The greylag parents with their six goslings. When I spotted them, the goslings were on one of West Park’s patches of short grass, eating. The parents were both on guard.
Near by, there were two other adult greylags. I thought they might have been acting as additional guards, which greylags sometimes seem to do. But them the parents began to herd the young ones across the footpath and towards the lake. This brought the family party closer to one of the other adults, a bird which seemed just to be standing around, not actively doing anything.
As the family neared this bird, the parents started to get threatening. One, presumably the gander, hissing loudly, so the other bird retreated a short distance. The goslings then settled down on the footpath and the bank of the lake, an arrangement the parents seemed to accept.