I arrived at my boat this afternoon to find an oystercatcher egg lying on the boats canvas cover. The egg didn’t feel particularly warm. The boat is on a swing mooring in Poole Harbour. The mother returned and called from a nearby vessel. I left the outside where it could easily be seen. I returned to the mooring a couple of hours later and again the mother returned and landed on the boat for a brief time. 
On leaving my boat I left the egg where I found it. Just wondering if anyone has any observations about this.