The Nature of the Beast (according to Susan McCarthy)

Polar bears and penguins

Near the North Pole, examining a submarine.

When we were getting ready to go to Antarctica, people warned us about polar bears. Polar bears, they pointed out, are fast, big, smart, dangerous. They are more inclined than other bears to view humans as fabulous taste explosions.

No, we said. We're going to the Antarctic, not the Arctic. There are no polar bears in Antarctica.

Oh yeah. Well, polar bears eat people!

During our stay, groups from our station occasionally visited passing cruise ships. The station manager and lab manager gave talks about the U.S. Antarctic Program. Then, Q & A for all of us from the station.

They told you that was a bear costume?

The ship passengers knew they would not be seeing polar bears. But some asked why. Ice and snow everywhere – perfect polar bear country. Why no big white bears?

Here are my responses – after looking it up – to the Big Questions.

Are there polar bears in Antarctica?
You already know: no.

Here's a way you might guess this from personal experience. Have you ever seen a photograph of a polar bear eating a penguin? Probably not. But if polar bears and penguins lived in the same place, there'd be photos. So far, no one's told me they've seen such a photo. Although there are zoos in this world, so who knows.


Why aren't there polar bears in Antarctica?

History! Really ancient history. There's a nice video by Sally Gillies that tells just how ancient. Basically, the bear family evolved in the northern hemisphere. As bears developed exciting new spin-offs (panda! sun bear! sloth bear!), some bears moved south. To this day, there are more bear species in the northern hemisphere than the south. The closest bear to Antarctica is the spectacled bear, which rambled south along the Andes. It gets no further down than northwest Argentina.

(In the Bronx Zoo.) Look at the size of those feet.

What with continents drifting apart and all, Antarctica is too far for a bear to swim. Up north, polar bears, who recently spun off from grizzly bears, had a smooth transition across land from warmer climates to icy ones. From there they could stroll onto sea ice. Or swim feasible distances.


So even if people weren't making life very difficult for bears (ask the extinct Atlas bear of northern Africa), and they were free to explore new niches, it'd be a long time, if ever, before a bear got far enough south to be selected for Antarctic living. And when we talk about people making life difficult for polar bears, the biggest factor is climate change.



Should there be polar bears in Antarctica?

No. You've heard that things are getting bad for polar bears. Because of Arctic warming, they're losing sea ice to hunt from. Habitat is melting out from under those huge furry feet.

Plate tectonics? What does that have to do with me?

You know somebody somewhere is thinking maybe polar bears could be transplanted to Antarctica. Sure, climate chaos is happening there, too, but for now there's still sea ice. Assisted migration! What could be bad?

Ask any penguin what could be bad. They will say “Awwwk! I see no problem! Awwwk!” That is because penguins are stupid about land predators. When early explorers brought sled dogs to Antarctica, penguins would walk up to the tethered dogs. “Awwwk! What's your story, furball?” The dogs would tear them to pieces. More penguins would walk up. “Awwwk! Are you new kids?” The dogs would tear them to pieces. More penguins would walk up. “Awwwk! Can I touch your fur?” And so on.

In the Svalbard Archipelago, eating a walrus. Gulls stand by ready to help.

Polar bears could devastate penguin colonies. In fact, polar bears are already turning to northern bird colonies. They're trying to survive by eating prey so small they previously didn't bother with them. Lots and lots of eggs.


So yeah no. Polar bears are an unpredictable bunch. Antarctic wildlife is also subject to the grievous insults of climate change. They don't need rapacious northerners on top of that.

Carpetbaggers, stay away!

Bears? Sure, bring 'em on. There's plenty of room. What ARE bears, anyway?

 

Prankster birds

 

Before coming to Palmer, we knew that sheathbills are ingenious seekers/thieves of every possible scrap of nourishment, and that seals are one source of opportunity for them. We'd read of sheathbills eating bits out of seal poop, snipping off scabs and dead tissue from seal wounds, and even of sheathbills snatching milk from the nipple of a nursing seal.

 

Thus no surprise when, during a period when Southern Elephant Seals suddenly decided that the station's boat ramp was the ideal place to relax, practically a spa, sheathbills gravitated to them and were seen plucking at them in a way the seals did not appear to appreciate.

esealandsbClip35 from Susan McCarthy on Vimeo.

