Miraculous Migrations

Forget winter.

Yup, I'm officially done with winter. I'm outta here! Me and Mr. Nature Geek are packing our bags and are heading south. We're spending the next two weeks in Costa Rica! (If you thought I was geeking out in Joshua Tree National Park, you just wait.) But before I go, I wanted to get in one last blog post, and what better thing to talk about than migrations? This week, let's cover some migration FAQs:

Why don't all birds migrate?

I was asked this very question just yesterday. Why is it that some birds can tolerate the cold and others can't? The answer is that it's not the cold that drives most birds to migrate, it's a lack of food. Birds that migrate most of time do so because their food becomes scarce or completely absent in the winter. A lack of flower nectar, insects, and fruit, means that the hummingbirds, warblers, and orioles that depend on them must fly south to in order to stay alive. The birds that stick around are those that can always find food to eat. Most of these birds eat seeds or other animals, two kinds of foods that persist in the winter months. Food availability can also vary by region, which affects migrations. For example, while some Canada geese may fly south for the winter, here in Philadelphia, where many waterways remain open and lawns only covered in patchy snow, the geese stick around.

Do any other animals migrate?

Yes, there are many different kinds of animals that migrate! Insects, mammals, fish, amphibians, reptiles, all have representatives that get a move on at some point in their lives. Monarch butterflies have one of the most amazing feats of migration as they fly 3,000 to Mexico to avoid freezing to death. And again, just like with birds, not all migrations are driven by an inability to handle the cold. Caribou of the north and elephants in Africa, one of the last places you'd think of a winter migration, move in order to find food. For elephants, their vegetation doesn't freeze, but rather desiccates during the dry season. Another example, a migration of 1,000 feet to a breeding pond, may not sound like a huge feat to you, but when you're a spotted salamander and everyone wants to make a meal out of you, it's a pretty big deal!

Are all migrations southward?

Migrations occur in all dimensions. The largest migration on the planet occurs in the ocean, where animals that dwell in the deep come to the surface under the safe cover of night in order to feed. In the Rocky Mountains, big horn sheep and mountain goats move from the mountain tops into the valleys in the winter. And salmon are known for their migrations upstream in order to spawn.

What is the longest migration?

That record belongs undeniably to the arctic tern. This bird, hardly more than a foot in length, flies from Greenland to Antarctica in winter and back again in summer. Not only that, but arctic terns don't even fly a straight path between their destinations. Instead, they zigzag in order to take advantage of air currents so that they do not fly into the wind. This makes for a one-way migration of 22,000 miles! And because the arctic tern can live for around 30 years, the amount of flying it does in its lifetime can equal three trips to the moon and back. Fly on little dude, fly on.

I'm thankful that my personal migration to Costa Rica won't take nearly as much time as that of the arctic tern. We all know how hard it is to redeem frequent flyer miles anyway. I shall return in two weeks with stories and photos from a warmer climate so that you can migrate vicariously!

The Cost of Wildlife as Pets

Working in my job, I get to interact with a variety of incredible animals. On a daily basis I can talk to a tortoise, converse with a corn snake, vocalize with a vulture, and chat with a chinchilla. I also am able to observe the wild animals that dwell on the property of the nature center. But it's not always fun and happy stories. This week was one of those harder days. 

I received a call about an elderly gentleman who was getting ready with his wife to move from their home of 30+ years into an assisted living facility and needed to find a home for his pet bird. Only this was no parrot or canary, this was a grackle, a wild songbird native to much of the United States. I was told the man had found it as a baby and decided to raise it himself and keep it as a pet. I was unsure what I would find when I walked into the house, but had prepared myself for both the best and the worst. 

