Today is, to all intents and purposes, a beautiful spring day in Brussels, but in Belgium you can never really be sure about when spring has truly arrived. The Belgians themselves refer frequently to the Saints des Glaces – roughly mid-May – beyond which better weather is more-or-less assured and certainly no frosts should occur. In my neighbourhood we have two fairly reliable indicators of our own. One is a grand old walnut tree that is always the last tree to leaf and seems to wait until it is really sure that spring is on the way. The other is a curious phenomenon visible in the streets right now. Some sort of insect – a wasp? a fly? – burrows out from between the cobblestones and flies away, leaving a small pile of distinctively sandy soil (picture). I have never seen the creatures that do this (and I’d be interested to find out what they are) but, like the walnut tree, they seem to wait until spring is a certainty and over the past few days they have made their break for freedom.