Tuesday, January 26, 2016

A Little Blue Heron in the Salt Marsh

As I mentioned in my previous post on the Cottonmouth, I recently took a 2000 mile solo road trip during my Winter Break. I spent most of my time birding throughout coastal South Carolina, racking up a total of 90 species (including 8 lifers) from December 28, 2015 to January 2, 2016. This wasn't my first time birding in South Carolina; just a few months prior I visited with my ornithology class for a 4 day field trip (which you can read about here: Part 1, and Part 2). It's an absolutely wonderful state to go birding in!

Pinckney Island National Wildlife Refuge
One of the locations I visited was Pinckney Island National Wildlife Refuge in the very, very southern tip of South Carolina. It's a very interesting preserve, and most of it is open saltwater or salt marsh. I went to visit a productive freshwater pond named the Ibis Pond, but first had to walk by an extremely shallow salt marsh. And in that marsh was a small white bird.

Juvenile Little Blue Heron

And that small white bird was a Little Blue Heron. You might be wondering why a "Little Blue Heron" is white, and this is because it is a juvenile Little Blue Heron. This species begins life in all-white plumage and individuals transition to their deep blue plumage upon maturity.

I would like to take a moment to talk a bit about the name "heron." As you might know, there are herons and egrets; both look essentially the same, aside from species-level color differences. You might be thinking there is some kind of difference between the two groups, like there's something that makes a heron a heron, and an egret an egret. I definitely thought that until I started my research for this post. Turns out, there is no significance to the names. Although the Little Blue Heron is called a heron, that name doesn't mean much in itself; in fact, the Little Blue Heron is most closely related to the Snowy Egret. So why the two groups of names? It's basically due to linguistic and societal differences. Birds in the family Ardeidae are called the herons. The name "heron," when talking about etymology (the study of a word's origin and history), comes from certain Germanic languages including Middle English. Egret, on the other hand, is still Germanic, but is based on the Old French word "aigrette," which is pronounced "egret." Aigrette can translate to "little white heron," but also refers to long, decorative plumes that certain heron species grow during breeding season. So basically, the French term "aigrette" was borrowed by English and morphed into "egret." This term was then applied to white herons, many of which also have those decorative plumes during their breeding season. However, when you look at the evolutionary history for these long-legged waders, you see that there's no biological basis for the differences in names; the birds we call egrets and the ones we call herons are all intermixed in various genera, and they don't break down into two completely separate groups. This is one of the many reasons why common names can be deceiving!

Immature Little Blue Heron
Back to the Little Blue Heron! This is a medium-sized heron species that stands about 2 feet tall. Here in the United States, Little Blue Herons are most commonly a resident of sub-tropical swamps and marshes in the southeast. However, like their cousin the Snowy Egret, the Little Blue Heron will also very sporadically breed in the northern half of the Eastern United States. Little Blues will also sometimes irrupt northward in the late summer after breeding is finished. When it comes to Ohio, the Little Blue Heron has an interesting history. A few pairs have actually nested in Ohio, and these pairs have been confined to the wading-bird nesting colony on West Sister Island in Lake Erie. These nesting individuals show up to forage in marshes throughout Ottawa and Lucas counties, including Ottawa National Wildlife Refuge and Magee Marsh. Even then, this is a very rare species to see in Ohio. To read more about the Little Blue Heron in Ohio, check out this link: OBBA Account

Little Blue Heron foraging
Although they are rare in Ohio, the Little Blue Heron is pretty common within their core range. They are typically a bit shyer than other herons, preferring to forage along the edges of wetlands either singly or in very small groups. The Little Blue is a stand-and-wait predator, meaning it prefers to quietly stand in one location and wait for prey to come to it instead of actively hunting them out. They typically feed on fish, amphibians, and crustaceans, but will also take insects and small mammals. This individual was in extremely shallow water (about 1 or so inches deep), and fish were nowhere to be found. I watched him as he slowly and carefully stalked about, turning his head to inspect the water for life. Eventually he struck the substrate and pulled up a bristle worm, as pictured above. Bristle worms, class Polychaeta, are a diverse group of mostly-marine segmented worms, and easy pickings for many wading birds.