 

But it began to seem like more of a discrete thing, a phenomenon worthy of naming and studying. It began to seem as if sheathbills and elephant seals had a relationship that was somewhat similar to the relationships corvids – ravens, crows, magpies, jackdaws, jays, etc. – have with larger animals. The classic example is ravens tweaking the tails of wolves at a kill. This may make an angry wolf spin around, giving another raven a chance to run in and grab something.

 

All kinds of corvids do this, to all kinds of animals, as in this Youtube compilation. (Other videos and photos in this post are by me.)

 

Corvids are a famously smart group of birds. Other kinds of birds, including parrots – also famously smart – don't seem to. (I may be wrong about this, but my quick scientific survey of Youtube videos doesn't reveal parrots using their bills on tails of other animals.)

 

But the sheathbills of Palmer Station do. (I'll bet other sheathbills who are around seals also do.)

lastClip93 from Susan McCarthy on Vimeo.

 

What good does this do them? I'll start with the corvids. This is a behavior where I think it's useful to separate ultimate and proximate causes. The ultimate cause is the one that benefits the genes and causes natural selection to benefit the possessors of the genes: ravens who tease wolves get more food. More of their babies survive.

 

Ultimately, when a raven pulls or tweaks a predator's tail, there's a significant chance the predator will move. Maybe it'll turn and go after the raven, and that raven's mate will be able to steal food. Basically, if they create a disturbance, there may be opportunity.

 

The proximate reason is the one that actually motivates an individual raven. Which might be trying to get more food. Or showing other ravens how brave and funny you are. Or just seeing the wolf jump.

 

It may be that on a day to day basis, a raven tweaks a wolf's tail, or a magpie pecks a dog's tail because it's hilarious. This is the same reason you might surreptitiously sneak up behind a person sitting in the galley and zip-tie their ankle to a chair leg.

 

Why do sheathbills do it? The elephant seals aren't crouching over kills. Sometimes it seems as if a sheathbill is actually nipping something off an elephant seal. Something it will eat. A bit of peeling skin, a scab. Nutritious things. (Don't knock it if you haven't tried it.) Similarly, if a sheathbill tweaks a seal's tail and makes it swivel around, the move may expose something the sheathbill can eat – seal poop, or bloody snow if the seal has wounds from fighting.

 

I suppose it's possible, although I am not convinced of it, that a sheathbill also might tweak a seal's tail in order to impress another sheathbill. Seriously, that's the first thing some ethologists would look at. Although they would call it displaying fitness.

 

But I personally suspect that, in addition to help them get stuff to eat, sheathbills also like to make elephant seals jump because it's funny.

 

Okay, so. If sheathbills have a twisted sense of humor, and super-smart birds like corvids have a twisted sense of humor, does that mean sheathbills are smart? Not necessarily. But I think it's a possibility worth looking at.

*****

Addendum: An intelligent reader (Hi, Anita!) mentions a duck she once had who used to sneak up and pinch her dog's tail.

 

Interesting. Why might a duck have such a behavior in its repertoire? Not to scavenge on carcasses, or make an elephant seal shift position.

 

I'm guessing the answer is nest defense. All kinds of birds get bold when their nests are threatened, or they think their nests might be threatened. Sometimes crazily bold. They'll chase larger birds, dive-bomb them, pluck at them. I once saw a pair of Western Kingbirds chase a Great Horned Owl. One landed on the flying owl's back, grabbing feathers with both feet, before wisely peeling off.

 

An evil-minded duck might well decide to apply that behavior to a dog even if the duck had no nest.

 

 

Wipe that smirk off your face. Act natural.

Several sheathbills live right around Palmer Station, which is handy. Especially since pack ice has prevented me from leaving the station by water ever since I got here.

I am getting some useful photographs of sheathbills, documenting their behavior. It's important to focus on things they're doing in this part of the breeding season, which they may not be doing by the time a vital part of our project, the artist, gets here. That way there will be photos and video for Terri.

I'm also trying to document some behavior for the Macaulay Library at the Cornell Lab of Ornithology. This is harder, because they prefer their recordings of bird sound not to be filled with generator roars, tractors backing up, and people shouting “Where's the bucket? Bucket. I said BUCKET!” Anthropogenic sound, they call that.

To a lesser extent, they prefer their video recordings not to feature birds in unnatural contexts, standing on man-made objects, and eating human junk food or, um, detritus. They want recordings of natural behavior in natural surroundings.

We all like that look.

