Monday, December 13, 2010

Silver-eye, wax-eye or white-eye


Zosterops lateralis, the little silver-eye, is not so numerous in the Wairarapa as it is up north where huge flocks congregate in the winter and descend upon berry producing trees and shrubs in their hoards. Hurrying from tree to tree, from one garden to another, with a continuous, noisy twitter, or uttering short plaintive notes, they set about distributing seeds, mindless as to what is is they are casting about, and with no concern at all as to whether the seeds are native or obnoxious. Poroporo keeps on sprouting in my garden here, undoubtedly spread by silver-eyes.

Now that the house sparrow numbers are very much in decline, the silver-eye is probably New Zealand's most numerous bird, far out numbering the more obvious starlings which tend to get the blame for the silver-eyes' crimes against orchardists. Silver-eyes have a particular fondness for fruit. They happily eat their way through a wide range of fruits, including apples, kiwi fruit, feijoas, figs, grapes, pears and persimmons. Their pointed beaks can break the skin of fruit more readily than other birds, and once the skin is broken it allows other birds the opportunity to feast. But as Buller said, “It far more than compensates for this petty pilfering by the wholesale war it carries on against the various insects that affect our fruit trees and vegetables”.

The silver-eye is a small olive–green bird with white rings around the eyes. They have a fine tapered bill and a brush tipped tongue like the Tui and Korimako, the bellbird, for drinking nectar. There are many species in Africa, southern Asia, and the south western Pacific, but it is the Tasmanian sub–Australian species which migrates to the eastern states of the Australian mainland in winter which colonised New Zealand. They were recorded in New Zealand as early as 1832 but it was not until 1856 that they arrived in very large numbers. It is assumed that a storm caught a migrating flock in Australia and diverted them here. The Maori name, Tauhou, means “stranger”.
Their success as a species has probably a lot to do with their varied diet which is mainly comprised of insects, fruit and nectar, but they will also readily take fat, cooked meat, bread and sugar water from bird tables.
They are delightful, busy little birds and are strongly territorial and are often seen fluttering their wings aggressively at another bird. I have seen them cuddling up in pairs on a branch busy preening and feeding each other. With their white ringed eyes set close together, they look so much like clowns. And then to see them with a bright red cotoneaster berry in their beaks, the picture is complete.

Thursday, December 02, 2010

The Persecution of rooks in New Zealand

On the local radio throughout this spring, Greater Wellington Regional Council was once again asking people to report on rookeries in the area. This pursuit of rooks brings into question Regional Council's pest strategies especially in relation to birds.

Rooks are a minor agricultural pest, certainly no worse than say yellowhammers, so why is one being pursued and not the other? It would seem that one of requirements of the Biosecurity Act is that pest control must be cost effective, so the yellowhammer is too numerous and widespread to eradicate but the rook is apparently a viable target for eradication. Both birds were introduced from Europe in the 19th century, as bio-control agents. These birds are not a threat to native or endemic species.

In perusing the voluminous amount of data on Regional Council pest strategies on line, I have managed to glean that over a period of twenty years 2002-2022 at a cost of $60,000 a year it is proposed to eradicate the rook. Part of that budget goes towards putting up helicopters to find the rookeries.

There is no similar proposal to eradicate more serious pests such as mustelids or rats as like the yellowhammer they are not cost effective. Possums are dealt with because of necessity for tb control.

However, there is an operational budget for the control of pests, cats, mustelids, rats, in a buffer zone around Mount Bruce, the wildlife sanctuary in the Wairarapa. The budget for one year 2007-2008 was $34,300. I was not able to glean what the long term strategy is for the buffer zone.

Now in looking at all this, the logic somehow escapes me. To eradicate the rook, a minor agricultural pest on a par with yellowhammers, will cost 1.2 million over 20 years. Given what has happened to the Kiwi at Mount Bruce, the losses from mustelid attacks, should we not be spending that money on increased pest control in the buffer zone around Mount Bruce and leaving the poor rook alone?

Thursday, November 18, 2010

Black fantails and and white blackbirds

I have been asked on several occasions about black fantails in Greytown. Indeed one of my reporters was a bit afraid he might have been imbibing too much and was very much reassured when I said that yes, we do have some black fantails in Greytown.

I have seen black fantails down Hawk Street, Wood Street, Mole Street and even near the park on Kuratawhiti Street, usually quite happily paired with a pied fantail.

There are three plumage phases or morphs in fantails: the pied phase has a grey head, white eyebrow, brown back and yellow under parts. The chest is banded and the tail is mainly white. The juvenile phase is similar but has a browner body and indistinct body markings. The black phase is overall sooty black with a white spot behind the eye. The black fantail is not regarded as a sub species but is a genetic colour variation within the species, like black sheep. They breed freely with pied fantails.

