THE WEEK IN WILDLIFE 05/18/2024
A big new hummer & sowing the seeds of insect apocalypse
by Richard Conniff
THE WORLD’S BIGGEST HUMMINGBIRD COMES OUT OF HIDING
A new giant hummingbird made its debut on the world stage this week—roughly three million years after it first evolved. Why the delay? Especially since we’re talking about a big, charismatic bird—-in fact, the biggest of the 363 hummingbird species?
The answer is that the newcomer to science is a cryptic species. That is, until now, everyone’s been mistaking the giant hummingbird for a single species, long familiar to the indigenous peoples of western South America, and closely observed (and dissected!) since then by countless others, including Charles Darwin in 1834 as he traveled the coast of Chile in HMS Beagle.
It turns out no one was looking closely enough. Beneath the lookalike surface, two species with dramatically different behaviors were in hiding. They are now known as the northern giant hummingbird (Patagona chaski) and the southern giant hummingbird, which will retain the old scientific name, Patagona gigas.
Lead researcher Jessie Williamson and her co-authors, who published their findings this week in Proceedings of the National Academy of Sciences (PNAS), originally set out merely to understand giant hummingbird migration. It took two field seasons just to design a satellite transmitter backpack small enough for the birds to carry without altering their behavior. As an alternative to the backpack, some other birds carried tiny geolocator devices worn as a sort of anklet.
Tracking the birds revealed that one set of birds stays put year-round in the high Andes. The other set makes a spectacular migration from 14,000 feet up in the Andes of Central Peru down to sea-level breeding grounds in Algarrobo, Chile, and back again. That’s a roundtrip of up to 5,200 miles, more than the distance from New York City to Istanbul. On the return trip, the migrating birds pause at stages, like human mountaineers, to acclimate to lower oxygen levels at increasing elevations.
When the researchers did whole genome sequencing of the two populations, they discovered that northern and southern giant hummingbirds are “as different from each other as chimpanzees are from bonobos,” said senior author Chris Witt, of the University of New Mexico. Among the physiological differences, the stay-at-home northern hummingbirds have larger lungs than their migratory cousins, like “Andean humans who have evolved larger pulmonary volumes” than humans living at sea level. But the southern hummingbirds have adapted to ramp up the oxygen-carrying capacity of the blood on their upward migration, ultimately attaining the same hemoglobin concentration as their upland counterparts.
So why would the two species have gone separate ways in the first place? The authors of the new study note an intriguing coincidence: About three million years ago, immediately before the two giant hummingbirds separated, the Central Andes mountain range experienced a sudden uplift that doubled its elevation. Geology, bringing on sudden expansion of habitat at different latitudes and elevations, may have been the unnamed third party behind the divorce.
REGULATING “JUST IN CASE” USE OF INSECTICIDES
Despite the sharp decline in insect and bird numbers, big agricultural corporations make it a standard practice to coat the seeds they sell with pesticides, notably including neonicotinoid (or “neonic”) insecticides. They do it on a “just case in case” basis, not to address any specific threat to crops.
Studies suggest that neonic seeds coatings provide no economic benefit, except to the big companies that profit from them. For the Xerces Society, the leading invertebrate conservation group, Rosemary Malfi reports:
While the economic benefits of prophylactic seed treatments are in question, the ecological costs of widespread neonic use are well documented. Neonics are highly toxic to bees, and they are specifically implicated in wild bee population declines. Because only a small fraction of the pesticide coating is absorbed by the crop plant, over 90% ends up in soil, water, and plants elsewhere in the environment. As a result, neonics pose a growing threat to aquatic ecosystems and waterways. Neonic-coated seeds can also harm birds when eaten. The EPA itself has determined that the three neonics most commonly used as seed treatments put over 200 threatened and endangered species at risk of extinction.
Shouldn’t the EPA or some other government agency limit their use? In fact, Quebec did that in 2019, over heavy lobbying by industry. Malfi goes on:
So what happened in Québec once neonic seed treatments were prohibited? Former agronomist with the Canadian Ministry of Agriculture Louis Robert has described the successful transition away from neonicotinoid treated seeds and Québec’s corn and soy growers are reaching out to other regions to share their positive experience. In spite of vigorous opposition from seed companies and the pesticide industry (which are often one and the same), they were able to adjust quickly to the new market conditions. Claims that grain crops would fail were not realized, and yield has not been affected by the change. Since 2019, neonicotinoid detections have dropped in surface water sampling. Québec growers report that they are spending less by buying untreated seeds, as have soybean growers in Iowa who also have chosen to forgo insecticide seed treatments.
Read the whole article to understand the prospects for regulating seed-coating with pesticides in the United States. Hint: You can start at the state level.