This isn't so easy on station. Birds like a good view, and that is best obtained on top of the roof. They like to nest in sheltered places, and that apparently is often best achieved under buildings or shipping containers.

Or they may be engaged in a natural behavior – teasing elephant seals – but if the elephant seals choose to snuggle up to shipping containers, what can you do?

I was able to photograph sheathbills foraging by the water's edge, jumping from one piece of ice to another, in a natural behavior that looks as if it's taking place in a natural setting until you know that they are doing this right where the station's outfall pipe is, which carries (macerated) kitchen waste and sewage. It's a favorite spot for sheathbills.

Fortunately, Terri will not have that problem. She can draw and paint a sheathbill that is standing on a five-gallon drum and make it so it's standing on a tasteful rock, perhaps a rock splashed with lichen.

Or she could make it so it's standing on a broken coffin, with a skeletal finger in its bill. Because art.

Meanwhile I'll wait for boating to resume, and try to find sheathbills acting natural. It's hard because I'm not allowed to bribe them.

Fine man, fine bird

Rich Stallcup died December 15, 2012. He was a kind, wonderful guy and a brilliant naturalist. Once he told me a story about a bristle-thighed curlew, and the people who admired it. Before the story I want to say what a freakily great bird the bristle-thighed curlew is.

 

First, the bristle thighed curlew (Numenius tahitiensis) spends the summer in Alaska and the winter in Hawaii. Or Tahiti or other tropical Pacific islands. Nice work if you can get it. Maybe not that easy to get, since there are only about 7,000 bristle-thighed curlews in the world.

 

That might be tundra with dwarf willow, so I'm guessing this bird is in Alaska

 

 

They're hard to see. The Hawaiian birds aren't hanging around Oahu, they're out on uninhabited islands. And the Alaskan birds are off in low-lying, mosquito-infested tundra. If you do see one, you might mistake it for the very similar whimbrel. Hearing its distinctive call might be your best bet for identifying it. Birdwatchers, especially birders who are trying to see every breeding bird species in the US, or in North America, long for sightings of these rare curlews, but most have never seen one.

 

Bristle-thighed Curlews on a Pacific island beach. Not Waikiki, Midway.

 

This curlew is a large brown moth-patterned shorebird with a long sickle bill. From a distance they just look brown. You can't see the complicated plumage patterns or the bristled thighs. I don't know why they have bristled thighs. I haven't run across any speculations. If you held a gun to my head and made me guess (part of a really sick scenario), I'd say it might have something to do with courtship, and showing another bristle-thighed curlew of the appealing sex that you too are a bristle-thighed curlew and you'd like to get to know them better. (Please put the gun down now.)

 

They eat almost anything. Flowers, bugs, berries, land crabs, invertebrates, and the eggs of other birds. Here's a startling thing: they use tools to break open large eggs. The long sickle bills aren't the best tool for smashing things, so they grab rocks or pieces of coral and slam them down on the egg.

 

They're the only shorebirds known to use tools, a habit that has been beautifully documented in a paper by Jeffrey S. Marks and C. Scott Hall, published in the 1992 Condor.

 

Marks and Hall observed bristle-thigheds on Tern Island and Laysan Island, in the far northwestern part of the Hawaiian Archipelago. When the curlews get a food item too big to swallow, like a largish ghost crab, they slam it against the ground or a rock until it breaks into delightful bite-sized morsels. Adults haven't been seen doing this in Alaska, but baby curlews there will slam bits of moss, lichen, or plastic flagging (presumably put up by curlew biologists trying to get their bearings).

 

When the young curlews arrive in the islands for the first time, having traveled 2,500 miles from their birthplace, they are in a slammin' mood, and will slam feathers, shells, or bits of seaweed. I presume they soon learn to focus on more edible things to slam.

 

From "Tool Use by Bristle-Thighed Curlews Feeding on Albatross Eggs," Marks, Jeffrey S. & Hall, C. Scott. Condor 94: 1032-1034. 1992. Used with kind permission of the Cooper Ornithological Society. Is this not the greatest bird? Note bristled thighs.

But sometimes a curlew comes across an abandoned albatross egg. It's too big to pick up and slam, and the shell is too thick for a curlew to puncture with its bill. That's when the tool use happens. Marks and Hall say it's probably an extension of slamming behavior, and I agree. But I still think it's clever. 

