1. Flock mating/natural pairing of Pateke was the key to the highly successful captive breeding programme – together with the enthusiasm of participants. Flock mating is now being used in a number of rare waterfowl recovery programmes.
2. Captive reared brown teal adapt readily to a wild environment, natural or created.
3. In Northland captive reared Pateke released at Mimiwhangata, Whananaki and Purerua between 1986-1992 survived for long periods and produced offspring – in spite of little predator control, with predator control Pateke are doing well.
4. Where predator control programmes have been in operation at suitably selected quality release sites in Northland (and more recently on the Coromandel) Pateke have survived very well and have successfully reared many progeny.
5. In the absence of waterfowl hunting and predators, captive reared brown teal released into quality Pateke habitat have few problems adapting to the wild.
6. A gradual transition from captive bred to wild, using pre-release pens and a supplementary diet was successful.
7. Brown teal are by far the most predator vulnerable species amongst all species of waterfowl
8. Captive reared teal released on off-shore islands that have suitable predator-free habitat survive and breed well.
9. When the release of captive reared Pateke into quality habitat is coupledwith predator control, a pre-release aviary, supplementary feeding and with the site having an adequate area for a significant population increase (such as at: Mimiwhangata, Purerua and Port Charles), the recovery process is a very simple one!
10. Between 1969-1992 it was learnt that releasing captive reared Pateke at a large number of unsuitable and disconnected habitats, with 35 different sites being used, achieved little, was counterproductive and very expensive.
11. Since the 2000 Audit of the recovery programme steady progress has been made towards increasing the wild populations of Pateke.
• Lack of continuity amongst Pateke management personnel and others directly involved in planning the survival of Pateke.
• Sites used were poorly selected.
• No pre-release study to see if there was an adequate food source.
• No pre-release study to determine whether the habitat was suitable.
• Little predator control and little knowledge of the subject.
• Little understanding about the main predators to control/ eliminate.
• Until early 2000 no sites had ongoing predator control.
• Many sites were out on a limb, with no wild Pateke in the area. • Many sites had no adjacent wetlands for progeny expansion or to which adults could escape.
• Many sites had no loafing facilities or aerial protection.
• Insufficient supplementary feeding of released birds. The value of this is recorded in a paper published in 2013.
• Pre-release aviaries rarely used.
• Competing waterfowl were present.
• Hybridisation with mallards and grey teal occurred.
• Instant dispersal of released birds occurred.
• A lack of ongoing support.
• A lack of monitoring of released birds.
A brief History of Ducks Unlimited Operation Pateke.
Neil Hayes QSM, DUNZ Life Member
Time is overdue to document what I believe is the most significant contribution made by any conservation group in the world – that is Ducks Unlimited (NZ) efforts to save the endangered NZ Brown Teal (Anas chlorotis) from extinction.
The contribution by DUNZ starting in 1975 was inspirational. DUNZ was founded in 1974 by Jack Worth - with a few like-minded individuals: Ian Pirani, Paul Pirani, Neil Hayes and Trevor Voss - all wetland and waterfowl enthusiasts.
In 1974 Jack suggested the DU profile could be considerably enhanced by dedicated recovery programmes for brown teal and grey teal. “Operation Pateke” and “Operation Gretel” were launched with clear objectives. These project titles were unique to DU and it was the first organisation to use the word “Pateke” (Maori brown teal).
Operation objectives were:
1. To establish 50 breeding pairs of Brown Teal in captivity
2. To breed over 1000 Brown Teal in captivity and release them into suitable areas
3. To save Brown Teal from extinction
In 1976 I was appointed Director of the project and continued in this role until 1991. My introduction to Pateke was in 1970 during a visit to waterfowl enthusiast Trevor Voss – a dairy farmer near Stratford. Trevor was the pioneer of breeding Pateke in captivity and on the day of our visit he had 21 recently reared Pateke in a mobile aviary on his lawn.
Just on dusk Trevor asked me to help catch three Pateke in an aviary to move to another aviary. The aviary was knee deep in grass and after a half hour of trying to find them we gave up – but just on dusk they appeared! I thought what a strange bird and I’ve spent the last 40 years attempting to understand Pateke.
By 1973 I was breeding Pateke in captivity, starting with a wild pair caught on Great Barrier Island by NZ Wildlife Service. Within three months they hatched five offspring and reared all five.
