All posts by traderscreek

Spring Peeper – Pseudacris crucifer

December 12, 2013 traderscreek

General: Spring Peepers (Pseudacris crucifer) are known for their songs that are often considered a melodic announcement of spring. Although these chorus frogs are known for their sounds, these tiny amphibians are rarely scene due in part to their camouflaged pigmentation and nocturnal habits.

Description: Spring Peepers are a diminutive amphibian, measuring a mere ¾” to 1½” in length and 3g to 5g in weight when fully grown. In addition to their petite size, their coloration aids in providing camouflage, making them elusive and hard to spot. Males and females are similar in appearance. Spring Peepers are generally tan, brown, olive or grey, accented with dark lines across their backs that form “X” patterns and dark bands around their legs and between their eyes. They may sometimes have a reddish or orange pigmentation. Spring Peepers have cream or white undersides and throats, although males display gray throats during the mating season. Spring Peepers are capable of a degree of color-change and can lighten or darken their pigmentation based on their surroundings. They have moderate webbing on their feet and large, round, sticky toe pads that aid in climbing1, although they rarely climb higher than 3’ off the ground. Spring Peepers can be identified by the large ‘vocal sacks’ located under their chins. In order to produce their signature songs, Spring Peepers inflate these sacs with air to a size equal to their entire bodies2.

Subspecies of the Spring Peeper may be identified by unique coloration. Northern Spring Peepers tend to have unmarked bellies while Southern Spring Peepers have spotted bellies3.

Spring Peepers are best known for their high-pitched songs, harkening the start of spring in northern habitats as males begin performing mating displays in March. However, southern Spring Peepers begin their mating songs as early as November, causing the name Spring Peeper to be quite ironic for these populations. Their monosyllabic whistle is often mistaken for the chirp of crickets as it is repeated at a rate of 20 times a minute, although crickets are only heard in the late summer and fall. Spring Peepers may be heard on rainy or cloudy days but are most frequently active on warm, damp nights. By late summer their calls have usually fallen silent but they can be heard again ringing from forests during the fall. Spring Peepers sometimes slur together two syllables and produce a trill-like sound. Males sing in trios and the males with the deepest calls typically lead the choruses. Groups of singing Spring Peepers are often described as sounding like sleigh bells.

Spring Peepers hibernate during the winter in spaces beneath tree bark or under logs, allowing their bodies to almost entirely freeze. In order to survive, Spring Peepers produce and store high levels of glucose in their cells that prevents cells from freezing and rupturing, preserving the frog until the spring thaw.

While their lifespan in the wild is still unknown, Spring Peepers live, on average, 3 to 4 years in captivity4.

Habitat: Spring Peepers live in close proximity to water sources such as ponds, streams, marshes and temporary pools and inhabit swampy wooded areas, and grassy lowlands. They spend the majority of the year amidst debris on forest floors but mate and deposit their eggs in the water.

Within their habitats Spring Peepers are preyed on by birds, snakes, and some mammals. Aquatic insects, turtles, and fish consume their eggs and tadpoles.

Location: Populations of Spring Peepers can be found in eastern and central portions of the United States and Canada. Native populations have been found as far south as eastern Texas and northern Florida and introduced populations have been reported in Cuba.

Diet: Spring Peepers are carnivorous, consuming a diet of beetles, flies, ants, spiders, mosquitoes, gnats, aphids, termites, and crickets. Spring Peepers hunt and feed on forest floors and in low vegetation, rarely exceeding an elevation of 3’.

Reproduction: Spring Peepers breed once annually, from November to March in southern habitats and from March to June in northern areas. The breeding season begins as males emerge from hibernation and commence their mating songs during damp, warm nights. Males gather by the hundreds around water sources, singing in trios and establishing individual territories. Females choose their mates by the quality and frequency of their calls and their overall size.

Spring Peepers mate and deposit their eggs in freshwater ponds or temporary pools that lack fish, showing preference for areas deeper than those used by other species. Males play no reproductive role beyond fertilization. Females deposit the eggs with a nourishing yolk but provide no additional parental care. Females deposit up to 1000 eggs, which measure 1mm in diameter, individually or in clusters of two to three along submerged vegetation. Eggs double in size when fully hydrated and hatch within 6 to 12 days, depending on temperatures. Embryos and larvae are sensitive to water conditions and cannot survive in a pH ranging from 4.2 to 4.5. During the larval stage, tadpoles feed on algae and aquatic organisms. Spring Peepers are slightly larger in their larval stage than when fully mature. The length of the larval stage is partially dependent on water conditions and availability, but ranges from 45 to 90 days.

Spring Peepers reach sexual maturity in 2 to 3 years5.

Notes of Interest: Spring Peepers’ scientific classification, crucifer, is Latin for ‘cross-bearer,’ appropriately assigned to this tiny frog who bears an x-shaped marking on its back.

The choral song produced by groups of Spring Peepers is similar to the sound of jingle bells and has earned them the nickname Pinkletinks from residents of Martha’s Vineyard6.