 

So: smart rare mysterious long-distance travelers. A bird I'd love to see.

* 

At one time Rich Stallcup led 30-day Alaskan birding tours for the company Wings, tours for the fanatical and obsessed. On his fifth tour his group – 20 devoted birders – was exhausted from days of camping. They flew to St. Paul Island in the Pribilofs, arriving at 9 p.m. There were three hours of daylight left in the long Alaskan summer day, but word on the birder grapevine was that no notable rare birds were about. No vagrant Siberian birds had been spotted. The seabird nesting colonies – the two species of kittiwakes, three auklets, two murres, two puffins – would still be there in the morning.

Rich assembled the weary group in the lobby of the King Eider Hotel, the island's only hostelry, run by Aleuts. He went over the next day's plan. Since there were no rarities around, he said they could all go to bed early, and sleep in.

 After five hours sleep, Rich found himself wide awake. He wandered down to the beach. “I'm just admiring the Kittlitz's Murrelets,” he told me, when he heard a bird call he'd never heard before. (He whistled this for me – Sibley gives the flight call as “teeoip.”) “I go, 'Ho, shit. What's that?'” Teeoip! 

“Straight in from Hawaii, here comes the Bristle-thighed Curlew, one of the most wanted and rare birds in America. It flies right in front of me – teeoip! – real low. I'm just quivering because it's so great.” The curlew flies away, low and to the west, whistling teeoip “as if it wanted to land,” leaving Rich on the beach, in awe and dread, wondering “What am I gonna say at breakfast?” 

The trip leader is not supposed to sneak off and see the good birds himself after telling everyone to sleep in. And the Bristle-thighed Curlew is an unspeakably good bird. 

Rich spent the day trying to atone. If only they could find the curlew again! He dragged the group all over the island, even when they whimpered about missing lunch. (They must have despaired of seeing the curlew by then, to complain about such a petty thing. And maybe they had been too agitated to eat their breakfasts. Still.) 

Late in the afternoon, at Stony Point Lake, the curlew sprang up. It landed where everyone could see it and drink in its exotic beauty, marvel at its thighs. They returned to the King Eider in triumph, rejoicing mightily. 

“That evening we went over in a bus. We brought most of the Aleuts, the seal-killers and the mechanics. Everybody wanted to see this wonderful thing.” That's not something that usually happens on birding trips. That Rich's excitement was so infectious, and that he was so intent on sharing the experience, tells you a lot about him.

This photo of Rich Stallcup appears in a lobby display at the headquarters of PRBO Conservation Science (www.prbo.org). The building is dedicated to Rich, who co-founded PRBO in the 1960s and served as Naturalist and Bird-A-Thon Committee chairperson until his death in December 2012. Photo by Janet Wessel.

At the lake the curlew was bathing in company with a Eurasian Whimbrel (Numenius phaeopus phaeopus), a bird ordinarily notable in itself. Eventually the Whimbrel wanted to leave. “The Whimbrel jumps out of the water and starts screaming. Quiquiquiquiqui! The curlew gets out. Quiquiquiquiqui! The whimbrel's so anxious, it jumps up into flight, and finally the curlew jumps up too, and they tower up to a thousand feet – with oldsquaws chittering, and Black-legged Kittiwakes – kitti-weeik! Kitti-weeik! – and they fly off. People were on the ground weeping.”

 

Teeoip!

 

Teeoip, Rich.

 

 

 

 

 

 

 

 

 

Consider the ravens

Long ago, starter birdwatchers in an Arizona desert spotted a huge black bird. Perched commandingly, unimpressed by puny humans.

 Could it be – a raven? In the desert? Weren't they forest wilderness birds? A handy bird guide said the raven was “Common only in the Far North and in the West, especially near heavy timber.” No timber in the Chihuahuan Desert.

A more authoritative bird book said, “Resident of wild regions.” This desert was fairly wild.... A western bird guide said, “Habitat: Mts., deserts, canyons, coastal cliffs, boreal forests.” Okay! Deserts! Common Raven, Corvus corax! World's largest songbird! Yay!

The resident of wild regions has become increasingly common in urban regions. In the last 25 years, there's been a population explosion of ravens and crows in cities. If you can find a wild region, you can still find ravens residing there. But other ravens have decided to join us for dinner.

