It was a cold but calm night in Lake Wanaka. The lake water level was surprisingly high such that the tree trunk was completely sunk under the water. But this tree, which was beautifully illuminated by city light from right side, was obviously a safe shelter for these little birds.
Taking this image was a bit tedious: as the water level was too high, there was no possibility to frame the scene that I was interested from the lake shore. Luckily, with my wader on, I was able to stand in the cold water for a long time to take my shots.