I've seen this done for monarch butterflies; this is the first for hummers I've encountered. Source at THIS LINK, which also has maps for eastern Canada and for prior years.
Click to enlarge.
Hummingbird migration map
I've seen this done for monarch butterflies; this is the first for hummers I've encountered. Source at THIS LINK, which also has maps for eastern Canada and for prior years.
Click to enlarge.
