Wood Frog

Originally published in The Manitoban, January 26, 2011.

Hello and welcome to January, 2011. I was looking out the window earlier, enjoying the hoar frost, when it occurred to me that really, Winnipeg isn't so bad in winter. We give ourselves a lot of credit for how tough we are out here on the prairie, boldly heading out to party and bullshit in windchills that bring the mercury plummeting to -40°C but really, we don't know what tough is. We would not stand a chance in a Winnipeg winter without all our scarves, sweaters, Uggs, Emus, Fox Racing jackets, and opposable thumbs. If you wanna see some serious winter survival, look to those who must breathe through their skin, I say. Look to Rana sylvatica, the humble North American wood frog.

The wood frog is a small anuran, two to six centimetres in length, found throughout Canada and much of the mid-eastern United States. In fact, the wood frog is the only amphibian in North America that can live north of the Arctic Circle. It is that brownish little frog you have very likely seen before; the one wearing the cute little black mask.

During the spring breeding season, male wood frogs congregate in small ponds, working day and night to attract females. Their call, which sounds a bit like the 'quack' of a duck, is produced by inflating the lungs and expelling air at high pressure across the vocal chords. The neck pouch, or vocal sac, acts as a resonating chamber to amplify the frog's call. 

Tadpoles hatch in late spring and feed primarily on algae and plant materials, while the adult diet consists of invertebrates such as insects, worms, and snails. Adults have also been known to eat other small frogs on occasion. 

In order to deter would-be predators such as shrews and aquatic insects, adults and older tadpoles produce repulsive skin secretions. Adults also make a defensive call, more grotesquely referred to as a “mercy scream,” if they find themselves under attack by shrews; tiny but ruthless mammalian predators. 

This is all pretty great stuff, yet the coolest thing about the wood frog is arguably their capacity for freeze tolerance.

Freeze tolerance is the ability to survive the formation of ice crystals within the body. This is typically a bad state of affairs for living organisms as ice crystals can puncture delicate yet important tissues such as blood vessels and cell membranes, causing all the vital stuff inside to spill out—at which point, as you can imagine, chaos and death will ensue. 

There are all kinds of other negative side effects associated with ice crystal formation in the body. Forming ice will draw water out of cells, causing them to shrink and become damaged. If blood cells were to freeze, the delivery of oxygen and nutrients to vital organs would be interrupted, spelling out bad times for the future of said organs.

With all these crazy, deadly drawbacks, how can freeze tolerance be a good winter survival strategy, you ask? Why does the wood frog not simply borrow some fur from a fox, or some fat from a bear, you want to know? How the hell does the bloody frog just go and freeze until spring thaw like it ain't no thang?! I will tell you, of course.

Animals such as our hero the wood frog successfully engage in the practice of freeze tolerance by combining the ability to allow fluids outside of the cells (extracellular fluids) to freeze with mechanisms that prevent the fluids inside the cells (intracellular fluids) from freezing. 

The wood frog hibernates on land under leaf litter and produces special ice nucleating proteins that allow the frog to seed (start) ice crystal formation early; typically when the temperature reaches just below 0°C. By starting the freezing process at a higher temperature, the frog can freeze slowly, allowing time to make the metabolic changes necessary to survive the freeze. 

While frozen, the metabolic, breathing, and heart rates slow dramatically. The organs and tissues are well adapted to survive in spite of very low and slow rates of oxygen and nutrient delivery. In order to prevent the insides of the cells from freezing, wood frogs build up high concentrations of glucose sugar in their tissues. Water will be drawn out of the tissues and everything around the organs and tissues will freeze, while inside the cells and organs, the highly concentrated sugar solution will remain liquid, thus preventing freeze damage. In fact, wood frogs can tolerate blood sugar levels 100 times their normal amount, without ill effect.

There are many unknowns about the freeze-abilities of the wood frog, Rana sylvatica. The chemical signals which allow the frog to respond to its metabolic needs throughout the winter are not well understood, nor are the ways in which the frog can fine-tune the freezing process. For example, ice sometimes begin to form within the blood, an event that would be deadly, and yet the frog is able to make subtle changes in the concentrations of its bodily fluids that quickly break apart these unwanted ice crystals, leaving the remarkable wood frog frozen solid and ready to face another cold, winter day.

Extinction Edition: Labrador Duck and Steller's Sea Cow

Originally published in The Manitoban, December 1, 2010.

