For those times when waterfowl descend upon waters around Ohio, here are some identification tips compiled by expert birders Dave Horn and Darlene Sillick.

• Pattern, pattern, pattern . Look for the distribution of light and dark on the bird. This is especially important with waterfowl, because lighting conditions can make color a useless aid. Unless you are close or you have REALLY good optics (binoculars or scope) and a steady hand, you will not see the saturated colors illustrated in field guides.
• Puddle vs. diver.  Puddle ducks are typically birds of fresh, shallow marshes and rivers rather than of large lakes and bays. They usually feed by dabbling or tipping rather than submerging or diving. The speculum, or colored wing patch, is generally iridescent and bright.
• How is it sitting in the water?  Loons, grebes, scoters, and cormorants lie lower in the water than other waterfowl. Cormorants tilt their head up. Gulls ride higher than ducks.
• The bill is a good indicator, IF you see it clearly!  Ducks have broad and flat bills; the bills of mergansers, loons and grebes are long and thin.
• Watch the take-off.  Dabbling ducks and gulls can take off nearly vertically. Diving ducks, loons and grebes patter a long way before getting airborne. In a mixed flock, teal are fastest (and smallest). They take off last and will be 100 yards ahead of the flock within a minute. Odd gulls are very rare away from Lake Erie - 99% of what we see in central Ohio are ring-billed and herring gulls with Bonaparte's in late fall. Migration dates are good guidelines, but waterfowl will have stragglers.
• Habitat is a semi-reliable clue .  Diving ducks and loons like larger and deeper bodies of water (most of the time). Puddle ducks often feed on croplands given their diet is mostly vegetable.    Mallards and pintails are grain fed. Wood ducks fatten up on acorns and do nest in trees.
• Check every bird.  Study the common birds well so you notice what is different. Examine the wedge of geese for a smaller individual, perhaps a Brant (a black-necked goose the size of a mallard). Study the common species. Things that just don't fit in a flock are likely to be interesting. The dark, first-year herring gull flying twice as fast as the others might really be a jaeger (a falcon-like seabird).