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Scott Weidensaul’s twenty-year experience as an active field researcher brings an extra depth to his new book, A World on the Wing: A Global Odyssey of Migration (2020).

The book opens and closes in Alaska, where researchers trap, band and put small geolocators (solar-powered tracking devices) on birds, all while being watchful of polar bears. The new devices are a third of an inch long and weigh a fraction of a gram.

Kirkland Warbler

Weidensaul writes about other areas of the world, too. The crucial stopover for migrators on the East Asian-Australasian Flyway is China’s Yellow Sea, at risk due to coastal reclamation. Conservationists have tried to stop people who use nets and sonic decoys (bird calls) to capture songbirds in Cyprus for a traditional food delicacy. The Kirkland Warbler that migrates between the jackpine habitat in northern Michigan and the Bahamas is threatened with rising ocean level.

The tracking devices give researchers insight into where birds winter, nest and pick up the energy reserves for their next long flight. With one type of device, researchers have to capture the same bird again (!) and download the stored data. Birds that return to the same nesting spots every year make that job easier.

The other type is tiny radio transmitters that are part of the Motus Wildlife Tracking System. Receiver stations, each with directional antennas, a basic computer, and a GPS receiver, cost less than $5,000. The international research network has 1000 stations that receive the transmission of identification codes unique to each device as the birds fly by.

Amur Falcon

One chapter focuses on the tens of thousands of Amur falcons who fly from southeastern Siberia through Nagaland in northeast India on their way to winter in southern Africa (and back again). The small raptors roost near a reservoir in Nagaland for ten or so days each way, filling the sky at dawn and dusk as they fly to and from their feeding grounds. The Naga, former headhunters, were capturing 10-12,000 falcons per day in nets to sell as food in nearby communities. The slaughter stopped in 2013 after a local conservationist and others spoke to village elders. Ecotourism is slowly giving the Naga a new source of revenue.

I was surprised by this paragraph near the end of the chapter.

"The enormous steepled Baptist church, white and green, occupied the top of the hill, while the Catholic and Assembly of God churches were considerably more modest. The Naga were originally an animist culture, and pushed back ferociously against British control starting in the 1830s. . . . But evangelizing by American Baptist missionaries that started in the mid-nineteenth century made slow progress and accelerated rapidly in the twentieth. Ironically, the decision by the newly independent Indian government to expel foreign missionaries caused the conversion rate to explode – in direct reaction, some scholars have argued, by the Naga to the widely despised government’s attacks on churches and ministers. The wholesale conversion of the Naga was, in one expert’s view, “the most massive movement to Christianity in all of Asia, second only to that of the Philippines.” Such is the underlying weirdness of Nagaland that today, even the Maoist militants coming across from Myanmar are also mostly Baptists.” (p. 334)

Today around 90% of people from Nagaland identify as Christians. See “Christianity in Nagaland” on Wikipedia.

Hudsonian Whimbrel

P.S. For a glimpse into Hudsonian whimbrels that fly as many as 7,000 miles between South America and northern Canada, see “Leave This Island to the Birds” in the New York Times, June 20, 2021.

P.S.S. We finally bought Wingspan. Anyone out there a fanatic?

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