Category Archives: Musings & News

A Snake and a Sparrow Have Fire in Common: Nov 19

Massasauga rattlesnake and Florida grasshopper sparrow have fire in common (photos: Jim Chapman and Wikimedia Commons)

6 November 2025

Habitat is everything. We tend to forget this because humans are versatile and avoid places where we cannot survive (Antarctica). Many species, though, require a specific habitat for their livelihood. When it becomes scarce, they have nowhere to live and may go extinct.

Less than 200 years ago grasslands dominated much of the continental U.S. where fires and less rainfall kept them open. Since then most grasslands have been converted to farmland, cattle ranges, or suburbs and now more than half of what remains is at risk of range-wide collapse. Relict grasslands support the last remaining species. The relicts themselves would disappear were it not for prescribed fire.

Last week I highlighted the massasauga rattlesnake, a habitat specialist that relies on prairies for its survival. Two weeks from now Phipps Conservatory will highlight another grassland specialist, the Florida grasshopper sparrow (Ammodramus savannarum floridanus), with a screening of the film The Little Brown Bird and a panel discussion.

screenshot from The Little Brown Bird Film website

On Wednesday November 19, 7:00pm – 8:30pm, Phipps Conservatory is hosting a screening of the new nature documentary The Little Brown Bird, which tells the story of the Florida grasshopper sparrow, one of the most endangered birds in North America. A few years ago, there were as few as 50 Florida grasshopper sparrows remaining – today, there are as many as 200.

The 30-minute film focuses on the work of wildlife biologist Fabiola ‘Fabby’ Baeza-Tarin and a coalition of conservation partners who are working to rescue this sparrow back from the brink. The film’s director and cinematographer, KT Bryden, will join attendees virtually for a discussion after the film, and a panel of local speakers—including Ryan Miller, a wildlife biologist with the Western Pennsylvania Conservancy; Julie Travaglini, the director of education for the Allegheny Land Trust; and myself, Andrew Moore, a nature writer and author.

— lightly edited quote from Andy Moore

In addition to the Florida grasshopper sparrow the panel discussion will touch on the plight of grasslands and the endangered species they host, such as the massasauga rattlesnake in Pennsylvania.

Join Phipps for a screening and discussion of The Little Brown Bird. Price is $15 for members, $20 for non-members. Click here for tickets.

Want a preview? Here’s a link to the 30 min film.

p.s. There are 12 subspecies of grasshopper sparrows. We see Ammodramus savannarum pratensis in Pennsylvania as it breeds in the eastern U.S. and southeastern Canada. The Florida grasshopper sparrow is non-migratory and only occurs in a small part of Central Florida.

Armchair Lifers

Mangrove yellow warbler at Bonaire island (photo from Wikimedia Commons)

2 November 2025

In the world of birding a Life Bird, or “Lifer,” is a species seen for the first time in one’s life. For many years I kept a handwritten list but I didn’t know the count. Once I started using eBird the software automatically kept my Life List so every time I open the website eBird presents me with my current Life Bird count.

On 30 October I noticed that my Life List had jumped from 1,569 to 1,574 birds. I’d heard the whimbrel would split into two species during eBird’s taxonomy update last week, so I expected to gain one Life Bird without any effort. But FIVE Armchair Lifers?

With the help of eBird News I found 4 out of the 5 additions but I’ll have to spend lots of time with the 2025 eBird Taxonomy Update to find the fifth.

In the meantime, here’s what I gained in taxonomic order. All of them are “travel” birds (no splits in Pittsburgh) but you, too, may have gained a Life Bird within the U.S.

Formerly “Striated Heron” everywhere

This bird split three ways. I saw two of the three species in Panama and Southern Africa. The Central and South American bird retains the original common name.

Striated heron, Panama (photo from Wikimedia Commons)
  • Striated Heron (Butorides striata)— Central and South America
  • Lava Heron (Butorides sundevalli)—dark-plumaged, Galapagos endemic
  • Little Heron (Butorides atricapilla)—widespread from Africa through the Middle East, South, East, and Southeastern Asia to Australasia.
eBird 2025 Taxonomy Update News
Little heron, former striated heron, South Africa (photo from Wikimedia Commons)

Formerly “Whimbrel”

I’ve seen Hudsonian whimbrels in the Western Hemisphere and the Eurasian whimbrel in Spain. This Hudsonian whimbrel has a brown rump which is not visible.

