It’s mesmerizing to fall asleep, or awaken, to a soft hooting in
the early evening, or in the wee morning hours. Such is a common occurrence at
our house. These love calls begin in late fall and result in the laying of four
eggs in late winter. Incubation is started at once and results in separate
hatching times for each egg. This situation is known as a “stairstep” family and
whether all, or part, of the young are raised depends on the food supply. The
biggest baby is always fed first and it will survive even if the others don’t.
When the young fledge, they are ½ again larger than the adults. This allows for
an adjustment period when they are learning to fend for themselves.
The GREAT HORNED OWL is not only “tender” with its own but is very formidable
with others. They can take prey as large as a skunk and I have seen young cats
(in our yard) that have been torn in half. A smack on your head with their
talons could be very injurious.
They are identified by size (22”), a white throat, and ear-like feather
projections. They are quite adaptable and wide spread across North America and
are important rodent controllers. Mice and voles make up the lion’s share of
their diet. Other bird species will often “mob” them during daylight hours. Our
yard and lower tree plots are to their liking and we get to witness the raising
and fledging of young each year.
by Dave Hanks
Vertebrates (animals with backbones) have four general types of body coverings: skin (amphibians and humans), scales (reptiles and fish), hair (mammals), or feathers. Birds and feathers go together. Feathers are what define a bird!
Birds have claws, but so do mammals. Birds have beaks, but so do turtles and squid. Birds lay eggs, but so do fish and reptiles. Birds can fly, but so do bats and insects. And, also, some birds don’t fly. Feathers are the one thing that all birds have, and only birds have, that other species don’t have.
Feathers have several uses. One such purpose is for warmth. Military airmen must wear cold inhibiting clothing to withstand the increased cold at high altitudes. Birds are unaffected and have no concern about leaving ground temperatures because of their feathers. No synthetic insulation has yet been invented that is equal to feathers. “A mountain climber would have to wear 11 pairs of polypropylene long johns to achieve the same heat retention as one down-filled expedition jacket”. (Thor Hanson – Audubon Magazine – January/February, 2012). Nothing compares with the soft, fluffy down that is close to a bird’s body for warmth. The bristle-like projections that cover most of an owl’s beak, or feet, are actually feathers.
The WESTERN SCREECH OWL (pictured) can be found in urban areas as well as western wild lands. They get their name from a very high pitched call. They have feathers that extend over the base of their beaks and down their legs. They are well equipped for the cold, as they stay year round in their habitat.
Looking like a miniature Great Horned – A distant relative)
Barred Owls are quite large – 17 to 20 inches. They most closely resemble the Spotted Owl, except their white underside has dark streaking instead of dots. They have a bold, round head and the female is the larger of the two sexes. They prefer mixed deciduous/coniferous second growth woodlands. The Great Horned Owl is their major enemy. They are carefully avoided.
We first experienced this bird in Missouri’s woods. A resonant series of hoots, that some describe as sounding like “who’s cooking for you”, brought it immediately to our attention. I thought that it’s called faintly resembled a dog’s bark.
On an early December excursion to the mid-west, this was one of several species we were seeking. No luck! We tried calling it with our bird-call mechanism, but to no avail. The only picture that we had of this bird was in a cage – hardly a desirable background. Barred Owls are an eastern and northern species. It has been reported that their range is increasing, but the chances of us (here in southern Idaho) having a sighting is slim to say the least.
We were certainly taken by surprise on snowy day after Christmas! Carolyn spotted a large owl from the window of our front room. Thinking it to be a Great Horned, I rushed to get my camera & tripod. Sneaking up to a large maple tree by our driveway, I suddenly realized what I was photographing. Lo and behold – it was a Barred Owl right here in our yard. One of our Missouri goals met right here at home!
(Riding out a snow storm in our maple tree)
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
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