Bristol by me

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