Friday, May 13, 2016
|Wilson's Warbler, male, returning from Central America|
Text and photos by Christine Southwick
The second Saturday of May has been declared the International Migratory Bird Day (IMBD) in the Americas.
Why is this important? At least fifty of our favorite King County species migrate here each summer and return to Central or South America each fall. Almost all warblers, swallows and swifts, even some of our raptors, like Merlin, have flown long distances to breed here.
|MacGillivray's Warbler stop over on migration from S. Amer.- bathing necessary too|
Additionally there are another fifty over-wintering birds, like Fox Sparrows, that shelter in our mild winters here and leave about April to fly further north, often to breed in the Boreal Forests.
All shorebirds have long circular migration routes, some exceeding 15,000 miles annually, most flying from Central or South America up to their breeding grounds in the Arctic, and then back southward in the fall.
The majority of the 20 million shorebirds that migrate through the United States to their Arctic breeding sites each year depend on five key staging sites: Washington’s Gray’s Harbor, Alaska’s Copper River Delta, eastern Canada’s Bay of Fundy, Kansas’ Cheyenne Bottoms, and the beaches of Delaware Bay.
Some shorebirds, like Godwits and Snowy Plovers, do breed here and arrive at night after a prolonged flight, arriving in mid-March and leaving by sometime in October.
|White-crowned Sparrow, breeds locally, migrates south in winter|
The majority of songbirds fly during the night, mainly, it is believed, to avoid predators, and their mass migrations are such that the beginnings of their southward movements show up on evening radar.
Strictly bug eaters, like the swallows and Vaux’s Swift, are forced to fly during the day to find the insects which fuel their long arduous flights.
For all birds on migration, resting and refueling sites make the difference between surviving or perishing.
Without stops along their routes that have water, and food, many die. Some of you may have heard the term, “Fall-out” when referring to spring migration, especially along coastlines or after a storm.
|Varied Thrush, male winters-over here goes higher to breed|
Exhausted birds, after an especially hard leg of their journey, upon reaching their much needed refueling stop, are so tired and famished, that they don’t have the strength to grasp a perch, and literally bounce off branches and sometimes fall to the ground. I had that happen one time in my yard, after a storm that caught a flock of returning robins. It was amazing.
Conservation efforts to save destinations and route stops were the impetuous for creating the IMBD, to raise awareness of the need to preserve unique feeding, resting and nesting stops and habitat.