Christmas is for the Birds

This year is the 120th annual Audubon Christmas Bird Count. It began December 14th and runs through January 5th. The tradition started in 1900 in at the beginning of the conservation movement. Since the beginning, citizen scientists have used the information gathered to track trends in bird populations.
I took part on December 15th and had an eventful and cold day. Once again, I put my discomfort aside for the sake of nature. The day began at 4 AM with three hours of owling. My partner Chris drove us around to a few sites where we'd listen in the dark for owl calls. In an attempt to draw them out, he played owl calls on his phone. We heard a screech owl at one location and a pair of great horned owls in a duet at another place.

Great horned owl

After a pit stop around 7 AM we picked up the third member of our trio at sunrise and began our visual observations with nearly three dozen turkey vultures overhead near a roosting site. I happen to know about this roost because I drive past it on the way to and from work, and depending on my schedule I see the vultures either leaving for the day or returning for the night. Right away my presence paid off. In past years, Chris and John start their count headed the other direction.
Over half our time was spent in the car. Much of what we saw was from the road. We did some walking though, and it was tough in some places. Recent rain meant soggy ground. It's December and Pennsylvania, which is rarely a good combination. In addition to the cold, it was windy. The wind made for great raptor conditions, but bad for everything else. It was difficult to hear bird calls over the sound of the wind. Watching for motion in the trees and bushes was confusing because everything was moving.

Turkey vulture

This year we counted 47 different species, and a total of 735 birds. In 2018 we counted 38 species and 754 birds. Canada geese were the big winners this year, coming in at 266. However, they were mainly in two flocks. The birds we spotted the most times were turkey vultures and house finches. I look forward to counting more birds in 2020!

Canada goose

Species of the Month

Christmas is upon us once again and in keeping with tradition, we have another festive Species of the
Month. American mistletoe, like its European cousin, is a Christmas symbol dating back to the arrival
of European settlers who brought their customs with them. The mistletoe association with Christmas
dates back hundreds of years before Europeans reached American shores. Learn more about this little
plant below!

American mistletoe

Scientific name: Phoradendron leucarpum

Kingdom: Plantae (plants)

Class: Magnoliopsida (dicots)

Order: Santalales (hemi-parasitic plants)

Range: Eastern and Southwestern US

Habitat: Forest, swamps, and desert

Diet: Sunlight and water for photosynthesis; xylem and phloem of host plant through parasitism

Predators: Birds and small mammals

Conservation Status: No special protection

Mistletoe berries

Other Information: While it may bring good luck to have mistletoe in your home during Christmas, it
certainly isn't lucky to eat the berries. They are poisonous to humans, though not usually fatal. Mistletoe
is hemi-parasitic, meaning it is a parasitic plant but can also photosynthesize. Berries contain a single
seed, which is spread by when birds defecate after eating the berry. The seed is sticky, and with any
luck the bird will be sitting in a tree when it passes. This sequence of events gave mistletoe its name.
"Mistle" the Anglo-Saxon word for dung, and "tan", the word for twig were combined, as folks in
those days noticed mistletoe grew were birds left dung on the branches. Because it seems to grow out
of nothing, mistletoe was thought to have fertility properties. Mistletoe acts as a parasite by growing
a root-like haustorium (your big word of the day) through the host tree's bark and tapping into its sugars
and water. Parasitization can cause the host tree to become deformed or distorted.

Pine tree with deformations from mistletoe

This week's pictures and information come from University of Wisconsin at LaCrosse.

A Breath of Fresh Air

If you like fresh air, you're probably a big fan of the Clean Air Act and its amendments. While the air in many places is far from ideal, prior to federal legislation it was downright deadly in American cities. A clear gray sky on a summer's day in Philadelphia is a little off-putting, but it beats a smothering fog in the valleys outside Pittsburgh. After the deadly Donora smog in 1948 killed 20 and sickened thousands of others. Federal investigators were asked to come in, and determined that air pollution was in fact the killer, among other factors.

Donora smog, 1948 (Smithsonian)

The government prefers to take baby steps when implementing positive change, rather than jumping in feet first, and tackling air pollution is no exception. The first step came in 1955 with the Air Pollution Control Act, which provided funding for research and led to the Clean Air Act of 1963 and Air Quality Act of 1967. These provided the first air quality monitoring.

