Southbound Warblers

A beautiful male American redstart pauses on a branch only for a moment before continuing its search for insects

October 10, 2022 – There are telling changes in the air that don’t require a calendar to say fall has arrived. As the days grow shorter and the cool nights summon an extra blanket or two, the long-anticipated little fall warblers from points north have been moving through Northeastern Illinois for some weeks now on their travels south to warmer climates for the long winter months. Many warbler species have been showing up in backyards, parks, and thickets throughout our river valley for a needed rest and nourishment required for such a challenging journey as this grand autumnal event. From the tree tops to the shadowy undergrowth, the little birds search for insects and wild seeds to replenish the fat reserves lost during their long flights. North America certainly has a variety of these stunning fairy-like little birds. There are more than 50 species of warblers across the contiguous United States, 35 of which are known to the midwest. A number of the little birds will spend only a brief time in our area during the great migrations as they are just passing through. Some species of warblers nest here in Northeastern Illinois, often noted by bird watchers throughout the summer months. Other species that briefly appear during the spring and fall migrations require some understanding of avian behavior and timing with a bit of luck to observe those little beauties. Weather fronts, prevailing winds, and years of collected data from bird observations are closely monitored by bird enthusiasts during the spring and fall as they watch for the big push north or south of migrants. Today, bird watchers can also take advantage of the radar technology that monitors bird movement. A collaborative called BirdCast provides this service; BirdCast is accessed on the internet and gives daily updates on bird movements in an easy-to-understand animated graphical interface helpful in locating the little travelers moving through your area. Bird migrations have been going on for thousands of years, adapting and evolving with a planet in flux. Today a rapidly warming environment is having a noticeable impact on bird behavior that is playing out before our eyes. The collection of data by citizen scientists reveals changes in migratory birds’ behavior. The data shows birds are migrating earlier in spring and later in the fall, with nesting ranges expanding, bringing into focus our canary in the coal mine, which should be a warning for us all.

A southbound Black-throated green warbler on its long journey to Mexico for the winter

The Autumn Nudge

A Neotropical bird, the Black-throated Green warbler pauses for a moment on a dried stem in Iroquois County with a freshly caught caterpillar.

October 11, 2021 – Another year has tilted quietly into the splendid season of autumn, a time of bounty, preparedness, and introspection that nudges all living things in the Northern Hemisphere. While humans adjust to their seasonal changes and challenges, animals have been fattening up, growing new coats, and gathering food. Birds and insects have been on the move for weeks. Many plants continue to provide, but many have gone to seed and withered, a change is in the air. Feeding, resting, and building strength, many species have been working their way south towards their winter ranges. Recent weather radar over the Great Plains displayed not a weather disturbance moving south but a remarkable radar return of many thousands of Monarch butterflies on their fall migration. Changing weather systems across the American flyways, like cold fronts, air pressure, and strong autumn tailwinds can be a great predictor and the ideal opportunity for a mass movement of birds and insects out of the north. Bird enthusiasts, throughout the range of bird migration, hope and watch for unusual avian visitors to their woodlands, wetlands, and backyard feeders in their areas, including the highly anticipated and always delightful many species of warblers. Those early migrating warblers can still show their beautiful summer plumage, but as the weeks pass, the birds become a bit harder to identify as they transition into their winter plumage. Young birds born during the summer may look different than adults. The fading of the adult warbler’s strong summer markings may also require close study with thorough identification guides and even the valued opinions of expert birders to help identify those notoriously difficult fall migrants. By mid-October, many warblers and other songbirds have moved farther south out of Illinois. The tiny Ruby-crowned and Yellow-crowned Kinglets, Yellow-rumped, and Palm warblers continue to pluck insects from the bushes and trees in our area. Sparrows that spent their nesting season north of Illinois, some as far as the Arctic, have arrived and are taking advantage of the available seeds and insects. Sandhill cranes, Whooping cranes, Arctic hawks, Golden eagles, Short-eared owls, and Snowy owls are moving south and will satisfactorily fill the void of our summer visitors until the spring rings true once again.

A boreal songbird, the Blackpoll warbler, is bound for northern South America for the winter. The small wooded area in Iroquois County and others like it along the migration route are lifesavers and provides the much-needed food for that bird and many others on their long journeys south.