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.

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At rest in a northern California shrub

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!

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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.

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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.

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Caught in its act of midnight thievery

Great Gray Owl

by Dave Hanks

We were in Yellowstone Park approaching the Canyon intersection, when I said to my wife: “You know what would make this a really great trip? – finding a Great Gray Owl.” We turned south and had traveled less than a half mile when my eye caught what looked like a knob on the end of a stick. My heart leaped and I said: “There’s one!” Sure enough, it was an owl, not just one but two! I started taking pictures at a great distance by stalking – moving up six feet, stopping, shooting, and moving again. I took off each of my extension lens as I got closer and closer. I got quite close, and one seemed content to just sit and watch me. Luckily he was low down, on a bare branch in a Lodgepole Pine.

The GREAT GRAY OWL is not the heaviest owl, but it is the biggest in volume. Its head is smooth (lacking the ear tuffs that identify the Great Horned Owl) and it has huge, heavily ringed facial disks that make its eyes look smaller than they are. These disks are tremendous aids in channeling sounds to the ears. The ears are to the sides of the eyes and concealed by feathers. Its hearing is acute. A mouse or vole, running underneath the snow, can be heard and pinpointed at a surprising distance. With both excellent vision and hearing, this bird is adept at nighttime, dawn, or dusk hunting.

Boreal forests and wooded bogs of the far north are this species preferred habitats. Although not common further south, they may also be found in mountainous, coniferous forests where they hunt the forest clearings. Their call is a series of deep, resonant “whoo’s”.

Of all the raptors, owls stir my senses the most. The Great Gray Owl is not easy to come upon and an observation, especially a photographic session, is a very special event.

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Watching me as well as scanning for voles

Eurasian Collared Dove – An Immigrant Comes to Burley

by Dave Hanks

A rare bird report has been on IBLE (Idaho birders website) all this spring (2007). This same bird was described to me, in a telephone conversation, by a resident of southeast Burley. But “lo and behold”, the species had appeared in our yard. In fact a pair of Collared Doves has favored us with their presence since early spring. I assume that they must have a nest here. We have many and a great variety of trees. This species likes yards and conifers to nest in.

It is 13 inches long with a sandy gray body. The name is the result of a distinctive half collar on the back of its neck. A bit of white can be seen in their tail when taking flight. They are somewhat bigger than the Mourning Dove (which it associates with in our yard) and looks similar to the Ringed Turtle Dove (which it will hybridize with). A growling three note “Koo-KOO-kook” call is made while in flight. Both sexes look alike, and they will try to breed throughout the entire year. The producing of several broods annually has led to their rapid increase.

It’s an old world species that originated in India, spread across Europe, and was introduced to the Bahamas in the 1970s. The USA population is mainly in Florida but spreading. This bird has been tamed, and our population is the result of caged birds being released into the wild. When first appearing in England in 1963, it was protected and a boy was fined for shooting one. Protection was later raised, as the bird was becoming a pest – much like the European Starling that haunts farm yards in our area.

We were most surprised to look out our front window and suddenly realize that a new species, and an uncommon one at that, was utilizing our yard.

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A Eurasian Collared Dove making use of bird seed strewn on our lawn

There is something I hold dear

There is something that I hold dear
It’s a roomy black matron that I revere

Rugged, but feminine is this beast
Extremely adaptable, to say the least

It’s the Angus cow of much renown
There is no equal to be found

She’s maternal and fertile, and easy to calve
A quality that is certainly good to have

Her calves are vigorous and jump to their feet And when fed-out, yield high quality meat
She’s easy to care for with maintenance minimal
And contrary to belief, she is very gentle

On what she is fed I’ve seen other types try
Their competition lags – Of that I don’t lie

But this cow, comes through with great zeal
Does it with ease and preserves eye-appeal

If you ask why it’s Angus I feed
It’s basically the cow – She’s the strength of the breed!

(Recalled from the years when I bred cattle in Montana)

 

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)