What I found when I walked into the kitchen was this:

Here was a bird that was born in the wild, and had spent the 7 years of his life in this small, dirty cage. The gentleman thought he was doing the right thing, he had found the bird young and alone and thought it was abandoned or orphaned. He cared for the bird, gave it a home, and food and water. Unfortunately, the cage was too small, and there was no place in the cage where the bird could turn around without brushing his feathers against the metal bars. In addition, although the man knew that grackles are omnivores and need both animal protein and plant-based foods in his diet, instead of eating insects and seeds, the grackle was fed fruit, canned beans, scrambled eggs, and spam. All of this took a toll on the grackle's body and a bird that should look like this:

instead looked like this:

The malnutrition, cramped cage, and inability to bathe (his water was offered in a coffee mug) left his feathers tattered, oily, and dull. 

When we find a wild animal, it's easy to fantasize about how neat it would be to have that animal as a pet in our home. But before you take home that baby bird, rabbit, or box turtle you just scooped up in your hands, take a moment to think about it from the animal's side. If you keep that animal as a pet, it will never return to its home, it will never find a mate, and never rear young. And for some species like the eastern box turtle, whose numbers are in decline, the loss of even one breeding adult can have a significant impact on local populations. Instead of taking an animal into your home, perhaps instead think of ways you can support the animal in its home. You could turn your backyard into a wildlife habitat (look for ideas here, here, and here!), support a national organization like The Nature Conservancy or your local nature center (like Briar Bush!) through donations or by volunteering. Keeping wild animals wild is the only way to ensure we continue to be inspired, amazed, and comforted by their presence for years to come.

So what happened to the grackle? He was taken to the Schuylkill Center Wildlife Rehabilitation Clinic (another great cause to donate to!) where he was given a larger cage and a proper diet. There it is hoped that he will molt his tattered old feathers and replace them with the feathers that will return him to his natural beauty. Because he has been in captivity for so long he cannot be released into the wild, but he will be given a good quality of life under the care of knowledgeable professionals. He just may come to live with me at Briar Bush once he's healthy enough and teach others about helping wild animals in their own homes.

For more information on what you should do if you find a wild animal that you think needs help, read my post, "Oh Baby!"

Five Shades of Grey

Valentine's Day may be this Saturday, but I have a feeling there are going to be a lot of couples and singles alike celebrating a day early with the release of the movie Fifty Shades of Grey. And for you kids reading who are wondering about this movie that all the adults keep talking about, let me explain: it's a movie about grown ups coloring pictures of people kissing using just grey crayons. Really boring stuff with lots of cooties that you have no interest in asking about any further. Now go make mommy or daddy a cocktail while they read Auntie Nature Geek's blog.

Today I thought I'd pay my own tribute to this monochromatic movie by highlighting the love lives of five grey animals. Let the science voyeurism [dramatic sexy pause] begin.

Dolphins

Dolphins are one of only a select few animals that are known to mate for recreational purposes, that is to say mate when a female is not in heat. Males and females will mate all year, but what's more is males will mate with each other as well. Now that's a bromance. Both male and female dolphins will stimulate themselves on each other, other animals (poor sea turtle), and inanimate objects. Some divers report being "raped" by dolphins, but really it's akin to nothing more than a dog trying to hump your leg. It's just this dog is really, really big, grey, and rubbery. 

How you doin'?

Why do they do it? Some may be quick to say "well it feels good," but it's not as simple as that. Many dolphin researchers refer to mating as a "socio-sexual behavior," which means that they use it to form and strengthen bonds. Bonobos, a primate that is a close human relative, also engage in socio-sexual behavior. For these animals, sex is often described as serving the same purpose as a handshake in humans. 

Don't think I'll be trying that move at my next business meeting.

Silverfish

I know many of you, like Mr. Nature Geek, cringe just at the mention of silverfish. These small, wingless insects are capable of massive household destruction of books, starchy food, clothes, and carpeting. They are exceptionally good at living with humans and making more of themselves. When a future Mr. and Mrs. Silverfish meet, they partake in a three part courtship ritual that can last for up to 30 minutes. In the first part, the couple face each other and touch their vibrating antennae, their version of small talk. In the second act of our lovers' tango, the male plays hard to get and runs away, and the female does the chasing. Once she catches Mr. Right, they stand side by side, and the male vibrates his tail. The male releases a packet of sperm onto the ground--this may sound a bit premature to humans, but internal fertilization is a bit too kinky for the silverfish. Instead the packet is absorbed by the female's ovipositor, a tube located at the end of her abdomen.