Creationists be damned; I insist that we are all creatures of the sea. Look in your heart of hearts and I think you'll agree. Regardless of your personal beliefs, how else can you possibly explain the salinity of tears or the grains of sand in our ears? Don't question it. And on that note, I would like to force upon you the tragic tales of two wonderful inhabitants of the sea that are, alas, no more. First, the Labrador Duck.

Described as a striking sea duck on many a website, the Labrador Duck (Camptorhynchus

labradorius) once inhabited the east coast of North America but was probably never very abundant. Males in breeding plumage had attractive black and white patterning on the head while females and juveniles were a mottled brownish-grey. Both males and females had bright white wing patches. Little is known about the breeding biology of these ducks and no nests have ever been described, but it is supposed that they bred along the Gulf of St. Lawrence and possibly along the coast of Labrador and elsewhere further north along the east coast. 

Labrador Ducks had a unique bill structure, different from that of most ducks. The bill was wide and flat, with numerous lamellae (long, thin, hair-like projections) on the inner surface, suggesting that these animals sieved through silt and sediments for shellfish, and small molluscs such as snails.

The Labrador Duck is considered the first bird to have become extinct in North America after the year 1500. The last observation of a Labrador Duck is reported to have been in Elmira, New York on December 12, 1878, while the last specimen collected (i.e. shot) was taken in 1875 on the coast of Long Island, New York. There are likely only 55 remaining specimens hanging around museums and in cupboards worldwide.

It is not fully understood why the Labrador Duck went extinct. They apparently rotted quickly and did not taste good to human hunters, so over harvesting wasn't likely a major cause. Their eggs may have been over harvested (but not by scientists since no nests were ever described) and all you feather-wearing folk may be shocked and appalled to hear that another proposed contributing factor to the extinction of the Labrador Duck was harvesting for the feather trade. Perhaps it is time to consider just where the feathers we buy are actually sourced from. 

Other factors leading to the extinction of the Labrador Duck may have included declines in the food upon which these ducks were heavily reliant, such as the aforementioned molluscs and shellfish. These declines occurred largely as a result of increases in human population, pollution, and industry as settlement along the east coast of North America continued to develop during the late 1800s.

Painted by Louis Agassiz Fuertes in 1922-1926

The second tale of woe I shall recount regarding extinct oceanic species is that of the Steller's sea cow (Hydrodamalis gigas). Once the largest member of the order Sirenia, which includes such fat and fun-loving creatures as the manatees and dugongs, the Steller's sea cow appears to have become extinct in 1768, a mere 27 years after its initial discovery by shipwrecked explorers of the North Pacific in 1741.

The sea cows were huge. They grew up to 8 or 9 metres in length and existing information on their weight puts them anywhere from 5400 to over 11 0000 kg, expressed in such endearing terms as 'puds' and 'hundredweights'. In contrast, manatees weigh in at anywhere from 400 to 550 kg and dugongs 150 to 300kg. 

While impressive in size, the Steller's sea cow was apparently a gentle giant. They were herbivorous, lived in groups, were slow moving and provided stupidly easy targets for human hunters (due to a combination of their slow speed, low ability to submerge, and lack of fear of their new discoverers, the humans). 

They did not have teeth but ground sea grasses, algae, and kelp between large mandibular (jaw) plates made of keratin (the stuff of fingernails). They had small heads and horizontally fluked tails, similar to that of whales. Their large size was primarily due to the fact that, unlike other sirenians, they inhabited cold water,. Their large size and generous helping of blubber (fat) were adaptations designed to keep them warm.

Steller's sea cows were found exclusively around the Kamchatka (Commander) Islands, in particular the Bering, Copper and Medney Islands. They apparently tasted delicious, a bit like veal or beef (if you like that sort of thing), and their fat was reported to have resembled that of almonds in flavour. According to reports of the time, the meat of the Steller's sea cow had the additional virtue of being slow to rot (unlike that of the ill-fated Labrador ducks still holding out over on the east coast back in the 1750s). 

Being so slow and edible, the Steller's sea cows were hunted to extinction; largely for human consumption but also for making lamp oil and implements such as boots, belts and skin-covered boats. 

The indiscriminate hunting of sea otters may have also contributed to the extinction of Steller's sea cows due to the keystone relationship between otters, sea urchins, and kelp. Otters are one of the few animals that eat sea urchins, which in turn eat kelp. Upon removal of large numbers of otters, urchin populations begin to increase and can decimate kelp forests. The sea cows were vulnerable due to their small population size, estimated at around 1500 individuals, and perhaps the additional pressure of not being able to find enough kelp to eat was simply too much for them to bear.