Black phase fantails are found mainly in the South Island and are quite rare in the North Island. In all the twenty-five or so years I lived in the Bay of Plenty I never saw one, so we are quite privileged in Greytown. Why they are more numerous in the South Island is a matter for speculation. The darker colour may be selected for its survival value in the colder climate.

The other birds that get some comment are the blackbirds down Wood street which often have some white patches on them. It is not altogether uncommon to see perfectly white blackbirds. These are usually leucistic birds, not albinos. I have also seen a perfectly white Tui.

Leucism is caused by a mutation that prevents melanin from being properly expressed in feathers. The plumage color changes may be white patches, paler overall plumage that looks faint, diluted or bleached, and overall white plumage.
There are distinct differences between albino and leucistic birds. Leucism affects only the bird’s feathers, and typically only those with melanin pigment – usually dark feathers. A leucistic bird with different colors may show some colors brightly, especially red, orange or yellow, while feathers that should be brown or black are instead pale or white. Some leucistic birds, however, can lose all the pigment in their feathers and may appear pure white.
Albinism, on the other hand, affects all the pigments, and albino birds show no color whatsoever in their feathers. Furthermore, an albino mutation also affects the bird’s other pigments in the skin and eyes, and albino birds show pale pink or reddish eyes, legs, feet and a pale bill, while leucistic birds have normally colored eyes, legs, feet and bills.

Tuesday, November 16, 2010

Kotare, the Kingfisher

 I heard the old familiar piping of Kotare, the kingfisher, this morning. I do occasionally see a kingfisher, always solitary, usually along Wood Street, in Greytown, but nothing like the large numbers I used to see around Ohiwa Harbour in the eastern Bay of Plenty. There they would congregate during the winter, sitting on power lines, waiting for crabs to emerge from their holes in the mud flats at low tide. A concentration of kingfishers indeed! In the summer they would disperse up the river valleys to nest.

I do wonder if they used to be more numerous around here when frogs and tadpoles were commonly found in ponds and cattle troughs around the farms or even in backyard ponds. Alas, the green bell frog is seldom seen these days, something no one seems to lament as they are an Australian import. However, some of our birds have suffered from their demise, notably the kingfisher, the herons and the bitterns. With the loss of the native fishery with the introduction of trout, these birds no doubt took advantage of the introduced species. Birds do not distinguish between native and introduced.

The kingfisher species, Halcyon sanctus, is found in New Guinea, Australia, Tasmania, New Caledonia, the Solomon, Kermadec, Lord Howe, Norfolk and Loyalty Islands. The New Zealand sub-species, vagans, is distinguished from the Australian sub-species by its larger size and broader bill and generally by the distinctiveness of its green and blue colours.

Halcyon is the Greek word for kingfisher and refers to a bird fabled to breed about the time of the winter solstice in a nest floating on the sea and to charm the wind and waves so that the sea was then specially calm, hence “halcyon days”. The specific name of sanctus, the Sacred Kingfisher, was, according to the ornithologist W.R.B Oliver, bestowed on the species as far back as 1782 because of the veneration paid to the bird in some Pacific Islands.

According Oliver, it is a fearless bird and readily attacks mammals and birds of its own size and larger. “Starlings are driven away, red billed gulls put to flight, a Tui killed, cats and dogs blinded in one eye and even weasels attacked. Every kind of small animal is attacked, killed and eaten by the kingfisher. The mouse is a first favourite and the bird’s sharp eyes and quick actions are usually effective when one comes into view. Before being swallowed the victim is pulped and its bones broken by battering on the kingfisher’s perch. Small birds such as Tauhou, the white eye, are eaten and lizards where they are plentiful. Larger insects also form part of the diet.” However, around here, I have mostly observed them taking nothing more than worms and insects so I must take their bad reputation on trust.

They nest in a burrow either in a clay bank or a tree, very often a decaying willow. To start a tunnel they sit on a branch slightly above and several metres away from the site and fly straight at it, neck outstretched and uttering a peculiar whirring call, and strike it forcedly with the bill tip. They continue until the hole is big enough to perch in and scoop out. The nesting burrow can be as much as 24cm long and will be used year after year. The female does most of the brooding while the male supplies the food. They are bad housekeepers and the nests are often quite filthy.

Elsdon Best expressed some surprise that Maori never used the feathers of Kotare for decorative cloaks, considering the bird’s very colourful feathers. However, he also said some Maori were prejudiced against them because it was observed that they ate lizards which are regarded as guardians of the mauri of the forest.

