Courtesy Andreas Trepte
Climate change. Rising seas. GMOs. Humans have such an incredible impact on Earth's environment that it's clear we're now the dominant force of change on Earth. This situation has even led some scientists to rename this geologic epoch the Anthropocene, or the human epoch. But as we alter, tweak, and pollute more each year, what will it mean for the survival of other species into the future?
According to Dr. Stephen Kress, they can look forward to human stalkers and creepy mechanical scarecrows. Kress began his career in the islands along Maine's coast during the late 60s and early 70s. In response to the loss of bird species diversity on many islands, he decided to start a human-led migration program that would move puffins to some of the islands. Puffins had once been abundant in the area, but their population dwindled due to overhunting and egg harvesting.
Still others accused Kress of trying to play God. “We’d been playing the Devil for about 500 years,” says Tony Diamond, a Canadian seabird researcher who has collaborated with Kress for decades. “It was time to join the other side.”
(same article as above)
Amid the skepticism of fellow scientists and the stubbornness of birds, Kress persevered and now boasts growing puffin populations on a few islands. But after several attempts to set natural protections and population controls in place, including a mechanical scarecrow to ward off predators, Kress and assistants continue to monitor and protect the puffins themselves. It's the only way they can maintain the new populations. After all, in a human-dominated environment, we get all the benefits and all the responsibilities--a job some might conclude is for the birds.
We are as gods and have to get good at it.
Stewart Brand, Whole Earth Discipline
Another sad day for wildlife lovers as yet another one of the world’s beautiful creatures is declared extinct. The Alaotra grebe from Madagascar was added to a growing list of modern day extinctions of bird species, nearly 190 total out of the 10,000 bird species remaining in the world. I shudder to think how the threatened and endangered list will change with this terrible oil spill in the gulf.
Courtesy William Warby
The blue morpho does. Scientists have found that this large butterfly of Central and South America has ears on its wings. These primitive ears can distinguish between the high-frequency sound of a bid singing, and the low-frequency sound of a bird flapping its wings. A singing bird is a sitting bird, and thus no threat to the morpho, but a flying bird could be attacking, and detecting those sounds tells the butterfly when to beat a slow, erratic retreat.
(Wait a minute…Blue Morpho…wasn’t he a character in Yellow Submarine Reloaded?)
Courtesy SiamEyeI don’t even know where to begin today! All I can think is “OMG!!!!” And each exclamation point I think is like a blood vessel bursting in my brain!
OMG pop pop pop
So why is this a day of excitement, instead of quiet family tragedy? Because the biggest explosions today aren’t happening in little tubes in my head, they’re happening in the world of science! (I don’t consider the physiology of my head to be science. More like magic. Or trial and error.) I just don’t know what to do with all this science.
See, unlike your average Friday Extravaganza, a Thursday Explosion has no focus; it’s just kind of all over the place. A mess! There are all these stories, but we really have to stretch to fit them into a single post… so the loose theme of this explosion will, fittingly, be “flying things.” Am I not helping? Just wait, you’ll see.
Normal mouse becomes flying mouse, doesn’t care!
Check it out: a baby mouse was put into a little chamber and subjected to an intense magnetic field. What happened? All the water in the mouse’s body was levitated. And because those squishy little mice are so full of water, the mouse itself levitated along with the water.
Unfortunately, the first mouse wasn’t quite ready for life as an aviator, and upon levitation, he began to, as scientists say, “flip his Schmidt.” Lil’ mousey started kicking, and spinning, and with minimal resistance in the chamber, he started spinning faster and faster. He was removed from the machine, and put wherever little mice go to relax. Subsequent floating mice were given a mild sedative before flying (pretty much the same thing my mom does), and they seemed cool with it. Now and again the floating mice would drift out of the region of the magnetic field, but upon falling back into it they’d float right back up. After remaining in a levitating state for several hours, the mice got used to it, and even ate and drank normally. Afterwards, the mice had no apparent ill-effects from the experiment (rats had previously been made to live in non-levitating magnetic fields for 10 weeks, and they seemed fine too.)
Aside from the excitement normally associated with floating mice, the experiment is promising in that it may be a useful way to study the effects of long term exposure to microgravity without bringing a subject to space.
pop pop pop
It’s true! Forget everything you thought you knew about great tits and get schooled once again, my friends, for great tits are killers!
I’m not talking about the senseless murder of bugs, either—everybody already knew that great tits are primarily insectivores. A population of great tits in Hungary have been observed hunting bats!
As fun as it is to keep writing “great tits” with no explanation, I suppose we should be clear that great tits are a type of song bird common in Europe and Asia. Little, bat-hunting songbirds.
