By the middle of March here in central Illinois, signs of the transitioning seasons have been apparent for several weeks, although most are easily missed, such as the minor swelling of buds on what otherwise appear to be dormant plants. Changes in bird behavior or the sudden appearance of some species and lack of others are more obvious. But even with the birds, one has to be attentive to subtleties.
On Chautauqua National Wildlife Refuge’s Beer-can Trail, which follows the bluff top for a half-mile before dropping to the shoreline, the cool winds robbed much of the warmth from under my thin jacket. I walked quickly. Abundant lesser scaup and ruddy ducks bobbed within the white-capped waves of the refuge’s north pool; bright black and white male buffleheads occasionally stood out in contrast from the other waterfowl. Bald eagles soared over the refuge as they had all through the winter. Silver maple trees along the Illinois River showed a hint of pink from millions of miniature flower buds nearly ready to open. Though I panned back and forth with binoculars, there was little else to draw my attention. So I rested on a log for a few minutes behind a sheltering bur oak tree, picked out a bald eagle nest on the far side of the refuge, and then, because the lower shoreline return loop was submerged in flood waters, walked back on the same trail.
Trail intersection at Chautauqua National Wildlife Refuge, Mason Co.
Before heading home, I stopped at our Quiver Lake cabin, still shut down for the winter. Half way down the steps to the sandy beach, I trained my spotting scope on a bald eagle nest, just barely visible above the floodplain forest canopy between Quiver Lake and the Illinois River. An eagle perched on a dead branch above the nest. I looked forward to watching the young eaglets develop in the coming months.
On the beach, I sat back in a comfortable chair, scanning the water and skies; and within a few minutes, found what I searched for all day (March 17th): the first tree swallows of the year. Several flew over the lake with more over the floodplain forest.
The tree swallows mark a significant threshold in the spring bird migration. They are aerial insectivores, picking individual insects out of the air without a hitch as they fly up to great heights, dip down to the water level, climb back up to higher altitudes, or sharply turn as if pulled with reins—wherever an insect is detected. Energy is burned and replenished at the same time. Without the insects, the swallows would stay further south. Individuals that I saw were, in fact, the vanguard; if winter briefly returned with Arctic winds and snow, these birds would suffer, or possibly die; if not, they would have the first choice of the best nesting cavities. It’s a gamble. But this is how species adapt to expand their ranges or alter migration timing. Individuals are always testing the edge, pushing the envelope.
More species will soon follow, now that the trees swallows have led the way. But my notes from previous years show that eastern phoebes, a flycatcher, should have already arrived. In some others years, American hazelnut began blooming in late February; this year it was mid-March. The seasonal transition seems a bit behind schedule. But is it? The timing of events in nature from year to year is an illustration of how variability is an inherent quality of nature, which is more like an ancient grandfather clock with slightly worn gears than a modern, precisely engineered Rolex watch. So taking that into consideration, this particular season seems to be right on track.