February 2015

Love is in the air!

Marla Mertz, Marion County Conservation

“Birds, not rooted to the earth, are among

the most eloquent expressions of life.”

~Roger Tory Peterson

As spring approaches and the desire to begin anew, we often forget that there has been courtship, defending territory, bonding and nesting already occurring in some groups of our winter birds. The colorful birds and waterfowl that make a grand return in spring are actually some of the later nesters but begin moving back to historic breeding grounds to begin their theatrical expressions to gain a mate. Male and female birds form pairs for nesting on the basis of courtship behaviors. The male mostly initiates courtship, depending on species.

One of Iowa’s earliest nesters is the great horned owl. This “tiger of the woods” is Iowa’s largest and most adaptable owl, commonly laying two eggs in late January or early February. The mated pairs don’t normally move too far away from their territory, defending it all through the fall. When it is close to mating time, the male can be extremely vocal in his lower pitched tone and may bow with wings drooping, mutual bill rubbing and preening. The owls will locate old nests from crows, red-tailed hawks, eagles, or squirrels, and occasionally locate a cavity. Great horned owls are monogamous (one male and one female and neither has any involvement with other nesting birds).

Iowa winters bring some of our most regarded raptors. The migration of northern bald eagles move into Iowa where many of our reservoirs offer open water and roost trees along the river corridors to brave the winter months. The Mississippi River holds numerous eagles each year bringing many tourists and travelers to view our nation’s symbol. No matter your destination you may embrace the opportunity of the occasional airborne food fight challenge or the breathtaking plummet of mating rituals. Cartwheeling or whirling is a spectacular aerial courtship display sometimes mistaken for battle. Only a few species of raptors perform such sky dancing where the pair lock feet and tumble dramatically earthwards, often to separate just above the land and water. Birders often travel off of the beaten path to locate areas where our resident eagle populations begin repairing and conducting stick carrying rituals often beginning in the fall and nesting as early as February. Those pairs may have already bonded ‘til death do us part’.

Mating and breeding rituals often bring a multitude of offerings that we don’t always pay attention to or notice. Some of the most common mating rituals begin with the molting of feathers and regrowth of exotic vibrancy of color in plumage of the male to eye-ring color changes, brightly colored knob-like protuberances at the base of the bill, facial wattles, inflatable throat sacs, and brightly colored eyecombs. Some bird attire seems so exotic for Midwest rituals.

One animal that dons new attire and color changes is the wild turkey. Beginning in early spring, the male adorns color and bulk that commands attention. The head is featherless but screams the colors of red, white, and blue. Wattles dangle and the fleshy flap of skin over the bill is called a snood. When the male gets excited, the bare skin, wattles, and snood become engorged with blood and the whole head undergoes color changes. The blue signifies sexual arousal, and the red aggression. The puffed up body of feathers maximize his appearance, the tail is fanned and the wings are dropped creating the impression of a feathered ball. Male turkeys are polygamous and will mate with as many females as he can. Sometimes we call this promiscuous breeding.

Spring migration of the American white pelican moving northward to their breeding grounds appear in Iowa in late March, early April. Breeding birds always appear first in the spring....like the old saying “early bird gets the worm” or in their case, their nesting area. The long bill is vibrant in color, they arrive with a half-moon looking growth on their bill called a nuptial tubercle, and their legs are vibrant orange. The special tuft of feathers remind you of a bad hair day, and sometimes are tinted yellow.

Pelicans are known to be monogamous and most likely pair each year on their breeding grounds, performing a variety of flying and walking courtship displays. After breeding, the nuptial tubercle breaks apart and falls off, and the back of their heads become a light grey. Their nesting areas are usually within dense colonies in northern states like Minnesota.

Waterfowl migration is a magnificent burst of color and sound. The courting styles of waterfowl are all a little different and monogamous relationships are usually for only one breeding season. Plumage is vibrant and extremely detailed. Eye rings and bills are an explosion of color. The wood duck is one of the most stunning of Iowa’s waterfowl. They are one of the few species that nest in tree cavities and quickly adapt to nest boxes. Most wood ducks begin to pair up in January and most birds returning in the spring are already paired up. A courting male will swim before a female with his wings and tail elevated and occasionally tilt his head backwards. They also have been noted to ritualize their drinking, preening, and shaking movements and both may preen each other.

Another magnificent ritual is performed by the hooded merganser sporting his fan-shaped hood, and making short display flights. The fan-shaped crest, head throwing and head bobbing are common rituals he uses to entice the female. He swims next to her with his crest raised and throws his head back until it lies on his back. As he raises his head, he may give a loud frog-like croaking call which can be heard up to a half mile away. The female will either ignore him or accept him by bobbing her head and flattening her tail on the water.

In most migratory songbird species, the males are normally the first to arrive to their breeding range in spring. The male chooses a territory that will provide a good nest site and enough food to raise a family. He then will announce his territory by singing and displaying, so other males will know that territory has already been taken. Song, length of song, and the number of songs are sometimes a clue to the female that he is a desirable mate. As the females trickle into their breeding range, they are attracted to the males with the best songs, showiest plumage, energetic displays, dancing, posturing and aerial acrobatics, and any other displays they can do to entice her.

As each individual species pair up, it is almost a given that they will need to defend their pairing and/or their chosen territory. Each species have specific posturing or calls to signal whether they will attack or retreat. Occasionally disputes include aggressive displays in hopes that the intruder will give up without resolving conflicts with physical fights.

Watch prairie chickens booming on their lek! Video posted by the Iowa Department of Natural Resources on their Facebook Page, 3/28/15

Prairie Chickens Booming and Dancing - Although all adult male greater prairie chickens boom (call) and dance, only the most dominate birds occupy center stage. This is where females will eventually come to be courted. In the seeming chaos of booming, sparring, and retreating, the daily pecking order is reestablished.

Links to learn more:

View the "Courtship and Nest Building" album in Google Photos!

Grab those binoculars, be open to hearing new song and watch your area for the preparation of a new year! If you feed the birds in the winter, begin watching bird behavior in your own backyard. Always remember... if the bird and book disagree, always believe the bird.