In the USA, where I hail from, the sight of a red-red robin (comes bob-bob bobbin' along) heralds the start of spring.
Although Japan has robins - known as "komadori" - most people don't associate the sighting of one as the beginning of spring. In fact, most probably wouldn't know what a komadori looks like. (Photo below for those of us who don't.)
For the Japanese, and most foreigners who have been here any length of time, spring starts in Japan when the sakura (cherry) trees start to blossom. Actually, the plum trees bloom 2 to 4 weeks before the sakura, but to me those are the pre-spring blossoms. Lovely pink and white plum flowers to get our thoughts turning to spring.
Japanese Plum Blossom
At our Toastmasters meeting this week, when asked what brings spring to mind for them, most all the participants, Japanese and non-Japanese alike said it's when the sakura trees bloom. Now that the flowers are opening up we can expect to see hordes of people in almost any location where there is a sakura tree or three. People will be clustered under the trees, sitting on blue ground tarps, enjoying snacks, sake, wine, beer, or any other of their favorite liquid refreshments for an afternoon or evening of "hanami" - viewing the flowers. Of course, there will be a little flower viewing done, but by the time the evening is over most of the viewing will be at ground level since sake heavy heads are pretty hard to lift up to where the actual flowers are.
So, if you're one of the hanami party goers - enjoy - and kampai!