MBD

Species of September: American White Pelican

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Anyone who has walked through or even glanced into the Tetrapod Collection will have surely seen the taxidermy mount of an American White Pelican standing in the corner of the room. It truly is a charismatic bird.

taxidermy mount of an American White Pelican

Taxidermy mount of an American White Pelican

The American White Pelican (Pelecanus erythrorhynchos) is one of the largest birds in North America with an average wingspan of 9 feet. That’s even more impressive than the Bald Eagle’s 6-7 foot wingspan. During the summer breeding months, American White Pelicans flock to the Northern Great Plains of the U.S. and the southern parts of Canada. After breeding season, they migrate across the U.S. to their wintering grounds in the Gulf of Mexico and along the Southern U.S./Mexican coastline. During migration, they may be seen resting and feeding right here in Ohio, in particular at some of the larger lakes in the state.

American White Pelican sightings close to Columbus

Sightings (as reported on ebird) of American White Pelicans close to Columbus within the last 10 years

Like all individuals of the eight living pelican species (two of which, the White and the Brown Pelican, occur in North America), the American White Pelican has the distinctive throat pouch that is used to scoop up fish while feeding. Due to their large size, American White Pelicans can’t dive from the air for fish like other fish-eating species such as the Belted Kingfisher; instead they swim on the water’s surface and dip their bills into the water to scoop up fish. The pelicans will then tip their heads to drain out the water and swallow only the fish. To find out more general facts about these birds, visit The Cornell Lab of Ornithology.

As if the pelican’s beak wasn’t peculiar enough, scientists now say it may be used to tell males and females apart. In many birds, distinguishing males and females is easy since males have colorful and extravagant plumage features. When a male and female of a species look different in some way, it is known as a sexual dimorphism. However, there are some species of birds, such as the American White Pelican, where males and females have very similar plumage making distinguishing the different males and females difficult. However, research done by Brian Dorr et. al (2005) shows that male American White Pelicans have significantly longer bills than females. The researchers measured the culmen, the area of a bird’s beak that stretches from where the beak’s base meets the feathers to the end, of 188 American White Pelican specimens that were collected in Mississippi and Louisiana. Dorr et al’s research shows that measuring culmen length can be used to determine the sex of American White Pelicans.

Measuring the beak length of an American White Pelican

Measuring the beak length of our American White Pelican

So, can we use this method to at least determine our pelican’s sex? I went to work with a metric ruler and measured the culmen to a length of 280 mm. According to the study, a culmen length of ≥310 mm indicates a male and ≤309 mm indicates a female. Thus our specimen is most likely a female.

This is a great example of how research on museum specimens can help with identifying individuals in the wild. In our case, it helped with adding a piece of information to an old, well-preserved specimen and making it more valuable to the scientific community.

 

 

 

 

References

“American White Pelican.” Identification, All About Birds. The Cornell Lab of Ornithology, n.d. Web. 26 Aug. 2015. http://www.allaboutbirds.org/guide/American_White_Pelican/id

Dorr B., King D.T., Harrel J.B., Gerard P., and Spalding M.G. 2005 The Use of Culmen Length to Determine Sex of the American White Pelican. The Waterbird Society 28, 102-106. BioOne. http://www.bioone.org/doi/full/10.1675/1524 4695(2005)28[102:TUOCLT]2.0.CO;2

Species of August: Timber Rattlesnake

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by Raymond Gonzo

Part of the Tetrapod collection holds preserved reptiles, most of which represent native Ohio species along with several species from other parts of North America. To find a Species of the Month, I ventured down the aisles of shelves with jars of snakes, lizards, turtles, and tortoises. When I saw this Timber Rattlesnake, one of our collection’s most impressive reptilian specimens, I made my choice. I chose an animal that is feared, and misunderstood, by many.

Attaining an average length of about 3-4 feet, the Timber Rattlesnake (Crotalus horridus – a frightening name for an animal that rather avoids than seeks conflict) is a fairly large snake. Like most snakes, Timber Rattlesnakes are feared by a lot of people who don’t understand them well enough. It’s important to remember that snakes such as the Timber Rattlesnake don’t seek out conflict with humans, but rather try to avoid it. A part of the fear people have for snakes comes from common misconceptions, which these facts below will hopefully clear up.

Their range stretches throughout most of the temperate forests in the Eastern United States and Canada, however they can no longer be found in Maine and Ontario. Here in Ohio, they can really only be found at the southern end of the state. Timber Rattlesnakes will mate during the spring and fall with the females giving birth to anywhere from 4-14 young during the late summer. What’s interesting about rattlesnakes (Timbers included) is that they give birth to live young, which is very unusual for a reptile. Many reptiles, just like birds, usually lay eggs from which their young hatch after some incubation time. When the snakes feel threatened, Timber Rattlesnakes will rattle their iconic tails as a warning to potential predators that get too close. These snakes eat a wide assortment of small mammals and can sense their prey using special heat sensory organs that are located on their heads. These sensory organs are known as loreal pits and are a characteristic common to all members of the pit viper family, which includes rattlesnakes.

When Timber Rattlesnakes deliver a bite, deadly venom will be injected through the snake’s hollow fangs and into the victim. A common misconception is that snakes are poisonous; when in actuality they are venomous. Venomous organisms directly inject venom into the victim whereas poisonous organisms have a poisonous substance covering their body making them dangerous only when eaten or touched. Learn more general facts about Timber Rattlesnakes from an Ohio Certified Volunteer Naturalist.

Quite a bit of research has been done on these snakes, a few years ago Rokyta et al (2013) reported that components of their venom seem to have changed. Some species of snakes (Timber Rattlesnake included) have undergone a dramatic shift in the lethality, and composition of the venoms they produce. Traditionally, Timer Rattlesnakes produced a hemorrhagic type of venom, which causes the snake’s victims to bleed to death from the inside out (visit the Snakes and Spiders web site for a full description of how snake venom works). However, this study shows that, at the southern end of their range, Timber Rattlesnakes are beginning to develop a bite consisting of neurotoxin venom. Neurotoxins attack the victim’s central nervous system resulting in cardiac arrest and trouble breathing thus making it much deadlier than hemorrhagic toxins. Similar research on the evolution of snake venoms is being done at the molecular level by researchers in the Gibbs lab here at OSU.

Timber Rattlesnakes are amazing animals that encompass both beauty and lethality. Their status as a top predator has even landed them a place in history as the species of snake that appears on the “Don’t Tread on Me” flag. While these are highly venomous creatures, it’s important to remember that they just want to be left alone and do their best to avoid conflict with humans. Should a Timber Rattle snake bite you or someone you are with then please follow the procedures outlined by the Wild Backpacker to ensure a safe and speedy recovery from any venom related injuries. If you ever encounter a Timber Rattlesnake NEVER try to approach or pick it up, instead leave it alone and in turn it will leave you alone. Timber Rattlesnakes remind us that sometimes it best to admire natural beauty from a distance.

References

“Snake Bite First Aid and Treatment.” Wild Backpacker – Survival articles
http://www.wildbackpacker.com/wilderness-survival/articles/treating-a-snake-bite

Rokyta D.R., Wray K.P., and Margres M.J. 2013 The Genesis of an Exceptionally Lethal Venom in the Timber Rattlesnake (Crotalus Horridus) Revealed through Comparative Venom-gland Transcriptomics. BMC Genomics 14, 394. BioMed Central. http://www.biomedcentral.com/1471-2164/14/394/

“Understanding Snake Venom and How It Works.” Snakes and Spiders, 3 Nov 2009.
http://www.snakesandspiders.com/understanding-snake-venom-works/