Footnotes
1. http://animals.nationalgeographic.com/animals/amphibians/spring-peeper/
2. http://www.dnr.state.md.us/features/spring_peepers.asp
3. http://www.enature.com/fieldguides/detail.asp?recnum=AR0014
4. http://animaldiversity.ummz.umich.edu/accounts/Pseudacris_crucifer/
5. http://animaldiversity.ummz.umich.edu/accounts/Pseudacris_crucifer/
6. http://www.dnr.state.md.us/features/spring_peepers.asp

http://www.enature.com/fieldguides/detail.asp?recnum=AR0014
http://animals.nationalgeographic.com/animals/amphibians/spring-peeper/
http://www.fcps.edu/islandcreekes/ecology/spring_peeper.htm
http://www.cmnh.org/site/ResearchandCollections/VertebrateZoology/Research/Treefrogs/NSpringPeeper.aspx
http://animaldiversity.ummz.umich.edu/accounts/Pseudacris_crucifer/
http://www.dnr.state.md.us/features/spring_peepers.asp

Reptiles, Wildlife

American Toad – Bufo americanus

December 11, 2013 traderscreek

General: The American Toad (Bufo americanus) is a common inhabitant of gardens and shady backyard spaces across much of North America. These amphibians are often identified first by their musical trills, heard on warm nights in the spring and fall. Stout and stubby in appearance, it is comical to watch an American Toad lumbering across organic debris and vegetation. American Toads have the greatest geographic range of all toad species in North America and have no special conservation designation.

Description: American Toads are rotund amphibians that reach an adult size of 2” to 4.5” long, females usually reaching a greater overall size than males. They are often described as chubby and stout, with short limbs, wide heads, and muscular hind legs. The front legs have four toes, while the back legs have five webbed toes. American Toads have black ovular pupils often circled with gold and prominent cranial ridges with lateral branches that extend behind the eyes1. The cranial crests occur in front of two large parotid glands, which may be identified by their bean-shape, that are capable of producing a foul smelling chemical used to ward off predators. Their thick, rough skin ranges from brown, gray, brick red or olive in color and is accented by noticeable warts. These warts, which are yellow or brown, appear singly or in pairs and are contained within large brown or black spots across the back. These spots may be circled by yellow or white. Some toads have patterns of light, yellow, or buff on their bodies, which may create a light ‘stripe’ down the back. Males and females have white or yellow undersides with dark speckling, but males often display a darker throat that is black or brown2. The skin of American Toads may change color due to temperature, time of day, humidity, stress, age or sex. American Toads shed their external skin four times a year. The skin is sloughed off in one piece and then consumed by the toad. Immature American Toads shed their skin every few weeks3.

Two subspecies of the American Toad exist. Dwarf American Toads, Bufo americanus charlesmithi, are typically found in western parts of the geographic range and can be identified by their smaller size (adults reaching only 2.5” in length,) dark red coloration, and fewer or no spots on their backs (spots that are present contain one wart, at most.) The Eastern American Toad, Bufo americanus americanus, inhabits the eastern portions of the range and is medium in size (reaching lengths of 3.5”,) has variable coloration, has one to two warts contained within each spot, enlarged warts on the lower legs, and speckling only on the front half of the belly4. American Toads are often confused with Fowler’s Toads because of their similar appearances. However, where the American Toad only has one or two warts in each spot, a Fowler’s Toad has several warts in each spot on its back.

American Toads produce a high-pitched trill, most often heard during the early spring (when calling mates,) or in the fall (when locating a hibernation area,) that is held for 4 to 30 seconds. Males produce this call by inflating their round vocal sac, called the dewlap, and use it to attract females during the breeding season. At the height of the season calls can sound frantic and loud as males compete for mates. In addition to their recognizable calls, American Toads also use touch, chemical cues and posture to communicate5. In response to predators, American Toads may release a toxic chemical from their parotid glands, play dead or puff-up their bodies to appear larger.

American Toads are nocturnal and are most active during warm and humid weather. During the day they tend to burrow into soil or leaf litter, or under rocks or logs6. They are also a solitary species, only social when at breeding ponds during the mating season. During the winter, American Toads burrow into soil below the frost line, continuing to burrow further as the frost deepens.

In captivity American Toads have been known to live to over 30 years old. However, in the wild, many tadpoles perish before completing their complete metamorphosis into mature toads. Adult toads live, on average, a couple years in the wild but have been known to live as long as ten years.

Habitat: American Toads are a highly adaptable species and can be found in a variety of habitats. Preference changes seasonally but American Toads generally require some source of moisture, vegetation for burrowing and hunting, and a constant supply of food.

During the breeding season, American Toads inhabit areas that provide a body of freshwater that is either temporary or permanent. These areas include wetlands, temporary pools, shallow bays, swamps, streams, and ditches. These freshwater bodies are used for mating and depositing eggs as well as throughout the early development of tadpoles.

After the spring breeding season, American Toads are able to move further from water sources and can be found in forests, meadows, woodlands, shady suburban yards, grasslands, gardens, farmlands, and prairies. Their muscular hind legs make it possible to move amongst the leaf litter and debris on the ground.

During winter hibernation, American Toads burrow into the ground, remaining below the frost line.

Predators of the American Toad include snakes, skunks, owls and raccoons, although predators are often deterred by the toxic chemicals released by the parotid glands and the bitter tasting skin. Raccoons have adapted to this occurrence by eating from the undersides of toads, far from the chemical producing glands.

Location: American Toads are found across most of North America (except for most southern states) since they are a highly adaptable species that only requires seasonal water for breeding7.

Diet: American Toads are carnivores, consuming a massive quantity –up to 1000 insects a day- of insects, spiders, snails, slugs, and worms. They catch prey by thrusting out their sticky tongues and using their forearms to hold large prey and pack it into their mouths. While American Toads do not drink water, they are able to absorb moisture from their environments through their thick, rough skin.

Tadpoles are herbivorous, consuming aquatic vegetation along the edges of their freshwater habitats.

