Category: Birds

March is the month where we experience the greatest number of bird species migrating northward to spring and summer breeding locations.  Birds that spend the winter at the southern end of their range in northern Illinois will be migrating back to Canadian and tundra regions.  Other species will migrate to our area from southern locations to find a mate and breed here in spring and early summer.          

Far northern regions have a shorter breeding season, but research has revealed several possible advantages to these locations.  These include an abundance of food in the summer due to a lack of competition for it, fewer parasites that survive the winter and exert less impact on returning bird populations, and fewer predators that live in these regions.  Some birds that spend the winter in northern Illinois but you may not see again until next fall are the American tree sparrow,  snowy owl, short-eared owl, long-eared owl, and common redpoll.

Many more birds migrate from southern locations into our area to breed over the spring and summer months.  Let’s take a look at a few with catchy behaviors.  Sandhill Cranes, Antigone canadensis, fly in a “V” formation at altitudes of 500 to 2500 feet and can cover up to 500 miles in ten hours.  Their nests are a simple platform of vegetation found in marshy areas.  You can oftentimes hear their loud, warbling  call as they soar overhead, and may get to observe their dancing courtship displays, often performed in the early morning hours.

The American woodcock, Scolopax minor, a member of the Sandpiper family, likes moist woodlands and brushy marsh.  During spring migration, males often call at dawn and dusk with a buzzy ‘peet’.  At dusk, calls are accompanied by a display involving a spiral flight up from the ground to almost 300 feet where the bird plunges downward, making several arcs back and forth, to a hard landing only feet from where it took off.  Combined with another display called the Woodcock dance, it’s all about showing off, and displays gets repeated until dark and again each night until he attracts a mate.

Several waterfowl species move into the lakes, rivers, and ponds just as soon as the ice melts.  Dabbling ducks have bills adapted to remove food including aquatic vegetation, seeds, and invertebrates from the top few inches of water.  Common species in our area include northern pintail, mallard, and blue-winged teal.  Diving ducks are found on deeper lakes and rivers that may thaw a bit earlier.  Their food lives in deeper water and includes fish, mollusks, and bottom vegetation.  Birds include canvasback duck, redhead duck, hooded merganser, and common merganser.

There are numerous other species to watch for including swallows, purple martin, eastern phoebe, yellow-bellied sapsucker, golden-crowned kinglet, killdeer, common grackle, and hermit thrush.  Bluebirds, robins, and red-winged blackbirds are migrating to northern Illinois and points farther north, spreading out throughout much of the Midwest. 

Be on the lookout for these new arrivals in your neighborhood.  Walking trails in nearby marsh and woodland areas may allow observation of one of the more spectacular courtship displays, many of which occur in Chicago collar-county forest preserves.  March is a busy start for the breeding season, and you can find more species and information on their impending arrivals at Cornell University’s eBird website at ebird.org/home.

The Cooper’s hawk, Accipiter cooperii, is a woodland inhabitant and hunter.  In Illinois, they were state listed as endangered from 1977 to 1997.  Since then, with less pesticide use in the environment, we are seeing more of them in backyards here and across North American urban areas.

Cooper’s hawks are blue-gray on the back,  with a black cap, and a belly of white with rufous streaks.  The tail is long and  rounded with black horizontal bars.  Hooked bills for tearing, needle-sharp talons for grabbing prey, and forward-facing eyes providing good depth perception contribute to making this bird an excellent hunter.  They approach stealthily, or sit and watch, then attack with a burst of speed.  Using their tails as rudders, Cooper’s hawks are able to turn quickly and sharply when in flight, giving them outstanding chase and catch abilities while on the wing in a wooded habitat.  Chases can become intense, and several birds have been found to have cracked or broken ribs from encounters with tree branches.

