The Phenomenal Speed of Bird Migration

by Dave Hanks

A big break-through in bird studies is the result of the invention of a tiny mechanism the size of a dime. The device is a light weight geolocator backpack that is attached at the base of a bird’s spine. This is a location that doesn’t off-set the bird’s balance.

This device surprised researchers by revealing that migration speed is three times faster than was previously believed. One example: an individual leaving Brazil on April 12th will arrive on its USA breeding grounds by the end of the month. It is interesting to note that the desire to reach the breeding area results in a faster spring migration than the fall movement to warmer sites for wintering.

Most species migrate on a strict schedule – often the same day each year, which is determined by the length of daylight. To conserve energy, birds will ride thermal currents. Soaring is much easier than flap-flying. After the initial round trip, an individual can find their way – even if blown or thrown off course. It is almost as if one has a set of maps.

The GOLDEN-CROWNED SPARROW (pictured) breeds in southern Alaska and the Yukon, and winters in California. The relative short flying distance is a survival advantage for this species.

At rest in a northern California shrub

Carryovers from an Ancient Past

by Dave Hanks

Most all of us have visited museums that feature the huge skeletons of dinosaurs in their many and interesting forms. Although they are now extinct, their remnants now abound in much smaller forms. These modern ones come in four classes: Crocodilians, turtles, lizards, and snakes.

Reptiles are vertebrates (backbone), which breathe air and are cold-blooded. Their bodies cannot regulate their body temperature – which must be done by either seeking the sunshine’s warmth or the shade’s coolness. They are not “slimy”, but have dry, tough, scaly skin. Their skin has a high level of keratin to protect their bodies and prevent water loss.

All have four legs, with the exception of snakes. However the big constrictors have vestiges of hind legs in the form of stumps that are hidden under the skin. It is interesting to know that these big snakes will use these stumps to caress their partner when mating. The young develop inside an amniotic membrane, inside an egg, laid on land. Most reptiles are poor mothers that lay their eggs and leave them to hatch and care for themselves. Crocs and alligators will watch the nest and tear it open when the babies hatch. The little ones cries alert mom, who then transports them, in her mouth, to safety. Some python will curl around their eggs and the big King Cobra makes a two chambered nest – one chamber for the eggs and the other for the mother, and woe unto any whom dare to disturb her.

American Alligator, Pond Slider Turtle, Desert Spiny Lizard, and Western Diamond-Backed Rattlesnake

The Sharpening of one’s Senses

by Dave Hanks

How many times have you been startled by a snake, that you didn’t know was there, but almost stepped on? Or been distressed by finding a tiny bug crawling on your clothing? There are so many small, quiet species (and even some large ones) that you could bypass and never know they are near. Big predators make a habit of silence to enable them to stalk their prey. What slips so quietly through the habitat as a Mountain Lion? Forest employees in fire lookout towers have reported watching grizzlies move off a trail as hikers pass by – oblivious to the bear’s presence. The bear then returns to the original spot and continues its foraging.

A small, quiet bird that most would never notice is the BROWN CREEPER. It is a well camouflaged bird of woodlands. Resembling a small nuthatch, it flies to the base of a tree and then moves up the trunk in a spiral movement picking off invertebrates as it goes. Its movement is the opposite of nuthatches, which move down the trunk headfirst.

Brown Creepers build a hammock-shaped nest behind peeling flakes of bark. This is a common species, but one would hardly guess it because they are so small and silent. They rarely call, but when they do, it is a piercing sound.

There are so many insects, reptiles, rodents, and birds that move so quietly – that the quantity and variety that is going unnoticed is surprising! Many folks are missing out on a world of intrigue, because they have yet to become aware of what’s underfoot or partially hidden in the vegetation.

The quiet things are all around – But we don’t notice, there’s so little sound.

But oh for him whose ears are keen – A rich reward, things seldom seen.

So when you’re about ‘mongst shrubs or wings – Take time to notice the quiet things!

A tiny Brown Creeper moving up the tree trunk

Arena Behavior

by Dave Hanks

A lek is a strutting ground. It’s a Dutch word that science has adopted. The lek is comparatively small when compared against the whole habitat living area. Species that engage in Arena behavior display no sex drive or fighting drive outside of the arena.

This may seem strange to us. Perhaps nature has evolved a method to keep tensions at a minimum and promote harmony. Animals that engage in Arena Behavior do all their courtship, fighting, and mating within the arena (or Lek). It’s like all the boys gathering at the gym to show off their prowess. The girls show up and select the male that appeals to them and then mate with him right there in the gym. It is interesting (from research) to see that the males in the center of the Lek – which is usually on ground slightly higher in elevation – are usually preferred more often. I wonder if the human drive to have their home in the higher areas of a city has any subconscious relationship to this.

