Category Archives: Climate Change

Fewer Hybrid Golden-Wings Thanks to Climate Change

Golden-winged warbler (photo from Wikimedia Commons)

9 January 2023

Golden-winged warblers (Vermivora chrysoptera) and blue-winged warblers (Vermivora cyanoptera) do not look or sound alike but they are well known to hybridize. Because of this ornithologists used to worried that the more numerous blue-winged warbler would force the golden-winged out of existence. Then a 2016 genetic study showed no need to worry — they are very closely related. Now a 2022 study shows that hybridization will become less likely thanks to climate change.

Blue-winged warbler (photo from Wikimedia Commons)

In 2016 we learned that golden-winged and blue-winged warblers are virtually the same bird — 99.97% genetically alike! No wonder they interbreed.

Put another way, the striking visual differences between Golden- and Blue-winged warblers could be considered akin to the differences between humans with and without freckles. Golden-wings and blue-wings have even less genetic differentiation than two subspecies of the Swainson’s Thrush.

All About Birds: Mixed Wing Warblers: Golden-wings and Blue-wings are 99.97 percent alike genetically

Their colors and songs fooled us so we called them hybrids and even named them Brewster’s and Lawrence’s warblers, but the difference is moot to the birds themselves. This illustration embedded from All About Birds, shows their four color phases governed by a dominant/recessive throat-color gene.

If you’re still worried about hybrids, the newest study should put your mind at ease. Entitled “Change in climatically suitable breeding distributions reduces hybridization potential between Vermivora warblers,” it maps the birds’ past and present breeding ranges and models their future under 6 climate scenarios.

Historically (1932-1997) the warblers’ ranges overlapped a lot but by 2012-2021 it was evident they were moving apart. Climate change has moved the golden-wing’s preferred cooler habitat to the north and higher elevations.

The future will move their ranges even more, shown in six scenarios below. The left column shows climate altering emissions peaking in 2040 and then declining. The right column shows emissions continuing to rise through 2100.

Predicted climate suitability for Golden-winged Warblers (yellow) and Blue-winged Warblers (blue) distributions under future climate scenarios (https://onlinelibrary.wiley.com/doi/full/10.1111/ddi.13659).

Unfortunately climate change may force one or both warblers out of existence. Map (d) is the only happy one for both of them but they will disappear as breeding birds in western Pennsylvania.

Don’t worry about golden-winged warbler hybrids. The real problem is climate change.

* Read more about golden-wing and blue-wing relatedness in All About Birds, Living Bird Magazine: Golden-Winged And Blue-Winged Warblers Are 99.97 Percent Alike Genetically.

* See the breeding range study at Wiley Online: Change in climatically suitable breeding distributions reduces hybridization potential between Vermivora warblers.

(photos from Wikimedia Commons, illustration embedded from All About Birds, maps are open access at Wiley Online Library)

Was The Snow Really Deeper When I Was A Kid?

Snow on sweet gum seed balls, Pittsburgh, 17 December 2020 (photo by Kate St. John)

4 January 2023

Rain. Rain. Rain! For two days it’s been raining in Pittsburgh while the high temperature holds at 61oF. Total rainfall will be 1.4 inches, some of which splashed the Cathedral of Learning falconcam.

Rain distorts the Cathedral of Learning falconcam, 3 January 2023

If the weather had been below freezing we’d be looking at 14 inches of snow! I’m glad it isn’t snowing but heavy rain in January got me thinking … Wasn’t the snow deeper when I was a kid?

I grew up in Pittsburgh so my memories of winter apply to where I live today, but are my memories distorted? Using Pittsburgh’s historical snowfall data I compared my 12 years of growing up in Pittsburgh(*) to the most recent 12 years.

The answer is mixed. There was more snow in winter when I was a kid (maximum winter total and highest minimum), but both the highest and lowest snowfall per month both occurred in the recent past — in fact in the same winter of 2020-21.

DescriptionWhen I Was a KidInchesInchesThe Last 12 Winters
Max Winter TotalWinter 1960-6176.063.4Winter 2013-14
Min Winter TotalWinter 1968-6930.422.4Winter 2019-20
Max Monthly TotalJan 196624.627.5Jan 2021
Min Monthly TotalMar 19611.40.1Mar 2021 (same yr as max)
Snow in May?Up to 3.1 inchesNo snow sticks in May

The wild swings in snowfall nowadays mirror the wild swings in temperature.

Remember how bitter cold it was only 11 days ago? Look at the temperature swing then (Christmas Eve 2022) and now (3 January 2023)!

So the answer is Yes & No. Yes, there was more snow in Pittsburgh when I was a kid. But, No, the snow is deeper today on rare occasions.

Curious about snowfall in Pittsburgh? Check out the historical data at NWS Pittsburgh and the Rain to Snow Calculator here.