Cooper’s Hawk [back], Accipiter Cooperii by Alan D. Wilson, 2010

Historically, these birds nested in woodlands with extensive canopies and ate songbirds feeding in agricultural row crops.  Many birds have moved to living in urban settings, favoring white pines and oak trees that offer good canopy coverage.  Individuals are loners except at breeding time in the mid-spring.  Males will build a simple nest, and females will lay 2-6 white eggs.  Females incubate the eggs for four to five weeks, then both parents teach the young to hunt.  Juveniles are fully independent and able to live on their own after five weeks.  Egg predation is minimal, with the average clutch losing 25% or fewer of its eggs.  First year mortality rates are high, around 70%, but drop off quickly to 30% for adults.  The average life span in the wild is comparatively long at eight years.  Many birds die from mid-air collisions with wires, autos and windows, especially in urban settings.  Birds are susceptible to a number of bacterial diseases, which may impair the birds’ abilities, but are normally not deadly.

In Illinois, there are populations that are year-round residents, and there are migrating populations in both spring and fall.  Resident birds may move 50 to 150 miles for short periods depending on temperature and storms, and then move back again.  Spring migrators leave the southern parts of North America headed for breeding areas across Canada for the summer and return in fall to warmer climates.  Our best data on population numbers for this species come from the Christmas backyard bird count and individual watchers journaling their daily observations.

Cooper’s hawks eat small to medium-size birds including cardinals, sparrows, doves, robins, and starlings.  They will also supplement this fare with small mammals such as field mice and squirrels, and other prey including snakes and toads.  With the rise in backyard bird feeding and the restoration of natural areas across the state, birds of prey and Accipiter hawks in particular have become common urban residents.  Two other Accipiter hawks that share habitat and hunting ranges with the Cooper’s hawk are sharp-shinned hawks and Northern goshawks.  These hunters may be considered a natural biological control for larger populations of birds such as sparrows and starlings, but hawks are generalists with their prey and may pose as big a danger to rare birds, as well.

Cooper’s hawks are more active in early morning hours, and they are considered one of the top daytime predators.  As you watch your feeders this winter, be aware of this opportunity to observe a skilled hunter in flight.  They are exciting to observe, sitting close up in a backyards or chasing prey through the trees.

Migration is in full swing for hawk species in North America.  Many hawk species leave North America to spend the winter in Central America or South America.  October thermals, updrafts created by the sun warming the earth, provide a boost for hawks.  In northern Illinois, we can observe about sixteen species of raptors including eight hawks.

Depending on the species and their breeding locations, hawks migrate from late summer in Arctic regions through autumn and early winter in the midwestern United States.  Hawks leaving breeding grounds in Arctic regions in late August arrive in Illinois six to eight weeks later after a journey of 2,000 miles or more.  Some will spend the winter here, and others will join resident hawks of Illinois and continue heading south for the winter.

There are eight species of hawks found in Illinois throughout the year.  The most common is the red-tailed hawk, Buteo jamaicensis, which is seen year-round soaring over fields or open areas hunting for prey.  Another common species is the sharp-shinned hawk, Accipiter striatus, the smallest hawk in North America.  They breed in northern Canada and winter in Central America and are notorious for raiding backyard bird feeders.  Cooper’s hawk, Accipiter cooperii, feeds exclusively on other birds in forests and woodlands.  It is hard to tell apart from the sharp-shinned hawk, but is generally larger.  Another year-round resident of forested areas is the red-shouldered hawk, Buteo lineatus.  Populations have been increasing over the last fifty years, despite the clearing of forested lands, a constant threat to the species.

The remaining four species are less well known due to remote habitat or because they are only here during migration.  The broad-winged hawk, Buteo platypterus, breeds in deciduous forests near wetlands.  There is a small population breeding in Illinois, but it is usually observed during migration.  Swainson’s Hawk, Buteo swainsoni, also has a small breeding population in far northwest Illinois.  This bird has the longest migration  route, flying from breeding grounds in the northern United States to winter at the far southern tip of South America.  Rough-legged hawks, Buteo lagopus, are the only hawks in North America with feathers extending over their legs all the way to their toes.  They breed in the northern Arctic and winter in our area.  Northern goshawk, Accipiter gentilis, is rare in Illinois, requiring large forests with very high nest sites.  It is a fierce protector of its young, attacking any animal, including humans, who comes near the nest.