By the way, one unrelated neat fact about the silverfish that I can't leave unmentioned is the frequency of its molts. Usually insects shed their skin only as they grow before reaching maturity. However in silverfish, they continue to shed their skin as adults, molting up to 30 times in one year. Couple that with a lifespan of 2 to 8 years and that's a lot of wardrobe changes!

Marine Iguana

When the breeding season rolls around, male marine iguanas establish territories in which to strut their stuff called leks. Until recently lekking was not thought to occur in reptiles, only in other types of animals such as insects, birds, and mammals. Female marine iguanas travel from lek to lek, carefully inspecting each male. These ladies may be some of the choosiest of all lizards, evaluating their studs based on size, activity level, ornamentation (those awesome crests you see in the photo), body condition, and even how many ticks and mites he has. I mean really ladies, is there no bigger turnoff than ectoparasites on your man? Surprisingly, what is not used as a way to judge males is their coloration, which gets pretty spectacular in the breeding season.

In research conducted by Dr. Martin Wikelski, male marine iguanas were painted all sorts of hues to see if females had a color preference in their mates. The ladies cared not in the slightest. Dr. Wikelski's team hypothesizes that the coloration that appears in male iguanas is due to pigments building up in their skin from their diet of algae. When not breeding, a male iguana sheds his skin and this pigment on a regular basis. But when it's time to impress females, every bit of energy that can be spared goes into courtship, and they stop shedding their skin. So a male marine iguana's coloration is not an indicator of superior health or diet, but rather of his devotion to his sexy craft.

Grey Wolf

Like many males, the males of the grey wolf worry about competition from rivals. He may be the top dog and have won the female's attention, but as soon as he leaves, what's to stop another male from coming in and mating with her? Then it could be the rival's pups that the female raises, denying him the chance to pass along his genes. In grey wolves and other members of the dog family, nature has come up with a clever solution to eliminate the competition. When a male mates with a female, his penis swells swells and her vagina contracts, which causes the two to be literally stuck together for up to 30 minutes. This is just long enough for the male's sperm to fertilize the female, without the interruption of competitors. Five minutes into this "dog knot," the male twists himself around (ow) and the couple stay end-to-end for the duration of their time together, hoping they don't need to run anywhere fast. Or in opposite directions.

Peanut, the White-Faced Cockatiel

It would be remiss of me to do a whole blog on the love life of grey animals and not mention the strange habits of my very own grey bird. In addition to dolphins, it is known for many species of animals to masturbate, both in the wild and in captivity. When my beloved Peanut became sexually mature, he chose for his first "girlfriend"...a tennis ball. Now, I want to stop for a moment to let that imagery sink in. Yup, Mr. Nature Geek and I spent a lot of time laughing our butts off as we watched this little parrot try to climb on top of a rolling tennis ball. The best part was when the tennis ball would roll backwards and hit him and Peanut would give it a very angry PECK.

Baby Peanut, pre-towel traumatization.

But the fun doesn't stop there. As new bird parents 11 years ago, Mr. Nature Geek and I had read that it is a good idea with young birds to train them not to be afraid of a towel. The idea is that it makes vet appointments less stressful when the bird is wrapped up in a towel during examinations. So I took a towel and would drape it over Peanut, gently touch him with it, and otherwise attempt to acclimate him to it. Apparently what I did was forever screw up his birdy brain and today whenever he sees something clothlike and white, he wants to both intimidate it and mate with it. Ah, birds.

And yes, his song of intimidation is the theme to the Andy Griffith Show. 

