Interesting Facts About Great Blue Herons

Great blue herons (Ardea herodias) are River Legacy native birds that can be seen year-round. Though they are a rather common sight near bodies of water and most people are familiar with them, did you know these interesting facts about them?

  • Great blue herons are the largest North American herons! They can be up to 54 inches tall and have a wingspan of up to 79 inches.
  • Despite these measurements, they barely register a weight of about 5 to 6 pounds. This is mainly due to the fact that their bones are hollow, a characteristic they share with most birds.
  • Because of special neck bones, they can be incredibly fast hunters at a distance. This is especially striking when they are hunting for fish.
  • They build their nests usually on trees in colonies. These large colonies can, sometimes, have up to 500 nests!

Next time you are taking a walk through River Legacy, be on the lookout for great blue herons in a pond or creek. In addition, our annual Great Backyard Bird Count Festival is coming up on February 17th from 10 A.M. to 2 P.M. There will be bird hikes throughout the event and perhaps a great blue heron can be spotted that day! You can also learn more interesting facts about other species of birds. More information about the event can be found here.

Great blue herons and their nests
Great blue heron showing its characteristic, S-shaped neck

The beauty of Frostweed

When the thermometer drops to below freezing, there is a plant found at River Legacy that forms captivating ice structures on its body. The aptly named frostweed or the white-crowned beard (Verbesina virginica) forms ribbon-like ice structures when the stem opens up during a freeze and the sap comes out of the plant frozen. This only seems to occur at the base of the plant, near the ground. These formations are sometimes also referred to as crystallofolia, meaning “leaves of crystal.” There is no evidence to suggest that the plant is permanently damaged by this phenomenon. These past couple of weeks, as the area succumbed to one of the coldest winters in years, some frostweed ice “ribbons” were observed in the woods of River Legacy. Winter is not over yet. If there is another freeze, it is possible that these plants could display their ice structures once again. But, if you do miss them this winter, do not forget to come back next winter and take a walk through the trails at River Legacy to see them!

Winter At River Legacy

Winter is in full swing at River Legacy and plants and animals have to adapt to the changing season. Winters tend to be mild in North Texas but temperatures still drop to freezing and below, as it has been the case for a few days in the past couple of weeks. How do the animals and plants survive the cold?

It turns out that many species have unique adaptations that allow them to survive the harsh conditions of this season. Let us take plants, for example. Annuals, plants that live for only one growing season (usually spring to fall), survive the winter as seeds in the soil. The soil tends to be warmer than the surface, which allows for the seeds to survive. Perennials, plants that live year after year, survive in a different manner. They can go into a state of dormancy (trees losing their leaves, for example), which is akin to mammal hibernation. In addition, if it gets too cold, some plants can produce chemical substances that lower the freezing point of the fluid inside their cells and in between their cells, so that ice crystals do not form and kill the plant from the inside.

Animals too have to cope with the freezing and sub-freezing temperatures. Some mammals hibernate, meaning they basically shut down for the entirety of winter and sleep in a warm place. Others can find a nice den and stay there most of the time for the coldest part of the winter. Fox squirrels (Sciurus niger), a very iconic River Legacy mammal, will build dreys and also share their dens with other squirrels to keep each other warm. They also prepare in advance by increasing their food consumption and caching in the fall so that they have enough from which to survive in the winter. Reptiles, being cold-blooded, cannot survive drastic drops in temperature so they find a warm shelter and go into a state similar to hibernation called brumation. The difference is that reptiles can wake up from this state if a warm winter day happens to arrive. Aquatic reptiles and fish will hang out at the bottom of their habitat (creek, pond, river, etc.), where it is warmer and slow down their metabolism. Birds will either migrate, hunker down, get together in groups, shiver to increase body temperature, and cover their feet with their downy feathers when sitting down.

Next time you use the walking trails at River Legacy when it is cold, think about the animals and plants all around and their incredible adaptations that enable them to survive!

Animal tracks in snow from a couple of years ago at River Legacy Living Science Center.
Top layer of Snider Creek frozen. Clump of leaves frozen in place can be seen underneath. January 2018

Bird winter migration is here!

Late fall and winter are perfect opportunities to go birding and see species not seen typically at other times during the year. Several species of birds are now migrating south to spend winter in warmer places. River Legacy sits right in the heart of the Central Flyway, which is one of the main bird migratory routes in North America.

Some of the birds that can be seen this time of year include the cedar waxwing (Bombycilla cedrorum), white-throated sparrow (Zonotrichia albicollis), ruby-crowned kinglet (Regulus calendula), yellow-rumped warbler (Setophaga coronata), lesser scaup (Aythya affinis), northern shoveler (Anas clypeata), and hermit thrush (Catharus guttatus), among others.

