I noticed that morels and asparagus make their initial emergence at the same time; apparently from the strength of the sun warming the soil enough to trigger growth. This also coincides with the first Ruby-throated Hummingbird sighting of the year.
Now don't go out and expect to find a full-grown edible morel at this time. You need to know exactly where they are, just to see them barely peeking through the grass. It will be a week or more before they are of picking size. But when the first asparagus pokes through the soil, so does the little bald head of the morel. It is now time to put out your hummingbird feeders too.
When is this magic day ? Here, in my yard it is April 18-20, the true first day of Spring.
How to Find Morels