Over the next 19 years we reared close to 200 Pateke in our Wainuiomata home garden – this featured numerous times on national TV, generating great publicity for DU and Pateke!
Pateke in the wild - 1973
My introduction to Pateke in the wild was during a trip to Russell, Bay of Islands, December 1973 to visit to wife Sylvia’s sister’s family.
My interest in saving brown teal prompted Sylvia’s sister to say “there are hundreds just down the road”. How right she was! At Parakura Bay south of Russell on the east coast we counted 96 brown teal and when Grant Dumbell was completing his PhD on Pateke between in 1986 - 1991 there was still a healthy population. By the mid 1990s there were none.
Brief natural history of Pateke
Fossil research by Trevor Worthy determined Pateke have been present in New Zealand for over 10,000 years and was once the most populous New Zealand waterfowl. Pateke were found throughout New Zealand’s once vast wetlands and inhabited lakes, rivers, lagoons, ponds, creeks, forest streams, swamps and estuaries. The 2002 fossil research confirmed what Peter Scott (Founder of the Wildfowl & Welands Trust) wrote in 1960. “Brown teal are an ancient and primitive form of duck”.
Large Pateke populations were also on Stewart Island, the last sighting in 1972 and on the Chatham Islands, last sighting in 1920. Pateke were believed to have become extinct in the South Island during the 1980s.
So, from millions of Pateke throughout the country until 1800 the decline to less than 850 by 1999 represents the world’s most dramatic decline of a waterfowl species!
Pateke are believed to have evolved from the very beginning of life in New Zealand, resulting in them having many unique dabbling duck behavioural characteristics, as well as unique colour, body shape, egg size, vocal sound and more.
Once New Zealand’s most common duck, estimated at several million, Pateke have been under threat of premature extinction (influenced by humans) since Europeans arrived in New Zealand in the 1840s; accompanied by rats, cats, dogs, ferrets, stoats, weasels and hedgehogs; all of which found the country’s endemic birds easier to kill and probably more palatable than imported rabbits, hares, possums, mallards, black swan, geese, etc! These alien predators also enjoy the eggs of our endemic birds and so wreaked havoc amongst the country’s endemic bird numbers. This was recognised as early as the mid 1850s.
European immigrants bought sporting firearms and duck hunting had a major impact on Pateke survival and in spite of Pateke being accorded legal protection in 1921 many continued to be shot during duck hunting season.
Wetland destruction was also rampant until the 1990s this, in association with predation and duck hunting, impacted heavily on Pateke survival. Prior to 1990 70 percent of New Zealand once vast wetlands and 50 percent of New Zealand indigenous forests had been eliminated.
Self introduced species such as harrier and pukeko also influenced the decline of Pateke, and all New Zealand endemic birds, frogs and invertebrates.
Captive breeding While captive breeding of Pateke was gradually increasing, with 19 birds reared in 1976, 18 in 1977, 29 in 1978 and 45 in 1979, numbers increased dramatically soon after DU was awarded a Mobil Oil Environmental Grant in 1979 - to hold a Brown Teal Management Seminar in Auckland in July 1980. Twenty five people attended, including from the NZ Wildlife Service, personnel from Auckland and Wellington Zoos, major aviculturalists and DU members keen to join the recovery programme. In addition to this important award, and immediately upon his appointment as Director of the NZ Wildlife Service Ralph Adams MBE phoned the DU Secretary in 1979 informing him that the entire brown teal recovery programme was to be handed to Ducks Unlimited. The proceedings of the seminar were published by DU in 1981, the outcome being that annual productivity jumped to 89 birds reared by DU participants in 1981. Another 47 were reared by the Mt Bruce National Wildlife Centre.
The published document entitled “The Aviculture, Re-Establishment & Status of the New Zealand Brown Teal” covered aviary design, the needs of Pateke in captivity, the Re-Establishment programme and the numbers of Pateke in the wild in 1981. After publication, Pateke reared in captivity expanded dramatically, as did the number of breeders and by 1984 DU had 39 captive breeders spread from Northland to Southland holding over 60 pairs and producing over 100 Pateke/season, with a record 153 reared in 1987. All this was greatly assisted by the injection of new blood from Great Barrier Island in 1974 by the Wildlife Service and a 1987 capture totally organised by DUNZ. For many years the Wildlife Service paid breeders $5 and DU also paid each breeder $5 for each Pateke reared.