During the short time the Steller's sea cow was known to us humans here on earth they fed and clothed us, gave us light and warmth, and inspired writings by influential authors of the day including Rudyard Kipling and Jules Verne.

Rest in peace, Camptorhynchus labradorius. Rest in peace, Hydrodamalis gigas. No one left alive on this planet today ever got to see either of you, but I for one wish I'd had the chance.

This author is definitely going to pour some libations

out in the snow tonight to honour dead friends from the sea.

Hercules Beetle

Originally published in The Manitoban, November 10, 2010.

Love 'em or hate 'em, insects are arguably the most important animals on earth. They are often viewed as the most successful animals on the planet, too. Many insects are essential for the continuation of life on earth (as we know it) through their roles as plant pollinators and degraders of waste products left by other organisms, which prevents massive build-up of organic wastes that would otherwise bury the planet. In fact, about two-thirds of all flowering plants are pollinated by insects. 

Insects are also among the most important carriers of and vectors for diseases that kill millions of humans and other economically important mammals annually. Insects are frequently used as models in scientific research—due to their (often) small size and rapid generation times, many can be bred quickly and in large numbers in laboratories for experimentation in various areas, including genetics and medicine. 

Insects have been around for a long time—at least 400 million years. For comparison, the first mammals appeared roughly 225 million years ago. And boy are there lots of insects! Estimates vary, but it is thought that there are anywhere from six to ten million living species of insects alive today, and these species are grouped into 29 different orders.

Beetles make up the order coleoptera which, I don't mind telling you, with over 360, 000 described species, is the largest order of insects in the world. In fact, at least 25% of all species rambling over the planet today are beetles. 

How will you know if you are looking at one of these wonderful, wildly abundant beetles or just some other type of insect, you want to know? Beetles are perhaps most easily recognized by their two sets of wings. One set is the kind of wing you think of when you imagine insects flying (I'm sure you imagine insects flying quite often), while the other set of wings, called elytra, are hardened into a protective, leathery sort of cover that protects the more delicate wings underneath, and may also act as aerofoils. 

The order coleoptera is amazingly diverse and contains both the largest and some of the smallest insects on the planet today. It is about one of the largest living insects that you, the enthralled reader, are going to learn—the Hercules beetle.

The Hercules beetle, Dynastes hercules, is a type of rhinoceros beetle (subfamily dynastinae) and is a member of the family scarabaeidae, the scarab beetles. These Hercs, as I'll call them, are native to South and Central American rainforests and the Lesser Antilles. They range from 50 to 170mm (over 6 inches) in body length—making them one of the world's largest beetles¹ and the largest of the six beetles in the genus Dynastes. As if their size weren't impressive enough, male Hercs have two big horns that can be even longer than their body; one that comes from the lower (ventral) portion of the head, curving upward, and another that comes from the thorax at the base of the upper (dorsal) region of the head curving downward, like pincers or pliers. When males fight, they try to pick one another up with their horns and slam them headfirst to the ground. Females lack horns.

Hercules beetles are not poisonous, and do not attack humans. They mostly just hang out in leaf litter trying to survive the decimation of the rainforest while looking really cool and menacing. They are herbivorous; larvae eat rotting wood and dung while adults feed on decaying fruit and vegetable matter. Again, just cleaning up the garbage. Really, they are humble civil servants of the rainforest, never complaining about their smelly job or asking for recognition, even though they deserve it. 

Hercs live for about 1.5 years, only 3 to 4 months of which are spent as adults. They are primarily nocturnal and yet are strongly attracted to light.

My favourite thing about Hercs is that if you correct for size, Hercules beetles are, proportionally, the strongest animals on the planet. They are able to lift up to 850 times their own body weight! 

1 The record for world's largest beetle is held by the aptly named Titan beetle, Titanus giganteus, which is a member of the family cerambycidae or longhorn beetles, and reaches 170-175mm in length.

 

Woolly Flying Squirel

Originally published in The Manitoban, October 27, 2010.

The woolly flying squirrel, Eupetaurus cinereus, is the largest known squirrel alive today. This massive sciurid, as the scientific family containing squirrels is known, measures around 53 centimetres (two feet) in length, not including the massive fluffy tail, which is an additional 53cm long. It is the largest gliding animal known, majestically flinging itself out into open air amongst the boulders and Himalayan mountains of northern Pakistan. Never having seen a woolly flying squirrel before, I'm just assuming it's majestic but come on, it has to be. Think about it.

