The Migration of Lapland Longspurs to Alaska

Irving, Laurence

Lapland Longspurs, ascribed to Calcarius lapponicus alascensis Ridgeway, nest in great numbers over the arctic tundra and grassy land west of the forests of Alaska and over the Aleutian Islands. During 10 years great numbers of longspurs have been observed in May migrating north through Anaktuvuk Pass. Similar migrations proceed through other interior valleys of the Brooks Range, taking vast numbers of longspurs toward the arctic tundra. There is no evidence that the migration proceeds westward to Alaska through arctic Yukon Territory or eastward from Siberia. In the last week of April and first of May 1958, great numbers of longspurs, in flocks at first containing mostly males, were seen migrating westward over a distance of 260 kilometers (160 miles) through the headwater valleys of the Yukon River in southwestern Yukon Territory. Longspurs reach northern and western localities north of the Alaska Range after their appearance in southwestern Yukon Territory at dates indicating plausible rates of migration from Yukon Territory through Alaska. South of the Alaska Range and on the Aleutian Islands, arrivals are so early that these regions cannot be settled by the migrants observed in Yukon Territory. Unobserved flights coastwise or overwater are suggested. The northward advance of the front of longspurs migrating through Alaska is slow, but it increases as the northward component of migration diminishes and as the westward component increases.

The Migration of Lapland Longspurs to Alaska

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