 My San Francisco neighborhood is full of them. They swoop over City College, bursting out of the pines. They holler from roofs. They strut in the gutter, disemboweling that helpless urban victim, the fast-food bag. Ravens evolved as carrion eaters. In a forest, ravens track wolves. If wolves kill a moose, ravens wade in, grabbing bites. In my neighborhood, ravens keep an eye on people, especially the ones walking away from Beep's Burgers.

What changed to make residents of wild regions feel so comfortable in the city? Lots of garbage around, but that's not new. Probably what changed is raven culture. Young ravens stay with their parents for months learning what's safe, what's dangerous, and where food is. 

There are several hundred ravens in San Francisco, and not nearly enough places for all those giant birds to nest. So most birds around town are non-breeders, hip young consumers with spare time and a burning curiosity about the world and which parts of it can be eaten. They know the best dumpsters, the most spacious dumps, and the most generous handouts.

 Many people feed ravens. People love the contact with wild animals, and ravens are cool. They are huge and hilarious as they high-step toward your offerings. Sometimes feeding them lets you observe their intelligence. I met a woman who feeds ravens at Fort Funston. When she arrives, ravens gather even before she parks – they recognize her car. She scatters peanuts across the iceplant, and dozens of ravens search for them.

 Another time I met a man sitting on a bench overlooking the sea. A raven stood on the seat next to him. Another perched on the back of the bench. He doled out snacks. He said these ravens knew him well, and described their family structure. (He said they were father and child.)

  I love ravens. Feeding animals is fun, and it feels like a win-win. Certainly the ravens would vote for it. But I don't feed them, and I think no one should.

 

The problem is that ravens are clever wild animals who find their food in many ways. One way is robbing nests of other birds and eating eggs and nestlings. The ravens of wild regions have always done this, and city ravens have kept up the skill. Stuffed with garbage and treats, urban ravens have plenty of leisure time to look for nests of little birds. It would be nice if well-fed ravens didn't feel like robbing nests, but no. They still enjoy the hunt.

 Nature's way, even if it's kind of depressing, right? Are we supposed to try to convert wild animals into kind vegetarians?

 No. It's nature's way for ravens to rob nests, but it's not nature's way for there to be so many ravens. We've created surplus predators, whose numbers aren't controlled by prey supply. Nature's way includes predators starving if they destroy prey populations. City ravens don't starve, because they have garbage and handouts. Many ravens means many sharp black eyes looking for nests. A project to bring California Quail back to Fort Funston failed, apparently because ravens got all the quail chicks. But they didn't starve, because there are still plenty of french fries scampering around the parking lots.

Rangers in state and national parks are trying to discourage visitors from feeding ravens. (I know, they discourage you from feeding everything, and why can't a chickadee have a damn crumb, but they're particularly worried about ravens.) In 1989, in Big Basin State Park, near Santa Cruz, biologists discovered only the second known Marbled Murrelet nest. Thrilled, they began observing the nest, which produced one silent thoughtful chick. Just as the chick was almost old enough to fly, ravens killed and ate it. They'd been observing too. The Big Basin ranger campaign to make sure no garbage gets left around for ravens to eat is called “crumb management.”

 To speak of surplus predators is also to speak of outdoor cats. Same deal – we support them in high numbers, which have nothing to do with prey supply. They behave naturally, but not in a natural context. Both cats and ravens are clever, fascinating creatures. Interacting with them puts us in touch with a fragment of wildness. We shouldn't do that in a way that lays waste other fragments of wildness.

 I dislike telling people they shouldn't do fun things (feeding animals) and I dislike depriving animals of fun things (free food). So here's a loophole for city dwellers. Next time you have a moose carcass, I think it's okay to leave it out for the ravens.

 

 

 

 

What shall I do with this prehensile tail?

I had heard that the Audubon Zoo in New Orleans was a really great zoo. The people who told me this (not zoo aficionados) were never able to say what was great about it. They didn't mention rare species, successful breeding programs, or brilliant enrichment schemes.

It was just really great.

I recently got to go for the first time, and I think I know the reason for their enthusiasm.

Frozen daiquiris.

They sell these along with the usual fast food available at American zoos. I asked the server what was in them, thinking maybe it was some sort of lime soda. She found the question strange. “Rum?” she said.

I shouldn't have been surprised. New Orleans is the wettest town I know, one that could have a banner at the airport reading WELCOME SLOPPY DRUNKS. It just hadn't occurred to me that this spirit extended to the zoo.