Three well-known observation sites in our area provide an exciting opportunity to get out to see many of these birds, as well as other migrating species including ospreys, eagles, falcons, butterflies, cranes and dragonflies.  Volunteers record their observations daily, at each of these sites, throughout the migration season which continues into early November.  Illinois Beach State Park, near Lake Michigan and the Illinois-Wisconsin state line, averages over 5,000 raptors observed every year.  Fort Sheridan, a little farther south along the Lake Michigan shoreline, is where we are learning about how larger bodies of water affect migration patterns.  And in DuPage County, the Greene Valley Forest Preserve scenic overlook is located on the highest point open to the public.  From here, observers can see several miles on clear days over urban areas, fields and the DuPage River valley.

For more information on each of these sites, take a look at:

Greene Valley: https://www.dupageforest.org/catching-nature/greene-valley-hawkwatch

Fort Sheridan Hawkwatch on Facebook

Illinois Beach State Park: https://www2.illinois.gov/dnr/parks/pages/adelinejaygeo-karisillinoisbeach.aspx

For the past week, we have been hearing warbling sounds from high overhead as sandhill cranes return to their spring breeding areas from their winter stay in Mexico and the southern U.S.  Even though their large size makes it possible to see these birds for long distances, they fly at such high altitudes that their size looks deceptively tiny, making them hard to find in bright daylight skies.  Flying in a ‘V’-shaped pattern, flocks from a dozen to several hundred noisy birds pass by repeatedly during the day. 

Sandhill cranes, Antigone canadensis, are classified into five subspecies.  Lesser sandhill cranes, A.c. canadensis, and greater sandhill cranes, A.c. tabida, both overwinter in Florida and Mexico.  In spring, they migrate north to breeding grounds in the northern U.S. and across Canada into the Arctic, Alaska and northeast Siberia.  There are two separate flyways, one from Florida bearing slightly northwest and passing through Indiana and Illinois.  The second is from Mexico heading due north through Texas, Nebraska, and Colorado.  Three quarters of all the cranes will pass through the Sand Hills region of Nebraska from which their name is derived.  This flock, crossing the Platte River area in spring, is comprised of 250,000 to 500,000 birds.  There are three small populations of non-migratory birds named for their respective locations including the Florida sandhill, A.c. pratensis; the Cuban sandhill A.c. nesiotes, and the Mississippi sandhill, A.c. pulla.

Sandhills are large birds, standing between 3’6″ and 5′ tall.  Their broad wingspans of up to six feet provide enough power to lift their considerable weight, for a bird, of six to fourteen pounds.  They have a small head, long straight bill, a long neck, and a short tail covered by drooping feathers called a “bustle”.  Cranes are slate gray with pale cheeks and black legs.  Adults display a bright red crown and some rusty tones in their backs from mud used in preening.

Birds fly during the day when the sun is up and air currents are strongest.  The birds will use thermals, a column of air that is heated by the sun and rises upwards, to carry them aloft.  As cranes ascend, they are searching for air currents blowing in the direction they want to fly.  Typically, they will fly between 4,000 and 5,000 feet high, but may ride a thermal all the way up 12,000 feet.  Cranes are able to cover 150 to 400 miles each day at speeds of 15 to 50 miles per hour.

Upon reaching their summer breeding grounds, both sexes will engage in courtship displays that includes a dance involving outstretched wings and head pumping, bowing and leaping into the air.  Males and females will call in unison as part of their bonding.  They mate for life, only taking another partner if one dies.  A normal life span is a little over twenty years; the oldest recorded bird was 36 years 7 months old.  Females may begin breeding as early as age two, but most are seven years old and up.  They will lay 1-2 eggs, but normally only one survives.  The juvenile, called a ‘colt’, will remain with the parents for 10-12 months, until leaving for their own life the spring following their birth.

