Closely related to the six-lined racerunner of the Mid-Atlantic and Southeastern U.S., the prairie racerunner is found from northwestern Indiana and southern Wisconsin, westward to southern Wyoming and southward to Arkansas, West Texas and New Mexico. Favoring dry, sandy soil and hot weather, these lizards inhabit prairie grasslands, abandoned farms, glades and rocky hillsides; attracted to disturbed areas, they are known to spread along power line swaths and railroad lines. Here in Colorado, prairie racerunners are abundant from the High Plains to the shrub zone of the lower Front Range foothills.
Emerging from hibernation in late April or May, prairie racerunners are best observed during the morning and early afternoon hours of June and July, dashing across trails or clearings and disappearing into clumps of vegetation to snare prey or to avoid predators. Their long tail, twice the length of their body, is thought to serve as a counter-balance as they zig-zag at speeds up to 18 miles per hour. Mating occurs by late spring and five eggs are generally produced; as with most lizards, the hatchlings are miniature replicas of the adults and must fend for themselves. While a second brood may be produced within a few weeks, adult prairie racerunners begin to hibernate by late August or early September; the young, needing more time to generate fat stores, wait until late September or October to settle in their winter burrows (depending on their home latitude).
Feasting on a wide variety of insects and other invertebrates during their brief season of activity, prairie racerunners may fall victim to grassland hawks, prairie falcons, burrowing owls, fox, coyotes, roadrunners, magpies and a variety of snakes. Using shallow burrows during the warmer months, they dig a deeper channel with a terminal chamber for their prolonged hibernation; during that time, in sharp contrast to their frenzied life above ground, their metabolic rate falls dramatically and they rely on fat deposits to fuel their survival. If they make it through their first winter, adult prairie racerunners are thought to have a natural life span of 4-5 years.
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Rabu, 11 Juli 2012
Minggu, 25 Maret 2012
The Garth Wetlands
Stretching across the Bear Creek floodplain in north Columbia, Missouri, the Garth Nature Preserve harbors one of the best urban wetlands that I have yet to encounter. Accessed by a fine network of trails, it is visited primarily by joggers, dog-walkers and couples focused more on their conversation than on the natural beauty that surrounds them. For those of us who care to look, there is always much to see.
This morning I found the flora and fauna to be well ahead of schedule, as is occurring across much of North America in the midst of our ongoing heat wave. The rosy glow of redbuds brightened the greening woodlands while a background chorus was provided by northern flickers, chorus frogs, trilling toads and red-winged blackbirds. Though the latter songsters are commonly heard in late March, they were joined by the distinctive chortle of leopard frogs, the scattered call of cricket frogs and, if I was not mistaken, the deep croaks of a few groggy bullfrogs. Aquatic turtles were abundant, peering from the shallows or basking on mats of vegetation and a lone water snake wound through the cattails. Eastern bluebirds, tree swallows and eastern phoebes feasted on a new generation of insects and a pair of red-tailed hawks cavorted overhead, already well into their nesting season.
While all ecosystems offer unique sightings during each season of the year, wetlands are especially interesting in the spring as amphibians and reptiles emerge from their winter slumber and colorful birds return from the south to nest and raise their young. Of course, this riot of life is fueled by the insect hordes, most of which overwintered as eggs, pupae or larvae in these same marshlands.
This morning I found the flora and fauna to be well ahead of schedule, as is occurring across much of North America in the midst of our ongoing heat wave. The rosy glow of redbuds brightened the greening woodlands while a background chorus was provided by northern flickers, chorus frogs, trilling toads and red-winged blackbirds. Though the latter songsters are commonly heard in late March, they were joined by the distinctive chortle of leopard frogs, the scattered call of cricket frogs and, if I was not mistaken, the deep croaks of a few groggy bullfrogs. Aquatic turtles were abundant, peering from the shallows or basking on mats of vegetation and a lone water snake wound through the cattails. Eastern bluebirds, tree swallows and eastern phoebes feasted on a new generation of insects and a pair of red-tailed hawks cavorted overhead, already well into their nesting season.
While all ecosystems offer unique sightings during each season of the year, wetlands are especially interesting in the spring as amphibians and reptiles emerge from their winter slumber and colorful birds return from the south to nest and raise their young. Of course, this riot of life is fueled by the insect hordes, most of which overwintered as eggs, pupae or larvae in these same marshlands.
Jumat, 27 Januari 2012
American Gators
Crocodilians, now represented by crocodiles, alligators and caimans, split from other reptiles and early dinosaurs back in the Triassic Period, some 200 million years ago. Modern alligators are limited to two species: the American alligator and its smaller cousin in southern China; our gator, the largest reptile in North America, inhabits the Southeast Coastal Plain, from North Carolina to Texas.