Reproduction: American Toads are polygamous and mate once annually, typically between April and July. Breeding activity is triggered by the rising temperatures and lengthening days of spring. Male toads arrive at breeding ponds before females in order to establish territories. These congregations of males produce their signature calls to attract females, who select mates based on the quality of their calls and breeding territories8.

Males grasp the larger females from behind during egg deposit and fertilization in a position called amplexus. Females lay between 4000 to 8000 1.5mm counter-shaded eggs (white on the bottom and black on the top for camouflage,) within long tubes of jelly attached to submerged vegetation. Females provide nutrients to the eggs internally but males and females provide no parental care past egg fertilization and deposit. Females prefer breeding ponds without fish to ensure greater survival rates for their offspring. The eggs will hatch in 3 to 12 days, with maturation rates depending on environmental temperatures9.

The tiny tadpoles hatch with rounded tails and bodies, gills on the sides of their heads, and smooth black skin, which emits defensive chemicals (similar to adults) for defense. Tadpoles swim in schools and consume plant matter that will fuel their steady growth into mature toads. For 50 to 60 days following hatching, tadpoles go through a process called metamorphosis, in which they transform into miniature versions of mature toads. Over the first 20 days, tadpoles develop hind legs. The front legs develop between 30 and 40 days old, emerging from underneath a layer of skin. During this period, tadpoles begin breathing air as their gills disappear. Over the last few days of metamorphosis, tadpoles reabsorb their tales and begin eating animal matter10. Tadpoles reach a length of just over a centimeter before transforming into toadlets, or small versions of fully mature toads that are between .8cm and 1.3cm in length11. These young toads remain in close proximity to the breeding pond for several days after completing metamorphosis and then move into terrestrial habitats12. American Toads reach sexual maturity in two to three years.

Notes of Interest: Despite popular belief, humans cannot get warts from touching a toad. It is, however, advisable to use caution when handling these creatures because the chemicals released from the parotid glands can cause irritation if they are consumed or come in contact with your skin or eyes.

http://www.fcps.edu/islandcreekes/ecology/american_toad.htm
http://www.dnr.state.mn.us/reptiles_amphibians/frogs_toads/toads/american.html
http://www.dnr.state.oh.us/tabid/6602/Default.aspx
http://www.biokids.umich.edu/critters/Bufo_americanus/
http://www.uri.edu/cels/nrs/paton/LH_ea_toad.html
http://www.npwrc.usgs.gov/resource/herps/amphibid/species/american.htm

Mammals, Wildlife

Red Fox – Vulpes vulpes

December 10, 2013 traderscreek

General: The Red Fox (Vulpes vulpes) is a clever and cunning mammal, known for its adaptability and broad geographic range, which has expanded relative to human populations. A member of the canidae family, the Red Fox is closely related to the domestic dog, coyotes and wolves and is the largest of all species of foxes. With growing and stable populations, the Red Fox is unique from other fox species in that it is not listed as endangered in any geographic area.

Description: The largest of the Vulpes species, the Red Fox reaches a mature length of 18” to 34”, standing approximately 16” tall. Their full-grown weight ranges from 6.5lbs. to 24lbs., males typically larger than females by as much as 25%. Mature size is partially dependent on geographic location. Populations living in southern desert climates and southern parts of North America tend to be smaller, on average, than populations in northern European habitats. Generally, northern populations tend to have a greater body mass than southern populations.

Anatomically, the Red Fox bear a similar appearance to dogs, coyotes, and wolves, all classified in the canidae family. They have conical muzzles, prominent pointed ears, and tail glands located on the upper portion of the root of the tail, within the dermis. The dental composition is also similar to other members of the canidae family, with molars built for crushing, and pointed premolars. The tooth row stretches half the length of the entire skull. The front paws have five claws and the rear have four. The first digit of each paw, called the dewclaw, is clawed but otherwise simple in structure and does not come in contact with the ground1.

Red Foxes are easily identifiable by their thick coats that range in color from rusty-red, red-brown, or yellow-red, coving their backs, shoulders, and head. Two color variations of the Red Fox exist, including the Silver Fox, making-up 10% of Red Fox populations and silver to nearly black in color, and the Cross Fox variation, a hybrid of the Red Fox and Silver Fox that accounts for 25% of all Red Foxes, with reddish-brown fur and black stripes across the back and shoulders. Red Foxes have white or gray undersides, chins and throats. The rear may be covered in red fur or gray fur, similar to the underside. The bottoms of the legs and pointed, erect ears are black and the nose is either black or dark brown. The eyes of mature Red Fox are yellow. About half the length of a full-grown Red Fox is the bushy, cylindrical tail. The tail, 12” to 22” in length, is typically a combination of red and black and has a white or black tip. The tail of the Red Fox not only aids in balance, but also provides warmth and protection from extreme weather conditions and is used to signal and communicate with other foxes.

Red Foxes are shy animals that are rarely seen during the day. This nocturnal species is most active during twilight hours and at night. Unlike wolves, which are social animals that form packs, Red Foxes are solitary and generally live alone outside of the mating season. They are active year round and only inhabit a den during periods of reproduction. Home ranges are established and used throughout the life of a fox. These ranges are usually distinct from other ranges since Red Foxes are known to be territorial. These ranges may be 2 sq. miles to 4.5 sq. miles in ideal habitats and often contain one adult male and one or more adult females with their young. In habitats with poor or limited food supplies and during winter months, home ranges may expand to include 7.5 sq. miles to 20 sq. miles. In poor conditions, Red Foxes are capable of traveling several miles in a single day. They are a highly mobile species and are able to reach 30mph, jump obstacles over 6’ tall, and span 15’ in a single bound2. In the wild, Red Foxes live an average of 2 to 4 years, but have been known to live to 12 years old in captivity.