In addition to these birds, other common species such as the downy woodpecker (Picoides pubescens), northern cardinal (Cardinalis cardinalis), Carolina chickadee (Poecile carolinensis), and  great blue heron (Ardea herodias) can be seen this time of year as well.

River Legacy is the perfect place to check some winter species off your list.  In fact, from December 14th to January 5th, thousands of people around the nation are engaging in bird counts for the annual Christmas Bird Count. In addition, we encourage you to visit us February 17th for our Great Backyard Bird Count Festival. River Legacy is proud to participate in this global count, hosted by the Cornell Lab of Ornithology and the National Audubon Society. There will be bird counts, games, crafts, and activities celebrating the avian world.

Lastly, make sure to keep up with the latest bird sightings at River Legacy by following our Birding Blog, which can be accessed through the link to the left of Nature Notes Blog on our website. Happy winter birding!

Downy Woodpecker
Female Lesser Scaup

Beautiful Autumn Colors

As we welcome December, the end of fall is fast approaching. In fact, there are only 17 days left of autumn. While River Legacy and North Texas in general do not see much traditional autumn foliage, there are a few trees that exhibit some fall hues. By now, most of the leaves have begun to fall to the ground, but there are still some trees with their green, orange, brown, red, or yellow foliage.

But, what drives the leaf color change? It has to do with the chemistry inside the leaves and how it responds to seasonal changes. Leaves contain many pigments, including chlorophyll as well as carotenes, xanthophyll and others. Chlorophyll is probably the one most of us are familiar with. This is the pigment that gives leaves their green color. When a plant undergoes photosynthesis, the process by which it creates its own food, chlorophyll takes center stage. It absorbs energy from the sun’s rays to be used in creating this food. As autumn approaches, the temperature gets cooler and the length of sunlight the leaves receive shortens. This causes chlorophyll to break down, making the green color go away. So, leaves are left with the other pigments and these become visible. Carotenes and the other pigments give leaves their yellow to orange colors in the fall. There are other chemical processes at work that add the red hues that are commonly seen as well.

Eventually, the leaves break off the tree. Since trees will no longer be able to make their food during the winter, they go into a state of dormancy where their metabolism slows down. It is a process that is very similar to animal hibernation. The trees are not dead during this time, contrary to what it might seem.

Before all of the leaves fall in a few days, come take a walk at River Legacy to catch a glimpse of some of the beautiful tree color changes in the park and Science Center grounds.

 

What is basking?

Whenever you take a walk through the woods, you might see lots of reptiles and amphibians enjoying a sunbath. Turtles usually gather on top of a log, all lined up neatly one behind the other. Sometimes, they decide to take in the sun just off the side of a creek or river. Snakes and lizards usually like to receive the sun’s heat just off the side of a trail or on top of a log or surface. Amphibians, likewise, exhibit similar behavior.

But, have you ever wondered why these particular animals do this? What reptiles and amphibians are doing is called basking. Basking is the action of receiving warmth directly from a heat source, such as the sun or a heat lamp, by simply standing or sitting under it. Both reptiles and amphibians are ectotherms, which means that they are not able to regulate their own body temperature in the same way that other vertebrates, such as mammals or birds, can. Sometimes, this is also referred to as being “cold-blooded.” Their body temperature basically depends on their environment. Basking allows these animals to be able to obtain the energy that they need in order to move about, find food, mate, and all the other things that they need to do. This is the reason why, if a reptile or amphibian gets cold, it starts acting in a very sluggish manner.

Next time you visit River Legacy Living Science Center, take a close look at our pond. In it, you will find a small island in the middle that is a very popular spot for basking turtles. You can also search for basking lizards on any surface where the sun is hitting.

Have you seen box turtles yet?

Box turtles are small turtles in the genus Terrapene. They have a dome-like shell that has a hinge at the bottom, allowing the turtle to close its shell completely in order to escape predators. Males are characterized by having usually red or orange eyes while females have brown eyes. River Legacy Park and the woods adjacent to River Legacy Living Science Center are home to two species of box turtles: the three-toed box turtle (Terrapene carolina triunguis) and the western ornate box turtle (Terrapene ornate ornata).

The three-toed box turtle is a subspecies of the common box turtle (Terrapene carolina). As the name indicates, this turtle has three toes on its back feet. These turtles can be found walking through the forest looking for food including vegetation, small insects, mushrooms, fruits, earthworms, and snails. The males of this turtle can sometimes exhibit orange or red spots on its throat and head. Three-toed box turtles will bury themselves underneath the leaf litter during the dry season to try to conserve moisture.

The other River Legacy box turtle, the western ornate box turtle, is a subspecies of the ornate box turtle (Terrapene ornata). It is characterized by ornate patterns on its shell, which are usually bright yellow. In contrast, the three-toed box turtle does not have these patterns. Males of this species tend to be a bit smaller than the females and also tend to have a thicker tail. Ornate box turtles tend to prefer grassland or prairie habitats rather than dense forest though they will also venture into the woods.