Meat eating great tits had been reported in other parts of Europe, but it was thought that those individuals had only consumed already-dead animals. The tits of Hungary were actually observed flying into bat caves, where they would capture tiny, hibernating pipistrelle bats and drag them out of the cave to devour them alive. It even appeared that the birds had learned to listen for the bats’ disturbed squeaking (or, as I like to think of it, their horrified shrieking)—when the same noise (which is too high for humans to hear) was played back for captured tits, 80% of the birds became interested (read: bloodthirsty) at the sound.
If it really is just the Hungarian population that engages in this behavior, the situation also brings up the possibility of culture in the birds. That is, if this isn’t some sort of innate behavior, but something learned and taught, and passed through generations that way, it could be considered culture. Amazing! Great tits are cultured!
pop pop pop
Well, not so much flying as falling. But falling with purpose. (What was it Buzz Lightyear said? Oh yeah, “I’m so lonely all the time.”)
We all know about how awesome raptors are. I think it’s part of kindergarten curriculum now, just between how not to accidentally poison yourself, and why you shouldn’t swear and hit. Well, I remember reading a news item a couple years ago about how some paleontologists were thinking that raptors’ famous giant toe claws may not have been for disemboweling their prey. Instead, the scientists proposed, raptors would lodge the massive claw into the skin of their prey with a kick, and then use it to hang on to the unlucky animal while the raptor went bite-crazy. The researchers had made a simulation of a raptor claw, and found that it could easily puncture thick skin and flesh, it didn’t seem to be sharp enough to actually cut the skin. (Cutting is necessary for a good disemboweling.) One might argue over the strength and sharpness of raptor claws, considering that the fossilized bone claws we see in museums would have been covered with a tough, horny substance, which did not fossilize, but whatever—the new scenario was still pretty cool.
Now, the same group of paleontologists is proposing that raptor claws were also well suited to tree climbing. Raptors could have waited on overhanging limbs, and then pounced on their prey from above. Pretty neat! The researchers point out that the microraptor a tiny relative of the velociraptor, had feathered limbs to help it glide down from high places, so it’s not a stretch to think that its cousins were comfortable in trees too. “The leg and tail musculature,” one scientist says, “show that these animals are adapted for climbing rather than running.”
I’ll take his word for it, I guess, but I do have some questions on that point. There’s a dromaeosaur (it looks a lot like a velociraptor) skeleton here at the museum, and I seem to remember that its tale was supposed to be very stiff—it has these cartilage rods running the length of the tail to keep it rigid. I feel like a long, stiff tail would be a pain in the butt up in a tree. It’s not the sort of thing arboreal animals invest in these days. Also, I wonder what sort of vegetation was around in the areas raptors lived. Plenty of big trees with good, raptor-supporting limbs? (I’m not implying that there weren’t, I’m just curious.)
The researchers do acknowledge that tree climbing wouldn’t have been every raptor’s cup of tea, however. Species like the utahraptor, weighing many hundreds of pounds, and measuring about 20 feet in length would have been “hard put to find a tree they could climb.”
pop pop pop
Pretty neat stuff, huh? Explosions usually are. But you see now why I couldn’t wait for three posts to get it all out there.
Courtesy Joe ShlabotnikFor years now, members of the robust camp of biologists—paleontologists in particular—arguing that birds evolved directly from dinosaurs have kneeled on the thighs and arms of paleontologists who believe that birds did not evolve from dinosaurs, slapped their scrawny bellies pink, and rubbed dirt and grass in their bifocaled faces. And it was only right—the birds from dino people are bigger, and their veiny biceps ripple with the science of a substantial fossil record, while the clammy palms and toast-rack ribcages of the alternate theory paleontologists positively reek of onions and contrary opinions for the sake of argument. It’s only natural.
I mean, we have fossil impressions of feathers on dinosaurs, analogous bones and body-structures in birds and theropod dinosaurs (theropods, again, are two-legged meat-eaters, like T-Rex, velociraptor, etc.), similar bird-dinosaur proteins (take a look at that last link—Liza listed a bunch of other stories in that post)… the list goes on. Some paleontologists pretty much consider birds to be dinosaurs themselves (little dinos that never went extinct). The book is closed. It’s not even fun beating up on those other paleontologists anymore, because… what’s the point? You wouldn’t beat up on a worm, would you?
Ah, but these worms may have gotten their hands on something soft in this fight, and they’re about to give it a twist…
Check it out—like a hammer from nowhere, or sudden and blatant disregard for the no-scratching rule, the birds-didn’t-evolve-from-dinosaurs people have a new weapon, and they’re back on their feet.
Before we go on, I’m just going to emphasize something real quick here: nobody is saying that birds didn’t evolve, or that they didn’t evolve from something very different from birds as we know them. The question is, from what did birds first evolve, and when?
