Deferred Maturity

by Dave Hanks

Young song birds hatch, fledge, and are ready for migration. The young birds usually resemble the female parent. However, by the following spring the males acquire their adult breeding plumage and assume parenthood. Their development is relative simple and quick. However, most raptors and gulls go through several stages before reaching sexual maturity. Large birds like eagles or buzzards have 4 to 5 stages of development. Hawks usually have two stages to go through over a two year period to reach maturity.

Buteos are large hawks with broad wings. The FERRUGINOUS HAWK (pictured) is the largest American Buteo. Only the Bald Eagle, Golden Eagle, and female Snowy Owl weigh more than this hawk. Ferruginous Hawks go through three stages after the nestling stage: juvenile, sub-adult, and finally adult – three years from hatching to adulthood. This species has been known to live for 20 years (determined by re-catching banded birds), although the majority die within a 5 year period –which allows a five year old bird two opportunities to nest.

Ferruginous Hawk’s first year mortality is estimated at around 66% and adult mortality at about 25% per year thereafter. This ground nesting bird is preyed upon by Coyotes, Golden eagles, and Great horned Owls. Jackrabbits rank high on this species food list. When prey sources are at a low, many hatchlings will die of starvation. Illegal shooting of adult birds has also caused a problem to this not-so-common species.

This magnificent hawk has been used as a falconry bird in its native range.

fergp3

A young Ferruginous in the sub-adult phase

 

Two Ecological Terms and Examples

by Dave Hanks

Symbiosis or (Mutualism)

The above term refers to species that depend upon each other for the
benefit of both organisms. This points out the fact that we all depend
upon others for our own wellbeing. In fact, others depending on us
makes their return help to us even more beneficial.

Here are some special symbiotic relationships:

CLARK’S NUTCRACKER and LIMBER PINE – The bird feeds on the nuts
and in return spreads the pine’s seeds, which the tree, being
rooted in the earth,is unable to do.

GRAY WOLF and BARREN GROUND CARIBOU – The caribou furnish the
wolf its food, and the wolf gets rid of the diseased and
unproductive, thus keeping the caribou population healthy and
at its maximum.

SHARK and REMORAS (a tiny fish) – The Remoras are hygienic
because they clean the shark’s teeth. In return they get some
food and much protection from potential enemies by staying close
or in the shark’s jaws.

HONEY BEE and FLOWERS – Bee gets nectar and plant gets pollinated.

Ice Cream Species

This refers to an animal’s favorite food – that food it will always
select if it is available.

Here are some preferences:
GRIZZLIES -> Ground Squirrels
SWAINSON’S HAWK -> Rabbits
CARIBOU -> Lichens
MOUNTIAN LION -> Deer
Isolated or semi-isolated areas, with good deer populations, are also
endowed with healthy Mountain Lion populations

btdeerp

Black-Tailed doe – a sub-species of Mule deer

 

OUT AND ABOUT

by Dave Hanks



 The snow is fluffily,
			“sifting” down.
		It leaves a thick “carpet-like” covering
				upon the ground.
			 

		Its mystical magic
			that floats on the air.
		And it’s an invigorating joy
				to be out where –
			


		The wonders of life
			move to and fro.
		And lucky we are,
			that much I know,
			


		To have natural treasures
			so close at hand
		And everywhere present
			across sky and land
			


   Winter can be a good time to observe large mammals.
   Heavy snow makes movement inefficient for conserving 
   energy. Energy that is so important for winter survival, 
   when one must compete for the scarcity of available 
   food, and the energy to maintain body temperature under 
   cold conditions. The beasts are reluctant to move
   much, and if you are careful not to stress them, 
   you can get close up and personal.
    

Targee snow and moose

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

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

Homeostasis and Waterfowl

by Dave Hanks

The bodies of all of us, both human and animal, have homeostatic mechanisms. These are both physiological and behavioral. Homeostasis means a state of constancy. The body must maintain its functions on a steady plain. If we’re too hot, we sweat; if we are too cold, we shiver; if we are sick to our stomach, we vomit. We could, also, turn on the air conditioner, or turn up the furnace, or take some Alka Seltzer. These are all examples of how we keep our bodies running on an even keel.

Waterfowl, with basically the same problems as ours, do basically the same things. “WATER RUNS OFF A DUCK’S BACK” is true, but only with a little homeostatic help – both physiological and behavioral. When trying to photograph waterfowl, it can be disconcerting when they won’t remain still – always fixing their feathers and probing at their tail. There is an oil gland at the base of the tail. The oil is the body’s answer for water proofing feathers, but can’t reach its destination without some help.

BARROW’S GOLDENEYE (pictured) is a northern species that graces our area’s open water during the winter months. By staying dry, their hollow, air trapping, feathers will protect them from the cold. To do this the feathers must repel the cold water. Hence, the duck rubs oil up and down each feather’s shaft. The feather filaments each have barbules which hook on to the adjoining filament. This forms a continuous covering to keep out the wet. When you observe the bird preening, they are doing two things. They are re-hooking the barbules and oiling their feathers. Also, without this constant oiling and barbule hooking, the bird would be unable to fly because the feathers would be waterlogged, and the unhooked feathers would be unable to trap air.

Comfortable swimming in an icy pool

Types of Migration

by Dave Hanks

When one thinks of migration, one usually thinks that animals go south in the autumn and go north in springtime. That is what is called COMPLETE MIGRATION, but it is an over simplification. Amount of daylight, weather conditions, or food supplies; are factors that influence the time or type of movement. Some species like Robins, Red-Tailed Hawks, and Towhees are PARTIAL MIGRATORS. Many of these species migrate but a portion stay around all year long – especially if food sources are adequate or to protect a territory and nesting site. Young birds are more apt to make the long trip because of a low social rank. Adult individuals force them to vacate the area.

DISPERSAL is the result of newly fledged birds moving to find space where they can establish their own territory. It is believed that this type of movement is the origin of complete south/north migratory patterns. Another type of migration is called DIFFERENTIAL. This type is influenced by existing conditions. Where nest cavities are in short supply, the American Kestrel may not move away from his established nest box. Water birds may move to the closest area that has open water. ALTITUDINAL MIGRATION is from High Mountain (where weather conditions mimic the more northern latitudes) down to lower elevations to spend the winter. Pine Grosbeaks and Juncos fit this type. Juncos that are abundant around bird feeders in winter are absent in summer.

IRRUPTIVE MIGRATION is very irregular. This is not necessarily a north/south trajectory, but often a lateral movement for better feeding conditions, and is not made every year. Years of severe weather can be a stimulus. A shortage of conifer cones makes Crossbills move to more productive forest areas. Abundance of small rodents (voles, mice, gophers, etc) affects predator movements. Owls especially are birds that are subject to these conditions.

Like all things in life, what appears simple on the surface is usually much more complicated.

A Great Gray Owl: An irruptive species

A Great Gray Owl: An irruptive species