I know, from being in athletics – that venting aggressions on the playing field made me, and others, very low keyed and easy going when away from competition. This is one of the benefits that is no longer available to me, since I am no longer participating.

A male SAGE GROUSE (pictured) with chest and tail feathers extended and his yellow air sacs puffed up to make a booming sound. This is an early spring ritual.

Strutting on the lek

The Bruce Effect

by Dave Hanks

The Bruce Effect is the result of sexual pheromones in rodents. It is the manipulation of pregnancy by pheromones. For instance, a female rat comes into estrus and mates. She is very familiar with her partner’s scent (pheromones), and will not tolerate a strange male. If another male appears, his odor will cause the female to abort her fetuses.

This pregnancy block effect was first noted in 1959 by Hilda M. Bruce – thus the name. Besides rats, the pheromone was observed in deer mice, meadow voles, and collared lemmings. The blockage has also been suggested, but not confirmed, in lions.

Rodents are the largest group in the mammal category. These species include mice, rats, hamsters, guinea pigs, beavers, muskrats, porcupines, prairiedogs, marmots, chinchillas, voles, and lemmings. Rabbits are sometimes (but not always) included. Over one quarter of all mammals are rodents and are found on all continents except Antarctica. The landmass with the most rodent diversity is South America.

The DESERT WOODRAT (pictured) is identified by its large ears, white feet, dark throat hairs, gray-brown back, and bi-colored tail. It is adept at moving among the spines of cacti without injuring itself. Cactus serves as food, along with yucca pods, Pinyon nuts, bark, berries, and any available green vegetation.

Caught in its act of midnight thievery

The Varied Thrush – The Northern Robin

by Dave Hanks

If you are in “wild” country, and will but stop to listen, there is a whole cornucopia of sounds. Some sounds, like Elk bugling or geese honking overhead, are very intriguing. One such sound haunted my wife and I over and over again whenever we were in northern Canada. It was a bird call. We could never pin-point the location from which it came and, because it was a call we were not familiar with, could not identify the species. One evening, southward bound out of the Yukon into northern British Columbia, we were resting our bodies by lying in an open-air hot pool at Liard Hot Springs, B.C. We heard that haunting call again, very close this time. It was coming from a branch just above our pool. It was a Varied Thrush, and it was very mesmerizing to be soaking in hot water, out of doors, and having that bird serenade us!

This Thrush is slightly smaller than the American Robin, but it also has a reddish-orange breast. The breast, however, has a bluish stripe across it. The face also has a stripe across the eye, and the male’s back and crown are a bluish tint. This summer resident of the far north migrates to the Washington, Oregon, and California coasts for the winter months. We have even been lucky enough to have had one of them in our yard one spring – a rare southern Idaho occurrence.

Varied Thrushes like to nest in mature, coniferous woodlands that are dense and moist. If you have been in the far north, you will realize that there are lots of insects. These birds like to spend much time in the trees feeding upon them and will defend their feeding territory from intruders. They do this by first turning their back and giving a tail-up display. If that doesn’t work, the male will then turn to face the problem and extend his wings to display the colors on his under-wings, plus the white tips on his tail. The tail is then extended over his head.

The logging of mature forests has caused a reduction of breeding populations of this species. My wife has a love affair with this beautiful bird, and we would feel sad if we could no longer hear its eerie song.

Along the Oregon coast in February

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.

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)

Phainopepla or “The Black Cardinal”

by Dave Hanks

The Phainopepla only looks like a Cardinal in its body configuration and crest. It is actually in a different family – a family known as silky flycatchers. They are closely related to waxwings. The erect crest, deep red eye, silky black body, and white wing patches (seen when in flight) give it a distinctive aura. The female is a brownish-gray, but still quite distinctive. She shows evidence of the white in her wings while perched – which the male doesn’t. I personally think that the female of this species is as attractive as the male.

This bird is found in the arid regions of the south-western USA. They prefer vegetative tangles in trees, such as old Mistletoe, in which to nest. They have a special relationship with mistletoe. They not only nest in it, but feed upon the berries and spread the seeds. This black flycatcher also eats a great quantity of insects.

Their flight is fluttery but direct, and their call is a low-pitched, whistled “wurp.” They will raise two broods a year. The second nesting occurs after they have moved into habitat that is cooler and wetter.

Whenever we find ourselves in the arid regions of Southern California, we almost always experience this bird. My wife is always calling to me to come and see a bird. The bird is usually gone by the time I arrive. The bird in this picture was an exception. He sat there patiently and allowed me to photograph him.

This male is perched in Mesquite

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)