Thursday, May 10, 2012

So Long, Snowbirds

Well, they are each not exactly snowbirds, but our winter residents are returning to their second homes.

The Kōlea, Pacific Golden Plover, is a migratory bird that comes to Hawai‘i from Siberia and Alaska at the end of August and leaves for its trip across the north Pacific in late-April to early-May.

The bird’s Hawaiian name, Kōlea, is a phonetic imitation of the sound of its flight call.  One olelo no‘eau (Hawaiian proverb) states ‘Ai no ke kolea a momona hoi i Kahiki!’ (The Kōlea eats until he is fat, and then returns to the land from which he came.)

Unlike many birds capable of trans-oceanic migrations, Kōlea can neither soar nor glide; and, they can’t swim.

When Kōlea fly between Hawai‘i and Alaska, they will continuously beat their wings twice per second for about fifty hours over some 2,500 miles of open ocean—one of the most grueling non-stop migrations in the avian world.

Kōlea spend each summer on the treeless tundra of western Alaska and Siberia; there, they’ll breed and incubate a clutch of eggs—Kōlea chicks are left largely on their own once they’re born.

Chicks can fly at three weeks, though not yet as far as Hawaii; when adult Kōlea lift off for the Islands in late August, they leave the young behind to follow some weeks later.

Scientists aren’t certain how the chicks find Hawai‘i.  By October the juveniles arrive on our shores.

Kōlea return to and vigorously defend the same spot in their summer and winter grounds, an extreme example of what ornithologists call "site faithfulness."

During late winter and spring, the Kōlea eat voraciously, nearly doubling their body weight to make the demanding flight north.

Another seasonal visitor is the Koholā, the Humpback Whale (part of the North Pacific stock – whales in the North Pacific also winter in western Mexico and southern Japan.)

From mid-December through mid-May the Koholā make their home in the waters surrounding the Hawaiian Islands.

An endangered species, the Hawaiian Islands Humpback Whale National Marine Sanctuary was created by Congress in 1992 to protect humpback whales and their habitat in Hawai‘i.

The sanctuary, which lies within the shallow (less than 600 feet), warm waters surrounding the main Hawaiian Islands, constitutes one of the world's most important humpback whale habitats.

While they were here, the humpback whales were involved in courtship rituals, mating, calving and nursing their young (gestation lasts about 11 months.)

Both male and female humpback whales vocalize, however only males produce the long, loud, complex "songs" for which the species is famous.

In the Pacific, humpbacks migrate seasonally from Alaska to Hawaii - they can complete the 3,000-mile trip in as few as 36 days.

Humpbacks continuously travel at approximately three to seven miles per hour with very few stops; they typically stay near the surface during migration.

The humpbacks don't eat during their stay in the Hawaiian Islands.  Hawai‘i doesn't offer their food, krill and herring; they carry their summer food supply in their fat.

During the summer months, humpbacks spend the majority of their time feeding and building up fat stores (blubber) that they will live off of during the winter.  Humpback feeding grounds are in cold, productive coastal waters.

Soon, the last of the Kōlea and Koholā will be gone; to return, again, in the fall.

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