(*) The span is 12 years because I moved to Pittsburgh when I was 6 years old.

(photo by Kate St. John, maps and data from the National Weather Service)

Disappearing Islands in Chesapeake Bay

High tide at Tangier Island, Virginia, 16 Sept 2016 (photo from Wikimedia Commons)

7 December 2022

Sea level is rising overall about 3 millimeters (0.1 inches) per year due to climate change but Chesapeake Bay is rising even faster than the ocean — as much as 4.6 millimeters per year — because the area is still subsiding after the last Ice Age. Some Chesapeake Bay islands are disappearing.

NASA’s Landsat images of lower Chesapeake Bay from 1999 and 2019 show how much land has been lost in only 20 years. In 1999 there were white sand beaches on the island edges. By 2019 the beaches are gone and Great Fox Island in the center of the image has almost disappeared.

Satellite imagery from “Great Fox is Disappearing” NASA Landsat Image Gallery

The Chesapeake Bay Foundation used to hold in-residence educational programs on Great Fox (also called Fox Island) but in October 2019, with only 34 island acres left, they declared the end of the program. You can see why in the video below.

Just across the Virginia line (at the bottom of the satellite images) is Tangier Island whose land mass has shrunk 67% since the 1850s. Its population shrank as well. By now Tangier has only 345 acres and a population of about 470.

Residents are routinely flooded during the highest tides, pictured at top and below.

Tide water floods yards on Tangier Island, Virginia, Sept 2016 (photo from Wikimedia Commons)
Tide water floods streets on Tangier Island, Virginia, Sept 2016 (photo from Wikimedia Commons)
Tidewater rising in the yards at Tangier Island, Virginia, Sep 2016 (photo from Wikimedia Commons)

A 2015 analysis by the U.S. Army Corps of Engineers predicted that Tangier Island will become uninhabitable within 25-50 years, about mid-century.

The harbor channel, Tangier Island, Dec 2011 (photo from Wikimedia Commons)

Tangier Island will eventually join Great Fox Island under the bay.

For more information see Great Fox is Disappearing at NASA’s Landsat Image Gallery, Wikipedia’s Tangier Island account and this April 2022 NBC News video about Tangier Island.

(photos from Wikimedia Commons and NASA Landsat Image Gallery; click on the captions to see the originals)

More or Less Drought

Ranking the states by average percentage of land in drought, 2000-to-March-2021 (original map from Wikimedia Commons colored by Kate St. John)

27 November 2022

The western U.S. has always been drier than the east but as climate change heats up the planet, drought has become more prevalent. NOAA’s quarterly weather outlooks now include a 3-month drought prediction along with temperature and precipitation forecasts. Some places are more likely to experience drought than others. Which states are more likely? Which are least?

The graphic above is based on Stacker’s article, States With the Worst Droughts, that ranks states by average percentage of land in drought from 2000 to March 2021. Listing the states in order, I grouped them in 10s with darkest Orange indicating the top ten drought states and darkest Green for the 10 wettest. (White = the middle 10)

  • The top state for drought is Arizona. No surprise; it’s a desert.
  • The state with the least drought is Ohio!
  • Georgia and South Carolina stand alone with a lot more drought than their neighbors. Their drought ranking is like Kansas.
  • Hawaii (dark orange) and Alaska (dark green) are at opposite extremes.
Sign at Georgia Tech during the 2008 drought (photo by Mingaling via Flickr Creative Commons license)

As climate change continues to unfold human populations will migrate from less habitable to more habitable locations. In the U.S. we can expect people to move west to northeast in the coming century — from more drought to less.

Wondering about your state’s ranking? Click here for the Stacker article.

NOAA’s 2022-23 winter weather outlook is here.

(at top, base map from Wikimedia Commons, precipitation outlook from NOAA; click on the captions to see the originals)

8 Billion Of Us!

15 November 2022

Today the global human population has reached 8 billion. Lest we think our current growth rate is normal, this graph shows that human population since 10,000 BCE (the start of agriculture) has had a rapid and unnatural growth spurt in the last 70 years.

World population 100,000 BCE to 2021 from Our World in Data

There are so many humans now that we have changed the surface of the Earth, its atmosphere, and its climate just to supply our own needs.

Satellite image of Amazon basin in Bolivia (photo from Wikimedia Commons)
Smog over Mexico City (photo from Wikimedia Commons)

This rate of growth is unsustainable and somehow our species naturally knows it. Population growth will continue but is slowing to a rate of only 1% by the end of this century. Unfortunately there will be 10.9 billion of us by then!

World population growth from Our World in Data

Asia will lead the world in slowing the rate while North America remains relatively stable. (Note: The dip in 2020 is COVID deaths outperforming births.)

Annual population growth by region from Our World in Data

How will we feed 8 to 10.9 billion people? Where will we live when the sea rises and the deserts expand?

