Seagulls have easily adapted to life in urban areas, and can be annoyingly abundant. There are many other species of water based bird who have not taken up to living in urban areas, though. The Eurasian oystercatcher is one of them.
One couple has been breeding in a park area surrounding office block buildings just off the waterfront outside the centre of Oslo. The couple had three chicks this summer. Here is one of the parents with two of the juveniles:
The oystercatcher is a wader which walks along the shore and eats snails and clams. In high tide, it can also go on the lawn, and eat worms and snails. Here, it is feeding the juveniles with snails and molluscs:
The oystercatcher doesn't generally eat oysters, but it is capable of opening molluscs by prying it open or hammering through the shell. Often, the technique it handed down to the offspring, so that individual birds will specialize in one way of opening the shells.
Nikon 1 V3 with Nikon 1 CX 70-300mm f/4.5-5.6.