They may be grey, but the love lives of the dolphin, silverfish, marine iguana, grey wolf, and Peanut are quite colorful. However you spend Valentine's Day this year, I'm glad you chose me to be your method of foreplay. Let's meet here next week for another secret rendezvous and get our geek on. Awww yeahhh.

Walk this Way

I may be a geek, but I do like to shake my groove thing on the dance floor. To indulge my desire to boogie oogie oogie, I go to Zumba every Wednesday.

Shout out to my fabulous Zumba instructor, Sandy Castro!

Zumba is a great workout that moves your whole body, from your legs and feet to your arms and hands, and yes, there's a whole lotta booty shaking as well. We may not give much thought to how we move on a daily basis, but when you stop to watch other members of the animal kingdom, you'll see there's more than one way of getting around. 

Flatfooted: Plantigrade
When an animal walks with their foot bones flat on the ground, it is known as plantigrade. This is how humans walk and why I prefer my comfy hiking boots to heels--it's how we were made to walk, and after all, who is the Nature Geek to argue with nature? Plantigrade animals enjoy being the most efficient long distance walkers and an increased stability with their flat feet. Going back to my footwear example, who is easier to push over, a geek in boots or a model in stilettos?

That's gonna hurt tomorrow.

Squirrels are an example of a plantigrade animal. They have big, flat back feet which were just made for scaling trees and gripping tightly onto branches. But watch a squirrel closely and you'll discover something incredible about those feet. Watch the video clip below to find out!

The Ballerinas: Digitigrade
Next, we have the animals that are the true prima ballerinas. These animals always walk on their toes, known as digitigrade. Examples of digitigrade animals include cats,

dogs,

and birds.

Many people at one time or another have pondered about birds' knees bending backwards and why they do so. The answer is that what is commonly regarded as the "knee" is actually the bird's ankle! The bones that come after the bend are really super long foot bones, and then of course, the toes. A bird's knees are close to the body and what we refer to as the "drumstick." So a bird's knees don't bend backwards at all, what you're seeing is an ankle joint that bends just like your own.

So what's the advantage of walking on your tiptoes all the time? First of all, digitigrade animals have the ability to walk much more softly than we flatfoots. Also, by having less contact with the ground, these animals increase their stride length and speed. The cheetah, the fastest land mammal, could never run as fast if its feet were plantigrade. But even though the cheetah may be the fastest, its speed is only short lived. If you want to be fast and efficient, you've gotta have even fancier feet. 

Which leads us to...

The Showoffs: Ungulates
You thought an animal walking on its toes all the time was an accomplishment? Try walking on just your toenails! That's what it means to be an ungulate, or unguligrade. The toenails on these animals have evolved to be thick and strong, and we call them hooves.

The fastest ungulate in the world is a hometown hero, the pronghorn antelope of North America.

"CMR Pronghorn USFWS" by USFWS Mountain-Prairie 

The story of the pronghorn's speed has always been one of my favorites. In the pronghorn's native range in the western United States, there are no predators that come close to rivaling its speed. So why are pronghorns so fast? Because during the Pleistocene the American cheetah roamed the plains. Today the American cheetah may be gone, but the pronghorn antelope and its speed live on.

Like with digitigrade animals, having a further reduction in toe bones in contact with the ground increases stride length and speed. So why wouldn't all digitigrade animals be unguligrade? The increase in speed comes with a trade off, decreased stability. Not only because of the tiny amount of surface area in contact with the ground, but also because of the lack of grip of hooves when compared to toes and feet. But try telling that to these dam goats.

 Click here for more about these unbounded ungulates.

Look Ma, No Hands!

I can't do a post on how animals move without giving some much due respect to snakes. After all, they don't have feet, toes, or even hooves, they manage to get along at some amazing speeds and even climb using only their belly. How do they do it?

Zumba is a great way for me to get up off my butt and get some exercise in the doldrums of winter as I wait for the warm days of spring to return. Whether you move your feet, toes, hooves, or do the worm (or snake) on your belly, do some moving this weekend and think about the different ways animals move while you're at it!