Fossils found in Nebraska date from the Miocene period about ten million years ago.  The bone structure of the fossils is the same as what is found in today’s birds, making the sandhill crane one of the oldest species of birds.  In the late 19th century, they were hunted for the wild meat market until they were considered extirpated east of the Mississippi River.  The Migratory Bird Treaty Act of 1918, passed with support of several early conservationists, is considered to be the critical step that saved the sandhill crane.  Current populations are doing well, but growing slowly since only one chick is born annually.  Conservation of all five species, especially the non-migratory birds, is tied to the preservation of wetlands for migratory staging and breeding.

Now is the time of year to get outside in late morning through the afternoon and listen for their warble, then see these great flocks heading northward overhead.  To learn more, take a look at the International Crane Foundation website at: https://www.savingcranes.org/

Winter is quickly turning into spring in our area.  Freezing temperatures that were here just two weeks ago have passed, and daytime temperatures are warm with temperatures often  staying above freezing overnight.  In the local bird communities, we are beginning to hear males singing for mates.  This will begin the cycle of courtship, mating, nest building and raising a new family.

As birds evolved from cold-blooded to warm-blooded animals several million years ago, they started to build nests to help keep their eggs warm.  Researchers think that the first nests were simple piles of twigs on the ground in depressions or among rocky or sheltered areas.  The first nests built off the ground were also made from loosely arranged twigs.  There are species today who still use both of these types of nests.

Nests have several functions.  They create a place to hide and guard the eggs from predators.  They  provide protection for the parent who remains with the eggs while incubation takes place.  They create a place where incubation is easier in variable weather conditions.  Eggs can be kept warmer and out of the wind and rain.  Many nests are built in places that are already sheltered, such as lower branches of trees where wind effects are less, under large limbs or next to tree trunks that provide protection from both wind and rain.  In urban areas, as well as woodlands containing a heavy shrub layer, most nests are less than ten feet off the ground.  The most complex nest construction is that of a cup nest, built of mud and grass, in a tree fork or hanging from a branch or plastered to the side of a building.

Robins build a cup nest of twigs and mud in the fork of a tree or on a horizontal branch close to the trunk.  Sparrows, of all species, make small cups of grass built either on or near the ground.  Goldfinches build a small nest lined with soft milkweed or grasses in the crotch of a tree. Hairy and downy woodpeckers, like all woodpeckers, prefer holes in trees.  Hairy woodpeckers will drill an oval-shaped hole in a dead branch of a living tree, while downy woodpeckers drill a perfect circle in a branch of a dead tree.  Most woodpecker holes face east or south under a branch to gather warmth from the sun and protection from the rain.  Geese build a large nest on the ground near water, typically lined with down for warmth and comfort. 

Finding nests in late spring and throughout the summer can be quite difficult.  You may try to follow a bird back to its nest, but many nests are only built by one partner, and you could follow the wrong one  and be disappointed.  Many birds will build a nest in one place, but will forage for food in an entirely different location.  If you should walk near a nest, birds will sing or make a display to distract you.  Getting out at this time of the year lets you see where many of last year’s nests were located.  Take a walk before leaves are out and see how many nests you can still find from last year.

Want to learn more?  There are many field guides that will have information on building nests and nesting behaviors.  You may want to consider a specialty volume such as “Eastern Bird Nests” by Peterson Field Guides for explicit information on nests of all kinds.

There are numerous species of birds that spend the winter in Illinois, but two that are infrequent visitors to northeastern Illinois can be easily seen in other areas of the state during this season.  The Bald Eagle, Haliaeetus leucocephalus and the Golden Eagle, Aquila chrysaetos.  They are both members of the family Accipitridae, which includes birds of prey that have broad wings and short tails which produce a distinctive flight pattern consisting of several short wing strokes followed by a long glide.  Members of this genus are all predators and use their talons to kill by repeatedly puncturing their prey.  They are able to stretch their long legs to keep the prey away from their head and eyes for safety.  All members of this family  have fearsome-looking, large, curved, sharply pointed beaks which are used strictly for plucking and tearing the food into bite-sized chunks.