Little Blue Heron South Carolina
While researching information for this post, I came across two very interesting studies that I would like to summarize. Both studies were done by Gloria S. Caldwell, and the papers can be found at this link: Caldwell 1981, Caldwell 1986. To give some background, most herons/egrets have the same plumage coloration throughout their life. The Little Blue Heron is a bit unusual in this as it is dimorphic in regard to age. The juveniles are white, while the adults are dark blue. Is there a significance to this color dimorphism? Turns out there is, and it’s incredibly interesting. Caldwell (1986) found that herons with white plumage were attacked by hawks more often than herons with "dark" plumage. At first glance, it seems that the juvenile plumage of the Little Blue would be a hindrance to survival, but it’s actually a bit more complicated than that. Caldwell also found that flocks of herons have a significantly lower chance to be preyed upon than an individual foraging alone, and this makes sense; the more eyes you have watching for predators, the less of a chance a predator will be able to commit a successful attack. How does this flocking feature factor in? Caldwell (1981) found that Snowy Egret flocks will more readily accept juvenile Little Blues than adult Little Blues (in fact, adults were attacked by the Snowy Egrets, while juveniles were left alone). Caldwell suggests that the white plumage of the juvenile Little Blues makes the Snowy Egrets, a white bird themselves, more apt to accept the juveniles than the dark-colored adults. So, although white juvenile Little Blues are more likely to be attacked by predators than the adults, they can mitigate this negative effect by foraging in a mixed flock with Snowy Egrets. In addition to all of this, Caldwell found that juvenile Little Blues actually had a higher success rate catching fish while in a flock than when they foraged alone.

Immature Little Blue Heron
Let me take a moment to sum everything up so far. Juvenile Little Blue Herons, which are white, are better accepted into mixed foraging flocks than the dark-colored adults. By being part of a flock, the juvenile Little Blues have a better chance to avoid predation. In addition, by being part of a flock, juvenile Little Blues have better success at catching fish. Therefore, by having a lower chance of being killed by a predator, and by being better-fed as they mature, a juvenile Little Blue Heron has a much better chance of making it to adulthood and passing on its genes. Having white plumage is, therefore, very beneficial, and natural selection ensures this white juvenile stage is maintained.

Little Blue Heron adult and juvenile
Now you might be wondering why there isn’t a selective pressure for the adults to be white, instead of dark blue, as well. There are some young white subadults that attempt to mate every year, and you would think those individuals would be heavily selected for, but those subadults almost always fail to mate. This implies there’s something else now at play, but what is it? It all has to do with breeding! As I mentioned previously, white herons are preyed upon at a higher rate than dark-colored herons. This is simply because white really stands out among the greens of swamps and marshes. To see this in action, look at the photo above; the white juvenile on the left stands out like a sore thumb, while the dark adult on the right blends in relatively well. Being inconspicuous is very important when it comes to nesting; nestling birds are incredibly easy pickings for predators as they can’t fly away and escape. Many predators know this, and many will actually watch for adults bringing food back to a nest in order to locate the nest. Once a predator knows where a nest is, and if they can get to it, then it’s all over for the nestlings. Because of this, adult birds try to hide the location of nests at all costs. If you are a conspicuous, attention-grabbing white, you might as well let predators waltz right up to your nest. By transitioning to a dark coloration upon maturity, Little Blue Herons reduce the chances that predators will attack them or their nest, which not only helps ensure their survival, but the survival of their nestlings as well.

In the end, natural selection selects for white-plumaged juveniles and dark-colored adults. By having this dimorphic coloration system, the Little Blue Heron optimizes survival across its entire life cycle from nestling to breeding adult.

That's it for this post! Thanks for reading!

