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By Nick Ledgard, Chairman of the Ashley Rakahuri Rivercare Group
In the last update, it was stated that annual survey numbers were well down on previous years, and that breeding success was similarly in decline. The one good-news story was the black-billed gulls, which nested successfully down at the Waikuku Beach dairy farm by SH1. Why did they set up shop there? Don’t be mislead by the pictures showing the colony surrounded by healthy green grass. They would never start nesting on a well grassed site. They chose that location, because in the 2016 spring when they were looking for a breeding site, this farm was being developed and had large areas of bare ground, while the nearby riverbed, where they have usually nested, was clogged up with weeds (more about that below). Right now it is mid-winter and most birds are away on their winter feeding grounds. Monthly walks on the riverbed at this time of the year only record Welcome swallows, a few Paradise ducks, spur-winged plovers, harrier hawks, the odd black shag and white-faced heron, plus a hand-full of black-fronted terns hawking up and down the waterways. Although, two unusual species were seen recently – a lone white heron and a lone spoonbill. But spring must be on its way, as when I was down there a few days ago, I did observe the first banded dotterels, pied stilts and oystercatchers, plus more BF terns.
This is now our No 1 concern relative to future bird breeding on the river. Habitat threats from predators and human disturbance have not changed recently, but weed invasion has advanced considerably. Ashley member, Grant Davey, has done an excellent job mapping the extent of weeds over the last 10+ years, and the picture appears to be grim. His work has shown that the total area of bare gravel has declined by 85% since January 2014 – from almost 200ha down to around 30ha. What’s more, this decline has occurred over the same period as the recent decline in annual bird numbers. A good flood on April 6, 2017 (240 cumecs), did increase the area of bare shingle (from 30 to 75ha), but more weed clearance is needed. As if in answer to our prayers, a major flood is moving down the river as I write. With a peak of 570 cumecs, it is greater than both the last decent flood of May, 2014 (480 cumecs) and the best in the last 10 years – a 540 cumec event in mid-2010. Although this will certainly make a difference, we still need to proceed with the machine clearance of weeds in the areas most preferred by birds. Such work has had good success elsewhere – in the lower Waitaki and upper Clarence rivers. Hence, a few months ago we started the process of gaining resource consent and funding. As this has been successful, we will begin clearances within the next 6 weeks, with a focus on creating islands which can be maintained as weed-free sites over future years.
The trapping continues as normal, with 10 members tending around 140 traps. Numbers caught remained low during the last breeding season, with 52 potential predators trapped in 15,114 trap-nights (the second highest ever). The overall summer trap-catch rate was 0.34 predators per 100 trap nights – the lowest annual rate recorded to date. Hedgehogs were the most trapped predator, followed by cats and rats (highest ever). Eleven mustelids were caught, just over half the number of the previous season, but very similar to the season before. As usual, the numbers caught picked up once the autumn / winter period got underway – due to the breeding season coming to its end, and young predators being pushed out to fend for themselves. There was a notable increase in stoats – 18 compared to just 2 in the winter of 2016. The trap-catch rate for the autumn-winter period was 0.57. The demand for DOC200 traps continues to grow, with 269 being made and sold over the past year. On-going thanks to Geoff Swailes for co-ordinating our trap construction and marketing efforts.
This remains high, with the majority of people sympathetic to our cause and acting accordingly. During the 2016/17 season there were many opportunities to improve awareness of the Group’s activities. Twelve articles appeared in local papers. Powerpoint presentations were given to five schools and four service clubs, plus in September, 2016, Canterbury TV visited the river and made a short video. Riverbed visits during the breeding season proved to be popular for the public, with over 30 attending in early November. On June 26, 150 attendees were present at the Lincoln Events Centre to enjoy a seminar on braided rivers organised by BRaid Inc. ARRG members gave two presentations – one on the weed invasion of our river, and the other on the successful black-billed colony at the Waikuku Beach farm.
Next meeting – our AGM
This is set down for 6pm on Thursday, October 26 in the DOC offices, River Road. Anyone is welcome to attend.
Annual report, 2016-17
This report is virtually complete and will be available soon on both ours and BRaid’s websites
Below are the draft Recommendations which are included in the Report:
1 Continue annual bird surveys and monitoring activities – focussing on the three key threatened shorebird species (wrybill, black-billed gull and black-fronted tern).
To date: Surveys and monitoring being maintained adequately.
Needless to say, we welcome any comments on these Recommendations, which will be put to our AGM in October. Please send those comments to myself (email@example.com).