Red Foxes use a variety of methods of communication, including facial expressions, tail gestures, scent marking and vocalizations. Red Foxes use urine, feces, and glandular secretions as scent posts. Red Foxes are known to have unique voices and are capable of making upwards of 28 noises, used to communicate in close range and over distances. These noises include a dog-like bark and a scream, emitted when a fox becomes alarmed. In addition to their vocal abilities, Red Foxes have advanced senses of touch, smell and sight3.

Habitat: The Red Fox is a highly adaptable species whose populations are stable and wide spread in a variety of habitats, due in part to their ability to thrive in human-modified environments. They are found at elevations ranging from sea level to 14,500’, in forests, tundra, prairies, mountainous regions, deserts, grasslands, urban and suburban areas, and farmlands. Red Foxes prefer habitats that offer a mixture of vegetation and cover, living in brush piles, root systems, hollowed logs, or ground dens.

Red Foxes establish individual or family dens within their home ranges, used for protection during winter months and for birthing and raising young. These dens may be used for several generations. Their main dens are often supplemented with emergency burrows, multiple entrances, and pathways that connect the dens to food stores or hunting areas4. Red Foxes commonly steal dens from other animals, such as rabbits or woodchucks.

Within their habitats, Red Foxes have few predators. The young are at the highest risk of predation, but pups and adults are preyed on by hawks, owls, coyotes, and wolves.

Location: The Red Fox has the largest geographic distribution of all members of the canidae family. Their range has expanded alongside human populations, especially in areas where wolf populations are tightly controlled, eliminating a major predator and competitor of the Red Fox. Native populations are found across the northern hemisphere, throughout North America, northern parts of South America, Asia, Europe, and northern Africa. Populations were introduced to Australia and the Falkland Islands5 in the mid 1800’s as a sport animal.

Diet: Red Foxes are omnivores whose diets consist mainly of small mammals, such as mice, birds, squirrels, rabbits, opossums, woodchucks, skunks, shrews, voles, and moles. However, as opportunistic feeders, they will also consume fruits, vegetables, nuts, fish, worms, frogs, lizards, turtles, crustaceans, insects, domestic dogs and cats, and even carrion (decaying flesh) and garbage. With their excellent sense of hearing, Red Foxes are capable of picking-up the noises of underground animals, which are dug up and eaten. Red Foxes most often stalk their prey, quietly approaching before running the prey down and pouncing. Red Foxes are solitary hunters and do the majority of their hunting during twilight or at night, typically consuming .5 to 1kg of food each day6. Red Foxes are unique in that they are one of the few predators that store caches of food for future consumption.

Reproduction: Red Foxes are typically monogamous breeders, but it is not uncommon for males to have multiple mates, who may live together in the male’s den. A red fox group will not, however, have more than one mating male since males become territorial and aggressive during the breeding season. It is also possible for a mating pair to share their den with non-breeding females who contribute to rearing the young. Red Foxes reach sexual maturity by 10 months of age and breed annually. Estrus and breeding is partially dependent on geographic location, generally occurring in December or January in southern habitats, from January to February in central locations, and in February to April in northern areas. Females’ estrus period lasts from 1 to 6 days and ovulation does not require copulation but is spontaneous7.

Before females (or vixens) give birth, Red Foxes create a maternity den, which may be used for several years. These dens are created by enlarging another animal’s abandoned burrow, or within a hollow log, root cluster, cave, or brush pile. These dens usually have wide entrances (about 3’ wide) and multiple escape holes, and are lined with dry vegetation. Females stay in or around the maternity den prior to birth, receiving sustenance from mates. Gestation lasts from 50 to 60 days and females give birth to an average of 5 pups, although litters may contain from 1 to 12 pups. Pups are born weighing between 50g to 150g, and are blind and grey or brown in color. Their eyes open within 9 to 14 days and the signature red coat grows-in by around one month of age. Both parents, and sometimes offspring from previous litters, provide care to the young until the young are old enough to provide for themselves. Pups are fully weaned by 8 to 10 weeks old and are fed regurgitated meat by their mothers. Mothers begin bringing live prey to the pups in the den so they may learn to hunt and at 4 to 5 weeks old pups begin following their parents out of the den to learn to hunt. Pups live with their parents through their first fall (female pups may stay with their parents longer,) at which point they disperse to establish territories of their own. These new home ranges may be as close as 6 miles and as far as 250 miles from their birth dens8. Once the pups have left, parents may separate.

Notes of Interest: Red Foxes are one of the most common carriers of the Rabies virus. Red Foxes are a nocturnal species, and caution should be used around a Red Fox that is active during the day, as this might indicate an infected animal.

Red Foxes are a staple of the fur industry and are more commonly raised on fur-farms than any other fur bearer9.

http://animals.nationalgeographic.com/animals/mammals/red-fox/
http://www.fcps.edu/islandcreekes/ecology/red_fox.htm
http://animaldiversity.ummz.umich.edu/accounts/Vulpes_vulpes/
http://www.dec.ny.gov/animals/9354.html
http://www.dnr.state.mn.us/mammals/redfox.html
http://www.mnh.si.edu/mna/image_info.cfm?species_id=420

Birds

Yellow-Bellied Sapsucker – Sphyrapicus varius

December 9, 2013 traderscreek

General: Yellow-Bellied Sapsuckers (Sphyrapicus varius) are the small woodpeckers responsible for the neat rows of sap wells found drilled into trees across much of the southern and eastern United States and central Canada. These striking black and white birds can usually be found perched along tree trunks lapping up sap. Sapsucker populations are healthy and stable, earning the Yellow-Bellied Sapsucker the classification of Least Concern on the IUCN Red List.