Hudsonian whimbrel in Newfoundland (photo from Wikimedia Commons)
  • White-rumped Eurasian Whimbrel (Numenius phaeopus) Eurasia, Africa, Australia with vagrants to Eastern North America.
  • Brown-rumped Hudsonian Whimbrel (Numenius hudsonicus)  North, Central and South America including the Carribean
eBird 2025 Taxonomy Update News

This Eurasian whimbrel is hiding his white rump.

Eurasian whimbrel in France (photo from Wikimedia Commons)

Formerly “Warbling Vireo”

One in the east, one in the west. According to eBird: The breeding range splits roughly at the Rocky Mountains, breeding habitats differ somewhat, songs differ substantially. I saw the western one in Montana.

Eastern warbling vireo (photo by Lauri Shaffer)
  • Eastern Warbling Vireo (Vireo gilvus) a bird of lowland watercourses from the Great Plains eastward, usually in areas with cottonwoods, willows, and other riverside vegetation.
  • Western Warbling Vireo (Vireo swainsoni) Rocky Mountains and westward. Occurs in mountain forests—especially riparian forest adjacent to pines.
eBird 2025 Taxonomy Update News
Western warbling vireo on nest in Nevada (photo from Wikimedia Commons)

Formerly “Yellow Warbler”

Yellow warblers are extremely common in spring in eastern North America. I saw the mangrove yellow warbler in Panama. It’s the one with the little rusty cap (photo at top).

Northern yellow warbler in Michigan (photo from Wikimedia Commons)
  • Northern Yellow Warbler (Setophaga aestiva)—the migratory northern population that breeds in shrubland and riparian habitats across Canada, the United States, and northern Mexico.
  • Mangrove Yellow Warbler (Setophaga petechia)—the resident southern population that lives year-round in mangroves along the coasts of Mexico, Central America, and northern South America, and on the fringes of Caribbean islands.
eBird 2025 Taxonomy Update News
Mangrove yellow warbler, Galapagos (photo from Wikimedia Commons)

How many Armchair Lifers did you gain last week?

Extremely Rare Cuckoo on Long Island

Immature common cuckoo (photo from Wikimedia Commons)

28 October 2025

Remember the excitement when a barnacle goose came to Pittsburgh in late March and early April? That excitement was tripled or quadrupled last Friday when an extreme rarity — a common cuckoo (Cuculus canorus) — was found on Long Island, New York. Only four common cuckoos have ever been seen in the U.S.

This bird’s normal range is Eurasia in the summer, Africa and southeast Asia in the winter. The immature bird found on Long Island was on its way to Africa when it went off course.

range map of common cuckoo from Wikimedia Commons

We found out about the bird because a golfer, who is not a birder, thought it was unusual and texted a photo to his ornithologist nephew.

The Rare Bird Alerts were galvanizing. The cuckoo’s location on the eastern end of Long Island was only a two hour drive from Manhattan. Hundreds of birders and photographers came out to see it on Friday, Saturday and Sunday, 24-26 October.

ebird sightings map of common cuckoo on Long Island, NY, October 2025

More birders were searching for it yesterday, 27 October, when CBS New York published this video.

video embedded from CBS New York on YouTube

As far as I can tell, the cuckoo was not seen yesterday.

p.s. Like brown-headed cowbirds, common cuckoos are nest parasites who lay their eggs in the nests of other birds –> If You Think Cowbirds Are Bad… On the plus side, their song is the sound of a cuckoo clock. The CBS video explains that this bird is too young and in the wrong season to sing.

When Dinosaurs Ruled, Mammals Were Dark Gray

Fur color of two early mammals = Artistic reconstruction of pelage coloration of Arboroharamiya fuscus (CUGB-P1901) and Vilevolodon diplomylos (SDUST-V0010). Science 387, 1193-1198(2025). DOI:10.1126/science.ads9734 CREDIT: Chuang Zhao and Ruoshuang Li. (*)

19 October 2025

Mammalian ancestors have been around for 320 to 315 million years, but the first true mammals evolved during the time of the dinosaurs in the Late Triassic. These early mammals were uniformly nocturnal and small, no larger than a house cat, and they were furry. What did they look like? A study in Science in March 2025 examined six fossils species and found they were not as colorful as modern mammals. All of them were dark gray.