The woolly squirrel has a unique dentition among sciurids, affectionately referred to by anatomists and veterinarians as hyposodont, which means that the teeth have a high crown and enamel that extends past the gum line. This suggests that the squirrel eats highly abrasive plant material, probably the needles of coniferous pine trees found in the animal's known habitat. It is primarily this unique dentition which makes the woolly squirrel the only member of its genus, Eupetaurus.

The woolly flying squirrel is huge. Imagine a two foot squirrel roaming around the streets of Winnipeg. That's the stuff of so-bad-it's-good science fiction/horror films. I know I'd flee in terror if I ran into one. 

Squirrels bigger than ravens! Big and mean, I'll bet! Can you imagine?! Lucky for us Winnipeggers, who've got enough of our own problems, these squirrels like mountains and not prairies. Clearly there is a serious lack of mountain in Winnipeg (“Garbage hill” does not count). 

Well anyway, getting back to the squirrels: despite their absolutely huge size, woolly flying squirrels were believed extinct until just over a decade ago. Originally described in 1888, there had not been a confirmed sighting since 1924, and the species was known from only a few skins collected in the late 1800s. It was rediscovered by science in 1994 by Peter Zahler, a freelance editor and writer, and Chantel Dietemann, a math teacher.

Some locals of northern Pakistan believe that the dried urine of E. cinereus is an aphrodisiac. In this form, the sqiurrel's urine is known as salagit and sold in the bazaars of Gilgit, Pakistan. Two local men, collectors and retailers of salagit, were paid by Zahler to find him a woolly flying squirrel, which they did. They brought it to him in a sack for $150 USD. Zahler and Dietemann did not find anymore woolly squirrels during their trip, but they found lots of disembodied squirrel bits under the nest of a huge raptor, the eagle owl.

While little is known about the woolly flying squirrel at this time, and what is known has mainly been based on museum skin specimens, it is known that the squirrels are nocturnal and roost in caves and crevices on steep cliffs at elevations of between 2400 and 3800m. 

The woolly flying squirrel is currently listed by the International Union on the Conservancy of Nature (ICUN) as endangered, which means that it is believed to face a very high risk of extinction in the wild. The total population of these squirrels is estimated at between 1000 and 3000 individuals and as is so often the case, habitat loss via deforestation is the main factor responsible for its endangered status.

The cry of the woolly flying squirrel is believed by some to herald the death of a loved one. Spooky. 

Never trust a squirrel, I've always said...Never trust a squirrel.

Desert night lizard

Originally published in The Manitoban, October 20, 2010

I'm tired. I'm getting sick, I have exams coming up, papers due, grant applications to write, I had to cook my own Thanksgiving dinner, and I just want to curl up on the couch until January. Sound familiar? Well anyway, I read this great article about whale poop and my friend told me about Pacific barreleye fishes and I felt a lot better. The sun is still shining, after all. We've got until at least December 2012 and I am not going to write about whales or barreleyes just yet. I am going to write about lizards instead.

The desert night lizard, Xantusia vigilis, lives in the Mojave Desert, which occupies portions of California, Nevada, Utah and Arizona, and spends a lot of its time hiding under logs. They feed on invertebrates such as caterpillars, moths, termites, ants and beetles and are what is referred to as a 'sit and wait' predator—they don't hunt actively but tend to remain in hiding and then pounce on their unsuspecting prey when it comes near their hide out. 

They are viviparous (“live-bearing”), and females give birth to an average of two young per year. They are small, measuring between 1.5 and 2.75 inches long, not including the tail; which, when threatened, is very likely to break off and wiggle around as a distraction so the lizard can escape from potential predators. I wonder what would be the best appendage for humans to lose when confronted by late-night muggers or street gangs of ten-year-olds? Perhaps the wallet hand? I see potential for esoteric stem cell research grants...

So far the most interesting thing I've learned about the desert night lizard pertains to its complex social structure. A graduate student at UC Santa Cruz named Alison Davis, now a post-doctoral researcher at UC Berkeley, led a five-year study of the lizards and found out a bunch of really cool stuff. 

Unlike many lizard species, X. vigilis live in groups, often hanging out under the same log for years on end. Young lizards remain with their parents and siblings for several years. Genetic testing using DNA microsatellite markers confirmed that separate aggregations of the lizards were composed of related family groups, the largest so far tested being a group of 13 members. For the less genetically savvy, microsatellites are short segments of DNA that have a repeating sequence of base pairs (CACACA for example). These segments can be passed on from parents to offspring and eventually, populations will retain a characteristic set of microsatellites distinct from those of other populations.

