Birder's Guide

MAR 2017

Birder's Guide is the American Birding Association's newest publication. Each issue focuses on a key subject, providing tips from experienced birders on a wide variety of topics like Travel, Listing & Taxonomy, Gear, and Conservation & Community.

Issue link: http://bg.aba.org/i/799689

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39 March 2017 | Birder's Guide to Travel tanglements with Midway's tall ironwood trees. It is a gruesome reminder of the hav- oc introduced species can cause. Midway Atoll's most widely known problem is marine debris, which litters every beach and is scattered all over the islands. Tons of marine debris—plas- tic, glass, metal, and commercial fish- ing gear—wash ashore every year by the North Pacific Gyre, which collects and distributes debris from the so-called Great Pacific Garbage Patch. One study estimat- ed that several tons of plastic are brought by albatrosses alone to the atoll, every year. Albatrosses are opportunistic feeders and will ingest everything from live squid to action figures and Bic lighters. They have a neat trick of regurgitating anything they eat that they cannot digest (think gi- ant owl pellets), thus spreading plastic ev- erywhere on the atoll. But chicks do not have this ability, and no one knows how many albatross chicks die every year from filling up on plastic that their parents feed them by accident. Most of us who have been there are under the impression it is a great and disturbing number, and you never have to go very far without finding an old albatross carcass with a disconcert- ingly large pile of undigested plastic where the stomach used to be. The highly endangered Hawaiian monk seals, green sea turtles, and all seabirds are at risk of entanglement from marine de- bris, which can maim or drown wildlife. Old fishing nets ("ghost nets") are particu- larly troublesome; while drifting at sea, they are capable of catching anything from fish to spinner dolphins and can damage coral when snagged on the reef. At least one species of bird has gone ex- tinct on Midway: the Laysan Rail, formerly endemic to Laysan Island. Thanks to in- troduced rabbits, they were in imminent danger of extinction on Laysan from habi- tat loss, and as a rescue attempt, several were brought to Midway in the early 20th century, where they appeared to do well. The rails on Laysan did indeed blink out of existence, and rats brought to Midway by WWII shipping eventually wiped out the last survivors on Midway, too. The rails are not the only birds that took a hit from the rats. All ground-nesting birds were badly affected. People observed rats jumping on the backs of albatrosses and eating them alive. It must have been a hellish time for Midway's birdlife. Brown Boobies, the commonest booby of the atoll, ceased nesting there by the 1970s (Red-footed is now the most abundant booby). Tristram's Storm-Petrels and Bul- wer's Petrels were completely extirpated from the islands. Nonetheless, Midway is far from being all doom and gloom. Midway was not an ideal place for wildlife when it was a mas- sive military base, but as its strategic sig- nificance and human population declined, birds began to take back abandoned parts of the islands. When the base was fully decommis- sioned in the 1990s, the U.S. Navy went to great lengths to eradicate rats as part of its cleanup operation. The campaign n A male Great Frigatebird enthusiastically displays to a female. Photo © Steve Tucker n Masked Booby. Photo © Steve Tucker

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