It’s a good thing for humans and the planet that our species will stop reproducing quite so fast.

Read more about the slowing growth rate here at Our World in Data.

(photo/ graph links are in the captions. Slideshow photos from Wikimedia Commons in order: Rush hour in Russia, Beach in the Netherlands, Inauguration Day 2009, Crowded exhibit in India, Crowded street, Sao Paulo station, train surfing in Indonesia, crowded Faire in UK, train in Ecuador)

After the Sixth Mass Extinction, What Next?

Guam kingfisher at Bronx Zoo (photo from Wikimedia Commons)

23 October 2022

The archaeological record shows that life on Earth has experienced five mass extinctions in which 70% to 90% of all species disappeared (*). After each extinction life came back.

The extinction rate today indicates we are now in the midst of a sixth mass extinction. Scientists predict that due to human pressure, habitat loss and climate change as much as 50% of all species will go extinct by 2100. [1] [2] [3] [4]

Interestingly, the IUCN Red List’s extinction ranking shows that birds may not fare as badly as many other organisms. It’s bad news for conifers, frogs and horseshoe crabs, though.

from Wikimedia Commons

In the short term we are helping some species such as the Guam kingfisher (Todiramphus cinnamominus), shown above, already extinct in the wild and in a captive breeding program. In the long term we humans could change our ways to slow or stop species decline. Knowing humans, it doesn’t look good. We can mourn the future but if we take a very long view there is hope.

After the sixth mass extinction, what will happen next?

David Quammen‘s article Planet of Weeds in Harper’s October 1998 described the current mass extinction and asked eminent paleontologist David Jablonski “What next?” The article is quoted below.

Among the last questions I asked Jablonski was, What will happen after this mass extinction, assuming it proceeds to a worst-case scenario?  If we destroy half or two thirds of all living species, how long will it take for evolution to fill the planet back up?  “I don’t know the answer to that,” he said.  “I’d rather not bottom out and see what happens next.”  In the journal paper he had hazarded that, based on fossil evidence in rock laid down atop the K-T event and others, the time required for full recovery might be five or ten million years.  From a paleontological perspective, that’s fast.  “Biotic recoveries after mass extinctions are geologically rapid but immensely prolonged on human time scales,” he wrote.  There was also the proviso, cited from another expert, that recovery might not begin until after the extinction-causing circumstances have disappeared.  But in this case, of course, the circumstances won’t likely disappear until we do.

Still, evolution never rests.  It’s happening right now, in weed patches all over the planet. … So we might reasonably imagine an Earth upon which, ten million years after the extinction (or, alternatively, the drastic transformation) of Homo sapiens, wondrous forests are again filled with wondrous beasts.  That’s the good news.

— from Planet of Weeds, by David Quammen, Harper’s Magazine, October 1998

A 2018 study said the recovery time for mammals may be 3 million years, faster than predicted in Quammen’s article.

The future is a long way away but it looks bright. Earth will again have “wondrous forests filled with wondrous beasts.”

Paradise by Gillis d’Hondecoeter, after 1615 (image from Wikimedia Commons)

p.s. In the comments Liz Spence reminded me of a good book about the current mass extinction: The Sixth Extinction: An Unnatural History by Elizabeth Kolbert. This book won the Pulitzer Prize.

(photos and graph from Wikimedia Commons; click on the captions to see the originals)

(*) The Top Five Extinctions in Earth’s history are paraphrased below from the American Museum of Natural History and Wikipedia:

  • 440 million years ago: Ordovician-Silurian Extinction: Small marine organisms died out at a time when life only existed in the oceans. 85% of all species went extinct.
  • 365 million years ago: Devonian Extinction: Many tropical marine species went extinct. 70% of all species lost.
  • 250 million years ago: Permian-triassic Extinction: The largest mass extinction event in Earth’s history. 90% of all species.
  • 210 million years ago: Triassic-jurassic Extinction: The extinction of other vertebrate species on land allowed dinosaurs to flourish. 70% to 75% of all species went extinct.
  • 65 million years ago: K-Pg (or K-T) Extinction: The event that killed the dinosaurs. 75% of all species lost.

Birds at the Tipping Point

  • Chimney swift flying in Austin, Texas (photo by Jim McCullough, Creative Commons license, Wikimedia Commons)
    Chimney swift flying in Austin, Texas (photo by Jim McCullough, Creative Commons license, Wikimedia Commons)

20 October 2022

Just over a week ago the Cornell Lab of Ornithology published the 2022 State of the Birds in the U.S. The news was sobering. Population declines of 90 bird species have reached a tipping point into endangered status, having lost half or more of their populations since 1970.

70 of these species are on a trajectory to lose another 50% of their populations in the next 50 years if nothing changes. (That means losing another half of what’s left!) The slideshow above shows ten of my favorites that are falling off the cliff into the sixth mass extinction.