Up to 15 feet long and weighing as much as 800 pounds, adult males bellow in mid spring to attract a mate. Once impregnated, the female builds a nest mound of rotting vegetation and deposits 20-50 eggs before covering them with more vegetation. Staying close by until they hatch (usually in August), the mother protects her young, digging them out and carrying them to open water in her mouth; she will continue to watch over her offspring for their first year of life. Those eggs that incubate at temperatures above 90 degrees F produce males while those below 86 degrees produce females; nest temperatures in between these parameters yield a mix of genders.
Young alligators may fall victim to a variety of predators, including snakes, large fish, snapping turtles, raccoons, bobcats, bald eagles and other alligators; once fully grown, however, American gators are threatened only by human hunters and habitat loss and may live 50 years or more in the wild. Nearly driven to extinction by overhunting and swamp drainage during the first half of the 20th Century, these large reptiles are now common in freshwater marshlands (and some brackish areas) of the Coastal Plain; they are especially numerous in Florida and Louisiana. Adults feed on a wide variety of fish, reptiles, birds and mammals and can pose a threat to humans if harassed or startled; they have been known to grab pets or even young children on rare occasions. American gators are also raised in captivity for their meat and leathery hide and, unfortunately, are victims of the tourist carnival industry across the Deep South.
Up to 15 feet long and weighing as much as 800 pounds, adult males bellow in mid spring to attract a mate. Once impregnated, the female builds a nest mound of rotting vegetation and deposits 20-50 eggs before covering them with more vegetation. Staying close by until they hatch (usually in August), the mother protects her young, digging them out and carrying them to open water in her mouth; she will continue to watch over her offspring for their first year of life. Those eggs that incubate at temperatures above 90 degrees F produce males while those below 86 degrees produce females; nest temperatures in between these parameters yield a mix of genders.
Young alligators may fall victim to a variety of predators, including snakes, large fish, snapping turtles, raccoons, bobcats, bald eagles and other alligators; once fully grown, however, American gators are threatened only by human hunters and habitat loss and may live 50 years or more in the wild. Nearly driven to extinction by overhunting and swamp drainage during the first half of the 20th Century, these large reptiles are now common in freshwater marshlands (and some brackish areas) of the Coastal Plain; they are especially numerous in Florida and Louisiana. Adults feed on a wide variety of fish, reptiles, birds and mammals and can pose a threat to humans if harassed or startled; they have been known to grab pets or even young children on rare occasions. American gators are also raised in captivity for their meat and leathery hide and, unfortunately, are victims of the tourist carnival industry across the Deep South.
Sabtu, 21 Januari 2012
Along the Myakka
The Myakka River, in southwest Florida, one of only two rivers designated "Wild & Scenic" by the Sunshine State, rises in northern Manatee County and flows southward for 60 miles to Charlotte Harbor. Along the way, it passes through the lakes and marshlands of Myakka River State Park, east of Sarasota, and encounters little human development for much of its course; indeed, Sarasota County has been especially committed to protecting its natural channel and three preserves offer access to southern portions of this ecosystem.
Having enjoyed a week along the Gulf Coast, we decided to head inland and explore the lower Myakka corridor. Jelks Preserve, about two miles south of I-75 on North River Road (via the North Port/Englewood Exit), provides an excellent overview of natural habitats along the river as well as scenic views of the Myakka itself; oak hammocks, festooned with Spanish moss, border slash pine flatwoods, marsh-lined ponds and scrub meadows. Armadillos were abundant along the sandy trails, black vultures and bald eagles soared overhead and American alligators, though unseen on our visit, haunt the shallow pools and wetlands. Myakka River State Forest, about 5 miles south of U.S. 41 via River Road, offers an extensive network of trail loops through these same habitats; it was there that we encountered a massive flock of wintering tree swallows, surely numbering in the thousands, and watched a trio of Florida sandhill cranes drift across the bright blue sky. Finally, Myakka Islands Point, a Sarasota County preserve west of North Port, provides access to pine flatwoods (dominated by slash pine, cabbage palm and saw palmetto) which overlook broad swaths of riverside marsh.
South of these preserves the Myakka becomes increasing brackish as it receives tidal inflow; in concert, the river leaves its meandering, tree-lined corridor and open marshlands stretch across its broad floodplain. Alligators that bask along the River's more northern shores avoid these salty waters but manatees, moving in from the bay, now inhabit the Myakka. As expected, wading birds are abundant across this vibrant tidal zone, roosting in tree islands that rise above the marsh.
Having enjoyed a week along the Gulf Coast, we decided to head inland and explore the lower Myakka corridor. Jelks Preserve, about two miles south of I-75 on North River Road (via the North Port/Englewood Exit), provides an excellent overview of natural habitats along the river as well as scenic views of the Myakka itself; oak hammocks, festooned with Spanish moss, border slash pine flatwoods, marsh-lined ponds and scrub meadows. Armadillos were abundant along the sandy trails, black vultures and bald eagles soared overhead and American alligators, though unseen on our visit, haunt the shallow pools and wetlands. Myakka River State Forest, about 5 miles south of U.S. 41 via River Road, offers an extensive network of trail loops through these same habitats; it was there that we encountered a massive flock of wintering tree swallows, surely numbering in the thousands, and watched a trio of Florida sandhill cranes drift across the bright blue sky. Finally, Myakka Islands Point, a Sarasota County preserve west of North Port, provides access to pine flatwoods (dominated by slash pine, cabbage palm and saw palmetto) which overlook broad swaths of riverside marsh.