DU’s success with Pateke was recognised as the world’s most successful captive breeding programme for an endangered waterfowl species and the same DU flock mating programme began to be used world-wide and is now a standard procedure. Such status and recognition was an incredible achievement for DUNZ.
One thing learnt early in the captive breeding was that each pair must be retained in their own ‘exclusive’ aviary – because a mated pair of Pateke is the most murderous of all waterfowl. In a captive situation paired Pateke will kill other waterfowl in the aviary, including other Pateke.
The Mobil Oil Seminar publication discussed the aviary requirements for holding a pair of Pateke in captivity and it was soon determined that a flock mated pair would breed in their first season, with the number from each broods averaging four.
A combination of a good size pond, clean water, lots of cover, a food tray that only needs filling once per week, at least two nesting boxes, loafing platforms, a dabbling area, a totally rat/mouse/predator free environment, were all found to be an excellent guide to success. So much so that one captive female Pateke lived to be 24 years and 3 months. Lots of others have lived to be 12 to 18 years. This indicates the simplicity of the recovery programme – provide Pateke with a quality, predator free environment and they survive for many years.
In the wild we know of one male Pateke was captured again 90 kilometres from where he was released 8 years earlier. With such large numbers being reared a facility was needed to hold large numbers of birds prior to release and Jim Campbell built a large holding aviary at his farm north of Masterton.
Pateke reared in the South Island were air freighted to Wellington, picked up by DU and delivered to Jim’s aviary – well able to hold 100s of Pateke over fairly long periods. Most reared there went to release sites in the North Island.
The added value of the holding aviary was many birds were bonded as pairs before they were released.Pateke worth saving Having evolved from the beginning of life in New Zealand and with unique features not found in any other species of waterfowl makes Pateke worth saving. Some unique behaviours are:
The releases at Puke Puke and Nga Manu were organised by DUNZ members and whilst a number of birds released at Puke Puke reared young, very few of the birds survived for long periods, simply because the reasons for Pateke heading for extinction had not been addressed; the main reason being PREDATORS, accompanied by duck shooting.
Other releases in the Manawatu were undertaken by the NZ Wildlife Service, as was a single release at the Kaihoka Lakes, Nelson in 1978.
In addition and knowing that Pateke have done well on off-shore islands three DU organised three releases of Pateke on Matakana Island, Tauranga, between 1980 - 1981. Sadly, all the releases between 1969 and 1983, including those on Matakana Island failed to re-establish and in 1984 it was decided to concentrate the release programme in Northland, along the east coast that was still quality Pateke habitat – and where approximately 1200 Pateke were still surviving.
Release programme in Northland
By 1984 large numbers were reared each season and the Northland release programme commenced in August 1984. From 1984 to 1991 all Northland releases were organised by DUNZ, with considerable support from Dr Murray Williams of the NZ Wildlife Service.
Jim Campbell, Allan Elliott and I spend seven years carrying Pateke from Masterton to Northland, mainly in Jim’s Chevy Ute.
The August releases took place at the 350-hectare Government owned Mimiwhangata Farm Park on the east coast just north of Whangarei, where considerable Pateke habitat had been created and the farm was just south of the famous Helena Bay Pateke roost site: it regularly supported 50-70 Pateke and was only a stone throw from the large holiday camping grounds.
Two large lagoons were created by the Wildlife Service, together with lots of small breeding ponds and there was a small estuary on the farm. On the same day another Northland release took place at the upper reaches of the Matapouri Estuary – a little south of Mimiwhangata and only 20 minutes drive from Whangarei.
Recalling that in England pre-release aviaries are always used for holding captive reared birds for several weeks before the aviary door is opened. So for the first Northland release of captive reared DU Pateke the Wildlife Service erected large aviary at both Mimiwhangata and Matapouri - to hold the birds while they became adjusted to their new surroundings. At the Nga Manu Sanctuary a pre-release aviary was also used.
The aviaries worked well at Nga Manu and Mimiwhangata, but at Matapouri several Pateke escaped before a hole was plugged!
In total 42 Pateke were released at Mimiwhangata and 54 at Matapouri on August 4, 1984 and because Pateke were uplifted from various breeders on the way to Northland they had to be banded prior to being place in the pre-release. These two sites were the only Northland site where pre-release aviaries were used.
