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In a remote corner of Brazil’s Amazon rainforest, researchers have spent decades catching and measuring birds in a large swath of forest unmarred by roads or deforestation. An exemplar of the Amazon’s dazzling diversity, the experimental plot was to act as a baseline that would reveal how habitat fragmentation, from logging or roads, can hollow out rainforests’ wild menagerie.

But in this pristine pocket of wilderness, a more subtle shift is happening: The birds are shrinking.

Over 40 years, dozens of Amazonian bird species have declined in mass. Many species have lost nearly 2 percent of their average body weight each decade, researchers report November 12 in Science Advances. What’s more, some species have grown longer wings. The changes coincide with a hotter, more variable climate, which could put a premium on leaner, more efficient bodies that help birds stay cool, the researchers say.

“Climate change isn’t something of the future. It’s happening now and has been happening and has effects we haven’t thought of,” says Ben Winger, an ornithologist at the University of Michigan in Ann Arbor who wasn’t involved in the research but has documented similar shrinkage in migratory birds. Seeing the same patterns in so many bird species across widely different contexts “speaks to a more universal phenomenon,” he says.

Biologists have long linked body size and temperature. In colder climates, it pays to be big because having a smaller surface area relative to one’s volume reduces heat loss through the skin and keeps the body warmer. As the climate warms, “you’d expect shrinking body sizes to help organisms off-load heat better,” says Vitek Jirinec, an ecologist at the Integral Ecology Research Center in Blue Lake, Calif.

Many species of North American migratory birds are getting smaller, Winger and colleagues reported in 2020 in Ecology Letters. Climate change is the likely culprit, Winger says, but since migrators experience a wide range of conditions while globe-trotting, other factors such as degraded habitats that birds may encounter can’t be ruled out.

To see if birds that stay put have also been shrinking, Jirinec and colleagues analyzed data on nonmigratory birds collected from 1979 to 2019 in an intact region of the Amazon that spans 43 kilometers. The dataset includes measurements such as mass and wing length for over 11,000 individual birds of 77 species. The researchers also examined climate data for the region.
All species declined in mass over this period, the researchers found, including birds as different as the Rufous-capped antthrush (Formicarius colma), which snatches insects off the forest floor, and the Amazonian motmot (Momotus momota), which scarfs down fruit up in trees. Species lost from about 0.1 percent to nearly 2 percent of their average body weight each decade. The motmot, for example, shrunk from 133 grams to about 127 grams over the study period.

These changes coincided with an overall increase in the average temperature of 1 degree Celsius in the wet season and 1.65 degrees C in the dry season. Temperature and precipitation also became more variable over the time period, and these short-term fluctuations, such as an especially hot or dry season, better explained the size trends than the steady increase in temperature.

“The dry season is really stressful for birds,” Jirinec says. Birds’ mass decreased the most in the year or two after especially hot and dry spells, which tracks with the idea that birds are getting smaller to deal with heat stress.

Other factors, like decreased food availability, could also lead to smaller sizes. But since birds with widely different diets all declined in mass, a more pervasive force like climate change is the likely cause, Jirinec says.

Wing length also grew for 61 species, with a maximum increase of about 1 percent per decade. Jirinec thinks that longer wings make for more efficient, and thus cooler, fliers. For instance, a fighter jet, with its heavy body and compact wings, takes enormous power to maneuver. A light and long-winged glider, by contrast, can cruise along much more efficiently.

“Longer wings may be helping [birds] fly more efficiently and produce less metabolic heat,” which can be beneficial in hotter conditions, he says. “But that’s just a hypothesis.” This body change was most pronounced in birds that spend their time higher up in the canopy, where conditions are hotter and drier than the forest floor.

Whether these changes in shape and size represent an evolutionary adaptation to climate change, or simply a physiological response to warmer temperatures, remains unclear (SN: 5/8/20). Whichever is the case, Jirinec suggests that the change shows the pernicious power of human activity (SN: 10/26/21).

“The Amazon rainforest is mysterious, remote and teeming with biodiversity,” he says. “This study suggests that even in places like this, far removed from civilization, you can see signatures of climate change.”

Far too often, fighters say that they can’t afford to lose when they, in fact, can afford to lose.

