Creating better bird habitats on braided rivers
Those who have an interest in braided river birds know the importance of islands and lack of weeds when it comes to good breeding sites. Islands act as barriers to predators, although the likes of stoats have no problem crossing water. Tall weeds deter birds from nesting, and also offer cover for predators. We note that weed-free islands are becoming increasingly scarce, and wonder what to do about it.
One solution is to try to artificially create such sites. This has been tried in the past, with mixed success. One Waitaki island attracted breeding birds which appeared to suffer less from predation. Our earlier attempts on the Ashley-Rakahuri 10 years ago had no success – the birds largely ignored them. But, at that time we were less aware than we are now of the most favoured bird breeding sites.
So today, armed with a ‘de minimus’ resource consent from ECan for minor earthworks, I accompanied a Taggart’s bulldozer up the river for a few hours. Previously, I had walked the targeted stretch of riverbed many times, and knew where the best sites were located. These are on higher ground which is least likely to get flooded – hence they currently have the tallest weeds, nearly all lupins. I went first with some white electric fence standards and marked the borders of the areas to be cleared. The bulldozer followed, completing the work much more quickly than I had anticipated. I had to walk quickly to keep ahead. Tonight I shall probably wake suddenly, after a nightmare trying to flee over boulders up a riverbed, pursued by a clattering dozer with blade raised.
The work went well, and we ended up clearing seven raised shingle banks (all on existing islands) and diverting two channels to create extra islands. In addition, while the dozer worked nearby, I hand-cleared another bank of widely scattered lupins.
The dozer then clattered off back down the river, while I walked at leisure and admired our handiwork en route. Three wrybill flew past, courting black-fronted terns circled above, and a couple of banded dotterels were already inspecting one patch of freshly turned shingle. I shall certainly be watching with much interest to see if our prepared sites prove to be attractive to breeding birds.