See, the winning theory is that some theropod dinosaurs began getting smaller and more birdlike in the Jurassic period (with a couple interesting exceptions eventually getting bigger and more birdlike later on, but that’s a different story.) These dinosaurs got little, and feathery, and probably started living in trees, and adapted to leaping, gliding, and eventually flying. By the late Jurassic, we have the archaeopteryx, a feathered, toothed, clawed, and bony-tailed flying machine. By the Cretaceous, there are plenty of pretty normal-looking birds around. Easy-peasy, and there are all those fossils I mentioned before.
“Oh yeah?” say the other paleontologists, “Well what about… this?!” And with that, they flick the back of their hand into the crotch of the unsuspecting bird-dino scientists.
“What are you… aaaaaaahh….” They ask.
Birds, say the alternate theory dudes, don’t have the right legs to be descended from dinosaurs. It’s so obvious, even jerks like you should have seen it.
See, birds need to breath lots of air to be able to fly (it’s hard, I’ve tried). To breath more efficiently, birds have air-sacs in addition lungs. Running all over their bodies (even in their bones) the air-sacs help pump lots of air through the birds' respiratory systems. Fossilized bones appear to show the presence of air sacs in some dinosaur species, too, and this has been seen as further evidence for the bird dinosaur link.
The new argument doesn’t dispute that everybody loves air-sacs. It points out that birds can only move their legs in a very limited way, to keep from collapsing some of their air-sacs when they breath. Birds’ femurs (their thigh bones) are largely fixed—when they walk or run, most of the movement comes from their lower legs. All other walking and running animals—including dinosaurs—have moveable thighs.
This difference, some scientists believe, is great enough that fixed-legged birds couldn’t have evolved from moving-legged dinosaurs. They might have evolved alongside dinosaurs, sharing a common ancestor, possibly one of the thecodonts. Thecodonts were dinosaur-like (but definitely not dinosaurs) and they lived during the Triassic period. Some thecodonts evolved into dinosaurs, and the group died off by the end of the Triassic.
“That’s… all?” says mainstream paleontology, straightening up and cracking its knuckles. “Someone is about to get slapped.”
“…Hiss!” say the other guys, squaring their Gollum-like shoulders.
Until I know a little more about the research, I think I have to side with the traditional birds evolved from dinosaurs argument. The alternative theory folks point out that birds are found much earlier in the fossil record than the dinosaurs they are supposed to have evolved from, but it seems to me that that’s more of a problem of overlap than of a gap—couldn’t later bird-like dinosaurs just be the descendants of the dinosaur-to-bird transitional species? It’s not as if anyone thinks that we look at individuals in the fossil record and say, “ok, you evolved from this one, which evolved from this one” etc. If birds didn’t evolved from dinosaurs like the ones we find from the Cretaceous, then we’re left with a huge gap between thecodonts and archaeopteryx and his pals. And it would have to be some pre-dinosaur thecodont, because I feel like the independent evolution of air-sacs, feathers, and everything else in both lines would be a little too much convergent evolution otherwise.
Plus… I’m not clear on why dinosaurs couldn’t have just evolved to have a fixed leg later on, when they needed more efficient respiratory systems for flying. Their mode of locomotion would have necessarily been changing anyway…
Interesting, though, right?
What do y’all think? Is this ridiculous? Or are we too attached to the mainstream model of bird evolution that we’re unable to keep an open mind to new ideas?
"Female Gouldian finches 'decide' to have more male chicks if they are less compatible with their mate.
The birds, which have either red or black heads, prefer to mate with males with the same head colouring, as this signifies a better genetic match.
Chicks from a mismatched mating - particularly the females - are weaker and more likely to die very early.
A report in the journal Science says that the birds compensate for this by having more male chicks in their brood.
Join the ongoing discussion about whether or not humans should use technology to select the sex of offspring when a genetic roll of the dice is a risky proposition.
Now a new fossil has emerged from China that is complicating the picture. Tianyulong confuciusi was a small, two-legged plant-eater that lived in northeastern China about 130 million years ago. Its recently-discovered fossil included clear signs of feathers. This is nothing unusual—lots of dino fossils, especially from this part of China, have feathers.
What is unusual is that Tianyulong is not related to any previously known feather-bearing dinosaur. Not even remotely. All previously know dino feathers come from theropods, the two-legged meat-eaters like T. rex. Tianyulong was a type of hadrosaur—sometimes known as a “duck-billed dinosaur.” And the last time hadrosaurs and theropods shared a common ancestor was 230 million years ago!
This discovery raises several intriguing possibilities:
1. Perhaps feathers evolved very early in dinosaur history, far earlier than we now suspect. If the very first dinosaurs had feathers, then all other dinosaurs could inherit them, even after the various branches of the dino family tree split up and went their separate ways. But if that’s true, then why have we not found feathers on more dino skeletons?