Saturday, November 13, 2010

The decline and fall of sparrows

Why have house sparrows declined so dramatically, asks Bob Brockie (NZ Dompost, Monday, October 11, 2010)

Sparrows cannot live by bread alone. Chicks need protein in order to mature and survive. Based on research conducted in the UK it has been shown that sparrow chicks are starving in their nests because their parents can not find enough insects to feed them. However is this likely to be true in NZ and in other parts of the world? And is it just sparrows that are in decline?

The 2oth century biologist JBS Haldane said that “God has an inordinate fondness for beetles”. This is in reference to there being over 400,000 known species of beetles in the world, and that this represents 40% of all known insect species (at the time of the quote, it was over half of all known insect species).

According to the UK's Invertebrate Conservation Trust, at least 250 of Britain's 4,000 plus species of beetle have not been seen since 1970. This is over and above the general decline in beetles. Two-thirds of Britain's moth species have declined in the past 40 years, some by enormous amounts. Mayflies appear to have dropped in abundance by about two-thirds in the past 50 years.

This decline must be impacting hugely on birds. There are various estimates in the decline in birds, and some birds are doing better than others. RSPB conducts yearly surveys of garden birds in the UK and these surveys indicate a general decline of around 20 per cent in the last five years.

What is the situation in NZ? Are insects in decline here as they are elsewhere? We just don't seem to know, but how many years is it since we were “bugged” by insects splattered on our car windscreens? And are Mynahs still to be found up north prospecting for insects which have smashed into cars on highways? Are Mynahs in decline? Does anyone care? Just as noone cares at the disappearance of the green bell frog as it is not a native.

Generally, are our birds in decline? The OSNZ atlas which comes out every ten years records the presence of birds in any area but not whether or not there has been a decline. Garden bird surveys have been initated but have not been going long enough to tell us much yet. The native birds seem to be holding their own, probably due to increased predator control and the planting of native plant species. But will this situation last? Until we do some serious monitoring, we will not know.

For the last five years I have lived in Greytown in the Wairarapa and every summer the back door is left open, the lights on, and in all that time I have not seen a solitary huhu beetle and very few moths. How is this impacting on the morepork?

We spray the house for flies every summer and for spiders so they will not engulf the house with their webs and in doing so deprive birds, and particularly sparrows, of important protein for their chicks. We kill everything that moves in the back yard. We “clean up” our yards so that there is no refuge for wetas or other wildlife. Landscape gardeners create gardens which may have many native plants and are easy to care for but with hardly an insect, bee, or bird in sight.

District councils, golf clubs and bowling clubs use pesticides to exterminate worms on their sports fields without a thought for the impact on blackbirds and thrushes. So it goes on with species disappearing with hardly anyone noticing.

However, having said all this, sparrows in this neck of the woods anyway seem to have increased in numbers compared with two years ago, although still at very low numbers compared with ten years ago.

Friday, November 12, 2010

Welcome Swallows

The welcome swallow is something of a rare bird within Greytown itself but I have seen it in numbers out of town, up the top of Wood Street and along the Ruamahunga River. I've also seen a solitary bird along North Street and recently a couple this town end of Wood Street.

I've often wondered why they do not appear to have taken up residence in the town itself because even in my back yard there are good warm places for them to nest and shelter and I would have thought anywhere where the fantail prevails, so too would the swallow. So I was greatly interested when one of my neighbours recently told me about of pair of birds which were regularly visiting his shed off the Main Street. They were indeed welcome swallows. Hopefully they will nest there this coming spring.

The welcome, or house swallow, was self introduced from Australia in the 1950s so it is categorised as a fully protected native bird. Birds do keep coming across the Tasman from Australia. As well as Australasia, the bird breeds in Southern Asia from India to Malaysia and the western Pacific. The spread of the swallow has been spectacular and they are now a very common bird throughout New Zealand, although much more numerous in the warmer north.

They are small, graceful, dark blue and white birds, with variable amounts of rusty red on the head and breast. They have streamlined bodies with a short neck and long, pointed wings. The tail is a deeply forked “swallowtail”. Their flight is graceful and rapid as they hawk for insects on the wing. They are birds of open country, hunting over lakes, rivers and grassland and are often seen perching on power lines like so many clothes pegs.
They are in competition with Piwakawaka, the fantail, which also enjoys small insects on the wing but they seem to live happily enough together, although expert thinking says that no two species can occupy the same ecological niche without the demise of one. By my observations, it seems the fantail is better able to cope with winter and violent storms by its ability to use safe roosting places. However I do think the welcome swallow may now outnumber the fantail.
Having had the opportunity of watching swallows closely, I can say with certainty that the nest is made of small pellets of mud. The nest is built up line by line, the mud mixed with short lengths of grass to give greater adherence to the structure and lined with hair, wool and feathers. In shape the nest resembles a shallow bowl and is completed in just a few days with both birds sharing the workload. They particularly like bridges to nest under but will choose also to nest in garages and under the eaves of houses.
The Australian bird, like its European counterpart, is migratory. Indeed it is thought that during its yearly migration to and from Tasmania, the birds were blown off course by storms and so ended up here. The welcome swallow shows no signs of being migratory here in New Zealand.
The European swallows are regarded as harbingers of spring and the ancient Greeks had festivals to welcome their arrival. The proverb, “one swallow does not a summer make”, is a pretty near literal translation of an ancient Greek proverb. In the ancient world, the birds were particularly associated with the household gods and their presence was looked upon as fortuitous. Conversely, any harm done to them could bode evil for the household.