Tuesday, January 19, 2016

The Cottonmouth

From December 27th, 2015, to January 4th, 2016, I took a solo road trip to South Carolina and the Great Smoky Mountains in North Carolina and Tennessee. I traveled 2060 miles total, and saw a great deal of amazing things. I'm slowly moving through photos, but I've decided to make my first post about one of the most exciting lifers I had over the trip: the Cottonmouth. The Cottonmouth, also commonly known as the Water Moccasin, is a much-maligned snake species. There's many myths and just plain misinformation surrounding this interesting species, and this post will hopefully bring some truth to the matter.

Cottonmouth threat display
On December 29th, I traveled from my campsite in Francis Marion National Forest to the nearby Hampton Plantation State Park, one of the many state parks in South Carolina. As you might have guessed from the name, Hampton Plantation SP is an old plantation. As with many old plantations in South Carolina, the Hampton Plantation specialized in rice. Rice is grown in shallow ponds, and so a series of such ponds were dug out by slaves here at the Hampton Plantation in the first half of the 1800's. Water from the nearby Hampton Creek was used to flood the ponds, and a series of levees throughout the flooded fields were used to control water levels. Rice is no longer grown at the Hampton Plantation, and these flooded fields have reverted to a swamp along the Hampton Creek. And with that reversion, various organisms that live in swamps have returned. One of these organisms is the venomous Cottonmouth, Agkistrodon piscivorus, pictured above.

The range of the Cottonmouth.
The Cottonmouth is a snake of the southern Atlantic coastal plain and the lower Mississippi River basin. Now, one of the biggest snake-related myths that I hear throughout Ohio is that the Cottonmouth (AKA Water Moccasin) can be found in Ohio. This is completely untrue. The Cottonmouth can be found nowhere in Ohio. Regardless of what anyone might say, the Cottonmouth's range just doesn't extend into Ohio. There has been 1 record of a Cottonmouth in Ohio, but the story isn't what it seems at first glance. A Cottonmouth was once found on a shipping boat on the Ohio River while within the state borders. This ship had just come from southern Illinois where the Cottonmouth can be found, and one individual had stowed away on the ship to rest and was unknowingly transported to Ohio. However, since the snake naturally climbed onto the ship, the record technically counts.

Water Moccasin South Carolina
The Cottonmouth, as you might know, is a venomous snake. This brings me to a slight tangent: the snake is venomous, not poisonous. There is a difference between the two. If a creature injects a dangerous substance into you, then that creature is venomous. If a creature is poisonous, however, that means that a dangerous substance on or within a creature must be ingested for it to take effect. An easier way to put it is "If it bites you and you die, it is venomous; if you bite it and you die, it is poisonous." For example, a Cottonmouth is venomous while a Monarch is poisonous. Although highly uncommon, it is possible for an organism to be both venomous and poisonous at the same time though; for example, the Asian Tiger Snake, Rhabdophis tigrinus, is both at the same time (it has fangs which can inject a venom, but also secretes a poison it obtains from eating certain poisonous toads).

Anyway, the Cottonmouth is indeed dangerous, however they don't pose a threat to a cautious human aware of their surroundings. Although they are supposed to be highly aggressive (which is a myth), Cottonmouths, like all venomous snakes (and snakes in general), prefer to not attack anything they deem a threat. There's a few reasons for this. When a snake goes to bite you, it risks breaking a fang/tooth, which can lead to a much harder time obtaining food. Also, by biting any sort of animal, a snake opens itself up to being attack, and possibly killed, out of defense. When the ultimate goal of life is passing on your genetics as much as possible, dying is obviously something to avoid. In addition, when it comes to venomous snakes, venom is expensive to produce energy-wise. They use this venom to hunt, and therefore they want to conserve venom (and therefore energy) and use it only when needed. Needlessly wasting venom when it could just slither away is a silly choice for a snake to make.

Cottonmouth display

So, when would a snake bite then? Generally speaking, a snake will bite when it feels that its life is in immediate danger from you, and that the only way to escape this danger is to try and fight the threat off. It is important to note that the biting threshold varies not only from species to species, but also from individual to individual. Regardless, picking a snake up, poking it, stepping on it, attempting to move it, and other such actions usually push the snake past that threshold, and a snake will be very apt to bite from then on out. When it comes to the Cottonmouth, one study found that they would essentially only bite if they were picked up with a mechanical hand. If you give a snake space, and let it have obvious means of escape, then it will simply leave you alone. This includes Cottonmouths.