Pittsburgh in the 1940s (Citylab)

The Clean Air Act of 1970 was a major step forward. It developed limits on pollution and expanded federal enforcement powers. Among the controls included were auto emissions. States were mandated to implement plans to reduce pollution.
The Amendments of 1990 aimed to reduce air pollution linked to acid rain and ozone depletion.
Looking at a picture of the summer sky over Los Angeles, it might be hard to believe the Clean Air Act is working. However, the number of ugly sky days is lower than prior to enactment. Air quality monitors in California frequently show poor quality, and geography is partly to blame. Ocean breezes carry pollution as far as the mountains, where it gets stuck and sometimes builds up for days.

Los Angeles skyline (LAist)

Acid rain has been reduced as a result on the 1990 amendments. pH testing has shown freshwater pH levels in many areas have risen closer to neutral 7. Pure water is neutral, but in nature, water is rarely pure. Pristine rain is slightly acidic because of carbon dioxide in the atmosphere forming carbonic acid. However, the lowered pH in rivers and lakes nationwide was far lower than caused by carbonic acid. Targets of the 1990 amendments were nitrogen oxides (NOx) and sulfur dioxide (SO2). Emissions have been greatly reduced over the last 30 years, and ecosystems are continuing to slowly recover.

Visuals of higher pH meaning less acidic water samples
(National Atmospheric Deposition Program)

Information this week comes the EPA (Clean Air Act overview), Smithsonian Magazine (Donora), and more EPA (acid rain). For a great visual on showing higher pH and lower NOx and SO2, check out the National Atmospheric Deposition Program.

EPA: https://www.epa.gov/clean-air-act-overview/evolution-clean-air-act
Smithsonian: https://www.smithsonianmag.com/history/deadly-donora-smog-1948-spurred-environmental-protection-have-we-forgotten-lesson-180970533/
EPA: https://www.epa.gov/airmarkets/acid-rain-program
nm1 LAist: https://laist.com/2018/10/30/why_las_smog_has_been_extra_smoggy.php
nm2 Citylab: https://www.citylab.com/design/2012/06/what-pittsburgh-looked-when-it-decided-it-had-pollution-problem/2185/
nm3 Smithsonian
nm4 National Atmospheric Deposition Program http://nadp.slh.wisc.edu/data/animaps.aspx

Species of the Month

With Thanksgiving just a week away, once again we turn our attention to the dinner plate. In years past, November's Species of the Month has featured the wild turkey, venison, and clams that were likely present at the first Thanksgiving. This year, we look at a staple of the modern celebration, the North American cranberry.

Whole berry cranberries (UWLC)

Scientific name: Vaccinium macrocarpon

Kingdom: Plantae (plants)

Class: Magnoliopsida (dicots)
Order: Ericales (heath)

Cranberries on the shrub (UWLC)

Range: US west coast, northeast US and Great Lakes areas
Habitat: Bogs with acidic soil
Diet: Water and sunlight
Predators: Bears, rodents, birds, deer, humans
Conservation Status: Listed as endangered in Illinois and threatened in Tennessee

Cranberry bog

Other facts: Cranberries grow in freshwater peat bogs. They are grown commercially for use in food products. The best use is the canned jellied cranberry. Cranberry plants are useful as a food source for animals. Birds, bear, and rodents eat the berry, while deer browse the shrub. Birds and rodents also use the stems for nesting material. Birds may also build a nest in the shrub. Cranberries also form a symbiotic relationship with fungi, giving up sugar in exchange for access to soil nutrients. Cranberries can survive being submerged for long periods, and even being kept on ice over the winter.

Cranberry flower (Cape Cod Cranberry Growers)

This week's information comes from Cape Cod Cranberry Growers Association, USDA PLANTS, and University of Wisconsin- La Crosse. Pictures, except the flower, are also from University of Wisconsin- La Crosse.

Transit of Mercury

Frequently, we observe solar and lunar eclipses here on our blue marble we call Earth. Solar eclipses are when the moon passes in front of the sun. Lunar eclipses are when Earth cuts between the sun and moon, with the moon covered in our shadow. Less commonly observed are planetary transits. Because we live on the third rock from the sun, we only get to see Mercury and Venus pass in front of it. Because orbits wobble and planes aren't aligned, this is something that is only seen a few times per century.

Transit of Mercury as seen with the unaided eye

Mercury transited the sun on November 11. Because the sun is so bright and Mercury is so small, a telescope with solar filter is a requirement to witness the event. I took a field trip to Philadelphia's Franklin Institute to see it for myself with their telescope. Because seeing Mercury normally requires a clear horizon at sunrise or sunset, most folks don't get to see it. This was my first time, and now I've finally seen all six naked eye planets- I included Earth, which I see every day.