2. Perhaps feathers evolved twice—once in the theropods, and once in the hadrosaurs. That would be pretty unusual. Right now, there seems to be no information on whether these new feathers are very similar to previously-known feathers, or completely different.
3. One thing has always bugged me about the whole bird-dino link. All dinosaurs fall into two major groups: those with hips shaped like those found in modern lizards, and those with hips shaped like those found in modern birds. But all the previous bird-like features, including feathers, come from the lizard-hipped group. Seems odd to me that nature would evolve bird-like hips twice. Maybe—just maybe—birds evolved from the bird-hipped dinosaurs.
Now, there’s tons of other evidence besides just hips to link birds to theropods, so nobody is going to be re-writing the bird family tree any time soon. All we can do is keep our eyes peeled for more interesting discoveries.
As biologists we spend a lot of time observing our focal species but we try to minimize any disturbance our activities might cause. However, sometimes we cannot get the data we need without intruding on the lives of our study species. For example, to determine the number of eggs laid in a nest or to determine when egg laying begins, we need to look inside the nest and doing so could have the potential to disrupt normal bird activity.
Courtesy Jarosław Pocztarski
In the field of ornithology there has been some concern that nest monitoring could either increase or decrease the risk of nest predation. An increase or decrease in the risk of nest predation could occur for several reasons (1) we are leaving human scent trails to the nest that predators follow, (2) predators are watching us and follow us to the nest, (3) we disrupt the incubation process causing the female to stay off the nest longer or (4) our activity at the nest deters predators.
A study was just published in the AUK (a journal of the American Ornithologists Union - http://www.aou.org/) trying to determine if nest monitoring affects the risk of nest predation in 11 species of birds in the Czech Republic. Using temperature data loggers placed inside each nest to determine when females were present or absent from the nest, Karel Weidinger found that activity at the nest as a result of nest monitoring does not increase the risk of nest predation. However, she did find that the risk of nest predation was slightly lower two hours following observer activity at the nest but this reduced risk did not change overall nesting success. This work supports previous research suggesting that nest monitoring activities do not affect the risk of predation. This is great news for biologists because now we can be more confident that monitoring bird nests does not increase the risk of predation.
Many bird populations across North America have declined in recent years and researchers have been busy trying to determine why populations of birds are declining.
Courtesy West Coast Birding
My research focuses on factors that could affect survival of birds during the breeding season. The breeding season is an important time for birds because this is the time when individuals have an opportunity to raise young and the ability to successfully raise young can have a big effect on the bird population. However, producing young can be quite difficult for birds. In fact, the number one factor that affects the ability of birds to raise young is nest predation. Nest predation occurs when a predator, such as a chipmunk or squirrel eats the eggs or young in a bird’s nest. But do all birds have an equal chance of survival during the breeding season? Research suggests that the chance of survival for a bird’s nest is not equal and chances for survival change during the breeding season. Why might survival change during the breeding season? I have some ideas or hypotheses that might explain why survival changes during the breeding season. I am investigating whether plant cover, food resources for predators, temperature, or number of predators affects the ability of songbirds to raise their young.
When birds build their nests, they often hide them in plants to reduce the chance that a predator will find their nest. But many birds begin building their nests early in the spring and in early spring we often notice that plants and flowers in the forest are just starting to grow. So birds building their nests during this time have fewer plants to hide their nests in which could make their nests more visible to predators, such as chipmunks and squirrels. Because plant cover may be a key factor preventing predators from eating the eggs or young in a bird’s nest, I experimented with plant cover to test the importance of plant cover. I removed plant cover around Wilson’s Warbler nests and compared the fate (i.e., were the parents able to raise their young) of these nests to nests that did not have plant cover removed. I also measured plant cover at nests of Wilson's Warblers and Dusky Flycatchers and compared the amount of plant cover to the fate of each nest.
In addition to seasonal changes that we see in plants, the amount of food available in the forest for critters to eat also changes as we move from spring to summer to fall. Early in the summer, there may be less food available for the predators because pine cones and seeds from other plants are not yet available. If predators such as chipmunks, mice, or jays have less to eat they spend more time looking for food to eat in the forest. The increase in time spent searching for food could also increase the chance that one of these predators will find a bird nest and eat the eggs or young in the nest. Because the amount of food available might affect survival of a bird’s nest I conducted another experiment to find out if this was the case. I provided food (sunflower seeds and corn) to predators to see if providing extra food to predators will increase the ability of birds to raise their young.
Determining how both vegetation and food affect survival of bird’s nests during the breeding season is challenging but fun because I am able to experiment with nature and find out what happens. As a scientist I am like a detective trying to figure out why bird populations are declining. Finding the answer is challenging and exciting, but hopefully we will find an answer that will prevent further losses of our bird populations.