Of the 20 remaining species whose future is bleak I will especially miss the black-billed cuckoo, snowy owl, red-headed woodpecker, olive-sided flycatcher, wood thrush, and mourning, cerulean and Canada warblers.

Fortunately Cornell Lab describes actions we can take right now to turn this around, illustrating The Road to Recovery with one of the greatest recoveries of our lifetime: the peregrine falcon. We made a difference in the last 50 years and we can do it again. Click here to learn what you can do to help birds.

Peregrine falcon feeding young at Tarentum Bridge, May 2021 (photo by Lynn Mamros)

(photo credits in the captions. All of these photos were used in prior articles.)

Hurricane Pushed Birds to Scotland

Yellow-rumped warbler (“Myrtle warbler”), US, 2018 (photo from Wikimedia Commons)

9 October 2022

There was much excitement in British birding this week when two yellow-rumped warblers (Setophaga coronata) and a first-ever least bittern (Ixobrychus exilis) were sighted in the Shetland Islands, the northern tip of Scotland.

Both species are found only in the Americas but all three birds crossed more than 2,200 miles of the North Atlantic non-stop, likely forced offshore from the Canadian Maritimes or Newfoundland to escape Hurricane Fiona, the strongest hurricane ever recorded in Canada.

Possible origin & definite destination of 3 North American vagrants to The Shetlands, 5-7 October 2022 (map from Wikimedia Commons; markup by Kate St. John)

Fiona made landfall in Nova Scotia on 24 September.

The birds were found more than 10 days later in the Shetlands on 5-7 October. It is hard to imagine their ordeal. The yellow-rumped warblers seem fine but the least bittern was exhausted and underweight and was taken to rehab where it died overnight.

Catch the excitement of seeing birds far from home in these tweets from British birders.

I am impressed that the warblers gravitated to the only trees in the landscape. This is similar to warbler behavior at Magee Marsh in May when they are found in small patches of trees — the only trees among miles of marsh and farmland.

The least bittern was found hunched on the shore, not in good shape. It died that night in rehab.

9 October 2022. There’s more: A first-ever Empidonax flycatcher in Ireland and a Baltimore Oriole in Devon, UK. Unfortunately the Baltimore oriole was eaten by a sparrowhawk (an Accipiter).

15 October 2022: Blackburnian warbler at Isles of Scilly off the coast of Cornwall UK

(photo from Wikimedia Commons; embedded tweets)

When Will The Chipmunks Disappear?

Eastern chipmunk (photo from Wikimedia Commons)

3 October 2022

The hardest thing to notice in Nature is the date of an absence. When did the last junco leave in the spring? When did the last groundhog go into hibernation?

Right now eastern chipmunks (Tamias striatus) are busy gathering nuts to store in their underground burrows for the winter. As the season changes and temperatures drop they will disappear into their burrows to enter torpor, sleeping off and on through the winter.

The warm winters of climate change can fool them into not entering torpor but the result is deadly. Only 10% survive. Find out why in this vintage blog:

Meanwhile I will hope our chipmunks disappear and will try to figure when they do it.

Here’s how I notice an absence: I write down every day when I do see them and then scan my notes for days when I’ve not logged them anymore.

(photo from Wikimedia Commons; click on the link to see the original)

Hurricane Rain

Hurricane Ian spins northward (GOES East satellite Great Lakes sector, 30 Sept 2022, 3:40am to 5:30am from NOAA)

30 September 2022, 6am

UPDATE 30 SEPT, 6 PM. See UPDATED info at end

After wrecking a swath of Florida, Hurricane Ian popped out over the Atlantic Ocean, gained strength, and is bearing down on the Carolinas. Though Pittsburgh is quite far inland we will see the remnants of Hurricane Ian’s rain on Saturday.

These maps show total rainfall forecasts for the next three days as Hurricane Ian moves up the eastern U.S.

  • Quantitative Precipitation Forecast, Fri 30 Sep - Sat 1 Oct 2022 (map from NOAA)

Quantitative Precipitation Forecasts, Continental US, 30 Sept to 3 Oct 2022 (maps from NOAA)

Pittsburgh will receive less than an inch of precipitation because Ian is tracking south and east of here. Fortunately this is far different from our experience of Hurricane Agnes 50 years ago.

UPDATE 30 SEPT, 6 PM. I have corrected the captions on the slideshow based on an email from Dick Rhoton. Note that the slideshow maps show total rainfall potential, no matter what cause.

This map shows rainfall potential from Hurricane Ian alone — anything greater than an inch — as of 30 Sept 2022, 6am.

Hurricane Ian total rainfall potential, 30 Sep through 2 Oct 2022 (map from NOAA)

(maps and animation from NOAA; click on the captions to see the originals)