Teal are small ducks which, in migration, appear as fast, low-flying small flocks. Duck hunters know well how quickly they can appear over the reeds using their ground-hugging radar, and be past you before you know they are there. Early migrators, both species of teal have moved from their northern marsh breeding grounds to their homes in Central and South America by the time fall hunting season begins in the northern US. I doubt that we will bag any teal in our trip to Manitoba during the first week of October - they will be south.
The Blue-wing is the second most common duck in North America - after the mallard. (The blue wing patch is only visible in flight.) One of these days, we will get into the subject of duck plumage, an interesting subject because ducks have two plumages, breeding and non-breeding (or "eclipse.") Duck photos tend to show the colorful breeding plumage of the males, as in this photo, rather than the drab eclipse plumage which beginning birders and hunters find confusing.
During migration, both teal species are found in fresh-water or brackish ponds and marshes, often standing around on mud flats, looking bored but content. More on teal here.