Shocked, I purchased a daiquiri and set out to see some animals.

I am interested in zoos. I loved the giant anteaters, who were milling around madly, awaiting their chance to go back into their night quarters.
 

The humans were like zoo visitors everywhere, inclined to stand next to a large sign that explains that orangutans are not monkeys but apes and say “Look at the monkey, Jesse!” Yet they were less frenetic than usual, maybe because of the heat. In the languid humid air, people swanned dreamily along the paths. Some were clasping icy beverages. Perhaps the slow aimless pace of the visitors is less jangling to the animals.

While walking around the pond in the South American Pampas exhibit, I heard a splash. I turned to see a rhea hastily climbing out of the water. The other rheas seemed  fascinated and started following the damp one. (What was it like? Was it fun? Was it cool? Did you float? Are you gonna go in again? Go in again! You should go in  again!)



Was the rhea imitating the ducks in the pond? No. Later investigation revealed that rheas are known to swim. Darwin saw rheas swim across the Santa Cruz River in Argentina. So this zoo-born rhea was experimenting with a skill used by its wild relatives. That was interesting.

Finally I arrived at the spider monkeys (Ateles geoffroyi). 
The large exhibit, modeled on Central American ruins, was good to look at and, more importantly, full of things  a monkey can do with a prehensile tail.

If you had such a tail, you could hook it over something.  Or twine it along something.
   

You could use it for balance, like an outrigger,  or for artistic emphasis.


You could use it to carry things, even if all you have to tote is a bunch of grass.

  In a vision I now imagine the Audubon zoo extending its hospitality to its occupants. I behold anteaters even more avid to get into their evening quarters, where frosty beverages are served. I suppose that an individual with a prehensile tail is perfectly fitted to stroll a slack rope while holding a daiquiri. Dreamily, I even wonder if this policy hasn't already been implemented. Unscheduled swimming is the sort of thing alcohol often inspires in young creatures.

What a great zoo.

Tough fishy story

Once upon a time there was a giant diving ocean goose – wait, no, maybe a giant diving ocean duck – so specialized for diving after fish it couldn't fly. It was as big as a Canada goose – anyway, a small Canada goose – okay, probably as big as nine pounds.

Maybe it was tasty, too, because its bones are found abundantly in old kitchen middens on the California Channel Islands and along the coast. Although with all that diving it must have been tough. Tough and fishy. (Plenty of tough fishy meat for the whole gang!)

This extinct diver is called Chendytes lawii. (I'm saying chen DIE teez.)  Here's a picture made by Stanton F. Fink, who likes to portray extinct creatures.
 
I wouldn't have expected it to be so blue, but who knows? (I also like Fink's shastasaurs.)

Chendytes only went extinct around 2,500-3,000 years ago. We just missed it.

A Chendytes bone 10,000 years old was found in a cave on San Miguel Island. Maybe a duck-eating person left it there, or maybe it was some other duck-eating animal. Yeah, yeah, or maybe it tottered in there to be alone.

Chendytes is material for arguments about human-caused extinction. This charming big duck (imagine if you were hungry and this enormous creature popped up to the water surface within easy clubbing distance – you'd be totally charmed) became extinct before the arrival of Europeans, so we can't blame so-called Western civilization. (Actually, I bet netting was a more likely technique than clubbing, but clubbing sounds cartoonier.)

It's generally thought that an earlier Western civilization, that of the coastal Indians of California, drove or helped drive Chendytes to extinction. Climate changes may have contributed. But there is debate about whether it can be considered a late, outlying part of a hypothesized Pleistocene Overkill in North America, or whether its demise is actually evidence against an overkill “blitzkrieg.”

Here's the deal. A whole bunch of very large North American mammals went extinct right about the time humans (from the Clovis culture) showed up, about 11,000-13,000 years ago. Mammoths, mastodons, ground sloths, 8-foot long beavers, the stag-moose, a large camel – there must have been thundering herds everywhere you turned. As these species vanished, other species that preyed upon them or scavenged their carcasses, like saber-toothed cats (gone) or like condors (barely hanging on) were affected too.
 
Did they vanish because we killed them off, or because of climate change or other factors, or some of each? And if we killed them off, did it happen so fast because we indulged in “overkill”? The idea is that people killed far more than they could eat. The classic – and often repeated – example of this is the buffalo jump, in which a big herd of buffalo is chased off a cliff. (It doesn't seem like it's so easy to stage a buffalo jump, but I admit I've never tried.)

