Birds fueling up for migration

PHOTOS BY GARRY BRANDENBURG — A fall time migration will peak for many birds during September. While bird migration is a 365/24/7 event, there are peak times each spring and fall. As this fall season progresses, there will be a return of some species from northern latitudes as they migrate through Iowa, or your backyard. Keep watching and documenting any new arrivals. Radar screens at busy airports are able to watch night-time skies fill up with unique signals as millions of birds take wing to a major portion of their southward journey during night time hours.

Fall officially arrives on Sept. 23, the autumnal equinox. Birds that migrate do not have to consult a calendar to figure that out.

Their brains are hardwired to interpret day length/night lengths, and the azimuth of the sun overhead as our planet earth orbits around it. In addition, little bird brains show important indications of being able to navigate on subtle magnetic fields from the earth itself, and to key in on land topographic features. From a mathematics and physics standpoint, astronomers have calculated all kinds of data to understand the earth’s position along its orbital pathway, and distance from the sun, at any day of the year.

Birds are not astronomers, nor mathematicians, nor physicists, but they just do it anyway. The wonders of nature are and probably will remain for us humans just that, a wonderful achievement of their biological world.

How we use science to attempt to unravel the mysteries of nature is an excellent pursuit. It is fun and exciting to learn as much as we can, knowing full well that we will never know the entire process of migration mysteries.

Today’s Ruby-throated Hummingbird (female) photo illustrates just one kind of bird, a very small bird tipping the scale at about three grams, or about the weight of one penny. This species is fueling up at this time of the year because by the end of September, it will be well on its way toward winter habitats in southern Gulf Coast states and staging for the big push later on to fly non-stop over the Gulf of Mexico to Central America. That is a powerful feat to undertake for a bird so small.

Mother nature has provided this species with all that it takes to succeed in its journey through life. Hummingbirds have a needle-like beak and a long sticky tongue to sip nectar deep within flowers. They can also catch small insects while flying, using their incredible eyesight and wing maneuvering capabilities to position themselves for the kill.

Hovering above a real flower or an imitation flower of a backyard feeder is a fascinating thing to watch. It is easy for us humans to ask “How do they do that?”

Biologists can use super high speed photography to capture images of hummingbirds, slowing down the wing beats to super slow motion. What is incredible from a biology point of view is how those intricate muscles, tendons, and tiny hollow bones can operate at 60 times per second. The heart rate of the hummingbird is very fast, perfectly scaled to provide the oxygen to all of its muscles. All I can say is “Wow!”


Baltimore oriole birds are my other featured creature for this edition of my nature news this weekend. It is a colorful bird with bold black and orange feathers.

It is about 8.5 to 9 inches long. It eats insects, and it likes leafy deciduous forest habitats, open woodlands, forest edges and small groves of trees.

These requirements make urban areas one good place to find food and nesting sites. Speaking of nests, once fall progresses far enough to have trees drop their leaves, it may become noticeable to us humans that a basket-like nest is hanging conspicuously from those branches. The nest is constructed first by hanging long fibers over small tree branches, then poking her beak with other strands of long grasses to entangle a framework to form a hanging basket. The random poking of grasses seems to work as if knots were being tied (they are not) but if the results hold fast, it works.

The nest entrance is near the top of this basket, and the basket will have a bulging bottom about four inches across. Soft nest linings are obtained from downy fibers and feathers.

One brood of young will be hatched, from three to perhaps seven young, from each egg that is about one inch long. Incubation takes 11 to 14 days.

Nesting time after hatching takes another 11 to 14 days before the young fledge. By the time fall season is in full effect, the young and the parent birds have left Iowa on average by Sept. 7. Their winter habitat will be in Central and South America.


The month of September will have a wide variety of birds moving south, mostly at night. Daytime will be filled with resting and feeding. The list of species moving south is long and includes many hawks and other birds of prey.

Smaller wetland birds make the list such as greater yellowlegs, terns, swallows, swifts, thrushes, warblers, bobolinks, tanagers, sparrows, wrens, flycatchers and cuckoos. It pays to keep a pair of binoculars handy and at the ready during September.


Wolf and coyote comparative sizes, when side-by-side, make an impressive contrast. The body sizes alone tell a story both in length, height and overall build and weight. Coming soon to the TIP of Iowa, Inc. display and educational display trailer will be a full body mount of a wolf and a coyote. They will be set side-by-side along with a story board highlighting the main differences of these wild canine predators.

The reason the wolf/coyote display will be constructed is to help educate the public about the differences each species entails. Coyotes are very common throughout all of North America. As a predator of rodents, small mammals, ground nesting birds and opportunistic feeders on carrion and lots of other morsels, coyotes are survivors because they are very adaptable to whatever comes their way or whatever advantage they can make happen.

Wolves are much larger and better suited to take larger game animals. Both wolves and coyotes can hunt in packs, working together to take down prey. Wolves being larger, stronger and cunning, can and do take deer, elk, bison, moose, caribou in many far northern tundra and boreal forest habitats.

In the USA, wolves have their closest habitats in northern Minnesota and northern Wisconsin. Several mountain states have populations both native and re-introduced.

As for Iowa, on very rare occasions, a wolf sighting happens and is reported to biologists or game wardens. The coyote species seems to be unstoppable in its persistence on the landscape, filling a niche as a predator.

The wolf is a different critter, much maligned and misunderstood, and still very capable of doing considerable damage to livestock raised by farmers and ranchers across the country. Finding a way to manage wolf populations is fraught with biological issues and political issues. This is why the educational exhibit will be created for TIP of Iowa, Inc. TIP stands for Turn in Poachers, just one of many duties conservation officers/game wardens have on their list of duties.

The coyote is legal to take. The wolf is illegal to take. The public needs to know the difference.


Deer hunting within the City limits of Marshalltown is into its 13th year. Bowhunters, and crossbow users, are eligible to participate by obtaining a copy of the regulations and the necessary permit from Marshalltown’s Park and Recreation office.

An annual proficiency test is required of each hunter, which is overseen by a certified hunter safety instructor. The main reason many Iowa cities have an urban deer hunt program is to help thin the herd that may live its entire life within city limits. They find refuge there and no shortage of things to eat from gardens, shrubbery, and thereby becoming an increased risk of being struck by vehicles.

In 2008, deer depredation biologists conducted a survey of Marshalltown during a late winter time snow covered landscape. Snow made deer bodies more easily observed and counted. The results of that survey found the equivalent of 32 deer per square mile. Deer can and do easily move into and out of the city by crossing the Iowa River.

The river is not a deterrent to deer passage. Hunting pressure outside the city can be a motivation for some deer to cross the river and hang out in secluded places, and that is how the deer may ultimately become and add to the nuisance factor of too many deer in the wrong places.

The emphasis of urban deer hunts in Iowa cities is population management by taking doe deer. Deer licenses specific to the Marshalltown hunt, called zone 78 by the Iowa DNR, are only valid within the city limits.

Doe deer taken must be validated by checking in at either the Park and Rec office during business hours or at the Marshalltown Fire Department anytime. The Marshalltown city doe deer hunt runs from Sept. 16 through Jan. 10, 2024.


Garry Brandenburg is the retired director of the Marshall County Conservation Board. He is a graduate of Iowa State University with a BS degree in Fish & Wildlife Biology.

Contact him at:

P.O. Box 96

Albion, IA 50005


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