Back in 2008 we learned that dinosaurs were colorful. Studies of melanosomes found within their fossils indicated they were not only colorful but sometimes brilliant.

Coloration of Coelophysis bauri and size compared to human, from Wikimedia Commons

Using the same technique on six Mesozoic mammal fossils, researchers led by Matthew Shawkey compared the fossil melanosomes to those of 116 current (extant) mammals and found that extant mammals have more fur colors while the Mesozoic mammals were all the same color.

The diagram below shows the dark gray color scores compared to extant mammals (** see complete caption at bottom). I have added a pink line to diagram B to point out the difference. Extant mammals on left have a wider range of color (below line) than the fossil mammals (above line).

Fig. 3: Melanosome diversity and pelage coloration: (B) Width variation of melanosomes. Science 387, 1193-1198(2025). DOI:10.1126/science.ads9734 CREDIT: Chuang Zhao and Ruoshuang Li. (** see complete caption below)

It’s hard to imagine these ancient mammals until you see an illustration. I have cropped it into two parts. See the complete caption (**) for the entire Fig. 4 below.

  • At top: Two fossil mammals that resembled flying squirrels. “The green eyes of Arboroharamiya fuscus are an artistic license of the tapetum lucidum, an intraocular reflecting structure that enhances visual sensitivity, indicating nocturnality.
  • Below: Three more mammals. (**) see the caption for details.
Fur color of three early mammals = Artistic reconstruction of pelage coloration of Megaconus mammaliaformis (PMOL-AM00007), and Docodontans (SDUST-V0006 & SDUST-V0007). Science 387, 1193-1198(2025). DOI:10.1126/science.ads9734 CREDIT: Chuang Zhao and Ruoshuang Li. (*)

Modern mammals are more colorful because melanosomes have changed over millions of years. But the one dark color was just fine for early mammals. They needed nighttime camouflage to hide from many much larger predators.

Read about these ancient dark gray animals at Yahoo News.


The full study citation –> Mesozoic mammaliaforms illuminate the origins of pelage coloration. Science 387, 1193-1198(2025). DOI:10.1126/science.ads9734

(**) Complete caption for Fig. 4 Artistic reconstruction of pelage coloration of five Jurassic mammaliaforms. (Top to bottom) Arboroharamiya fuscus (CUGB-P1901), Vilevolodon diplomylos (SDUST-V0010), Megaconus mammaliaformis (PMOL-AM00007), and Docodontans (SDUST-V0006 & SDUST-V0007). The green eyes of A. fuscus are an artistic license of the tapetum lucidum, an intraocular reflecting structure that enhances visual sensitivity, indicating nocturnality. Eutherian SDUST-V0008 from the Lower Cretaceous is not included in this artistic reconstruction. CREDIT: Chuang Zhao and Ruoshuang Li.

(**) Complete caption for Fig. 3. Melanosome diversity and pelage coloration across extant mammals and Mesozoic mammaliaforms. (A) Scatterplot of individual melanosome measurements from 116 extant mammals and six fossils; dot color shows RGB values derived from spectral curves measured at specific hair locations. Extant hair melanosomes, n = 2615; A. fuscusn = 760; M. mammaliaformisn = 103; V. diplomylosn = 395; docodontan SDUST-V0006, n = 289; docodontan SDUST-V0007, n = 407; eutherian SDUST-V0008, n = 205. (B) Width variation of melanosomes. (C) Length variation of melanosomes. (D) Measured reflectance spectra of selected extant mammals [Vulpes vulpes (orange), Ailurus fulgens (red), Cephalophus dorsalis (brown), Pelomys fallax (darker brown), and Mephitis mephitis (black)] and predicted reflectance curves for six Mesozoic mammaliaforms (browns), highlighting their constrained brown coloration and minimal variation. (E) Detailed view of the predicted reflectance curves for the six Mesozoic mammaliaforms.

Where Does the Plume Go?

Quenching and smoke at Clairton Coke Works during inversion, 15 May 2021 (photo by Mark Dixon BlueLens via Flickr Creative Commons license)

15 October 2025. More on the subject of wind.

Though Pittsburgh’s air has improved since the Smoky City days, we still have heavy industry and unhealthy air too frequently. The rotten egg smell of sulfur lingers when there’s a temperature inversion, and since Pittsburgh averages 157 inversion days per year it’s likely there’s bad air somewhere here almost half the time. But not everyone smells it. It depends on where the plume goes, and that depends on the surface wind or lack thereof.

