Guest post by Jenny Sazama
One May many years ago, I was biking the Millennium Trail and Greenway from Lakewood in Wauconda to Singing Hills in Round Lake—two sites of the Lake County Forest Preserves in northern Illinois—to time out an activity for summer camp. That’s when I first noticed a distinctive blackbird magically appear from within the tall grasses.
This happened at least 30 times as I cycled the winding 1.62-mile trail section from Gilmer Road to the Singing Hills parking lot. As I coasted by these birds, I detected a “chunk” call and noticed their color pattern, which has been described as a classic black tuxedo worn backwards.
I wondered who this dapper fellow was and why there were so many along this route, emerging from this habitat. I would soon learn this pop-up-from-the-grasses blackbird was none other than the bobolink (Dolichonyx oryzivorus). It’s eastern North America’s only songbird whose feathers are black below and mostly white above, with a buttery, cream-yellow nape. Keep watch for a white rump, too, as he takes flight.
Unfortunately, the bobolink is also one of North America’s fastest-declining songbirds. Habitat loss and changes to agricultural practices such as fewer hayfields, earlier mowing and use of modern cutting and raking equipment have affected their populations. Despite these challenges, the bobolink is a common breeder in northern Illinois.
Its preferred habitats are tall grasslands, uncut pastures, overgrown fields, meadows and prairies—but only for courtship and breeding seasons, which run May through mid-July. The “chunk” call mentioned above is made by males and females during early breeding season whenever intruders disturb them, as I must have, bicycling through their territory.
The male bobolink molts into his fancy backwards tuxedo and sports a black beak from spring migration (mid-March to mid-May) through the end of the breeding season. That’s when he’ll move on to marshy areas and molt again into browns and tans that blend into the ground. This camouflage is much like the female’s feather pattern year-round: buff overall with a peachy-pink beak, pale eyebrow and dark eye line. However, the male’s non-breeding plumage is dark buff above and a golden buff underneath.
Most male bobolinks stake out their territories within 50 meters of previous breeding areas. They usually do this prior to the arrival of female bobolinks, one week after their own arrival. Talk about a fast-paced housing market! And an interesting one to watch, as bobolinks tend to nest in loose colonies, so there are plenty of behaviors to observe such as songflight. Songflight is when the male bobolink flies slowly with rapid, shallow wingbeats either high above the ground (territorial) or low in a circular pattern (courtship).
Males display their colorful feathers during courtship to attract females. And I mean females plural, because bobolink males are polygynous. They’re also polyandrous, “with each clutch of eggs laid by a single female often representing multiple fathers,” according to the Cornell Lab of Ornithology.
If there’s abundant food onsite, each male may have up to three females who build nests in his 1-acre territory. This can expand to 5–9 acres of territory when food is sparse. Let’s just say a male with more than one female nearby has more years of experience and often inhabits higher-quality habitats.
Now imagine if the 30-plus males I saw that May each had at least two females nesting nearby! But I didn’t see many female bobolinks that day. My guess is the males were still establishing their territories or the females were busy covertly constructing nests.
Females exclusively build their carefully concealed cup nests out of grass and forb stems in shallow depressions at the bases of tall grasses or wildflowers. After two days or more of nest-making—the final touches are soft, fine grasses and sedges lining the inner area of the nest—the female takes another two days before laying one egg daily. She continues until she has a clutch of five to six oval eggs that are expertly camouflaged in a cinnamon color and blotched heavily with brown.
The female incubates the eggs for about two weeks, taking a 10-minute break after 20 minutes of sitting. A wellness practice we humans can benefit from! All the eggs in the clutch hatch within a 36-hour period. The nestling phase lasts 10–11 days. During this time, papa bobolink helps raise the young in each of his female mates’ broods, giving the most assistance to his first mate of the season.
I’d like to pause for a moment of gratitude to the keen observers and scientists who documented this information, because bobolinks are crafty at keeping their nesting sites secret. Besides employing camouflage, bobolink parents land a distance away from their nest and walk stealthily through grasses and wildflowers, staying undetected to keep their family’s location protected.
They often don’t even need to reveal themselves in search of food, since their diet consists of seeds, grains, insects and other invertebrates hiding in low vegetation and on the ground. During the nestling phase both parents bring food, especially caterpillars.
The fledgling phase lasts three weeks or longer. Bobolink young learn to fly short distances in two days and follow their folks within five days. This newfound freedom of movement breaks down territories and leads to flocking behavior from mid-July through mid-August. It also shifts the habitat to marshy areas and cultivated fields. Within the safety of the marsh, another molt occurs for the breeding male, who replaces his dressed-to-impress tuxedo with a more blend-in-with-the-crowd look of dormant grasses.
Seasonal movement of bobolinks continues through late September and early October. These long-distance migrants journey more than 5,000 miles one-way (about 12,500 miles round-trip) to winter in South America. It’s the longest migration route of any North American songbird. According to Cornell, “throughout its lifetime, [the bobolink] may travel the equivalent of 4–5 times around the Earth’s circumference!”
Along the way, large flocks often rest and refuel in southern rice fields during the day. This is probably how the species got its nickname, the ricebird, and the meaning of its scientific name, oryzivorus, which means “rice eating.” The ricebirds continue along their flyway route under cover of night, over the Gulf of Mexico and across the Caribbean to spend the winter in southern Brazil, northern Argentina and Paraguay.
Often when we environmental educators scout areas for future programs, we discover something new that makes us smile, sparks curiosity and prompts us to learn more. This happened to me again last May when I was setting up a self-guided Trivia Trail at Rollins Savanna in Grayslake. I heard a familiar, bubbly, melodious birdsong.
When I looked toward the joyful sound coming from the avian fluttering over the grasses, I recognized it as the bird that wears a tuxedo backwards. A smile spread over my face as I spoke his name. Seriously, who doesn’t smile when saying that name? His name and his song (“bobolink, bobolink, spink, spank, spink”) spread a happy vibe. Go ahead. Say bobolink and try not to smile.