Description: Yellow-Bellied Sapsuckers are small relative to other species of woodpeckers. They reach a mature length of 7” to 8.75” and weight of 1.5oz. to 1.9oz. They can be identified by their black and white, boldly patterned plumage (in scallops across the back,) yellow or buff-white undersides, red caps, and long white patches on the sides of folded wings (that open to a wing span of 13.5” to 15.7”1.) Additionally, Sapsuckers have white rumps, black eyelines and two white stripes stretching from the eyes and sides of the bill toward the black bib on the chest. Males differ from females by the presence of a red chin and throat, both of which appear pale or entirely white on females. Juvenile Sapsuckers have buff and dusky black barring on their backs with pale underparts and white rumps. Yellow-Bellied Sapsuckers have straight thick bills that act as chisels, brush-tipped tongues used for lapping up sap and catching insects, rigid, pointed tails, and crown feathers on the backs of their heads, which they raise to form peaks.

Yellow-Bellied Sapsuckers behave in a similar manner to other woodpeckers. Their flight consists of rises and falls, a swooping pattern used by other woodpeckers. They hop along tree trunks, leaning back against their supporting tail feathers when feeding or tending to sap wells, an activity that takes up at least half their time2. Their communicative behaviors are similar to those executed by other woodpecker species. Mating displays consist of lifting the head to reveal throat patches, chases, and tapping. Aggression is expressed through raised crests and ruffled tail and throat feathers, head swaying, and raised tails and bills.

Yellow-Bellied Sapsuckers produce a number of sounds. A kwee-urk is associated with breeding as well as territory defense. Threatened birds may also shrill. Breeding pairs also create quirk noises to strengthen their bonds. These noises are produced by scratching on trees. Repetitive week-week and wurp-wurp sounds are made between pairs or parents and juveniles. Excited birds make a nasal, mewing c-waan3. Like all woodpeckers, Sapsuckers create the unmistakable drumming noise while hammering against trees.

Yellow-Bellied Sapsuckers have been known to live to nearly 8 years old; however, in the wild they live an average of 6.5 years4.

Habitat: Yellow-Bellied Sapsuckers live in hardwood, mixed, and coniferous forests, at elevations up to 6500’.

In the spring and summer, they establish breeding grounds in young or regenerating forests that offer ample opportunities to bore sap wells. Nesting often occurs in groves of small trees, such as aspens. During the winter, Sapsuckers relocate to open hardwood or mixed woodlands. While Sapsuckers will inhabit a greater variety of habitats in the winter than in the spring or summer, they will not settle in an area that is entirely coniferous during winter months5.

Location: Yellow-Bellied Sapsuckers may be found throughout the central, northern and eastern United States and into central Canada. Sapsuckers are the only species of woodpecker in the eastern United States that is entirely migratory. Some Sapsuckers may stay in their breeding areas throughout the winter, especially in southern parts of their range, but most populations relocate to winter habitats, ranging from south of New England and the Great Lakes to southern parts of the United States, Mexico, the West Indies and parts of Central America. It is common for females to migrate farther than males. Sapsuckers have been found in Iceland, Britain and Ireland; however, Sapsuckers are not native to these geographic areas and these sightings are attributed to accidental relocation6.

Diet: Yellow-Bellied Sapsuckers can often be spotted sitting along tree trunks feeding from their sap wells. They harvest sap by boring two distinct types of holes in over 1,000 species of trees and woody plants (although they prefer trees that have sap with high sugar concentrations, such as maple, hickory and birch trees.) They select trees that are alive and actively producing sap, a behavior that sets them apart from other species of woodpeckers who tend to prefer dead wood.

Sapsucker’s systematic drilling starts in the spring, when narrow circular wells are bored deep into the trunk, providing access to sap flowing upward through the tree’s xylem (which sapsuckers reach by inserting their long bills.) The second type of well is shallower than the first and rectangular in shape, drilled into the phloem of the tree. These wells provide access to sap as it runs down from leaves once the tree has bloomed. Sapsuckers lap-up sap leaking from these wells. Because these secondary holes are shallow, they must be continually maintained with fresh drilling so sap can continue to flow. This sap has a sugar content of over 10%. New holes are drilled year round in both breeding and winter territories, and are placed in a new row above or in line with existing holes.

Sapsuckers also feed on insects, such as ants, spiders and moths, suet, berries and fruit. They hop along the ground to forage for insects, but also catch flying insects while sitting at the ends of tree branches, dig for insects beneath tree bark and consume insects caught in sap. Sapsuckers may be found in orchards, which provide opportunities for harvesting sap and access to fruit.

Reproduction: Before mating in the spring, Sapsuckers exhibit playful courting displays, as one bird chases another in flight and across tree trunks and branches. As courting pairs stand facing each other on a branch, with ruffled feathers and raised crests, they swing their heads and emit winnowing sounds. These pairs also participate in ritual tapping, in which courting birds interact with echoing taps. These behaviors strengthen bonds and create mating pairs that may last for several breeding seasons.

