The American bald eagle (Haliaeetus leucocephalus) is now a common sight in winter, spring, summer, or fall for anyone interested in watching the skies or tree lines. A big-bodied bird sitting on a tree branch is always worth a second look.
And if the site lends itself to doing a photo op, even better. In today’s picture of the eagle perched on a snow-covered branch, the whiteness of the snow and the darkness of the tree’s bark were a perfect match to the whiteness of the eagle’s head and the darkness of the feathers of its body.
I only managed to take two photos of this adult eagle before it took off in flight, so I tracked it down with my camera and was lucky to get some decent in-flight shots of this giant bird. I don’t know if this eagle is male or female. Females are larger and have a wingspan of eight feet.
Males are smaller in body with a wingspan of six and a half to seven feet. Females can weigh anywhere from 12 to 14 lbs. Males are usually less than eight to 10 pounds. If two mature bald eagles are standing next to each other, perhaps at a nest site, the male will stand 32 inches and the female 42 inches.
Estimates of the total number of bald eagles soaring in the sky at the time the settlers arrived ranged from 25,000 to 75,000 over the continental United States. The problem with such a wide spread in numbers for this estimate is that the gap is huge.
Nobody really knows how many there once was. What can be safely said is that it was a lot. What can also be said is that eagle numbers have declined dramatically due to habitat loss and persecution during the two hundred or so years of settlement activities.
Fast forward to the present day, and biologists have learned a great deal about habitat needs, improved land conservation techniques, and positive education to the public about the role that large avian predators play in healthy ecosystems. Steady growth has been documented in census observations of eagle populations across Iowa since the 1970s. What was once rare is now common.
Examination of eagle sites in Iowa, particularly Decorah, Iowa, reveals nest buying and active defense by breeding pairs of bald eagles. Remote cameras monitor activities in the nest all the time.
It is always interesting to observe the interactions of the vultures as they bring food to their mate, exchanging duties of incubating the eggs, and later in the spring the young vultures participate in feeding pieces of rabbit, fish, duck or other crumbs of pulverized energy.
There are about 10 to 12 bald eagle nesting sites in Marshall County. Soon, these nests would become the focal point for much eagle activity.
However, during the winter months of January and February, Saylorville Lake will host around 100 roosting eagles. Red Rock Lake will do the same.
The open water below the dams of these lakes ensures easy spotting of fish and food gathering.
The other little bird featured today is the little woodpecker. It is called the Downy Woodpecker.
It is a small-bodied woodpecker that lives all year in southern Canada and most of the lower 48 states. The short, sharp beak is used to search the hollows of the bark of trees for insects, and to get into deeper insects, it – like all woodpeckers – has a long tongue for probing spaces.
A quick search of biology notes found that woodpecker tongues are used as special tools for finding hidden foods. The chisel-like bill can poke holes in woody material to access an insect-bearing cavity. The tongue then does the rest of the work to find and extract any edible foods.
Nature photographers try all kinds of creative ways to capture the mysteries of birds. It’s one thing to get great pictures of a bird, but it’s quite another to get a motion picture of a woodpecker examining the tongue of a woodpecker because the action is so fast.
I’ve been lucky to catch hummingbirds with their tongue sticking out sipping sweetened water at summer time feeders. Catching a Robin while pulling an earthworm out of the soil is much easier said than done.
Likewise, the task of seeing a woodpecker’s tongue extract a larva or other insect is a rare feat. What is different about woodpecker tongues is the length, with the tongue wrapping behind the skull and pointing up the beak.
A special bone called the hyoid is a muscle wrapped in the upper beak. The tissues of the tongue are divided into two parts as they pass backwards and behind the top of the skull, and then progress to the lower jaw and the beak. The total length of the tongue can be up to a third of the bird’s body length although this may vary with other species of woodpecker.
Woodpeckers’ brains are protected by unique cranial bone plates and special spongy bony areas that help absorb shock and distribute any shock away from the brain. High-speed cameras used to capture slow-motion 3D videos of woodpeckers in action reveal pecking details that would otherwise be too fast for us humans.
Woodpeckers pecking at dead tree branches is one way other woodpeckers can hear the echoing effect of their staccato messages. It is the equivalent of human talk, or other birds singing, as other birds are constantly communicating.
Mother Nature is way smarter than we think. That’s good.
There are some really great and exciting programs coming next month to Grimes Farm and Conservation Centre. The first is the date of February 14th at noon, actually from 11:30 am to 12:30 pm, for a program about South Georgia Island.
Photographer Ty Smedes will be showing his work on a recent visit to South Georgia which lies in the South Atlantic Ocean, halfway between the tip of South America and Africa. This 100-mile-long island is home to an estimated 100 million birds.
Pictures of Ty would be great recordings of what he lives on in this special location. Call MCCB at 641-752-5490 before February 10 to enroll in this free program.
On February 22nd from 5:30 to 7:30 pm, there will be an antler measurement program. This will also be located at Grimes Farm.
This is also free, but you must register before February 17th as space is limited. Call 641-752-5490 regarding this program.
Anyone curious as to what result an antler set might get and how that result is obtained would be interested in observing the process. The antlers could be from an animal taken last season or a deer taken a long time ago. An ancestor may have taken many moons long ago.
Gary Brandenburg is the retired Director of Marshall County County Council. Graduated from Iowa State University with a BA in Fish and Wildlife Biology.
Call him at:
PO Box 96
Albion, IA 50005