Weather's Influence on Birds
Weather conditions have a profound influence on birds. Birders will do well to pay attention to weather, and thus optimize the chances of finding the most birds and the best birding.
It is also prudent to be weather-aware in a region such as the Great Lakes, which is renowned for volatile weather and abrupt changes in conditions. The eastern end of Lake Erie, from Cleveland to Conneaut, is a renowned “snow belt.” Heavy winter snows can crop up with little warning, making travel perilous. It’s not much fun seeking birds if you aren’t prepared for the elements.
Oftentimes, the worst weather for people to endure is the best for finding birds. For instance, frigid blustery days in November, with north winds roaring off Lake Erie, is frequently the best weather for finding unusual birds. These are the conditions to watch the lake from select vantage points, and look for jaegers, scoters, or perhaps a Harlequin Duck. Thanks to systematic aerial surveys of the open waters of Lake Erie, we know that many species migrate well offshore and often can’t be seen from shoreline observers. For instance, some of these aerial surveys in November might tally well over 100 Common Loons, while shoreline observers might only note a handful of loons during the same period. Strong northerly winds seem to push birds near shore, where they are visible to birders on land.
When Lake Erie crusts over with ice and temperatures plummet well below freezing, power plant warm water outlets can provide fabulous birding. Such sites are often the only consistent areas of open water, and hardy species such as Greater Scaup, Common Merganser, Common Goldeneye, and many species of gulls, can be numerous. The open leads behind the Avon Lake Power Plant can be packed with ducks and gulls, and a careful searcher is often rewarded with uncommon Arctic species such as Glaucous and Iceland gulls. But the observer is liable to have to tolerate single digit temps and icy winds in the face, so be prepared.
Tremendous migrations of raptors – birds of prey – can occur both spring and fall along the shores of Lake Erie. Strong southerly winds are best for finding big numbers of birds in spring; winds from the north tend to produce the best flights in fall. Even though checklists and other references might note that the peak of Broad-winged Hawk migration occurs throughout September, it’s often only one or a few days that experience the greatest numbers. Typically, strong northwest winds on the heels of a cold front push through large numbers of Broad-winged Hawks and other raptors. Raptors take advantage of thermals – strong upwellings of air – as riding these “waves” of air allows them to expend less energy. As thermals don’t form very well over the open lake waters, the raptors tend to hug the shoreline where there is more thermal activity.
The southern shore of Lake Erie is known for producing spectacular “fallouts” of spring songbird migrants. Such days are unforgettable, as lakeside patches of woodland can be filled with hundreds or thousands of vireos, warblers, tanagers, grosbeaks, flycatchers and others. Even though there is a parade of different species of songbird migrants passing through the Lake Erie region from March through May, we are lucky to see one or two good fallouts each year. The atmospheric condition that can create spectacular fallouts is typically the first warm push of southerly winds after a period of cool weather characterized by northerly breezes.