Ears are an interesting adaptation

This photo is of a Black-Tailed Jackrabbit – photographed in southern Texas. “What big ears you have!” – “All the better to hear you with.” So goes the dialogue in a popular children’s story. However, ears do more than listen. They are also a mechanism to dissipate heat in warm climates. ALLEN’S RULE states: Animals that live close to the equator, have longer appendages & a smaller body mass (greater percent surface area) to get rid of excess heat – ones closer to the poles, have shorter appendages and a larger body mass (less percent surface area) in order to conserve heat. Thus, jackrabbits in Texas have longer ears than the ones here in Idaho.

Jackrabbits have extra long hind legs, which enable them to bound in 20 foot leaps and cover the ground at 45 miles an hour. Besides running, they find protection by crouching under the sparse desert or prairie vegetation. They do not live in burrows but have scrapes under bushes where they lay in the shade during the day. Twilight and nighttime are their most active times.

Grass, sage, and cactus (in southern states) are their main food sources. They nibble around cactus spines until a hole is made big enough to insert their head. The soft inner tissue is then consumed. Around agriculture areas, they can be a problem, when their population peaks. Many alfalfa fields, on the edge of the desert, have been stripped during these periods. Also, rabbits are coprophagous. They have inefficient digestion & that requires them to pass all food through their digestive system twice – by eating their own dung.

Baby jacks are born in open nests. These are concealed in grass or under a bush. There are usually around 8 born and they can walk almost immediately. However, they do not leave the nest until they are about 4 weeks old. Rabbits are renowned for their reproductive ability and this is good because they are prey for so many different kinds of predators.

In the dark of night, when one is driving through rabbit country, their eyes gleam in your headlights. They seem to be everywhere – darting out in front of your vehicle and narrowly missing getting hit. Sometimes one will get run over and is left on the road as carrion for scavenging birds to feast upon.

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Marsh Wren: A very vocal, perky fellow

You hear them long before you can locate where they’re at. This little “bundle-of-energy” builds a large nest for such a small bird. The nest hangs between the Bulrushes or Cattails – the habitat which they prefer. The nest is domed, but has a hole in the side for entrance. The male builds the nest. In fact, he builds several nests in hopes that one of them will appeal to a female. Or better yet – several females will be attracted to his nests. The female, after nest selection, will line it with soft materials.

It may be a little brown bird (4-5”), but it’s anything but dull. Like other wrens, its tail is striped with crossways bands and points straight up into the air. This gives the bird a very saucy demeanor. It’s an energetic singer, rarely quiet for very long. Both sexes sing. The male sings long and loud to proclaim his territory, and a softer, quieter song for courtship. The female’s song, while sitting on the nest, is the softest of all.

The female alone, incubates the eggs – which may be as many as 8 to 10 in temperate zones or as few as 2 or 3 in hot areas. Two weeks of incubation and two weeks to fledging is normal. The male helps in the feeding of the chicks, and they raise more than one brood each year.

A photo file of marsh species is not complete without a picture of this saucy little bird. They bob up and down through the marsh sedges, and you must be quick to catch one out in the open.

(This one was captured by sitting in a blind on the water’s edge)

Vivid white against dark vegetation

One animal, that was guaranteed to get student attention on high school biology field trips, was the SNOWY EGRET. The vivid whiteness, in the morning light, was a real attention getter. This 24” bird has a satiny white body, black legs with yellow feet, a yellow patch in front of the eye, and a long, narrow, dark bill. Its call is a loud, nasal squawk. A related species is the Great Egret, which is larger, has dark feet, and a yellow bill.

Their habitat is along the shallows of rivers, shallow ponds, or the shallow inlets along ocean coasts. These brackish waters furnish fish, crustaceans, amphibians, small snakes, and other aquatic forms that make up the egret’s diet. Foraging with other egrets makes for greater feeding success.

These very social birds not only feed together, but by nesting together they are provided a better alarm system against predators. Their nests may be found on the ground or 30 feet up in a tree. Breeding takes place in March and early April and is preceded with a “stretch display.” This involves the male pumping his body up and down with his bill extended skyward. He also fluffs out the feathers on his breast. Mating results in 3 to 6 eggs that both sexes incubate. The young fledge in 14 days and reach maturity in one or two years.

Egrets were nearly exterminated. This was due to a fashion trend that required feather plumes for women’s hats. They have since made a comeback. To see this beautiful bird, pay a visit along the Snake River, especially in the shallows and ditches below Minidoka Dam. They will be carefully stepping, sinister-like, through the water or standing very still and stately.

(Stalking the shallows – Yellow feet agleam)

Magpie: Our Black and White Jay

The Black-Billed Magpie is an extreme bird. People either love ‘um or hate ‘um. They probably have more detractors than supporters. However, I am one who likes this beautiful bird. Their satiny black and white feathers and long tails are most attractive. Seen in the right light, their feathers shine with an iridescence. People from the east who haven’t experienced this species are usually very impressed – much as westerners are with Blue Jays when visiting eastern states.

Like all jays, this bird is very raucous. When they are near, you can hear them “jabbering away” to each other. This intelligent species would have to be considered the valedictorian of the bird world. Very alert to their surroundings and very hard to approach, they have been known to do clever things – like the one that dropped nuts at a stop light. The nuts would be cracked when the traffic ran over them. The bird would then fly in to get the results when the light changed.