A loss isn't the end for all fighters and the greatest have come back from significant losses in their career. All losses aren't the same and there's often an overreaction to how much a loss hurts the future of a fighter.
Take, for instance, Canelo Alvarez vs. Caleb Plant. Plant was never expected to win the fight. Of course, he didn’t want to lose and the spoils go to the victor but the concept of a moral victory applied. He made a good showing of himself and will certainly be back, perhaps with more eyeballs on him now than before.

There are rarely fights that neither can afford to lose because of just how devastating to their future the loss would be.

Terence Crawford vs. Shawn Porter on Nov. 20 in Las Vegas is one of those fights.

Why Terence Crawford can’t afford to lose
If Terence Crawford loses to Shawn Porter, the allure is gone. And maybe he wasn’t as good as we thought he was.

Although he was named the Fighter of the Year by ESPN and the Boxing Writers Association of America all the way back in 2014 (and again by ESPN in 2017), the current WBO welterweight champion remains in pursuit of a signature win. The critics have had every right to have their questions because as great as Crawford has looked, his resume lacks that one opponent who is respected for his accomplishments and accolades.

Shawn Porter is that opponent.

A two-time welterweight champion that has given hell to every single opponent that he’s stepped into the ring with. With Manny Pacquiao retired, an argument can be made that Porter has the most impressive resume of every fighter in the 147-pound weight class. And if it wasn’t for Canelo, Porter might have the best resume in all of boxing. Although he hasn’t won all of his big fights, he has yet to be dominated by an opponent.
He’s defeated Danny Garcia, Yordenis Ugas, Adrian Broner while losing narrow decisions to Keith Thurman, Errol Spence Jr. and Kell Brook. As a matter of fact, 11 of his last 13 opponents were world titleholders.

It doesn’t get much better than that. And a Crawford victory opens the door wide open for him to challenge Spence and the rest of the division in an attempt to become undisputed in two division. They won't be able to deny him any longer unless they are scared. It's just that simple.

With all of this being said, one would think that Crawford could afford to lose given Porter’s credentials. Well, that’s certainly not the case. He has hovered as one of the top five pound-for-pound fighters without a marquee name on his resume because he’s been that damn good inside of the squared circle.

But what he hasn’t been is tested by an opponent who has given the best 147-pounders 36 minutes of pressure.
Crawford may have graduated with high honors from his pugilism undergraduate but now he has to prove that he’s Magna Cum Laude and get his master’s degree in the sweet science.

He has an opportunity to barely pass the test like Errol Spence and still be considered as one of the best in the world or he gets mowed down by Porter’s aggressive style and find himself possibly removed from the pound for pound list. Or, he destroys Porter and is undeniably the top dog of the division and once again in the conversation as the best fighter in the world.

Of even more significance is that he’ll be a free agent. It’s no secret that Top Rank has struggled to get him a marquee fight as opponents ranging from Errol Spence Jr., Keith Thurman and the recently retired Manny Pacquiao fought for a rival promotion. There’s an expectation that Crawford will see what’s on the other side of the street if he gets past Porter. But at 34 years of age and facing constant struggles to prove he’s a marketable star, a loss would be devastating to his future.

Bob Arum has spoken in less than flattering terms about Crawford while PBC will have proven their point that Crawford is not in the league of their current stable. Where does Crawford go if he loses all of his leverage?

He cannot afford to lose on Saturday night.

Why Shawn Porter can’t afford to lose
Boxing has been kind to Shawn Porter because Porter has been kind to the sport. He’s a fighter who could care less about politics and risks. He’ll fight anybody at any time. And if you step into the ring with Porter, it will be less fun for you than it is for him. He enjoys plowing into opponents and forcing them to fight his fight. It’s rare to find a Porter fight that lacked excitement and fans have had the opportunity to enjoy Porter’s fearlessness inside of the squared circle.

But, eventually, you have to win the big one.

Porter is a two-time world champion who is 4-3 in major world title bouts. He fell just a hair short against Keith Thurman, Kell Brook and Errol Spence Jr. And while all three of those fights were a round or two away from seeing Porter victorious, the fact remains that he lost. The record books won't explain how close he was and future generations just won't care. The stats are the stats.

