04 March 2011

Spring Migration

The spring migration is urgent and depending on the species of birds, there is a specific optimal time when the birds need to arrive for breeding.

So who arrives first?

Yellow-headed Blackbird: March 16 - April 30

Yellow-headed Blackbirds have a very systematic migration plan. Traveling to Montana from as far south as central Mexico, yellow-headed blackbirds migrate in large flocks that are segregated by sex and age. Arrival on the breeding grounds in spring is an orderly process. Mature males migrate first, followed by mature females as much as two weeks later. Next come the first-year males, followed in about a week by first-year females.

Swainson’s Hawk: April 1- April 30

The fall migration of this species is a spectacular phenomenon, as virtually all of the world's population of Swainson's Hawks funnels through Central America within a few days. Until very recently, these hawks were thought to disperse across the whole of South America, and no one really knew where or how they spent the northern winter.

Who are the final migrants to arrive?

Yellow Warblers: May 1 - Jun 15

The first Yellow Warblers to arrive in the U.S. are those that will reach southern California in mid-March. These birds, representing two subspecies, pass up the Pacific coast and reach southern Alaska by mid-May. The other five subspecies will arrive in the U.S. in early April. Their movement is rapid; some of these birds will reach the Great Lakes region before the end of April, and others may arrive in interior Alaska by mid-May. But for us, we will see these birds come May!

Western Tanager: May 16 - Jun 15

The majority of this striking species winters in southwestern Mexico and Central America. The actual migratory routes of Western Tanagers are largely unknown. These birds are nocturnal migrants that travel at high altitude covering great distances in one night!

All of these birds can be spotted at the Lee Metcalf National Wildlife Refuge.

Click Here for a list of all birds living at Lee Metcalf National Wildlife Refuge.

For more information on bird migration, check out the eNature website.

1 comment:

  1. I find that the nighthawks are one of the last birds to arrive, and seem to be one of the first to leave, at least at my altitude, 500 feet above Missoula. And hummingbirds seem to arrive surprisingly early in my neighborhood, considering the bloom of summer has yet to arrive when they do.