Aside from the fact that most lizard species are solitary, the sociality of the desert night lizard may provide future insights into the evolution of more complex social behaviours, like those seen in primates (including humans). 

There are only about twenty known species of lizards that live in family groups and of these, only two give birth to live young, implying that viviparity may be critical for the evolution of cooperative behaviour in animals. Insight into the social interactions of reptiles such as the desert lizard can provide valuable information about the evolution of kin-based groups and cooperative behaviour across a wide variety of taxa, including birds and mammals, and may help provide a means of reliably predicting other species that might be predisposed toward complex social and group behaviours. Such information could provide insight into our own evolutionary past and reveal a common evolutionary ground for social and family interactions throughout the animal kingdom. Neat!

Desert lizards don't have eyelids.

Fer-de-lance

Originally published in The Manitoban, September 29, 2010

In addition to Cuba and the Bahamas, the Caribbean island chain contains an unassuming little island called St. Lucia. A rainforested, mountainous, volcanic island roughly 43 by 23 kilometers, it was first inhabited by Indigenous peoples from South America early in the 2^nd century. 

“Discovered” by good old Christopher Columbus in 1499, British attempts at colonization begain in 1605 and French attempts in 1667. The island changed hands between British and French 14 times before achieving independence in 1979. Sugar plantations manned by African slaves made up the bulk of St. Lucia's economy in the 19^th century, whereas today the main economic boons consist of banana plantations and tourism. The island is mainly inhabited today by descendents of the early African slaves and has a population of about  

200, 000.

What does beautiful St. Lucia have to do with another great Zoological Investigations article, you ask? Interested readers might pass the hours by reading about theories of Island Biogeography and related concepts, perhaps even a little of Darwin's On the Origin... for good measure or, they might simply choose to take my word that islands, by virtue of their remoteness from the mainland, tend to harbour uniquely adapted, endemic (those which aren't found naturally elsewhere in the world) species and provide a rich grounds for evolutionary processes to take hold, leading to interesting and sometimes really weird organisms and community interactions. Often, island species evolve in a relative vacuum, until oh, let's say European settlers introduce hordes of ship rats ready to devour unsuspecting creatures that have never before faced predation. This, as you might guess, usually has disastrous results for island wildlife and let's not forget what happens when us humans begin settling in and ripping up the land for natural resources and hotels-- habitat loss and destruction, oh my.

So now you want to know what the hell is a fer-de-lance, eh? Well, my Canadian friends, that is a lovely french word for 'spearhead' (or the more literal and less poetic, “iron of the lance”) and refers to an extremely venomous snake that lives, you guessed it, on St. Lucia island in the sunny Caribbean. Also known by it's less beautiful sounding scientific name, Bothrops caribbaeus, the fer-de-lance is one of five species of snake found on the island (one of which is now extinct) and belongs to the family Viperidae (fancy talk for, “it's a viper”).

The fer-de-lance is viviparous, which means that it incubates eggs internally and gives birth to live young; around 60 at a time. Gestating females move in and out of the sun in order to regulate their body temperature and incubate the developing young. They mainly eat birds and mammals, and have even been known to eat those crazy vicious carnivores, the mongooses. Hunting takes primarily at night and the snakes will rear into an S-shape, strike quickly and then retreat while their prey dies a horrible, venomous death. 

Pit vipers such as the fer-de-lance have unique structures called pits that are found in grooves on the head which can detect infra-red radiation (i.e. heat) emanating from their prey. This allows the snakes to quickly and accurately locate their prey in the dark and what's more, the position of the pits is such that it allows for a type of “binocular scent” similar to how our human vision gives us depth perception and helps us to correctly gauge distances (most of the time).

The fer-de-lance is extremely venomous, and is considered by many to be the most dangerous snake of Central and South America. It can inject 105 mg of venom in a single bite (milking the snakes for venom has yielded up to 310 mg) and causes more human deaths than any other reptile. In case you wondered, the lethal dose of venom for humans (based on some undisclosed average weight, I assume) is a mere 50 mg.

The venom contains seven different toxins, including stuff that breaks down cell membranes (allowing that precious content to spill out all over the place and cause general mayhem in your poor, dying body) and proteins. The toxins also cause hemorrhage, internal bleeding, painful swelling, and blood clot formation in humans.