The expectation is that Porter will give Crawford all he can handle but fail to get the job done. Oddsmakers have installed him as a significant underdog despite his in-ring accomplishments. This is a sign that many people think that his time is up. And if he ends up proving the naysayers right, the idea that Shawn Porter is one of the best welterweights in the world is likely over.

Simply put, if he loses, he goes from contender to gatekeeper. He becomes the guy that young fighters target as a name for their resume. It’s highly unlikely that he’ll find himself in a marquee fight as the A-side and will spend the rest of his career as an opponent. Jarron "Boots" Ennis and Vergil Ortiz will look to use Porter's name as a stepping stone.

Nobody wants to be a stepping stone. But that's how Porter will be viewed if he is unable to get the job done.

It’s also possible that his hall of fame credentials hinges entirely on this fight.

A victory finds Porter back in the mix and rematches with Yordenis Ugas and Errol Spence Jr. will have to be made. There will be a reason to believe that Porter is absolutely one of the best fighters in the world and he'll certainly crash the pound for pound list with an exceptional performance.

But it all goes up in a cloud of smoke if he loses.

As you can see, the pendulum swing for both fighters is extreme. Neither can afford to lose because their respective futures rely so heavily on what happens inside of those 12 rounds. The stakes are high on both sides and that's more than enough reason to watch what could be an incredible fight with the respective futures of both Crawford and Porter hanging in the balance.

49ers fans waiting for the return of the "Trey Area" may have to wait a little longer.

The 49ers sending away two future first-round picks for the No. 3 overall pick for, what turned out to be, Trey Lance in the 2021 NFL Draft meant that the future was now. Or later. Or, apparently, eventually.
Kyle Shanahan and the 49ers have maintained that the best way to develop their prized QB prospect is to keep him on the bench, a strategy that may or may not work out long-term for them.

With Jimmy Garoppolo still a serviceable starter for San Francisco, the 3-5 start has fans calling for a change at the quarterback spot, leading to many wondering why Lance isn't starting. While draft philosophies differ, one thing is certain: The 49ers spent a lot of future draft capital for a guy who's gotten a very small sample size of work so far this season.

Shanahan's comments haven't painted a pretty picture for Lance's starting prospects in 2021, either.

Why isn't Trey Lance starting?
The answer: Anyone's guess.

While Lance got an opportunity to fill in for Jimmy Garoppolo in Week 5 vs. the Cardinals, he's been on the sidelines since then. Through a bye week, a knee injury and Garoppolo getting the opportunity to start once again, the 49ers have resisted the urge to let Lance see the field. Lance last got a snap in Week 5.

While Lance came out of college as something of a project, it seems like the 49ers' direction is to do more to try and develop Lance for the future than to shoehorn him into situations now after attempting to earlier in the season.

In late October, head coach Kyle Shanahan explained why Lance hasn't been given a longer leash to start:

“We didn’t draft Trey to just fix this year," Shanahan said. "We drafted him so he could be the quarterback of the future and that’s a matter of time. We are not playing him just because what our record is, or just because."

There's also the matter of Jimmy Garoppolo, who has played "all right" (Shanahan's words) despite missing a game with an injury. ESPN's Dan Graziano reported that he doesn't feel that Shanahan will make the change to Garoppolo anytime soon — not as long as Garoppolo is playing, well, all right.

On Halloween, Lance was seemingly healthy and ready to go. Shanahan, though, didn't want to risk putting Lance on the field in the event that Garoppolo was injured.

To that end, the question remains: Not that Lance's usage rate was out of this world, but why were the 49ers more willing to use Lance early on in the season (129 snaps in total through Week 5) and not now?

The resistance to want to use Lance continued in this past weekend: Following the rough Week 9 loss to an undermanned Cardinals team, Shanahan was asked if he'd consider making a QB change for the Niners' Week 10 game vs. the Rams.

"Probably not, but definitely not thinking about those things right now. I’m thinking about this game and the rest of our team," Shanahan said post-game.

Defenses have been playing the 49ers passing game tighter, with Garoppolo's propensity to work short throws and the middle of the field (as the Shanahan system accounts for). Garoppolo's ability to stretch the field has always been something of a question, something that Lance's physical traits would allow him to do.

But, come hell or high water, it sounds like it's going to be Garoppolo — for now.