Between 1984 and 1991 a total of just under 600 captive reared brown teal were released by DU onto five different wetlands in Northland - Mimiwhangata, Matapouri, Takou Bay, Purerua and Urupukapuka Island - with all releases carried out by DU personnel. One of the most remarkable things about all DU releases of Pateke between 1975-1991 is that only one bird of over 1000 released by DU had died in transit.
Two of the preferred Northland sites were Mimiwhangata and Purerua – with 295 Pateke being released at Mimiwhangata and 320 at the Purerua. The DU Pateke Recovery Team believed the 7-hectare created lake on the Purerua Peninsula, just north of Kerikeri was an excellent site and Pateke were known to breed there and in adjacent wetland.
Sadly the Dept of Conservation controlled Pateke Recovery group ignored the Purerua site for over 10-years.
Survival in Northland
Survival at Mimiwhangata, Purerua and Matapouri was extremely good – in spite of predator control only taking place at Mimiwhangata: and for only a short time.
A photo taken in early December 1987 showed 45 Pateke clearly identified from a release of 64 three and a half months earlier. Over 60 Pateke were present and it is believed all 64 were still alive.
The survival rate at Mimiwhangata was largely due to Pateke being fed a supplementary diet every morning and an extensive predator control programme.
The survival at the Purerua site was also good, but they needed the supplementary food and predator control. There were numerous reports of Pateke being seen at many sites in the district.
Matapouri survival was also encouraging and 18-months after the first release I counted 22 Pateke in the estuary.
Modern era (1991-2014) recovery programme
Unfortunately when DOC took over the recovery programme in 1991 they categorically stated that no more than 40 Pateke would be required each season. The result was numerous Pateke breeders threw in the towel and DU had a period of loss of interest.
By 1993 Pateke numbers in the wild were plummeting. I discussed this in an article published in NZ Outdoor magazine, entitled “The rapidly approaching demise of the New Zealand Brown Teal.” The Department took note and held an informal recovery group meeting at the Mimiwhangata Farm Park. The meeting decided to concentrate Pateke recovery in Northland with expanded predator control and over the next two years Northland Pateke numbers increased steadily. With Pateke also present on a number of small offshore islands; including Kapiti, Urupukapuka, Tiritiri Matangi and Little Barrier the total number in the wild in 1987 was 3000. But, by 2000 Pateke in Northland had declined to 350, on Great Barrier Island to 500 and on the Coromandel Peninsula to less than 20 birds. Two years after the involvement DOC again lost interest in Northland and commenced a release programme into totally unsuitable areas; such as Travis Wetland in Christchurch, Tawharunui (Warkworth), Cape Kidnappers (Hawke’s Bay), Warrenheip (Waikato) and more recently Fiordland. Though these sites had predator control programmes they all failed because:
1. There are no wild populations of Pateke in the area.
2. Habitat was not suitable.
3. No suitable flock-sites.
4. No suitable Pateke habitat adjacent to these sites.
5. No suitably protected adjacent wetland for population expansion.
The result - by 1999 nation-wide Pateke numbers had again dramatically plummeted – from close to 3000 in 1987 (Including Pateke on offshore island) to less than 800 in 1999 - and our graph showed that Pateke would be extinct on the mainland by 2004 and totally extinct by 2015.
Bearing in mind the 3000 recorded in 1987 was likely a conservation figure the dramatic race towards extinction is the most disastrous ever recorded for a rare and endangered waterfowl species.
The Race Towards Extinction – 1988 to 1998
1988 1990 1992 1994 1996 1998
In September 1999 two Pateke pragmatists featured on TV ONE News and in no uncertain terms pointed out that brown teal were in grave danger of premature extinction, and severely criticising the Department’s performance in the Pateke recovery programme.
The TV ONE presenter was undoubtedly the ‘star’ of the news item – standing in front of a Pateke aviary, she said “The whole recovery programme is a simple one, you give brown teal a protected environment like this and they live to be 24 years and 3 months.”
The outcome from this news item was that the Department carried out an audit of the programme, interviewing 39 people who were known to have had some involvement with brown teal and in 2000 the findings, recommendations and objectives of how to save Pateke from extinction were published. A two-day seminar/workshop was held in Kerikeri to determine how best the Audit recommendations could be implemented.