After CMU’s CREATE Lab published the SmellPGH app in 2016 for crowd-sourced bad air reports, they went on to develop the PlumePGH website in 2021 that shows where the bad air goes. I learned about PlumePGH in a Public Source article last week.

This two minute video explains how it works showing air movements on 10 December 2020. Back then the Cheswick power plant (orange plume) was still in operation; it closed on 31 March 2022.

video embedded from CREATE Lab on YouTube

To whet your appetite for the PlumePGH website, here are still shots from a recent bad air day on Saturday 4 October 2025. A screenshot of the SmellPGH map on 4 October shows that the air was really awful and a lot of people noticed it.

Selected screenshots from PlumePGH on the same day shows 3 plumes. U.S. Steel’s …

  • Clairton Coke Works (Clairton PA) in purple
  • Irvin Works (West Mifflin PA) in yellow
  • Edgar Thomson Works (Braddock PA) in blue-green.

At 3:48am the wind was from the south. All 3 plumes intermingled as they headed north.

screenshot from Plume PGH timelapse video of 2025-10-04

Around noon the wind died and a lot of people were unhappy in the river valleys.

screenshot from Plume PGH timelapse video of 2025-10-04

At 5:35pm the wind picked up out of the southeast and a whole new set of folks smelled rotten eggs.

screenshot from Plume PGH timelapse video of 2025-10-04

Click this link to see the whole Plume PGH timelapse video for 2025-10-04.

Visit the PlumePGH website for more information.

The Relentless Power of Plate Tectonics

Flysch in the Mediterranean at Torre del Guadelmesi, Andalusia, Spain, 12 Sept 2024 (photo by Kate St. John)

8 October 2025

A year ago on a birding trip at the Strait of Gibraltar we stopped at the Torre del Guadelmesi a watchtower on the Spanish coast. Below us in the Mediterranean was an odd formation of parallel rocks called flysch.

Flysch is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building episode.

Wikipedia: definition of Flysch

Here are two more examples near Tarifa, Spain.

Flysch at Parque Natural del Estrecho at the Strait of Gibraltar, Spain (from Wikimedia Commons)
Flysch at Parque Natural del Estrecho near the port of Tarifa, Spain (from Wikimedia Commons)

The layers erode at different rates so the formation looks striped. If it was not so eroded the rocks could look like this formation in Basque Country, northern Spain.

Flysch outcropping at Playa de Itzurun, Basque Country, Spain (photo from Wikimedia Commons)

What fascinated me was not the rock layers but the fact that they were tilted up, proving the relentless power of plate tectonics at the Strait. This animation shows how the horizontal layers became vertical.

Animated image of mountain formation by reverse fault (from Wikimedia Commons)

The Strait of Gibraltar is on the tectonic plate boundary where the African plate has been pushing into and under — subducting — the Eurasian plate.

Map of Mediterranean tectonic plate boundaries (from Wikimedia Commons)

The Eurasian and African plates are moving in generally the same direction but you can see on the map below that the African plate is moving a little faster so it is ramming into Spain.

Tectonic plates boundary types & movement from Wikimedia Commons

Geologists say that plate movement at the Mediterranean is complex and it has stalled so the plates may be changing places.

The continents are converging; and for many millions of years, the northern edge of the African tectonic plate has descended under Europe.

But this process has stalled; and at the European Geosciences Union (EGU) meeting last week [April 2011], scientists said we may be seeing Europe taking a turn.

If they are correct, this would signal the start of a new subduction zone – a rare event, scientifically fascinating.

“It looks possible that on the appropriate timescale, we are witnessing the beginning of subduction of Europe under Africa,” he told BBC News.

BBC: Europe’s future lies under Africa, scientists suggest. 11 April 2011

When (or if) this happens, tilted rocks will rise on the African side of the Mediterranean. It will happen relentlessly but very very slowly. None of us will be around to see it.