Cottonmouths also have another line of defense. The name "Cottonmouth" stems from their threat display; when confronted by a potential threat, they open their mouth to reveal a startling-white inner-covering. This white stands out in stark contrast to the browns and greens of the vegetation which you might see them among. It's meant to not only catch your attention, but to also suggest that it's a dangerous creature and not one to mess with. Essentially, the potential threat (in this case me) is supposed to think that this snake wouldn't obviously expose itself unless it had a good way to protect itself. It's the same principle as the brightly-colored Monarch, a poisonous butterfly.

Water Moccasin basking
I was a few feet away from him taking photos as he did his threat display. Eventually he realized that I didn't pose an immediate threat, and he slowly closed his mouth while still eyeing me closely.

Water Mocassin swimming
He then decided to explosively leave the scene and slither into the nearby water. The Cottonmouth, a semi-aquatic snake, is at home in nearly all types of freshwater habitats throughout much of the Southeast. They can be found most commonly in heavily-vegetated marshes, Bald Cypress Swamps, and river floodplains. The old rice fields where this individual was found, for example, lie in the South Santee River floodplain, close to the river itself. The Cottonmouth isn't completely aquatic, however, and can sometimes be found far from water in places like fields and other random places. They are an adept swimmer and prey mostly on fish and amphibians, but will also feed on birds, mammals, small turtles, and even small Alligators!

Northern Watersnake
A harmless Northern Watersnake, NOT a Cottonmouth!
Photo by Alayna Tokash.
As I mentioned earlier, there are no Cottonmouths in Ohio. And yet every year people swear up and down that they saw one somewhere in Ohio. So what are they talking about? The vast majority of the time, what they actually saw was a Northern Watersnake, Nerodia sipedon, pictured above. These harmless snakes are very common in Ohio, and they are superficially similar to the Cottonmouth in both appearance and behavior. As their name suggests, the Northern Watersnake is also semi-aquatic, but when people see a snake in the water they always seem to jump to the Cottonmouth. There are a few differences between the two species: Cottonmouths are much more bulky, have a triangular head, have heat-sensing pits near their eyes, and have vertical pupils in the shape of slits. On the other hand, Northern Watersnakes are slender, have a round head that isn't overly distinct from their body, have no pits, and have round pupils. Of course, telling the difference between the two isn't a problem in Ohio as we only have the Northern Watersnake. There are other Nerodia sp. water snakes down in the range of the Cottonmouth, but the general differences listed above hold true. And as with any animal, if you do not know for certain what an animal is, give it plenty of space and leave it alone. It is safer to wrongly assume something is very dangerous than to assume something very dangerous is harmless!

The Cottonmouth was a very exciting snake to see, and I'm incredibly happy I ran across one while on my trip. Although many people hate the Cottonmouth, they really pose no threat to the person who's aware of their surroundings and who gives these snakes their space. That's it for this post! Thanks for reading!

Tuesday, January 12, 2016

A New Year (General Update)

It's currently January 12; 2015 is now over, and 2016 has arrived. This blog has kind of been all over the place recently, and so I wanted to give an update over the state of this blog, what my plans are for it, and also give a review of 2015 and some potential future events/subjects for 2016. Basically, I want to regroup my thoughts.

