The previous blog post concluded with a isochrone map showing when to expect the Ruby-throated Hummingbird in spring in North America. eBird has animated versions for the entire year of the density of bird species in the USA. Animated in range maps for 57 species and their occurrence in the 48 continental United States. Below an example of showing the Savannah Sparrow during one year.
Savannah Sparrow range map from eBird
Watching this animation one can see the migration routes the Savannah Sparrow takes on it’s seasonal migration from southern wintering grounds to northern breeding grounds. These routes or flyway, follow geography (mountains, plains, rivers), food supply and wind conditions and vary between migratory species. National Geographic describes more about ranges and migration routes in the Americas in their blog post Mesmerizing Maps of Bird Migration including their 1971 map for many western hemisphere species. Migration routes tend to run North – South. Here the main international flyways.
Main international flyways of bird migration by Pinpin
Flyways from left to right:
Pacific Americas Flyway
Central Americas Flyway
Atlantic Americas Flyway
East Atlantic Flyway
Black Sea – Mediterranean Flyway
East Asia – East Africa Flyway
Central Asia Flyway
East Asia – Australasia Flyway
About 2,000 of bird species make regular seasonal movements. Sadly, due to threats along these flyways more than 40% of these migratory species are declining. Read more about projects to protect and conserve these migratory species at Bird Life.
Bird Life also recently published and article discussing 118 bird species seasonal migration routes of the western hemisphere including the detailed animation below.
By Frank A. La Sorte, Daniel Fink, Wesley M. Hochachka, Steve Kelling – Convergence of broad-scale migration strategies in terrestrial birds at the Cornell Lab.
Each dot represents a single bird species; the location represents the average of the population for each day of the year (see paper for a more precise explanation of the “average location”). Here’s a key to which species is which.
“We used millions of observations from the eBird citizen-science database,” says lead author Frank La Sorte, a research associate at the Cornell Lab. “After tracing the migration routes of all these species and comparing them, we concluded that a combination of geographic features and broad-scale atmospheric conditions influence the choice of routes used during spring and fall migration.”
Because the animations in the blog post were loading slowly for some for some internet surfers, it has been split into two, second part is Pancontinental highways that follow Flyways.