Amazing, simply amazing. The confluence between research science, technology, and volunteers on a massive scale yield these, I’ll say it again, amazing, heat maps of bird migration: Forecasts : BirdCast.
Without waiting for years of study to become published, and then instantly become irrelevant, this “real time” network of volunteers and bird scientists have been putting together easily readable maps and graphs that show how bird migration not only shapes up for this season, week by week, even day by day, but how it compares to other years at the same time.
To say that bird migration depends on the weather is an understatement, birds must follow weather patterns in order to move the distances they need to arrive at feeding and breeding grounds just in time to continue their life cycle. When those patterns are too early, birds can “hold on” to their current position to avoid being swept away to an area that is still too cold or dormant. When the wind and weather is too late, birds may be stranded in inhospitable locations. Even more complicated is when the seasons get mixed up, as in New England this spring, with winter and summer alternating rapidly, too cold, too hot, with “just right” fleeting fast away.
If you want a graphic example, in real time, of life trying to adapt to a rapidly changing climate regime, the heat maps of e-bird are a good place to look.