Franklin Institute's telescope with solar filter

I got a shot of Mercury being live-streamed on the big screen

Sadly, I wasn't able to get my own pictures of Mercury, but I did get pictures. NASA was live-streaming and has a video up on their Youtube page. If you want to see a Mercury transit live and in person, you'll have to wait until 2032. You'll need to be in Africa, eastern Europe, or western Russia to see it. Otherwise, the next transit here in the states won't be until 2049. But if you think that's bad, the next transit of Venus won't happen until 2117.

NASA posted this picture of a prior transit on their Facebook page.
The little black spot on the bottom is Mercury. The one on
the top is a sunspot.

Changing Leaves

Fall is in full swing. The sun keeps the air warm, but it's chilly in the shade. Honking geese fly overhead and crickets chirp throughout the lengthening nights. Dried leaves swirls about in the breeze, while those still in the trees for a riot of color. What is going on inside the tree that causes the color change?
Trees are getting ready for a long winter's nap. Like animals going into hibernation, everything is slowing down. Trees have been gorging themselves on sunlight all summer, and now their metabolism is slowing down. The chlorophyll is breaking down and water uptake is stopping. Chlorophyll absorbs all wavelengths of light except green, which is reflected back to us. Without chlorophyll, we see other chemicals in the leaf.

A yellow sugar maple catches the late morning sun

The yellow leaf of a sugar maple

Xanthophyll colors the leaves of aspens, birches, and beeches a bright yellow. It's also found in corn.  Red and purple in red maples and scarlet oaks comes from anthocyanin, which is produced when the chlorophyll stops and the leaf metabolizes extra sugars. Carotene, the same as what you find in a carrot, gives trees like sugar maple and sassafras their orange leaves. Orange can also come from a leaf that is showing both xanthophyll and anthocyanin. Brown, such as in oaks, comes from tannins. Carotene and Xanthophyll are present all year in the leaves, but are overshadowed by chlorophyll.

Another sugar maple, this one decked out in red

This red sugar maple leaf fell of a Canadian flag

The brilliance of each color, as well as the amount of colors relative to each other, are dependent on the weather. If fall is sunny and dry, trees will produce more anthocyanin. Trees will be a more brilliant red. Other years, trees won't produce as much or even none at all and nearly all leaves will change to yellow.
But of course, each tree is an individual so it may change well before its neighbor or have different or more vibrant colors, even among the same species. I've seen red maples that look like traffic lights with red, yellow, and green leaves on the same tree. I've even seen multi-colored leaves.

Brown oak leaf, rich in tannin

Yet another sugar maple, this time in orange

Get out there and enjoy some biochemistry in action before it's too late! The leaves have been great this year, peaking in my area this week and next. Up north you may be past peak, and down south it's on its way! This week's information comes from SUNY College of Environmental Science and Forestry and Montana Natural History Center.

Yellow and brown hickories and oaks basking in late
afternoon sunshine

Species of the Month

With Halloween right around the corner, October's Species of the Month is another creepy crawly. You might be afraid of spiders or bats, but no one wants to see a rat in the house. This month we profile the ubiquitous black rat (AKA house rat, AKA roof rat, AKA ship rat), destroyer of crops, chewer of things, and spreader of plague. 

Halloween rats from Pintrest

Scientific name: Rattus rattus
Kingdom: Animalia (animals)

Class:  Mammalia (mammals)
Order: Rodentia (rodents) 

Range: Worldwide; native to India and Southeast Asia
Habitat: Almost anywhere
Lifespan: Average 1 year, up to 4 years

Black rat (Inventaire National du Patrimoine Naturel)

Diet: Omnivorous, but mainly plant-based (fruits, grains, seeds)
Predators: House cats, birds of prey, foxes, coyotes
Conservation Status: No special protection
Other facts: The black rat was spread around the world by travelers. They are also called ship rats because if their affinity for sailing to new homes on distant shores. The moniker roof rat comes from their climbing skills. They are an invasive pest everywhere outside of their native range, ruining food stores by soiling what they don't consume. They were a disease vector during the plague outbreaks of Medieval Europe, carrying fleas that hosted the virus. While plague is not as serious a threat as it was in the Dark Ages, the fleas on a rat can still spread other diseases to humans and livestock. A similar species, the Norway rat, is just as widespread and will kill the smaller black rat. Despite the headaches caused by both rats, they are important links in the food chain now that they've become established. Hawks, owls, coyotes, and foxes are among their main predators.