Studies of the fer-de-lance undertaken by the National Forest Demarcation and Bio-Physical Resource Inventory Project have shown these vipers to be at a significant risk of extinction, primarily due to that old beast habitat destruction, coupled with the introduction of invasive species such as opossum (manicou), rats, dogs, cats, feral pigs and mongoose, as well as hunting and chemical pollution from agricultural processes. Fer-de-lance populations have declined significantly in beautiful St. Lucia over the last 50 years, and populations are now restricted primarily to two fragmented portions of the island. 

These snakes are not protected by St. Lucia's Wildlife Protection Act, which was implemented in 1980. Three other species of Fer-de-lance native to islands of Brazil, Bothrops alcatraz, B. insularis, and B. pirajaiare listed by the International Union for the Conservation of Nature (IUCN) as critically endangered and vulnerable (B. pirajai) but the St. Lucia fer-de-lance B. caribbaeus has not yet been assessed by the IUCN.

Zoological Investigations Double Back-to-School Feature: Cormorants & Nighthawks

Originally published in The Manitoban, September 15, 2010

The Double-crested Cormorant

The Double-crested Cormorant (Phalacrocorax auritus) is a large, fish-eating waterbird reaching 2.5 to 3 feet in length with a wingspan of almost 4 feet. They are found in Manitoba and throughout the Great Lakes region. They are one of the birds most frequently rescued by the Prairie Wildlife Rehabilitation Centre, or PWRC (see the science feature article). P. auritus spends its winters in the Gulf of Mexico, flying north to breed during our balmy Manitoba summers. They nest in colonies and incubate their clutch by wrapping their webbed feet around the eggs, which is unusual because most birds incubate eggs by ruffling their feathers around them and developing a brood patch, a featherless area where blood vessels close to the skin's surface provide warmth by bringing arterial blood into contact with the eggs. 

Double-crested cormorants often incorporate garbage and beach junk into their large nests, including parts of dead birds! Not the smartest of birds, P. auritus will sometimes mistake large pebbles for eggs and tries its darndest to hatch them! Those nesting in full sun help keep their chicks hydrated by carrying water in their bills to give to the young, which often leave their nest to hang out in a sort of Cormorant daycare called a creche (pronounced cree-sh), returning to the parent nest at feeding time.

Numbers of P. auritus declined severely throughout the 1950s through 70s as a result of high levels of environmental contaminants such as DDT responsible for the thinning of eggshells in these and other bird species but, you'll be glad to know, their numbers have since rebounded marvelously and the Cormorants no long appear to be in any danger from population declines.

Also of note according to Lisa Tretiak, board member and founder of the PWRC, young Double-crested Cormorants are very, very mean and not at all afraid to use their large, hooked bills in combat with would-be human rescuers! For more information on the wacky behaviour of rescued Cormorants, check out this link to the PWRC blog: http://pwrc.wordpress.com/2010/07/21/double-trouble/

 

The Common Nighthawk

The Common Nighthawk (Cordeiles minor) is not a hawk but a member of the Goatsucker or Nightjar family, which includes other nocturnal birds such as whippoorwills, frogmouths, and oilbirds. In addition to having really cool names they refuse to build a nest but instead lay eggs straight on the ground (or on city rooftops) without even bothering to conceal them. Perhaps as a defense against this shoddy parental care, nestling Nighthawks are able to fly as early as 18 days after hatching and can capture insects on their own within 25 to 30 days. Nighthawks have large mouths lined with sensitive bristles to aid them in catching insect prey during cool-looking aerial dives. They have a reflective structure in their eye called the tapetum lucidum (the same structure responsible for making nocturnal mammals' eyes like your cat's glow when a light is shined on them) that improves vision in low-light conditions. They are about 9 inches long with a wingspan of around 20 inches, and spend their winters in South America unlike the rest of us (goat)suckers. 

Common Nighthawks are also brought to the attention of the PWRC rather frequently, but they are often uninjured. The Common Nighthawk undergoes a daily period of inactivity called torpor, in which the body temperature and metabolism are reduced to conserve energy. Many a concerned naturalist has phoned the PWRC thinking these birds are in need of assistance when really, they are just resting up for an evening of insect massacre! C. minor populations have been in decline, probably due to the combination of heavy insecticide usage, habitat destruction, and increased numbers of predators such as cats, skunks, racoons, and crows. They are currently listed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) as threatened, and are a species of special concern under Ontario's Endangered Species Act as of 2007.