Olivia and I on top of Breathed Mountain in the Dolly Sods Wilderness, West Virginia.
First, a bit about my experience with 2015. It was an absolutely amazing year, probably the best year of my life so far when I think about it. I fulfilled many dreams and goals that I had for years and years. I finally had the chance to travel like I've never traveled before. Up until 2015, I was lucky if I traveled out of Ohio at any point during the year. Over the course of 2015, I ended up traveling to 16 states, including 10 I've never been to previously. I finally got the chance to go out West and see deserts, steppe grasslands, and high mountains. In March I camped in 15 inches of snow at 7,000 feet above sea level, and then in September I camped along the beach at about 3 feet above sea level. I went on several backpacking trips and ended up climbing my first mountain (although it wasn't that tall). I also had the chance to go caving, and ended up traveling a mile under a mountain in Virginia while going through incredibly tiny squeezes and past giant chasms. I spent my summer helping with salamander research across northern Ohio, finally getting the chance to explore the one section of Ohio I really hadn't yet. I saw many new creatures, including my first venomous snakes, dozens of new bird species, and more. My top sightings for the year include a California Condor (AZ), Northern Gannets (SC), Cave Salamanders (VA), Timber Rattlesnakes (OH), a Cecropia Moth (OH), Long-Tailed Skippers (SC), Crested Coralroot (OH), and so many more things I won't even begin to name. In addition, my year at Ohio University has been exceptional; I've gotten involved in a lot of research, I'm an officer in the Ohio University Wildlife Club, and my classes and the OU Outdoor Pursuits have exposed me to a whole new world essentially. And finally, I've met some absolutely amazing people throughout the year.

Anyway, onto the blog. I recently went on a 2060 mile solo road trip from December 27th to January 4th. I spent most of that time along the coast of South Carolina, and naturally I came across some cool stuff while down there. The next several blog posts I'm going to be writing will be covering some of the highlights from that trip. These posts will cover subjects including Cottonmouths, Corn Snakes, Little Blue Herons, and more, so stay tuned!

The La Sal Mountains as seen from Arches National Park.
The highlight of the year was a 5,000 some mile road trip out to the Southwest with the Ohio University Outdoor Pursuits, an absolutely wonderful group of outdoor-minded people. By way of a mini-bus (which knows no bounds), we visited several national parks, drove through the Painted Desert, passed tall mountains, and so much more over the course of Spring Break. This trip happened way back in March, and I've been putting off all posts pertaining to this trip for nearly a year now. So far I've only written a post on Petrified Forest National Park, which you can read here. Once again, this trip is going to be put on the back burner until I get through my more recent road trip material. But once that road trip is done, expect several posts on places out West!

The Grand Canyon during winter.
This leads to the next point I want to make. As you might know, I recently changed the URL of this blog. It was originally www.ohionature.blogspot.com, but it is now www.kylefromohio.blogspot.com. This change is due to my planning for the future. I am currently in my junior year of college. Once I graduate, I will have a degree in Wildlife and Conservation Biology. I plan to spend some time working seasonal field technician jobs upon graduation. The thing about these jobs is that they can be wherever. I don't plan on staying in Ohio for the rest of my life, and I decided it was kind of silly to have a URL of "Ohio Nature" if the posts aren't necessarily always (or at least a majority) from Ohio. In my opinion, it is better to have a more vague URL, and then simply tailor the blog name to whatever you want it to be. Of course, changing the URL proved to be a bigger deal than I had imagined; my pageviews took a dive bomb, and my blog disappeared from Google search for awhile. I later learned this is a normal reaction to a URL change, but it also shows that if you are going to change the URL, it is best to do it as early as possible. Since then, my posts are slowly being added back to Google search, and pageviews are increasing. Most of my pageviews came from people searching keywords such as "Spiders in Ohio," and Google then directing them to related posts of mine. The URL change basically ended that, but it is slowly coming back as my posts are re-cached.

What does this all mean for the future? Put bluntly, this blog will probably end up not being Ohio-based at some point in the future. There will most likely come a point where I will change the name of the blog (to what, I don't know). I do know that this blog will eventually become based around nature as a general subject, and not as a regionally-specific nature blog like it is now.

The view of the Great Smoky Mountains from the Blue Ridge Parkway. Taken this year during my winter break road trip.
I still have over a year until I graduate, so there won't be any name changes yet, but it will happen eventually. I have no idea where I'm going to end up yet, but I'll always be covering interesting things I come across!

That's about it for this yearly update. Stay tuned for some South Carolina based posts! Thanks for being a reader!