The grebes are different from other waterfowl such as swans, geese, ducks and loons, because they have lobed toes. These birds are divers who use their wings to propel themselves under water in order to get their food. Similar to loons, they are more able to swim in water than they are to walk on land. This is because their legs are farther back on their bodies than most waterfowl and it is very difficult for them to walk.
There are seven types of grebes found in North America. The Horned Grebe and Pied-billed Grebe have the widest ranges. These birds are more likely to be seen from the central parts of the continent into the more western regions. The Least Grebe is the smallest in the family and lives in the most southerly regions of the United States and into Mexico. The Clark's Grebe, Western Grebe, Eared Grebe and the Red-necked Grebe are found in the western regions.
Avibase - the world bird database This site provides the user with a complete list of bird species, broken down per country, or in the example of the US or Canada, per state and province. Here, bird species names are available in other languages, a great asset to be used as a translation of foreign bird names.
ABA - American Birding Association This site represents an organization that maintains official records of all birds species that have been proven to have been seen inside the perimeters of the North American Continent and the surrounding bodies of water. Regular revised versions are posted to keep the bird list current at all times. This is the list used by all serious birders over their lifetime. You may be aware of the movie called the "Big Year". It was with this list that all the competing birders used in an attempt to set a new record as to how many bird species that could be seen by an individual birder in one calendar year.
I hope you will take advantage of these suggested websites. I have used each of them, in one way or another, throughout the years in my quest to better identify and understand our fine feathered friends.