Date: 9/3/19 11:18 am From: 'Bill Rapai' via Birders <birders...> Subject: Re: [birders] Microtracker maps a rare bird's migration (Kirtland's warblers)
To answer your question about potential impacts of Dorian on the Kirtland's Warbler population, my guess would be minimal.
A few years ago, Nathan Cooper of the Smithsonian Migratory Bird Center put geotrackers on a handful of male Kirtland's. When the geotrackers were recovered the following year, he discovered that the data showed each of the birds spent the month of September and the first part of October in Ontario near Algonquin Provincial Park.
It seems that the birds learned that they should not go back to the Bahamas too early to avoid potential risks.
Now, the next question is, What impact did Dorian have on the winter habitat? My guess again would be minimal. Dorian absolutely wiped out some of the northern pine-dominate islands. The warblers tend to winter on the southern islands that are dominated by coppice habitat. If the warblers happen to land on Grand Bahama Island during migration they will likely find food but not much shelter. You will be amazed how quickly insects repopulate an island after a disaster like a major hurricane.
Bill RapaiGrosse Pointe
"Adopt the pace of nature: her secret is patience." -- Ralph Waldo Emerson
From: G M ARCHAMBAULT <gm72125...>
To: birders <birders...>; Larry Nooden <ldnum...>
Sent: Sun, Sep 1, 2019 9:21 pm
Subject: Re: [birders] Microtracker maps a rare bird's migration (Kirtland's warblers)
I found an old article about fall migration of Kirtland's Warbler based on a 1971 net specimen. Did not send a lot more time on it, but found another list of ample enough fall records to indicate this species arrives on its wintering grounds later than ... right now. With all the Hurricane Dorian news of catastrophic damage in the Bahamas, I bet others are also concerned about survival rates of the rare birds there.
I'm hoping in the coming days to read something on the Tropical Audubon Society's Bird Board, but perhaps some experts could weigh in with their knowledge to help us all understand if our concerns are well-founded or if the birds will come through this like they have for millenia.
I'm hoping that many if not the majority of Kirtland's Warblers will still be on the mainland at this time. -Ken Archambault, Birmingham, Alabama (two OLD eBird records of Kirtland's here in Alabama, fyi. 1908 and 1936, both spring sightings, if memory serves) On Saturday, August 31, 2019, 03:09:23 PM CDT, Larry Nooden <ldnum...> wrote:
The Kirtland's warbler travels thousands of kilometers in about 2 weeks.
https://science.sciencemag.org/content/355/6329/998 "Fifty years ago, fewer than 400 Kirtland's warblers were left in their summer habitat in upper Michigan. The species, Setophaga kirtlandii, became one of the first beneficiaries of the U.S. Endangered Species Act. Forest managers planted more jack pines—which the songbird needs for its summer nests—and the population of the species increased 10-fold. But even so, only about 40% of the birds survive the annual migration to the Bahamas and back. Researchers wanted to learn more about their round-trip route, so they outfitted 50 warblers with tiny geolocators weighing just 0.5 grams. Every 2 minutes, the geolocators record the intensity of light, a measure of sunrise and sunset that can be used to calculate latitude and longitude. In the fall, the team learned, the warblers headed east over Ontario to the Atlantic coast, then south to the Bahamas. For the spring leg, the warblers flew west and made a stop in Florida before turning north toward Michigan, the team reported last week in the Journal of Avian Biology. Each way, they travel about 4500 kilometers in about 16 days. Knowing the locations of those stopovers, the researchers note, is a starting point for improving the bird's protection."
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