The Rare Bird Effect

Red phalarope at Northmoreland Park, 5 Sept 2025 (photo by Steve Gosser)

14 September 2025

Northmoreland Park in Apollo, PA has a lake, walking paths, mountain bike trails and playing fields but is rarely visited by birders because there are few species of interest, just the usual suspects. All of that changed on 16 August when Mark McConaughy photographed a Baird’s sandpiper on the mudflat at the lake.

Baird’s sandpipers (Calidris bairdii) are rare in Pennsylvania because they breed in the arctic, winter in southern South America, and migrate over the Great Plains.

Range map of Baird’s sandpiper from Wikimedia Commons

Something diverted this individual from it’s normal route, perhaps bad weather or the wildfires in Canada. It veered east, entered southwestern Pennsylvania, and looked for a good place to land — a mudflat — just before dawn.

If southwestern PA wasn’t in a drought there would have been no mudflat and the Baird’s would have kept going. Instead he stayed for two days and attracted 9 more eBirders.

This time of year is shorebird migration season so birders continued to stop by to check the mudflat. “A rare bird was here and conditions are right for another one, so I’ll take a look just in case.” I like to call this The Rare Bird Effect. In Arizona there’s a similar concept called the Patagonia Picnic Table Effect. (Thank you, Deb Grove, for reminding me of it.)

The Rare Bird Effect paid off at 7:11pm on 4 September when Susan Miller photographed a phalarope. Merlin said it had to be a red-necked phalarope, which is rare but not impossible, but Susan thought that didn’t look right. Her photos helped identify it as a red phalarope (Phalaropus fulicarius) a super-rare bird in the continental interior because it winters on and migrates over the open ocean. Here’s what she saw.

Range map of red phalarope from Wikimedia Commons

The red phalarope stayed two days, 5 and 6 September, and generated 40 more eBird visits including the photo at top by Steve Gosser and photos below by Phillip Rodgers. The bird came close to shore for great photos!

Some of us showed up on 7 September, the morning after it left. Alas!

Right now Northmoreland’s mudflat is quite a birding hotspot so it’s worth checking just in case. “You see a lot by looking.”

Dogs Working From Home

Border collie ready to herd sheep (photo from Wikimedia Commons)

12 September 2025

Happy Friday, everyone’s favorite work-at-home day. Let’s take a lighthearted break with a cute domestic animal.

Can working dogs work from home? This border collie can’t work from home. His job is out in the field.

Border collie herding sheep (photo by Arbutus Photography via Wikimedia Commons)

This dog brought his work home with him, though he didn’t use a computer. Real live work.

video embedded from HodgeCattleCo on YouTube

And here’s a border collie literally “working from home” on a computer.

Happy Work From Home Day.

Microbes in Hot Springs Could Spawn New Antibiotics

Aerial image of Giant Prismatic Spring, Yellowstone National Park (photo from Wikimedia Commons)

28 August 2025

It’s been almost 100 years since penicillin was discovered and 70-80 years since it’s been widely used but penicillin’s effectiveness waned as bacteria evolved resistance to it. This has happened to many antibiotics so researchers are looking for new sources to kill bacteria. They recently found some in an unlikely place.

Archaea are microbes that thrive just about everywhere, including in our guts and in extremely harsh environments such as hot springs, pictured above. They were initially thought to be bacteria until scientists looked more closely.

Archaeal cells have unique properties separating them from Bacteria and Eukaryota, including: cell membranes made of ether-linked lipids; metabolisms such as methanogenesis; and a unique motility structure known as an archaellum.

Wikipedia: Archaea account

At the microscopic level, some of them look like this. Click here to see more examples.

Composite image to illustrate the morphological diversity of three Archaea. Blue =  Methanosarcina barkeri, White=  Ignicoccus hospitalis, Red= an artist’s rendering of Pyrococcus furiosus (image from Wikimedia Commons)

Archaea include both single-celled and multi-celled species and have been a separate kingdom since 1977.

Occurrence of unicellularity and multicellularity across the kingdoms of life (diagram from Wikimedia Commons)

In their search for antibiotics two recent studies looked for hardy organisms that co-exist with bacteria and have chemical defenses that may potentially kill bacteria. Archaea in hot springs are one such group.

The first study used an AI algorithm to scan the complete amino acid sequence of each organism, searching for fragments called encrypted peptides that often have antimicrobial properties. Scanning 233 archaea species revealed more than 12,600 likely encrypted peptides. They tested 80 of the most promising, 93% of which showed antibacterial activity in vitro against dangerous human pathogens such as Staphylococcus aureus(1) and Klebsiella pneumoniae(2).

