Studies have found that spring migration times have advanced over time and as spring has come earlier. Migratory songbirds, use weather and light changes as cues to tell them when it's time to migrate, but with the earth now getting hotter each year, birds can no longer rely on the once predictable climate. Now if the weather is good and there is food to support the journey north, we may see the birds early. Migrating birds follow the blooms and bugs. I’ve already had reports of blackbirds, robins, cranes and other waterfowl arriving.
In North America, the continuous trend in higher temperatures could delay the birds’ migration south or stop it all together. Recent research has found in fact that this very pattern is happening in the population of American Robins, Northern Flickers, Eastern Bluebirds and Carolina Wrens of Michigan, who are increasingly deciding not to leave.
The advantage of sticking around all year is that they get prime nesting spots. On the flip side, birds that migrate much longer distances are less affected by the temperature changes, the researchers found. That means they now arrive behind everyone else and get crowded out of nesting locations and breeding sites.
If you want to check the maps or report the sighting of a bird go to www.hummingbirds.net to check the status of hummingbirds and http://www.learner.org/jnorth/maps/Maps.html for a lot of other spring sightings.
Usui, T., Butchart, S. H. M. and Phillimore, A. B. (2017), Temporal shifts and temperature sensitivity of avian spring migratory phenology: a phylogenetic meta-analysis. J Anim Ecol, 86: 250–261. DOI:10.1111/1365-2656.12612
Adrienne Berchtold et al, Experimental temperature manipulations alter songbird autumnal nocturnal migratory restlessness, Animal Migration (2017). DOI: 10.1515/ami-2017-0001