Black rat (Australian Environmental Pest Managers Association)

This month's information comes from the University of Michigan's Animal Diversity Web once again.

nm1: 
nm2: https://www.aepma.com.au/PestDetail/96/Black%20Rat

Firefly Watch 2019 Results

Beginning in late May and concluding in September, I conducted observations for Massachusetts Audubon again this year. I count how many flashes I see in three separate periods of ten seconds each. I usually separate those periods by five to ten minutes, to allow for increasing level of darkness. Mass Audubon asks for data other than how many flashes. They also want time and date, weather conditions (cloud cover, precipitation, wind, and temperature), flashing patterns (single flash, double, triple, J-shaped), and color of flashes. Weather may affect firefly behavior, while color and pattern indicate separate species of fireflies.
After two years of submitting observations for my location (my parents' back yard), I don't have enough data to notice any population trends yet. To track population trends, I tried my best to conduct observations on the same dates as last year. This wasn't always possible, like the night I had to chose between fireflies and my daughter's graduation. Guess who won.

Graph of 2018 firefly flashes

Comparing 2018 to 2019, there was a slight decrease in number of flashes but not statistically significant. The first fireflies were seen the same day both years, while the last was seen about a month later in 2018 than in 2019. Peak flashing began almost two weeks earlier in 2019 than in 2018, and following crash was much sharper, without the brief rises that occurred in 2018. My guess is that with a earlier and longer peak, mating was successful and there was no need to keep looking for a date.

Graph of 2019 firefly flashes

What I was told by my mom before I began this project in 2018 was that there weren't really any fireflies around anymore. Since then, I've learned it's not true. She says there are definitely more now, but without any data to back it up I have to take her word for it. I don't remember if there are more or less than when I was a kid. It's not something I was looking at scientifically at the time. I do remember seeing fireflies in September only once before 2018 though. I don't remember what year it was, but I remember they didn't show up until late June, so we had them for the same length of time that I was used to.

Graph showing 2018 and 2019 flashes

Since the end of the season, I moved a few miles away. Despite having to drive a little farther, I will continue observations at my parents' house for consistency. It's hard to establish a trend if I don't use the same location. I may add my new location and start a data set here as well. After getting a second set of data, I am closer to being able to track populations. I am already looking forward to the return of next year's fireflies and the data they'll give me.

Be Bear Aware

With the arrival of fall and the approach of winter, food sources are becoming scarce for some animals. Bears spend the winter either hibernating or in torpor, a state of lowered metabolic and other bodily activities. To prepare, they begin gorging themselves this time of year so they can have enough calories to last through an extended period of not eating. While they generally try to avoid humans, now and when they emerge in spring (very hungry) are the most likely times you will encounter a bear. Here are some helpful tips on how to avoid or survive a bear encounter.

Don't let this happen to you! (US Forest Service)

Hungry bears are attracted to food and will follow their noses. When camping, store food, drinks, utensils, cookware, dishes, cosmetics, and hygiene products in a bearproof container, locked in a vehicle, or suspended 10-15 feet above ground and 4 feet on all sides from a climbable surface. Sleep in a tent or camper away from your cooking area. Don't sleep in clothes you cooked in. Don't set up camp near berry patches, carcasses, and bear signs. Avoid foods with a strong smell like bacon and fish, no matter how good they are. Sleep near your flashlight and bear spray. If you see a bear try scaring it away by making loud noises. If it is undeterred, move away to a safe area.

Ideal camp setup (WildAware Utah)