South of these preserves the Myakka becomes increasing brackish as it receives tidal inflow; in concert, the river leaves its meandering, tree-lined corridor and open marshlands stretch across its broad floodplain. Alligators that bask along the River's more northern shores avoid these salty waters but manatees, moving in from the bay, now inhabit the Myakka. As expected, wading birds are abundant across this vibrant tidal zone, roosting in tree islands that rise above the marsh.
Selasa, 07 Juni 2011
Fence Lizards
Fence lizards are the most common and widespread lizards in the eastern and central U.S. The northern fence lizard ranges from the Mid-Atlantic region to the edge of the Great Plains and is especially abundant in the wooded hills of the Appalachian and Ozark Plateaus; the southern subspecies inhabits the pine woodlands of the Coastal Plain, from the Carolinas to Texas.
Named for their habit of basking on fence posts, these lizards spend much of the day in trees, chasing down insects, spiders, caterpillars and other invertebrates. Hikers often encounter them as they sprint across trails or scurry through the leaf litter but these agile reptiles usually escape to the safety of a tree, hiding on the opposite side of the trunk.
While both sexes are drab colored, with gray-brown scales, males sport patches of blue on their throat and sides during the breeding season. Mating occurs soon after hibernation and up to 15 eggs are laid by late spring, hatching in late summer or early autumn. Miniature replicas of the adults, young fence lizards are vulnerable to a wide range of predators, including birds, shrews, opossums and raccoons.
Named for their habit of basking on fence posts, these lizards spend much of the day in trees, chasing down insects, spiders, caterpillars and other invertebrates. Hikers often encounter them as they sprint across trails or scurry through the leaf litter but these agile reptiles usually escape to the safety of a tree, hiding on the opposite side of the trunk.
While both sexes are drab colored, with gray-brown scales, males sport patches of blue on their throat and sides during the breeding season. Mating occurs soon after hibernation and up to 15 eggs are laid by late spring, hatching in late summer or early autumn. Miniature replicas of the adults, young fence lizards are vulnerable to a wide range of predators, including birds, shrews, opossums and raccoons.
Rabu, 01 Juni 2011
Common Snappers
Though widespread across North America, from the foot of the Rockies to the Atlantic Seaboard and from southern Canada to the Gulf Coast, common snapping turtles favor the muddy bottom of shallow lakes, ponds and rivers and are not often encountered by the casual naturalist. When seen, they are usually lumbering across country roads, searching for nest sites or new feeding grounds.
Despite their reputation as vicious predators, snapping turtles are opportunistic omnivores, feeding on a wide variety of plant and animal life, including carrion; while they will snare an occasional duckling or young muskrat, they are more likely to dine on decaying carp, aquatic vegetation, frogs, water snakes and smaller turtles. Mating is also opportunistic, occuring from mid spring to late autumn; since females can store viable sperm for years, one encounter is sufficient to fertilize several clutches of eggs. Up to ninety eggs are deposited in a pit, dug by the female in late spring, and will hatch in 2 to 4 months, depending upon the soil temperature; in northern latitudes, the young may not emerge until the following summer.
Hunted by humans for their meat, common snapping turtles cannot fully retract their head, legs and large, armored tail and are thus vulnerable to other predators when out of water; in southern lakes and streams, they may also become victims of alligators. Weighing up to 60 pounds and sporting a shell up to 20 inches in length, snappers may live for 30 years in their natural habitat of freshwater or brackish wetlands.
Despite their reputation as vicious predators, snapping turtles are opportunistic omnivores, feeding on a wide variety of plant and animal life, including carrion; while they will snare an occasional duckling or young muskrat, they are more likely to dine on decaying carp, aquatic vegetation, frogs, water snakes and smaller turtles. Mating is also opportunistic, occuring from mid spring to late autumn; since females can store viable sperm for years, one encounter is sufficient to fertilize several clutches of eggs. Up to ninety eggs are deposited in a pit, dug by the female in late spring, and will hatch in 2 to 4 months, depending upon the soil temperature; in northern latitudes, the young may not emerge until the following summer.
Hunted by humans for their meat, common snapping turtles cannot fully retract their head, legs and large, armored tail and are thus vulnerable to other predators when out of water; in southern lakes and streams, they may also become victims of alligators. Weighing up to 60 pounds and sporting a shell up to 20 inches in length, snappers may live for 30 years in their natural habitat of freshwater or brackish wetlands.
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