The last update was written in
mid-November, and as that was mid-season, a fair bit has happened since then.
Annual survey. This, the key event of our bird year, went ahead on Nov 24, co-ordinated by Bev Alexander and Grant Davey.
As Grant says in his excellent report, “Eighteen volunteers took part, this was enough to do a quality survey. The weather was cloudy with some drizzle in the upper reaches. River flow was approximately 9 cumecs as measured at the gorge. A small flood reaching about 82 cumecs had occurred on 9 November and bird numbers may still have been recovering after this. A more significant flood soon after the survey (November 26), measuring up to 140 cumecs at the gorge, would have severely impacted bird numbers.”
Indeed, we were very lucky to get this survey completed when we did. If you want a copy of Grant’s report, I can send you one. In brief, total bird numbers were about the same as last year, so we have seen a couple of stable years, after the big declines in 2015 and 2016. This was due to weed invasion, and after last year’s major flood clearances we were hoping for higher numbers, but not so – probably because this has been a disrupted season. However, wrybill numbers were considerably up – from 9 last year to 20, with the long-term average being 13.
Interestingly, and demonstrating how dynamic are braided rivers and their inhabitants, if the annual count had been 2 days later (after the flood), wrybill numbers could well have been zero, as I have not seen a single wrybill on the river since that event.
With a couple of exceptions, this season will probably go down as one of
the poorest, due to the floods which occurred at sensitive times. Fortunately, 4 of our 8 wrybill pairs managed
to fledge single chicks before floods intervened, but for other species
virtually all eggs and non-flying chicks were lost to the Nov 26 flood. Also swept away by that event was a large black-billed
(BBG) colony and some smaller colonies of black-fronted terns (BFTs). I thought that was the end of the season for
them, but not so – the BBGs soon resettled not far up-river, with the BFTs a km
or so further down. Needless to say, we
have kept a close eye on them, with Grant drone-counting the gulls regularly. There are just over 1000 pairs, now at the
stage of hatching chicks. The site is a
good one, being a relatively weed-free island with good water currents on both
sides. As the river flow declines, the
terns are not so island protected, and the wet season means that they are in
amongst rapidly growing lupins. Terns
cannot be counted from the air (drone), but there appears to be around 60
present – so probably 20+ pairs, also now at the egg hatching stage. The gull and tern colonies are all that is
left of breeding birds on the river, so we cross fingers for a successful
Predators. Despite having over 180
traps out on the riverbed, the predator catch over summer is often low, and
such is the case right now. Catches
increase in the autumn / early winter as young animals are kicked out of parent
territories and food becomes more scarce.
The Group is currently reviewing its trapping, with the aim of having
all the riverbed margin covered from around the estuary right up to the Okuku
junction – a distance of over 20km. This
will require over 150 new traps – so Geoff will be approaching our trap-making
team in the near future. Even though we
will always rely largely on volunteers, we have to face the reality that
servicing a large number of traps (well over 300) will require a new approach –
involving some professional input.
Weeds. The 2017 major floods did a
superb job clearing weeds, and vastly increased the areas of clean shingle
which are absolutely vital for successful bird feeding and breeding. However, the floods brought down a new load
of seeds, and these cleared stretches are rapidly being recolonised. Without doubt, our major challenge in the
near future is how to keep the core bird breeding sites clear of weeds. Aerial spraying would be the most
cost-effective means, but use of chemicals in waterways will always be
controversial, and we do not want to go that way. This autumn we may well ask for volunteers to
clear key sites. Although only small
areas can be treated this way, it is almost the only volunteer-team exercise we
can easily organise out on the riverbed – and if there is a good turnout, the
results are always more impressive than initially imagined. Machinery options are being explored for
Humans. As stated in the last Update, it is pleasing
to report that disturbance by people and their machines has been relatively
minor so far this season. Compared to 5+
years ago, it is relatively uncommon to see fresh vehicle tracks on the
riverbed. All the same, there has been
violations, one of which could result in a prosecution. I am sure that our signs and the access
blockages are the major reason behind this good state of affairs. We are committed to removing the blocks in
February, once the season is over.
Shingle extraction. We have always had great support from the major shingle extractor in the Ashley-Rakahuri riverbed – Taggarts Earthmoving Ltd. This year they have been working in the Hillcrest area, and we have spent much time monitoring bird activity within their concession site. Some of the nests found and followed have been within metres of regularly used tracks, so we have been able to collect useful data relative to how well-informed gravel extractors can work in close association with breeding birds.
the last year, we have spent some time compiling video material for documenting
how the Group operates over a typical season.
Tony Benny from Oxford (used to work on ‘Country Calendar’) was the
film-maker, and has recently sent us a draft of the 20-minute product. This is in the final process of editing, and
has impressed all viewers to date.
Meeting. We had a general meeting on
Dec 10, with 13 folk in attendance.
Award. In the last Update, it was related how the Group had won the 2019 Practical Management Award offered by the Australasian Wildlife Management Association. In early December, I went over to Tasmania to accept this Award at the Society’s annual conference in Hobart. On the framed certificate we received, it is stated ‘In recognition of outstanding best practice in wildlife management’. The presenter commented that we won from a strong field of entrants. The following morning I spoke of ARRG activities to the 180 conference attendees. We are fortunate that the AWMS goes out of its way to support applied conservation research and management. Consequently, they liked what we had to say, and a couple of subsequent speakers referenced us as the sort of community group they wanted to support. A number of attendees came up to me afterwards with positive comments and interesting questions. The conference covered a wide range of conservation topics, but as many of the over 100 presentations illustrated, the conservation challenges in Australia are quite different to ours – mainly as there are many mammals involved, plus a different set of predators. They do not have any mustelids or hedgehogs (and foxes only on the mainland – none in Tasmania). The most talked about predator of interest to us was the feral cat, which is arguably their major problem.
Coming up. With the season coming to an end, the focus moves to writing up results and preparing presentations for a shorebird workshop up in the Firth of Thames area (organised by the Pukorokoro-Miranda Naturalists’ Trust) in March, and another braided river workshop (organised by BRaid Inc) out at Lincoln in June. We are also setting up to review our trapping and weed control systems. Relative to the latter, look out for notification about weed control workdays this coming autumn. This will be one of the few opportunities for many members to get out there and do their bit.