When hiking, if you see a bear that hasn't noticed you, move away quickly, quietly, and calmly. Never try to run from a bear. Running might trigger the chase instinct and the bear will always beat you in a race. If you see a bear and it notices you, let it know that you are human and  not food or another bear. Talk to it calmly, move your arms about, and keep an eye on it without making eye contact. Hopefully the bear will leave. If it does, walk away in a different direction. If it remains, back away slowly but keep making small talk. If the bear approaches you and is acting defensively- making loud noises moving its head around, or stomping or pawing at the ground, stand your ground. If the bear approaches, it's probably bluffing. Keep talking calmly to it, and start backing away when it stops coming at you. If it comes at you again, stop moving but keep talking until it stops again. If it attacks you, now is the time to play dead. Face down on the ground, keep your backpack on if you have one. If the bear rolls you over, keep rolling until you are face down again. Otherwise, don't move and don't make any sound until you're sure the bear is gone.
If you are faced with a quiet bear that won't leave, you'll probably have to fight the bear or at least make it think you want to. If backing away doesn't keep the bear from you and it is behaving calmly, act aggressively to let the bear know that you are not an easy meal. Yell at the bear, make yourself appear as large as possible, throw things at it, swing a large stick at it, and make eye contact. The idea is to make the bear think that since you are crazy enough to fight a bear, it probably shouldn't be messing with you. If the bear decides to attack anyway, fight back with a focus on its face. If you have bear spray, use in situations where the bear is aggressively approaching you. Make sure you are not spraying into the wind, and don't spray it on yourself as a repellent. Read the instructions.
The reason I chose bear safety this week is because I just had my first bear encounter while camping in Virginia. I was tent camping about 30 miles south of Washington, DC and while I got up to use the bathroom at 1 AM a bear took advantage of my absence and ransacked my campsite. It put some holes in my tent, knocked my cooler off the picnic table, and tipped over my folding chair. What did I do wrong? I had my alarm set for 5:30 AM so I could catch an early train into the city. To move more quickly, I had my next day's clothes and my toiletries in the tent with me. That was my first mistake. My second mistake was leaving the cooler in the open. I had 8 bottles of water and 3 glass bottles of root beer in there. I decided the ice would last longer in the woods than it would in the car when drove into civilization, where it's generally hotter. My third mistake, which wasn't really a mistake but just the circumstances, was not having safety in numbers. Bears don't like people; we have a bad reputation in the animal world. Being off-season in the middle of the week, the campground was pretty much empty. With no people around, maybe the bear felt like the campground was OK to stroll through, and the only tent around was an easy target.

Holes in the tent were on the right side, so I'm guessing
the bear moved right to left, swatting the chair over for
dramatic effect.

When I came back to the campsite, the bear was gone. The tent was a heap, so I spent the rest of the night in the car with the doors locked. Yes, I've seen a news article where a bear gets in a car and steals it.  After sunrise, I inspected the damage. There were holes in the tent, nothing too big but they'll only grow each time the tent is set up. None of the drinks were opened and the glass bottles didn't break. Despite their superhuman strength, bears still need you to open a bottle for them. The chair was fine, but I have no idea why the bear decided to flip it. With a damaged tent, I ended my trip a day early. This week's bear safety tips come from the Grizzly and Wolf Discovery Center right outside fabulous Yellowstone National Park.

Crickets

Fall has almost fallen. It's hard to believe summer was in full swing when you last read a fresh Nature Minute blog. Internet issues and life in general kept me from my regular schedule. Maybe where you are, the leaves are starting to turn, there's a bit of crispness in the air, mornings are full of fog, and nights are longer and full of chirping crickets.

Black field cricket Gryllus assimilis (Texas A&M) 

Here in Pennsylvania, crickets typically begin their nightly serenades in the late summer, continuing through the fall. Only the males chirp. They do so by rubbing their wings together, as a mating call for the females. They are most active at night, and even during daytime are hard to find. If they notice you getting close, they'll stop chirping so you really need to look hard if you want to find the source of the chirp. Warmer temperatures will produce more chirps, and the number of chirps drops with the temperature. I never counted chirps before, so I never noticed this.

Northern mole cricket Neocurtilla hexadactyla
(University of Florida)

Many people consider crickets to be a pest because the chirping gets annoying, but they are generally harmless. Since crickets favor loose soil, they are frequently found in flower beds, which are usually right under your bedroom window, giving you a front row seat. At the bottom of the food chain, in large numbers they have the potential to attract other unwanted guests to your home such as raccoons and spiders.

Carolina ground cricket Eunemobius carolinus
(Oklahoma Panhandle State University)

Nature Minute will return in October with more autumnal awesomeness. I'm taking a much-needed vacation. Until then, relax to the sound of the crickets. Don't let them drive you nuts. They'll only be around a few more weeks, and then it will be too cold to keep the windows open at night. This week's cricket facts come from Terro.

