Relative to the future success of rare and endangered shorebird species breeding in the Ashley-Rakahuri river, the rising trend up to 2014 is now being reversed by a decline. Populations of all species are either lower than in the previous 2 years, or at best are only matching the long-term average. Pied stilt numbers in the 2016 survey were the lowest for 10 years. The breeding of the key study species, wrybill, black-fronted tern and black-billed gull, shows the same trend. Both the nesting and productivity success of wrybill and tern pairs declined, and not a single gull nested on the riverbed in the past year.
The major reason for the decline in bird numbers appears to be a surge of weed invasion leading to major losses of bare gravel areas needed for breeding, plus clear water-shingle margins essential for feeding. This cause–effect relationship is supported by the Group’s new mapping of riverbed vegetation changes since 2004 and the comparison of this with our long-term data on bird populations and the breeding success of core species. There is no evidence for major recent changes within the other two major bird influences, predation and human disturbance. Consequently, the Group is proposing large-scale clearance of weeds at four riverbed sites most favoured by birds. This intention has been assisted by a major flood in early April and an even bigger event (a ‘1-in-10-year’ flood) in mid-July, 2017.
The Group continues to maintain a high profile relative to public awareness and education, assisted by agencies such as DOC and ECan, particularly staff from DOC’s Rangiora Field Base and ECan’s Ashley-Rakahuri Regional Park. During 2016-17, the Group created many opportunities to improve awareness. Most involved media articles, presentations to schools and local groups, and displays at public events. Key presentations were made at two well-attended braided river seminars.
During all its initial years, the Group relied on outside agencies (eg. Lotteries, WWF) for funds, requiring considerable time and effort in writing applications and supplying reports. Hence, it is pleasing to record that for the last 5 years, the Group has been able to survive on its own fund-raising projects, plus donations. The generosity of the latter is due to our improved public profile.
Looking into the near future, the major challenges involve controlling weeds and improving bird nesting and feeding habitat, maintaining/improving the control of predators, plus banding more adult birds (particularly wrybills). To these challenges and opportunities must be added the ever-present challenge of maintaining public interest, and the involvement of the local community in bird management on the Ashley-Rakahuri River. This not only enhances fund raising opportunities, but also helps to reduce human disturbance in the riverbed during the breeding season.
All photos by ARRG members - Lynley Cook, John Dowding and Nick Ledgard