There's fierce debate about this. Some people would include Chendytes as an example of big animals wiped out. (See Tim Flannery, The Eternal Frontier: An Ecological History of North America and Its Peoples.) Others cite Chendytes as a counter-example – the species co-existed with people for thousands of years before it went extinct. Some say that's because they were relatively safe on the islands.

But Jones, et al. (T. L. Jones, J. F. Porcasi, J. M. Erlandson, H. Dallas, Jr., T. A. Wake, and R. Schwaderer) say that people seem to have been in the Channel Islands for about 11,500 years, so it took about 8,000 years to eat the last Chendytes. In “The protracted Holocene extinction of California’s flightless sea duck (Chendytes lawi) and its implications for the Pleistocene overkill hypothesis” Jones et al. argue that if it took so long for humans to hunt out Chendytes, it should have taken them a comparable time to eliminate other species. So maybe it was something else that happened to the megafauna.

Opinions differ on when Native Californians had boats that enabled them to get to the nesting islands that were probably Chendytes's last stronghold. (I say: right away. People always turn out to have been boating longer than we thought.)

Thus some say we co-existed with Chendytes for millennia. Others say we wiped Chendytes out practically the minute we got the seafaring equipment to get out to the nesting places and gorge ourselves (on tough fishy meat).

Occasionally I think about a Pleistocene Revival event, in which a little DNA cut-and-paste work would bring back cool megafauna. I'd love to see mastodons and mammoths and those giant beavers. (Did they make huge dams?) But if you didn't bring back giant predators the giant herbivores would multiply crazily. I'm not ready for dire wolves and saber-toothed cats. I'm not even sure how we would manage with the herbivores. Mastodons in the arboretum would not be popular. If you don't like gophers in your garden, you're gonna hate ground sloths. People skipping to the fruit stand for the beginning of cherry season would be upset to learn that giant camels had beaten them to it.
 
I was thinking that Chendytes might be easier to get along with. What if we could re-create them and let them hang out on the Channel Islands again? With our effete modern eating habits, most of us would readily agree not to eat those tough fishy types. Huge diving ducks! What could be bad?

Oh no. Unless they went after our shellfish.

That fish can read you like a book

My sister had a fire eel (Mastacembelus erythrotaenia), Thomas, living in an aquarium near the refrigerator in which his food was kept. The food was tasty live tubifex worms.

Thomas spent most of his time lurking under and behind rocks. Some predators like Thomas find this a useful default activity, since you might be thinking about nothing at all when, Oho! prey wanders by, and because you are under the rock, they suspect nothing.

When Thomas detected my sister heading for the refrigerator he truly shone as a wily predator. If she was going for “a glass of milk and a salami sandwich” Thomas took no action. But if her intent was to take out tubifex worms for the eel, Thomas was somehow able to tell. He swam out of the rocks and wriggled back and forth enthusiastically just below the surface. (It is not clear to me whether fire eels salivate, but if they do, Thomas may have been drooling.)

We can't figure out how Thomas knew when my sister was after human food and when she was after fish food. This was not a matter of timing, since Thomas was fed irregularly, at any hour of the day, and not on all days. It will probably remain a mystery, since it is no longer possible to do experiments (on my sister, not on the fire eel) under the same conditions. (Was she walking differently? Was she wearing tubifex gloves? Was she glancing at the tank? She says not.)

Perhaps you wonder why Thomas was not offered salami. Salami is fatty and salty, and probably not particularly good for little fire eels. Unlike many fire eels, Thomas was a good neighbor who did not eat the other denizens of the aquarium. On his salami-free regimen he waxed mighty, getting to be over a foot long before he perished in a reckless expedition to travel outside the aquarium. He was found in a desiccated condition on the keyboard of a nearby computer.

Let that be a lesson to all of us.

Smarter than the average bear

The Monterey county inn offered a special rate. The deal included a “breakfast basket.” Around 8:30 am someone would knock. On the step they would leave a basket with packaged  pastries, juice, fruit, yogurt, and hardboiled eggs, which you could draw inside and consume at leisure.

They warned that birds might steal from your basket if you left it out too long. True.

The first morning I didn't retrieve the basket for several minutes. I came out to find that a crow had seized an egg, and was attacking it  with powerful blows of its large black beak. I rescued the egg. The crow had barely started, cracking the shell, exposing the yolk, but eating only a teaspoon's worth.