Sound of the Wild

Think about the sounds you typically hear over the course of a  normal day. It starts with the alarm clock and quickly fills with noise. The toaster, the hairdryer, the microwave, cars, cars, and more cars, people talking and shouting, buses, trucks, trains, planes, and of course your phone. If you're lucky you heard some birds singing on the way out the door. Other than the lawnmower, popcorn, and a log on the fire, my favorite sounds come from a land far from modern conveniences.
Next time you are out and about pay attention to what you hear. Insects buzzing, birds singing and calling, the wind in the trees (or your ears). In the mountains you might hear pikas and marmots barking, or larger animals like coyotes or wolves howling in the distance. In the fall, you might be treated to the eerie sound of bugling elk.

A not-so-distant coyote, not howling

Water is life, and it also provides a great soundtrack. I can listen to crashing ocean waves or a gurgling river all day long. Rain falling on surfaces other than pavement is a wonderful experience. The pattering on a tree canopy is soothing enough to forget about being soaked, and rain falling in a pond is a magical sound. In a naturally quiet environment like a cave, there's a good chance you'll hear only a single drop of water at a time, maybe a few seconds apart, maybe a few minutes. Even better than rain is the sound of thunder in the distance. This can be a bit worrisome if you're a long way from shelter.

The soothing sounds of the Firehole River

Late summer nights, if there is no thunder, fall asleep to the sound of the crickets. In the spring, fall asleep to the sound of the tree frogs. Another special spring sound, which I've only heard once, is the knocking sound the trees make after the thaw when they start absorbing water and their sap is flowing again. It took a while to figure that one out.

Pacific tree frogs, a sure sign of spring

Here is a link to a short video of some sounds recorded at Yellowstone National Park. Note that the pictures don't necessarily correspond to the sounds. See how many sounds you can figure out!

Species of the Month

Shark Week is nigh upon us and we're getting in on it with July's Species of the Month. I've chosen the most famous (or infamous) sea creature, the great white shark. While they've been known to attack people, we are not their prey. Shark attacks may be curiosity or just a case of mistaken identity. Unlike Jaws, these apex predators won't eat you, even if they do happen to bite. Sink your teeth into this quick profile!

Scientific name: Carcharodon carcharias

Great white shark (NOAA)

Kingdom: Animalia (animals)

Class: Chondrichthyes (rays and sharks)
Order: Lamniformes (mackerel sharks) 

Range: Coastal ocean areas of Asia, Australia, Oceana, North and South America, Africa, and Europe

(NOAA)

Habitat: Marine
Lifespan: 30 to 40 years
Diet: Fish, seals, sea lions, sea birds, squid, sea turtles, dolphins, whale carcasses, rays
Predators: Humans, killer whales, other sharks
Conservation Status: IUCN consideres great whites to be vulnerable, protected in the US

(NOAA)

Other information: This massive apex predator can grow to lengths of 20 feet and weigh as much as 6600 pounds! It's mouth can open to over three feet wide, plenty of room for anything it wants to eat. And that mouth is packed with razor sharp teeth. Unlike humans, gifted with two sets of teeth, the great white can apparently grow an unlimited number, replacing teeth as needed. The shark's streamlined body is built for speed and power. Not much is known about their reproductive habits. Females give birth to live young, which eat unfertilized eggs and possibly even siblings in the womb. They are mostly solitary creatures, but sometimes congregate to feed, such as at a whale carcass. In situations like this, they form social hierarchies. In addition to a well-developed sense of smell, great whites can detect electrical fields. These highly developed sense allow them to detect prey by a single drop of blood in 100 liters of water, or by the beating of its heart. The great white's prefer hunting method is to strike from below. A powerful blow is enough to stun the prey, avoiding a chase or a struggle. Across the board, fish populations are declining at an alarming rate and the great white is no exception. Sport fishing, commercial fishing bycatch, and finning take a toll, and as a large species reproductive rates are generally low. As an apex predator, populations are already low to begin with. Sadly, despite its deadly reputation the great white shark has more to fear from us than we from it.
This month's information comes from the University of Michigan's Animal Diversity Web.
nm1 https://swfsc.noaa.gov/textblock.aspx?ParentMenuId=123&id=21434
nm2 https://sos.noaa.gov/datasets/marine-migration-great-white-shark-3d/
nm3 https://oceanexplorer.noaa.gov/explorations/18whitesharkcafe/welcome.html

Reef Madness

Last week we explored the dynamic barrier islands, a great place for wildlife and a popular vacation destination. This week, we venture beyond the island into the coral reefs just offshore. As an avowed landlubber, I'll probably never get to see a coral reef for myself, but I'll live vicariously through myself telling you all about them.