Male Sapsuckers are often responsible for choosing nesting sites and excavating nests, usually in the same species of trees used for drilling sap wells (such as birch, maple, aspen, and elm.) They show a preference for living trees hosting a fungus that softens the trees interior (making excavating a nest easier.) These nest cavities may be used for up to seven consecutive years. Entrances are approximately 1.5” in diameter and the cavity itself is around 10” in depth and lined only with woodchips.

Sapsuckers have one brood a year, consisting of 4 to 6 white eggs that are approximately 1” in length. The eggs are incubated by both adults for 10 to 13 days, although males spend more time incubating the eggs, especially at night7. The chicks are born naked and blind, with gray beaks. After 8 days, the chicks open their eyes8. During the nestling period of 25 to 30 days, parents must feed the chicks nine times an hour to ensure proper development, taking turns bringing the chicks sap and insects. Parents mix sawdust with droppings in the nest and remove them, to keep nest cavities sanitary9.

Juveniles fledge in mid-summer and gradually acquire their adult coloration throughout their first fall (with red plumage appearing first) and winter (when the black and white signature pattering appears on their heads and chests10.)

Notes of Interest: Sapsucker wells provide feeding opportunities for at least 35 other species of birds and mammals, attracted to the sap and/or insects11. One particular bird species attracted to the sap flows is the Ruby-Throated Hummingbird. This hummingbird’s reliance on the sap is so integral to their survival that they coordinate their spring migration with that of the sapsucker. Other species that use the sapsucker wells are bats and procupines12.

Footnotes:
1. http://www.allaboutbirds.org/guide/yellow-bellied_sapsucker/id
2. http://www.allaboutbirds.org/guide/yellow-bellied_sapsucker/id
3. http://animaldiversity.ummz.umich.edu/accounts/Sphyrapicus_varius/
4. http://animaldiversity.ummz.umich.edu/accounts/Sphyrapicus_varius/
5. http://www.allaboutbirds.org/guide/yellow-bellied_sapsucker/id
6. http://animals.nationalgeographic.com/animals/birding/yellow-bellied-sapsucker/
7. http://animaldiversity.ummz.umich.edu/accounts/Sphyrapicus_varius/
8. http://www.allaboutbirds.org/guide/yellow-bellied_sapsucker/id
9. http://animaldiversity.ummz.umich.edu/accounts/Sphyrapicus_varius/
10. http://animals.nationalgeographic.com/animals/birding/yellow-bellied-sapsucker/
11. http://www.houstonaudubon.org/
12. http://www.allaboutbirds.org/guide/yellow-bellied_sapsucker/id

http://www.allaboutbirds.org/guide/yellow-bellied_sapsucker/id
http://animals.nationalgeographic.com/animals/birding/yellow-bellied-sapsucker/
http://animaldiversity.ummz.umich.edu/accounts/Sphyrapicus_varius/
http://www.houstonaudubon.org/

Birds

Steller’s Jay – Cyanocitta stelleri

December 8, 2013 traderscreek

General: Steller’s Jays (Cyanocitta stelleri) are bold, social and extremely vocal birds that can be found in the mountainous areas of the North American west. They may best be known for their dark blue coloration and lack of white undersides. Be cautious of these vividly colored and inquisitive birds when picnicking, as they have been known to steal unguarded fare. Steller’s Jay populations are healthy and expanding and are listed as Least Concern on the IUCN Red List.

Description: Steller’s Jays are large, robust birds that reach adult weights of 3.5 to 5 oz. and lengths of 11.75 to 13.5”. They have full, long tails, large heads with thick, straight black bills and rounded wings that open to a span of over 17”. Steller’s Jays, like Blue Jays, have prominent crests that sit erect atop their heads. These two species are the only two in North American that have easily distinguishable crests1.

Steller’s Jays are identifiable by their allover dark coloration, lacking the light underparts common of many species. Their heads are charcoal in color with subtle white or blue markings and black crests. Their bodies are dark cobalt blue accented by vivid blue and black barring on the wings and tail. Sexual dimorphism is minimal within this species, with females only being slightly fainter in color and with slightly less barring than males. Juvenile Steller’s Jays lack the brilliance of adults and instead are brown or gray with less prominent crests.

Geographic variations occur across the seventeen known subspecies of Steller’s Jays. These differences can include greater amounts of blue or black across the bodies and crests, and variations in head sizes and patterning.

Steller’s Jays are intelligent, noisy and inquisitive birds that spend most of their time foraging and exploring their habitats. On the ground and in trees they move with bold hops (pausing often to investigate their surroundings) and in the air they travel with graceful, long and steady wing beats (their wings rarely extending past horizontal2.)

Steller’s Jays are extremely social birds, traveling in flocks of mating Steller’s Jay pairs as well as in mixed-species flocks. Their populations are built upon complex patterns of social hierarchies and dominance. To display aggression, two jays may partake in aerial fights, grasping and pecking at each other during flight. Social standings may also be determined through crest displays, wing spreading (to express submission) and an activity called “Aggressive Sliding.” To ward off predators, such as raptors, Steller’s Jays unite into mobs to use vocal and physical intimidation3.

Extremely vocal birds, Steller’s Jays are capable of a broad range of sounds and calls, including mimicking (the likes of dogs, cats, squirrels, chickens, other birds, and even some machines4.) Other sounds include squawks, screams, rattles, soft warbles, and piercing sheck sheck sheck screams5. Adult jays, while usually some of the most vocal birds in their habitats, are quiet and discreet when raising their young or robbing nests6.