The second morning I lurked. I had angled the shutter slats so I could see without being seen. At the knock, I rushed to peer. Already a crow was striding up the path with long confident steps of its shiny black legs.

I think not. I opened the door and the crow wheeled and fled. I enjoyed that. I refrained from shouting a lecture after the crow about how it should be foraging on wild foods. Or asking how it would like it if someone ate its egg.

Once I stayed at a place in Mendocino County, in much wilder country, with fancier breakfasts (frittata! cobbler!), where the competition was so severe that they enclosed the baskets in heavy lidded wooden boxes. That time I didn't have to fight wildlife to eat.

If I go again, maybe I'll wait and see who tries for the food, and how. I could leave tools around and see if they select any. Perhaps that's entrapment, legally, but since I have no plans to prosecute, evidence doesn't have to be admissible. No plans at present – if they get the cobbler, that could change.

DDWESQ
 

A secret ingredient in a Brunswick stew

Modoc County Road 1 runs through the long, narrow Surprise Valley in high desert of northeastern California. It's in a narrow band between mountains and alkaline lakebeds in the valley bottom. In this narrow band irrigation allows agriculture. Sagebrush has been replaced by grain crops.

Ground squirrels feel the need to dash across this road constantly. Agriculture has let their numbers boom. In spring these exuberant rodents (Spermophilus beldingi) are bulbous with health. When I visited in April, the huge ground squirrels looked to me like young marmots. To hawks and eagles they look delicious and convenient.

Since there aren't many trees in Surprise Valley, the abundant raptors don't have many places to perch. Power poles by the road are decked with birds of prey, including bald eagles.

To ranchers the ground squirrels look neither amusing nor tasty. They look destructive. Squirrels churn and pile the soil, making harvest harder. They eat crops. They excavate holes perfect for snapping the legs of livestock. They puncture drainage ditches with their burrows. They clear large areas around their burrows, endeavoring to turn alfalfa fields into Spermophilus subdivisions.

Ranchers used to poison them with sodium fluoroacetate, also called Compound 1080, until that was banned. They turned to guns. In March the Surprise Valley Chamber of Commerce holds a Squirrel Roundup. This doesn't involve actual rounding up but simply shooting as many as possible. Out-of-towners pay to participate. It's possible to shoot 300-400 in a day.  Hawks and eagles enthusiastically scavenge carcasses. “The fields... were...  swarmed by bald eagles, falcons and hawks... enjoying an evening meal,” wrote Jean Bilodeaux for the Klamath Falls Herald and News.

Judging by the number of squirrels frisking about in April, there are many ground squirrels left unscathed and unhumbled. I called the Chamber of Commerce to ask what kind of ammunition is used in the Squirrel Roundup, hoping to be told that lead is forbidden. They did not return my call.

Another source told me that squirrel hunters use lead. That narrow band of the Surprise Valley must be intensely pocked with the stuff. It probably doesn't hurt squirrels that aren't actually shot.

But birds of prey are gobblers of gravel. Lacking teeth, they grind food in their gizzards, which they stock with little pebbles. They swallow chips of bone, glass, or metal, anything hard that seems to them like it would make cool false teeth. When a hawk finds shot in a carcass, it's like getting take-out Chinese food with free chopsticks. Lead can also flake, tainting a carcass.

Lead poisoning kills an unknown number of raptors every year. Most deaths occur in the wild and aren't reported. But some birds end up in wildlife rescue centers, where the problem is diagnosed. Sometimes it can be successfully treated, sometimes not. (Other birds can get lead poisoning too. Birds of prey simply encounter more due to their gourmet interest in dead bodies.)

Lead poisoning is such a serious problem for California condors that self-supporting birds living wild lives must regularly be captured so blood lead levels can be tested and they can undergo chelation therapy if necessary. Biologists climb up or rappel down to nests to cleanse them of unsalubrious items chicks will swallow. The use of lead shot is banned in an exclusion zone covering about 20% of the state to lessen the amount of lead in condor habitat. The Surprise Valley is not in that zone.

Reader, if this report has inspired you to sign up for next year's Squirrel Roundup, please don't use lead ammunition. Use steel, copper, tungsten, unicorn horn. Lead is cheaper, but you're spending hundreds of dollars to shoot hundreds of squirrels. You can afford it!

Thanks.