They are a year-round bird and very adaptable. As generalists, their diet covers a wide range from fruits, grains, worms, slugs, and insects to small animals like snakes and mice. They also do much scavenging and are often seen on highways taking advantage of the “road-kill”. Magpies are early nesters and build roofed, dome shaped nests of sticks that protect the eggs from the early spring weather. The same nest is used each year. Five to nine eggs are laid and are incubated for 16 to 18 days. When fledging, the young have short tails which elongate as they mature. By early nesting, they are gone from the tree when other species arrive.

We have other jays in Cassia County: the Scrub Jay which is blue and gray, the Pinyon Jay which is all blue, Clark’s Nutcracker which is gray, black, and white, the American Crow, and the Common Raven. All are raucous, opportunistic, smart, and adaptable. The Black-billed has a cousin – the Yellow-billed which is slightly smaller and found in central California. Magpie behavior is always interesting. I’ve watched them “mob” hawks and owls, sneak food away from larger animals, and even perch on the rumps of deer – getting great pleasure out of annoying their hosts.

A River Otter Experience

There is nothing cuter than a River Otter. However, they are excellent predators – speeding under the water just like a torpedo. A fish doesn’t stand a chance. Otters are one of the larger members of the Weasel family – 28” from nose to tail tip. Weasels are mustelines. All mustelines give off a protective odor (i.e. skunks).

Otters are very active and many of their actions appear to be play. Sliding down river banks seems to be a favorite activity. They are semi-aquatic and move well on land (up to 18 mph), as well as in the water. Their long tail and webbed feet are a great aid in their under water navigation. Thick, dense fur keeps them well insulated from the cold and those prominent whiskers are sensitive to surrounding situations.

Fish is their main food source but they will also consume frogs, crustaceans, insects, and occasionally water fowl and small mammals. They den on land and the female evicts the male before birthing. He will return when the young are half grown and help in their care. Their lifespan is usually 10 to 15 years.

On two successive and very chilly mornings, at South Davis Lake, Oregon, we pursued a family of three. It was September and the mornings were cold in the woods. My fingers were so cold that it was difficult to work the camera. However, the cold was overlooked because we were experiencing a rare (for us) event. Following that family group up and down the stream, as they sped after trout, kept us at rapt attention – from just before sunrise to about 11:00 AM each day. Those mornings provided golden opportunities to observe and photograph these lovable creatures.

The Red Crossbill: An Unusual Beak

This beak is not deformed. Nature intended it to be thus. It is an adaptation for the opening of cones. While useful for that purpose, it does make the bird into a specialist and whether the beak crosses to the right or to the left runs about 50-50. Crossbills must have coniferous forests in order to survive and because conifer cones may last on the tree up to 20 years, there is no need to migrate out of an area of good cone production. Therefore their movements are irregular and controlled by cone availability.

There are two species of crossbills in North America: the Red Crossbill and the White-Winged Crossbill. The red variety is hard to “spot”, but is very abundant in the Cassia and Twin Falls mountain areas. The more glamorous White-Winged one is an inhabitant of boreal (northern) forests.

These interesting birds may not come to seed feeders, but water can be a major attraction. They are very gregarious and will come in to drink in large groups. The all-red, mature male is pictured. Immature birds are boldly streaked brown. The females are yellowish-olive and may show patches of red. The species is 6 ¼” long, with a large head, and a short, notched tail.

Different strains of the species are each adapted to a specific tree type (i.e. Lodgepole Pine, Ponderosa Pine, Douglas Fir, etc). Other species such as finches, chickadees, and siskin benefit from the nuts not consumed after a cone is opened. Crossbills are also quite vocal and will call while in flight. Each individual’s calls may vary somewhat from other individuals, giving that bird a character of its own. It gives a rapid series of harsh “jip” notes, started with several two-note phrases and followed by a warbled trill.

The female lays three eggs, but only two individuals usually fledge and there is about a 12% survival rate of the young into the second year. It is enough, however, to maintain the bird’s population numbers.

The crossbills of our south hills have the largest beaks of their kind. They are an isolated population and researchers are thinking of denoting them as a separate species. When camping, the presence of crossbills gives one a true flavor of the mountain experience. It is a truly unique bird!

How many rocks could a Rock-Chuck chuck?

Rock Chuck or Wood Chuck, both are marmots. The correct name however, for our local marmot, is the Yellow-Bellied Marmot. The marmot is the only mammal to have a USA holiday named for it (Ground Hog Day).

This large (14” to 20”) rodent loves rocky terrain where they can lay in the sun and also escape predators when alarmed. One individual always stands guard and gives an alarm call. The call will vary according to the type of predator (hawk vs. coyote, etc). It may be a “chuck”, whistle, or a trill. Rock habitats must be close to greenery, as the animal lives entirely on green vegetation of all types.

Yellow-Bellied Marmots spend 80% of their lives in burrows – this includes nighttime, as well as hibernation which lasts from August through February. They are meticulous about keeping their den and bedding clean. Their hearty appetite allows them to put on a good layer of fat for their 7 month hibernation. Sleeping late, then eating vigorously, and finally resting on a rock in the sun conserves the energy that turns into a layer of fat.

The males are “harem-polygymous” and litter sizes average a bit over 4 pups. Males leave the colony, but females tend to stay with their mothers and become reproducers at 2 years of age.

This “bear-like” rodent has a golden to rufus coat, brown head, and a yellowish-red belly. Wood Chucks are found in the east, but Yellow-Bellies are a western, intermountain species.

They are most interesting to observe, whether sunning on a large rock or scurrying across a road or trail into the closest cover.

(A big one sunning – a favorite pastime)