Box turtles can live up to their 30’s, which is fairly long for a small animal. As you walk through the trails of River Legacy, keep your eyes open and you might spot a box turtle walking through the woods. In addition, do not forget to visit River Legacy Living Science Center to see a three-toed box turtle in our exhibit hall!

Three-toed box turtle

Osage Oranges: Ancient Dwellers Of River Legacy

As you walk the trails at River Legacy, you probably have already noticed large orange-looking fruits on the ground. They are typically green in color.

These fruits belong to the Osage orange tree (Maclura pomifera). It is a relatively small tree (reaching about 30 to 50 feet tall) that is native to this area of the state. Despite its appearance and name, this plant is not related to oranges at all. In fact, it is a member of the mulberry family, the Moraceae. It is named after the Osage Native American tribe of Missouri.

Nowadays, it has been spread by people to 39 states in the United States and parts of Canada but its natural range only included the Red River drainage in Oklahoma, Texas, and Arkansas. River Legacy sits right in the heart of this tree’s natural range. There is evidence that in prehistoric times, its range included a much larger area in the central part of the North American continent. In fact, some scientists have proposed that it once relied on megafauna animals that lived hundreds of thousands of years ago such as giant ground sloths (genus Megatherium) and perhaps even Columbian mammoths (Mammuthus columbi) to disperse its seeds. The large animals would eat the fruits and disperse the seeds via their droppings.

Next time you take a walk at River Legacy and see Osage oranges on the ground or squirrels feeding on them, just think to what the park might have looked many hundreds of thousands of years ago with giant ground sloths and/or mammoths feasting on them. In fact, fall is a great time to come and see Osage oranges on the ground. As you walk from the parking lot to the inside of River Legacy Living Science Center, there are a couple of Osage orange trees that you can appreciate!

Osage Orange Tree Bark
Osage Orange Fruit

Snake Sightings On The Rise Again

Most species of snakes breed in the spring and summer, which is why most people see them during these two seasons. But, snakes can also be a common sight in the fall. With fall upon us, it is important to know what to do if you encounter a snake in the wild.

But first, it is worth knowing why snake sightings are a common fall occurrence as well. There are a few reasons for this. One, baby snakes usually are born in the summer. Fall is the perfect time for those that survived to start looking for their first meal before winter comes.

In addition, both adult and baby snakes start to search for safe places to hide where they will spend most of the winter in brumination, which is a term for the slowing down of their metabolism.

Copperhead (Agkistrodon contortrix)

Lastly, some species of snakes also breed in the fall. A couple of examples include the rough green snake (Opheodrys aestivus) and the copperhead (Agkistrodon contortrix).

If you encounter a snake along a trail, be sure to observe from a distance. Most snakes will move quickly off the path while others might stay as still as possible. If you can, walk around the snake, giving it a wide berth.

The best course of action is to leave it alone and observe or take pictures from a distance. Most snake bites occur when people try to pick up, move or kill a snake, all of which are unnecessary. Another way to avoid snake bites is to always be mindful of where you are stepping or placing your hands while hiking a trail that is either paved or off-the-beaten path. Be sure to look where you are walking and never reach down to grab something unless you have complete visibility.

Be sure to learn more about snakes at River Legacy Living Science Center!

Nature At Night

Most of our encounters with nature occur during the day, whether it’s hiking, or walking in a park and seeing plants and animals all around us. But, did you know that nature is just as active, if not more active, at night?

There are several species of animals that are strictly nocturnal. In August, we talked about why certain animals have evolved nocturnal behaviors. After Dark In The Park is coming up here at River Legacy Oct. 6th-8th. So, we think this is a good time to revisit the topic of nocturnality a bit more in depth with a couple of examples.

When you are out in nature at night, you may be able to spot some species of nocturnal animals. Bats (Order Chiroptera) are well adapted to night life. Some bats have evolved echolocation to find their prey, which includes flying insects such as moths and mosquitoes. Echolocation just means that bats emit sound waves and are able to detect when they bounce off their prey to determine where it is. Some common species of bats in this area include the Mexican free-tailed bat (Tadarida brasiliensis), the Eastern red bat (Lasiurus borealis), and the hoary bat (Lasiurus cinereus). When you are attending After Dark In The Park with us, take a few seconds to look up, especially near light posts, and see if you can spot any bats!

Other nocturnal animals that you might see or hear while being outdoors at night are owls, raccoons, and opossums.

Be sure to come out to After Dark In The Park and do not miss the fun, which obviously includes experiencing the forest at night. For more information about the event, please visit www.riverlegacy.org.

Eastern red bat