The workshop recommended the implementation of major predator control programmes and the race of Pateke towards extinction has being retarded. The Pateke population is steadily increasing, but only in the three areas of the country now recognised as vital to long-term Pateke survival; Northland, Great Barrier Island and Coromandel Peninsula; all three areas were where Pateke began their escape from the massive nation-wide increase in predators - feral cats, ferrets, stoats, weasels, rats, hedgehogs, harriers, pukeko, etc, believed to have been during the late early 1900s.
The rapid decline in Northland and the Coromandel can be attributed to the spread of predators, but on Great Barrier Island where there are no mustelids, hedgehogs or duck hunting, but large populations of feral cats, two species of rat, feral dogs (lost by pig hunters), Pukeko and the harrier hawk, the race towards extinction can be clearly attributed to an explosion of predators in all three areas; along with an almost total lack of endangered species management. Domestic dogs are also known to eliminate Pateke in these critically important areas.
Success on the Coromandel Peninsula
Little is known about the retreat of Pateke to Northland, the Coromandel and Great Barrier Island; though Great Barrier Island once had the largest national population of Pateke. However, in the early 1900s there was no record of Pateke being present on Great Barrier Island, and in 1868 Hutton, a highly regarded ornithologist, failed to record them in his extensive Great Barrier Island bird survey, but by 1987 there was 1500 Pateke on Great Barrier Island and 1200 on the east coast of Northland, but less than 20 on the Coromandel. Pateke were widespread on the Coromandel in the early 1900s but with the spread of predators less than 20 were surviving in the Port Charles area near the top of the Coromandel.
Thanks to the 2000 Audit the release of captive reared Pateke commenced on the Coromandel in 2003 and ended in 2007 with 250 Pateke released. This release was supported by the existing and extensive predator control programme in the Moehau Ranges in operation since 1999 and by 2013 there are several hundred Kiwi surviving in the ranges. An extensive predator control programme for Pateke at Port Charles and environs was launched in 2001, with a high level of survival of both released and wild teal.
And from 20 to 750 Pateke on the Coromendel is an incredible success story and clearly confirmed precisely what the TV Presenter stated in 1999 – “Provide brown teal with a predator free environment and they will live for 24-years”! The level of survival of released birds, their adaptability and their breeding success, coupled with major predator control programmes, no duck hunting and outstanding support from the local Port Charles community, including farmers, is an outstanding example of what can be achieved in a short space of time. Brown teal are now being observed in an increasing number in many areas of the Peninsula with one flock of 180 being counted in 2012 at Waikawau Bay.
istorically, a peninsula has proven to be readily defensible against predators and with ongoing predator control on the Coromandel Peninsula a population of over 2000 Pateke could be achieved.
Besides well organised and intensive predator control on the Coromandel the support of the local farming community and residents has been an intrinsically important part of the success, with a number of land owners creating quality Pateke habitat and the locals carrying out much of the predator control work.
In addition financial contributions from The Moehau Environmental Group, Banrock Station Wines of Adelaide, Isaac Wildlife Trust, DUNZ, DOC, Brown Teal Conservation Trust and, critically important to the whole programme - the Pateke captive breeders - all helped ensure the success of the Coromandel re-establishment programme.
There is still much to be done before Pateke are anywhere near being saved from extinction and a future for the species is assured. DUNZ can be justly proud of its achievements with Pateke.
Next issue of Flight - The Positives and negatives of Pateke recovery programme.
The Isaac Conservation and Wildlife Trust’s seven brown teal/pateke breeding pairs laid their first clutches, with 34 ducklings hatched in total.
Laying of second clutches has now begun. Two older pairs have been released on Rotoroa Island in the Hauraki Gulf, making way for a clutch of orphans coming off Great Barrier Island – providing new genes for the captive breeding programme. The Trust continues to be the major breeder in producing the largest brown teal output for release into the wild.
Find out more about the Trust’s captive breeding activities on Facebook
26 chicks were raised with some released at Waikawa and some at Motutapu. Four remain at Pukaha to continue with the breeding programme.
18 ducklings from the two breeding pairs at Pukaha. These were sent to the pre-release site, Peacock Springs near Christchurch, before they are released into the wild.
2 male and 1 female ducklings hatched and reared by a pair at Pukaha have been sent to the pre-release site at Turangi. 13 ducklings were hatched from eggs collected from wild sites and of these 9 are male and 4 are females. They will remain at Mt Bruce Pukaha.