Steller’s Jays have been known to live to approximately 16 years old.

Habitat: Steller’s Jays reside in mountainous coniferous and mixed forests of the North American West, where they can be spotted in the high canopy. They may also be found in arid woodlands in the American southwest and Mexico. Their habitats also include parks, campgrounds, and suburban areas.

Location: Steller’s Jay populations are generally resident and inhabit coniferous and mixed woods forests in western North America, from the southern coast of Alaska, through the Rocky Mountain Region (into eastern Colorado) and south into Mexico and Central America at elevations of 3,000’ to 10,000’. Along the Pacific Coast, Steller’s Jay populations tend to be found at lower elevations7.

Although Steller’s Jays are generally resident, some populations may migrate to lower elevations during winter months. Large irruptions in the fall and winter may also cause populations of Steller’s Jays to move into southern California, deserts of the American southwest, and the Great Plains. There has also been accidental population movement into Illinois, Nebraska, Kansas and central Texas8.

Diet: Steller’s Jays are generalist foragers, searching for food on the ground and in trees. Their omnivorous diets consist of two-thirds vegetable matter, including seeds, berries, and nuts. These jays are capable of carrying several large nuts or seeds simultaneously within their mouths and throats. Because they have developed spatial understanding and memory, Steller’s Jays are able to bury and store nuts and seeds for winter food caches. In addition to their own caches, it is common for Steller’s Jays to raid caches of other birds during winter months. Their diets also include insects, small rodents, reptiles, invertebrates and carrion. Steller’s Jays are habitual nest robbers and are known to eat eggs and nestlings. Populations living in close proximity to humans will eat garbage, bird feed and picnic fare9.

Reproduction: Steller’s Jays form long-term monogamous pairs that tend to remain together year round. Breeding generally occurs within dense coniferous forests, and begins with courting displays called “Sexual Sliding10.” Steller’s Jays have one brood per year. Nesting sites are selected by both mates who then collect materials and build the nest together. These nests are usually above ground, located on horizontal branches close to the trunk of a tree. One of only two species of New World Jays to use mud as a building material (the other is the Blue Jay,) Steller’s Jays construct cup-shaped nests of stems, moss, leaves, and sticks (all held together with mud.) These nests may be up to 17” in diameter, 7” tall and 2.5” to 3.5” in depth and are lined with pine needles, animal hair, rootlets and sometimes paper. Females are able to lay one egg per day, with typical clutches containing 2 to 6 blue-green eggs spotted with olive, brown or purple. The eggs are 1” to 1.4” in length and are incubated by the females for 16 days, although males have been known to share in incubation duties11. Both parents share in feeding their young. The chicks molt for the first time in 2 weeks and begin to fly at around 3 weeks of age, shortly after fledging. Although the fledglings begin foraging for their own food at one-month-old, parents continue to provide food for an additional month after their young fledge12.

As Blue Jay populations expand west, hybrids with Steller’s Jays are becoming more and more common.

Notes of Interest: Steller’s Jays received their namesake from naturalist Georg Steller. He first discovered this species in 1741 while exploring an Alaskan island as part of the crew of a Russian exploratory ship. Other species that share their namesake: Steller’s sea lions and Steller’s Sea-Eagles13. Over the last two decades, Steller’s Jay populations have expanded, infiltrating a broader range of habitats. As a result, the Steller’s Jay has become a much more common resident of towns and cities14.

Footnotes
1. http://www.allaboutbirds.org/guide/Stellers_Jay/id
2. http://animals.nationalgeographic.com/animals/birding/stellers-jay/
3. http://animaldiversity.ummz.umich.edu/accounts/Cyanocitta_stelleri/
4. http://www.allaboutbirds.org/guide/Stellers_Jay/id
5. http://animals.nationalgeographic.com/animals/birding/stellers-jay/
6. http://www.birdweb.org/birdweb/bird/stellers_jay
7. http://www.allaboutbirds.org/guide/Stellers_Jay/id
8. http://animals.nationalgeographic.com/animals/birding/stellers-jay/
9. http://www.allaboutbirds.org/guide/Stellers_Jay/id
10. http://animaldiversity.ummz.umich.edu/accounts/Cyanocitta_stelleri/
11. http://www.allaboutbirds.org/guide/Stellers_Jay/id
12. http://www.birdweb.org/birdweb/bird/stellers_jay
13. http://www.allaboutbirds.org/guide/Stellers_Jay/id
14. http://www.birdweb.org/birdweb/bird/stellers_jay

http://www.allaboutbirds.org/guide/Stellers_Jay/id
http://animals.nationalgeographic.com/animals/birding/stellers-jay/
http://www.birdweb.org/birdweb/bird/stellers_jay
http://animaldiversity.ummz.umich.edu/accounts/Cyanocitta_stelleri/

Mammals, Wildlife

Opossum – Didelphia virginiana

December 7, 2013 traderscreek

General: The opossum (Didelphia virginiana) is one of the oldest known mammals, having been traced back 70 million years through fossilized remains. Over 60 species of this common mammal are now found across North and Central America. The opossum is the only marsupial found in North America1 and is notable for the unique presence of a pouch that is used to protect, nourish and raise young. You may come across one of these nocturnal animals wondering quietly at night or even hanging from their prehensile tails from a tree branch. Unfortunately, many opossums are killed by automobiles because of their tendency to eat carrion. Despite their high mortality rates, opossums are widespread with healthy populations and are listed as least concern on the IUCN Red List.