The second study looked for enzymes that could break down the bacterial cell wall peptide shield called peptidoglycan. The group found these enzymes in 5% of the more than 3700 archaea species they surveyed. When exposed to bacteria in the lab, some of the enzymes shredded the bacterias’ peptidoglycan and killed them.”

Paraphrased from Science Magazine: Hot springs’ hardy microbes offer new source of antibiotics

Though the studies have not created new antibiotics, they point to new sources of investigation and potential antibiotic silver bullets.

Read more at Science Magazine: Hot springs’ hardy microbes offer new source of antibiotics.

p.s.

  1. Staphylococcus aureus causes skin infections, food poisoning, pneumonia, septicemia, osteomyelitis and infection of the heart valves (endocarditis)
  2. Klebsiella pneumoniae causes pneumonia, urinary tract infections, sepsis and meningitis.

Lead and Heavy Metals in Blue Hole Creek

A clean stream in York County, PA (photo by PStirk via Flickr Creative Commons license)

In case you missed it!

13 August 2025

This April Mountain Watershed Association (MWA) found lead and heavy metal pollution in Blue Hole Creek in Somerset County, a shocking discovery because the creek was an Exceptional Value waterway with clean water and abundant stream life.

As described in Paradise Lost: Heavy metal contamination (including lead) has been found in Blue Hole Creek, Forbes State Forest, Somerset County, Pennsylvania, MWA collected water samples at many locations along the creek and sent them in for testing. The lab found lead, cadmium, aluminum, zinc, and manganese and told MWA, “Our results indicate that the highest concentrations of lead were found near the Laurel Highlands Hiking Trail (LHHT).”

Laurel Highlands Hiking Trail sign, Aug 2010 (photo by sk via Flickr Creative Commons license)

At that sampling location the lead concentration was 30 times the lead found in Flint, Michigan in 2014! As MWA wrote:

This is very concerning due to the proximity of the Grindle Ridge Shelter Area, where many hikers spend the night. The water pumps at the shelter areas are known to have high iron concentrations, so hikers often use portable water filters at nearby streams for drinking water. Blue Hole Creek is one of the closest permanent water sources to the Grindle Ridge Shelters. Other hikers and several of our staff members have used this source while recreating on the LHHT in the last couple years.

Mountain Watershed Association: Paradise Lost: Lead contamination Found in Blue Hole Creek — (lightly edited for length)

Grindle Ridge Shelter area is circled on this portion of the Laurel Highlands Hiking Trail map.

part of the Laurel Highlands Hiking Trail map from DCNR. Grindle Ridge Shelter circled in the center

Apparently the state knew about problems in Blue Hole Creek for perhaps a year but no signs were posted by the state agencies. MWA writes in Blue Hole Creek: FAQ & Updates: “DEP wasn’t aware that hikers were using the creek for drinking water [since] the agency doesn’t recommend drinking surface water for any reason.” Oh no!

Fortunately MWA’s discovery lead to an investigation and on 18 July MWA wrote

The Solid Waste Dept at DEP has issued a Notice of Violation (NOV) to Highlands Sporting Clays for failure to comply with the Shooting Range Stewardship Best Management Practices, resulting in the contamination of Blue Hole Creek with Lead, Cadmium, Aluminum, Zinc, and Manganese.  …

Highlands Sporting Clays has been completing preliminary site remediation, which is permissible under the Shooting Range Stewardship plan. These efforts include removing the spent shot wads and clay pigeon debris from the course surface and applying lime and phosphorus to reduce the amount of toxins leaching into Blue Hole Creek.

MWA: PA DEP issues Notice of Violation for Blue Hole Creek pollution

Here’s how close Highlands Sporting Clays is to the Laurel Highlands Hiking Trail and Grindle Ridge Shelters. The map even shows Blue Hole Creek beginning near the sporting club.

Laurel Highlands Hiking Trail map closeup. Pink=lead pollution source Highland Sporting Clays (map from DCNR)

So where did the lead come from?

From clay pigeons used in target practice and from spent bullets. Spent bullets are the source of lead that kills bald eagles and other birds of prey.