Eagles form long-term pair bonds and both contribute to building their nests, constructed from twigs and vegetation, which are located in tree tops or on cliff ledges.  Softer, finer vegetation is used to line the nests so eggs do not drop through the twig cavities, and the vegetation provides insulation to keep the nest dry and warm.  Starting at about five feet in diameter, nests are reused over many years and may grow to nine feet or more and weigh several hundred pounds.  Eagles typically have more than one nest in an area and may move to another site if they feel threatened or they may use other nests for resting closer to hunting areas.  Eagles that migrate into the southern United States start nest construction and cleanup as early as November.  In Illinois, nest construction takes place in January and February.

Golden Eagles are the only member found in Illinois of the group known as “true eagles”.  They are closely related to buteos, a genus of broad-winged, soaring hawks.  Their main habitat includes mountains and rugged terrain where temperature and wind conditions are conducive to creating numerous updrafts.  They have a light brown head with a dark brown body, brown wings, and a tail of light grey-brown with a dark brown band across the end.  Juveniles may have white spots under the wings in flight, making it easy to misidentify them as Bald Eagles.  Golden Eagles hunt from the air for small mammals and flying birds.  They are mostly migratory visitors to Illinois, but a small population can be found in winter in the far southern part of the state.

Bald Eagles are members of the group called “fish eagles,” closely related to sea-eagles on other continents, but not at all closely related to Golden Eagles.  Adults have a dark brown body with a bright white head and tail, yellow feet and beak, and pale yellow eyes.  Juveniles have a dark head with mottled brown and white bellies and do not sport the distinctive white head until they are at least three years old.  A mature adult stands about three feet tall with a wingspan of 80″-90″.  This species is found only in North America with a population of about 70,000 birds of whom half live in Alaska.  Bald Eagles are always found near large bodies of water that support the abundant fish and waterfowl they feed on. 

As rivers, streams and lakes in Canada and parts of the northern United States freeze and open water becomes scarce, Bald Eagles move southward looking for open water to support fishing.  The Illinois Department of Natural Resources estimates that there are about 3,100 eagles that reside in Illinois in winter, the largest group in the lower 48 states.  They will remain in the area throughout January and February before migrating north as more northerly bodies of water begin to open during the spring thaw.

Thousands of people enjoy eagle watching during the winter months.  The fourth Saturday in January is Illinois Eagle Day, a celebration of the Bald Eagle across the state.  According to the DuPage Forest Preserve District, there have been several sightings in area forest preserves that have large water reservoirs including McDowell Grove, West Branch, Hidden Lake and Blackwell preserves.  There are also several places along the Illinois/Iowa shores of the upper Mississippi River with great viewing opportunities.  A list of many sites and celebration activities can be found at https://www2.illinois.gov/sites/eagles/Pages/EagleWatching.aspx.

Please be aware that we can easily disturb the birds by getting too close.  Stress and our presence can change the behavior of the birds, possibly putting them in danger, especially during nesting periods.  The U.S. Fish and Wildlife Service suggests maintaining a distance of about 330 feet for the birds’ comfort.  I have been to several areas along major rivers.  Viewing from a safe distance is exciting when you can see all of the activity including where the birds are sitting among ledges, flying out over the fishing areas, swooping low to pick up a large fish and flying back to a ledge or tall tree to eat.  Consider bringing binoculars, a spotting scope, or a camera to make it a fun day.

Hawks and their allies are members of the Accipitridae family.  We have several commonly seen species in DuPage County including Cooper’s Hawk and Red-Tailed Hawk, which are year-round residents and Sharp-Shinned Hawk, a species here only in winter.  Other species that may be seen in the area include Broad-Winged Hawk, a summertime only resident, Northern Harrier and Red-Shouldered Hawk, both seen year-round, and Northern Goshawk and Rough-Legged Hawk, also here only in the winter.

Hawks in our area are medium-sized birds, active during the day, with hooked beaks for feeding, and long, sharp talons for catching, holding and killing prey.  The Red-Tailed Hawk, Buteo jamaicensis, is often seen gliding on winds high aloft over open fields.  The  Sharp-Shinned Hawk, Accipiter striatus, and Cooper’s Hawk, Accipiter cooperii, are mostly seen zipping among the trees in open woodlands or in our backyards.