Coral reef (Smithsonian)

Coral reefs are hard, rocky structures made of the skeletal remains of what was once living coral. Corals are a marine animal, not a plant, and the best-known form a symbiotic relationship with algae. Because algae needs sunlight for photosynthesis, many coral reefs are found in clear, shallow water. Cold water corals that live in the deep sea. Without sunlight, these organisms filter feed plankton. Because of their inaccessibility, we are still learning about them.

Coral polyps (NPS)

The most popular corals are the shallow ones, because they are relatively easy to reach. Scuba diving, snorkeling, and even glass bottomed boats bring humans right to the biological hot spots. People are drawn to coral, not just because of the beauty of the coral itself, but the amazing biodiversity found within the reef. Fishes, crustaceans, sponges, anemones, and countless other sea creatures call the reef home. The coral structure provides hiding places for mobile critters and anchorages for sessile ones. Hiding places benefit predator and prey alike- they provide somewhere to hide from bigger fish, or place to launch a quick strike at an unsuspecting meal.

Coral reef (NPS)

Cold water corals provide the same habitat and ecosystem, and may be even more important than their shallower counterparts. Most sea life can be found near the coast and relatively shallow. Corals in the deep sea for a sort of island in an area that is otherwise mostly devoid of life.

Deep sea cold water coral (Joint Nature Conservation Committee)

Like just about every ecosystem in the world, coral reefs are in trouble. Coral is dying as sea temperatures and carbonic acid levels rise. The algae component of the coral either dies or evacuates in a process known as coral bleaching. Some corals show some resistance to slightly warmer temperatures. Research into this is continuing. If you ever get a chance to explore coral reefs, either by boat or underwater, remember to look but don't touch.
This week's information comes from NOAA and the Smithsonian Institute.

Getaway Islands

Summer is here and for many people it's the perfect time to relax at the beach. If you're at an East Coast beach, odds are you're on a barrier island. The Atlantic barrier islands extend from Canada to Florida, then up Florida's Gulf Coast and all the way around to Mexico. Prior to development, many of these islands came and went at the whims of the tides and storms. Now that we've built homes and resorts on them, there is a vested interest to make them more permanent by using jetties to block the outflow of sand and beach replenishment to restore what's been lost. Let's take a look at the natural history of where you built that sand castle.

Grassy dune in New Jersey

Barrier islands, if left to nature, live and die by the tides. Ocean currents carry sand away from the islands. The sand either moves out to the sea floor, where it can be brought back to the island by currents, or it is carried to another part of the island or to a different island. Strong storms can accelerate the process, wiping islands off the map or opening up a new inlet to the back bay.

Hurricane Irene cut these inlets across Hatteras Island (NOAA) 

Barrier islands can move toward the mainland as wind blows sand over the dunes to the bay side. The marshes fill in with sand and build up new dunes, while ocean moves to where the dunes originally were and new marshes form in the bay on the edge of the old marshes.

Salt marsh at Assateague Island (NPS)

The islands are important because they are barriers protecting the mainland from such storms. A few weeks ago we looked at hurricanes on this blog. Barrier islands absorb the brunt of the storm surge that comes in ahead of the hurricane. Developed barrier islands still absorb the storm surge, but not as well as undeveloped islands from times past. Impermeable surfaces like roads and parking are terrible at absorbing water, while sand drains quickly. If the dunes have been removed from an island, the storm surge rushes right over top with nothing but buildings to slow it down.
Barrier islands are also important as habitat for critters other than summer vacationers. On an undeveloped island, different plants and animals that can tolerate different amounts of salt water and exposure to the air make their homes in different zones. Clams live beneath the sandy shore, while birds that prey on them scurry above. Grasses hold the dunes in place, and at the highest points of the island you can find trees and shrubs where songbirds and mammals live. Brackish marshes on the other side of the dunes host crabs and serve as a nursery where fish can eat and grow before venturing into the open sea. Wading shorebirds take advantage of this bounty. Beyond the marsh is the back bay and the mainland.

Ghost crab (NPS)

Sandpiper feeding frenzy

The US has more barrier islands than any other country in the world. Best known are New York's Fire Island, Texas's South Padre Island, the Outer Banks of North Carolina, and the Jersey Shore. If you spend a summer weekend at the beach, be sure to check out the wild side of things.
This week's information comes from Science News for Students.