Greytown's birds - the Shining cuckoo

Here it is November already and I have yet to hear the shining cuckoo in Greytown. The Birding News Group reported a shining cuckoo in the Rimutaka Forest Park on September 21 and a friend reported them at the top of Wood Street in late October, which is about when I would have expected them here, as it has been late October in other years that I have first heard them. The extremely cold October weather may have deterred their moving south.
Talking to someone recently, they said they did not realise we had cuckoos here in New Zealand. Indeed, we have two, the shining and the long-tailed cuckoo, both migratory. The long-tailed cuckoo will only usually be seen outside the deep bush while it is in transit in the spring and autumn, when they very often are found dead after crashing into a window. (As I was writing this I had an email from soomeone living nearby in the Waiohine Gorge saying they had a long-tailed cuckoo crashed into the window!) But the shining cuckoo is everywhere, largely because its main dupe the grey warbler is very widespread.
Shining cuckoos are heard before they are seen. Their call starts like someone whistling for their dog and then tails off into a series of downward notes like a long sigh. Trying to follow the call to identify the bird can be a frustrating experience as it is very deceptive. The bird can be quite close without one knowing as the call starts off quietly as if a long way away, so they are difficult to actually sight.
However, I have been lucky in that they were want to frequent the kowhai trees in the garden on the farm where I used to live in the eastern Bay of Plenty and so I often watched them meticulously searching through the tree at my kitchen window for the larvae of the kowhai moth. Here in Greytown I have not seen them at all, just heard them.
The bird is a bit larger than a sparrow and is wonderfully marked with an iridescent greenish blue coat above a striped off-white body. Their diet consists almost entirely of insects and their larvae and includes the hairy caterpillar of the magpie moth which is avoided by all other birds.
There is probably no doubt that the scarcity of insects in the winter has been behind the evolutionary drive for the shining cuckoo to migrate. They leave around February or March and follow a route north which is not clear. On leaving their winter quarters many, if not most, birds, make their way down the eastern Australian coast before flying across the Tasman to New Zealand. Immature birds may travel the same route in reverse while adults may make a more direct flight of over 3000 km over the Pacific Ocean when trade winds could give some assistance. They have been recorded on Lord Howe and Norfolk Islands during the migration seasons.
Like other cuckoos, the shining cuckoo neither builds its nest nor rears its young. It leaves this job to the grey warbler who manages to rear one clutch of its own before the cuckoo arrives here around September from the Solomon Islands and the Bismarck Archipelago.
If the cuckoo’s migration path is a bit of a mystery, how it’s egg gets into the grey warbler’s nest is another. The grey warblers build a covered, hanging nest with a small circular entrance which is just too small for the cuckoo to enter without damaging the nest. However, in the September, 1991, Nortornis, the official publication of the New Zealand Ornithological Society, there is a photo of a cuckoo carrying an egg in its beak. In my view, this seems the most likely way in which the egg is placed in the warbler’s nest.
The birds that come to Greytown are those most likely born here. When one thinks of all the hazards between here and the islands, then it is not difficult to calculate that we could easily lose these birds locally. If just two or three pairs of birds come to Greytown, they have to breed successfully every year in order to make up for the losses incurred while migrating.
Climate change will also effect the future of these birds, but perhaps not negatively as a warmer climate may allow them to stay on through the winter rather than migrate.
Maori tradition believed the shining cuckoo wintered in Hawaiki, which indicates that they were well aware of the bird’s migratory habits. However, it was probably from observing the long tailed cuckoo, Koekoea, which winters chiefly in Fiji, Tonga, Samoa, Cook, Society and Tuamotu groups, which lead the voyaging ancestors of Maori to believe that there was land to the south.

Ko te uri au i te whenakonako
I te koekoea.
E riro nei ma te tataihore e whangai.


I am the offspring of the bronze cuckoo,
Of the long-tailed cuckoo,
Left here for the white-head to feed.




Maori and European tradition regarding cuckoos is not so different as is revealed by a song of Shakespeare’s: “The cuckoo then, on every tree, mocks married men; for thus sings he, cuckoo!”
Call of the Shining Cuckoo may be heard here: http://www.nzbirds.com/birds/pipiwharauroa.html