Description: Opossums are slow, clumsy heavyset mammals that reach a mature weight of 8.8 to 13.2lbs. and nose-to-tail length of up to 30”, with males being slightly larger than females. They have easily identifiable elongated heads with conical snouts and long whiskers. The skull of the opossum contains 50 teeth, more than most other mammals within their habitats (a feature that is indicative of the opossum’s ancient lineage2.) Opossums are possibly best known for their long, tapered prehensile tails that are scaly in appearance. This type of tail is used as a fifth limb and is adapted for gripping and wrapping, aiding in climbing and allowing opossums to hang from their tails for short periods of time. Opossums also have hand-shaped feet with sharp claws that aid in climbing and an opposable hallux located on the interior of each rear foot. A hallux functions similar to a thumb and aids in gripping3. Opossums use these digits to groom their fur, faces, and front feet4. As members of the Didelphidae family (and the only marsupials found in North America,) female opossums have wooly, fur-lined pouches on their abdomens that are used to carry their young.

The coloration of opossums varies by region, but opossums generally appear gray with small black eyes set into a lighter or white face, black feet with white or pink toes, and leathery black ears with white or pink tips. Their coloration is a result of a dense white undercoat that is tipped in gray (or sometimes brown) with dark or black guard hairs. Southern populations tend to have a sparser undercoat. Albino mutations are not uncommon and result in a white coat, ears and feet and pink eyes5.

Opossums are nocturnal and use their senses of smell to locate food. While their level of intelligence is undetermined, opossums are known to have poor and limited social interactions. Males tend to be solitary and aggressive when in close proximity to other males. Females often live in groups. Opossums exhibit a number of behaviors when threatened (both aggressive and passive,) including growling, urinating, defecating and belching. Outside of growling and audible aggressive displays, opossums are relatively quiet. Most notably, opossums may play dead or “play ‘possum” when threatened. This includes rolling over and lying stiff with closed or fixed eyes, drooling, sticking out their tongues, and slowing their breathing until almost undetectable. This behavior may last for hours until the threat has passed. Opossums may run from threats and have also been known to swim to escape danger.

Opossums do not hibernate but will retreat into dens during extreme temperatures to avoid the risk of frostbite on their hairless extremeties6.

Habitat: Opossums are skilled climbers and nest and spend much of their time in trees in habitats including deciduous forests, farmlands, and open forests. They may be found in arid environments, but prefer moist habitats, including marshes, streams, and swamps.

Opossums do not establish territories (except for when females tend to remain in a small range when raising young7.) Instead, opossums tend to constantly move in unusual patterns in search of food.

Within their habitats, opossums fall prey to many predators, such as birds of prey, foxes, coyotes, and humans, who often hit opossums with cars. The young are susceptible to predators such as snakes and birds of prey8.

Location: Opossums may be found across North and Central America, including parts of the United States east of the Rockies as well as along the west coast. Opossums were introduced to California in 1890 and proceeded to spread along the west coast9. Their range continues to spread northward and populations can now be found in southwestern Ontario and British Columbia, Canada.

Diet: Opossums are omnivorous scavengers whose diets range from human garbage and carrion, to grass, fruit, nuts, berries, insects, snails, mice, birds, worms, and pet food. Their developed senses of smell allow them to locate sources of food at night, when they are most active.

Reproduction: Female opossums may have up to 3 litters in a year, depending on geographic location, at anytime from early spring through summer. Females nest in trees or dens built by other animals. The young are born approximately two weeks after mating occurs and the last litter of the year may still be traveling with the mother when the first litter of the next year is born10. Males offer no parental care or support beyond fertilization. Females may give birth to up to twenty young, born helpless and the size of jellybeans, but litters typically contain 5 to 8 babies. Immediately after birth, the young crawl into the mother’s pouch in search of one of her thirteen teats. Some young do not survive the trip to the pouch and only those that make it to the pouch and find a teat have a chance at long-term survival. The young develop within the pouch attached to the teats for approximately a month, at which point they begin leaving the pouch for periods of time to travel along with their mother, sometimes atop her back or clinging to her tail. The young may remain with their mother for as long as three months11.

Few opossums live past 18 months old because of high mortality rates (many deaths due to car accidents.) The oldest opossum captured was determined to be 3 years old12.

Notes of Interest: Opossums are one of the oldest mammals on Earth. Fossilized remains have determined that opossums existed during the age of the dinosaurs, approximately 70 million years ago13.

Opossums are hunted as furbearers as well as food.

Opossums earned their westernized name in 1608 when first spotted by Captain John Smith, derived from the Algonquin word for ‘white animal,’ apasum14.

Footnotes
1. http://animals.nationalgeographic.com/animals/mammals/opossum/
2. http://www.in.gov/dnr/fishwild/3367.htm
3. http://www.nhptv.org/natureworks/opossum.htm
4. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
5. http://www.in.gov/dnr/fishwild/3367.htm
6. http://www.nhptv.org/natureworks/opossum.htm
7. http://www.opossum.org/
8. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
9. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
10. http://www.in.gov/dnr/fishwild/3367.htm
11. http://www.in.gov/dnr/fishwild/3367.htm
12. http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/
13. http://www.opossum.org/
14. http://www.nhptv.org/natureworks/opossum.htm

http://animals.nationalgeographic.com/animals/mammals/opossum/
http://www.opossum.org/
http://www.nhptv.org/natureworks/opossum.htm
http://www.in.gov/dnr/fishwild/3367.htm
http://animaldiversity.ummz.umich.edu/accounts/Didelphis_virginiana/

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