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

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.

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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!

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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

The Yellow-Breasted Chat is well named

by Dave Hanks

Never has a bird lived up to its name so well. If one is in the surrounding vegetation, you will hear a most unmistakable series of calls. They range from chattering clucks, rattles, clear whistles, and squawks. Their repertoire is wide, loud, and often harsh but definitely not dull. The Chat is secretive and lives in dense thickets and brush. However, once you are familiar with its calls you’ll know, without a doubt, that a chat is in the vicinity.

The Chat is listed as our largest warbler (7 ½”), but recent DNA tests have caused this classification to be disputed. However, like most warblers, yellow is a basic color. Another interesting DNA study has shown that up to a third of the chicks in a nest have been sired by a male other than the female’s mate.

The Chat’s bright yellow chest is very noticeable, and as it calls, its yellow throat puffs out as if it had a double chin. When the sun comes up to warm the cool morning air, the male will sit on a top branch solarizing and singing his heart out to greet the day and to proclaim his territory.

This bird made an indelible impression on me when I first became acquainted with it. The perky, vocal renditions were impressive to say the least, but to photograph a Chat was something else again. We have tried several times to connect with this reclusive fellow, only to be frustrated and forced to just listen to his amazing calls. Knowing that the Harrington Fork of Rock Creek in Twin Falls County is chat habitat, we tried once again on an early May morning. Luck was with us this time. My wife spotted one singing from a tangle of shrubs, and I set up our blind on the trail above that tangle. Patient waiting paid off. One perched close by and sang and sang and sang.

Sadly the species is in trouble because of decreasing habitat.

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Singing and solarizing

American Alligator: The Ultimate Bass Voice

By Dave Hanks

While walking beside a salt water marsh in Florida, I was startled by a loud, deep, resonate roar. It sounded much like an upset dairy bull, but there were no bovines anywhere near. Much to my surprise, it came from a clump of vegetation that held a large lizard-like animal – the American Alligator. Although startled, I was very glad that he had announced his presence.

This large reptile grows at the rate of a foot a year and can reach 28 feet and 450 to 500 lbs. Its tail is half its body weight and is very powerful. A swat from it could cause serious problems. Elevated eyes allow it to submerge and yet scan the surrounding area. Motionless in the water, it can be mistaken for a log. It can also be well camouflaged as it lies along a path in the available vegetation.

The Beaver is the master engineer of our fresh water habitat, but the Alligator fills the same niche in the swamp – making water holes that are also utilized by other species. It digs a hole with an opening below the water line, but then sloping upward to a dry den. The Alligator can always seek refuge here.

Mating takes place in April or May. The female will lay up to 60 eggs in a heap of mud and vegetation, and the heat generated by the sun incubates the eggs. This “best” of reptile mothers rips open the nest when the hatchlings “peep” and then carries each one to the safety of the gator hole.

Once endangered, this species has made a remarkable recovery. The increase in Alligator farms, for their hides, has helped bring them back from the brink.

Whenever we are in coastal Texas, we seem to stumble upon these animals on a somewhat regular basis.

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Resting in the morning sunlight

Evening Grosbeaks – Are Where You Find Them

by Dave Hanks

I like grosbeaks! They are heavy beaked, chunky bodied, and colorful. They are wild and yet bold enough to let you study them. They will, also, readily come to feeders. Then, you can get close up views. The Evening Grosbeak is no exception.

One April morning, my wife and I took a short excursion to the Elba vicinity to look for this bird. Not able to find any, discouraged and frustrated, we headed for home. But what a surprise was in store for us as we drove into our yard! Fifty or more of these birds were covering our front lawn. For the rest of that month, these Grosbeaks were common at our feeders. Luck was with us that spring! This is an IRRUPTIVE species. These are species that (because of varying food sources) are not regular in their movements but are not migratory. We usually get a few Evening Grosbeak each spring but not in the quantity or length of time that we got them that year.

This is a large, robust finch that is 6 to 7 inches in length. The male has a brownish-gold body with a yellow forehead. His wings are black but have a very vivid, large, white patch on them. The female is more subtly colored but still quite attractive.

This bird likes coniferous or mixed woodlands, usually in the western or northern parts of our continent. However, its range has expanded as people plant a greater variety of trees in their yards.

The male will chase the female in the early spring and perform a silent display of fluttering and extended wings. Later in his courtship, he will feed the female, and she will flirt with him by bobbing her head and swinging her body. Two broods are usually raised each year.

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After drinking at our backyard pond