As the end of the year approached, the Pateke at te Henga were still holding their own and week after week 17 birds were being detected, that is an 85 percent survival. Accordingly, the Pateke Recovery Group indicated that all would be on for a February release and could we please ensure that transmitters and harnesses were arranged and sent to Peacock Springs in readiness?
Again, as last year we would require 20 transmitters and harnesses while this year we would also have additional birds without transmitters and the success of this year would again be judged on the fate of the transmitter carrying birds. Expecting perhaps a total of 40 or 50 birds we were stunned to be told to expect 80!
Last year’s release took place on our Forest and Bird Matuku reserve and allowed only a brief glimpse of the Pateke as they rapidly scrambled across a couple of metres of water into dense reed beds rarely to be seen again.
Wanting a better spectacle this year and ensuring that the ducks would be released into the centre of our predator controlled area, the decision was made to renovate an old boardwalk that projected into a large pond so that most of the birds would be released here with a small number at a site offering easy access from a private property nearby.
Many days of activity followed with a couple of us clearing the old boardwalk and constructing a large deck at its far end. Pointed poles 3.6m in length were manhandled, forced through the weed mass then rammed into the muddy substrate below. Bearers, then joists were attached -often a tricky job as being without electricity, a brace and bit at or just below water level was needed. Of course, with the sea only one or two km away, all fittings had to be stainless steel to withstand possible wind driven salt exposure.
With four days to spare the deck was ready along with some under water weeding of the Eleocharis reeds done from kayaks.
Air New Zealand delivered even ahead of their ETA so we had a good start back from Mangere airport to te Henga. A large crowd was waiting and our PR representative had really done her job well with TV and newspapers both national and local all present. Volunteers helped move the boxed ducks across the river on the raft then walked them 500m to the deck where 60 birds were let go, five at a time.
Then it was all back to the more public site where after karakia and speeches, several people, old and young, had the opportunity to release a duck. My speech included a call to pass the hat around, as at this stage we still hadn’t obtained funding for the monitoring required of us- the handful of dollars received wasn’t going far but fortunately Auckland Council Biodiversity had decided to fund this aspect.
And what has happened since?
Big numbers certainly have made the difference in the number of sightings with groups of 8 or 9 having been seen. Again as last year, one or two birds absconded early on. Pateke Point we call it, is a site where pateke routinely seem to enjoy fluffing around protected by the overhanging willow canopy. What a dilemma, as I have been hell bent on getting rid of all the willows in our reserve. Perhaps we’ll leave just these few until replacement planting is mature enough. A transmitter carrying bird has perished cause unknown, while a non-transmitter carrying bird was killed by a car but apart from 3 or 4 adventurous birds, most seem to be sticking close to the release site.
Working back from the deck is a wide elevated boardwalk finished thanks to materials and some labour supplied by Henderson Rotary. A seat and information panel midway will give an opportunity to read about the serial vegetation starting from the cabbage trees, then flax then raupo and other increasingly water requiring sedges, and swamp millet etc.
Hopefully before winter arrives we will have had some nights monitoring where the Pateke forage. With a borrowed radio receiver we’ll have two teams attempting to get fixes from two different sites and follow a small number of Pateke at regular intervals for a few hours. An opportunity also to access some night vision glasses may give some insight as to the ducks movement or if nothing else will give the local mosquitoes a picnic. Then there is the planned pest monitoring using chew cards attached to stakes placed through parts of the swamp. Seems like an interesting project in theory but as always there’s plenty to do at te Henga.
We will obviously have to extend our daytime surveys further up into the forest in future.
I have seen Pateke way up on the open hills in pitch darkness probably 1km from their daytime roosts showing just how nocturnal they are. And Surprise, surprise WAY up stream on ecology track.
Roger and Patte Williams
Tawharanui Pateke Counts from Sharon Kast is a good record to have. This is consistent with the work of Katie Sheridan at Zealandia, her presentation to Sanctuaries of NZ hui last was of interest. Unfortunately no notes with her slides but I do remember the story was these birds go well up some of the waterways (consistent with sub fossil records that had pateke as one of our more common riverine forest bird species before mammalian depredation).
Also- ‘flock counts’ under represented the population by as much as 50 percent (proportion of known birds present at flock site at any one time, most go there eventually) and some birds with stable territories never left their home territory to visit flock sites.
For those interested in Pateke, here is a link to some interesting information and photos.