Hawks are among the top avian predators in this area.  They have excellent eyesight and can see clearly four to eight times farther than our human eyes.  As hunters in mainly terrestrial habitats, their coloring blends in with their environments.  Most are brown, grey or black, with pale underparts often streaked or barred in shades of brown.  Combining their coloration with their ability to fly very quietly, most prey are unaware of the hawk until they have already been set upon.  Hawks eat a wide variety of foods including other birds, mammals, fish, reptiles, amphibians and invertebrates. 

Many hawks show a distinct size difference between the sexes, with the female being larger.  There is no consensus as to why this difference exists.  In birds of the accipiter group, including Sharp-Shinned Hawk and Cooper’s Hawk, the males and females will select prey of different sizes and habitats.  This allows a mated pair to find food in two different ecological niches.  Members of the accipiter group feed mostly on other bird species and are just as well adapted to chasing smaller birds through open woodland areas as they are to attacking perching birds from available cover around backyard feeders.  Species in this group have long tails to increase maneuverability, particularly in open woods and forest edges.

Hawks in our area all mate for life, unless a partner is lost.  All species use display flights to attract a mate, and displays may be used by either sex.  Red-Tailed Hawks are unusual in that both sexes have display flights that are started individually, but end together.  Hawks in DuPage County are solitary nesters.  They actively defend the territory that includes their nest as well as nearby feeding habitat from other hawks of their own species.  Nests are built from vegetation, mostly sticks, and a pair may have more than one nest in an area, and nests may be used for many years.  Switching among nests occurs if breeding fails or a nest is infected by parasites.  Whenever possible, fresh vegetation or pine needles are placed in the nest, possibly to provide concealment, serve as a natural coolant, reduce odor or fungal growth, or to signal that the nest is currently occupied.  Nests are further insulated with finer material to keep the occupants warm as well as to keep eggs from falling between sticks.  Nests are very important, and hawks tend to spend several weeks or months building and constantly improving them. 

As egg laying time approaches in early to mid-spring, males will keep supplying nesting material, as females construct and shape the interior.  Egg laying consumes a lot of energy, so females tend to lay an egg every other day.  The number of eggs in a clutch varies from two to six depending on species and tends to increase in breeding locations farther north.  Both male and female will incubate the eggs for a period of 28 to 35 days.  Incubation starts as soon as the first egg is laid, so earlier chicks may be born first and tend to be stronger than later chicks.  After hatching, males do most of the hunting, and females spend all of their time with the chicks.  Chicks can hold up their heads, open their eyes and feed by sight within minutes of hatching.  Females will wave a bit of prey in front of each chick until the chick snatches it from the mother’s beak.  If the bit proves too big for the chick to swallow, the mother may take it back and eat it herself and start with a new bit of prey.  In the nest, chicks are very susceptible to weather changes, and females will spread their wings to protect them from both rain and hot sun.

In northern Illinois, the Broad-Winged Hawk migrates to Central America for the winter.  Several species from summer breeding grounds in central Canada, including Sharp-Shinned Hawk, Northern Goshawk, and Rough-Legged Hawk, migrate into northern Illinois for the winter.  All migrating species fly during the day when winds are more favorable for long distance flight.  Juveniles and adults will fly at different times and different speeds, coming together at their destinations.  Some species may flock together, but most are solitary flyers.  However, none will attempt long water crossings, tending to follow land for the whole journey.  Fall migration starts in mid-August and lasts through November, normally on days following the passage of a cold front, when the air is cooler, drier and more stable.

Over the past few decades, hawks have faced a number of threats including hunting, pesticides and loss of habitat.  However, they have been able to adapt well to their changing environment.  Breeding bird survey statistics indicate that most species have seen increasing populations in the past twenty years, assisted by reduced pesticide use, increased dedication of rehabilitation facilities, and better education, altering the views of hawks held by the general public.