Warblers. They're a group of birds that many people struggle with. If you think about it though, they're really easy. Here's how I do it:
So, your first step is IDing a Warbler. The question then comes up, what is a warbler?
Warblers are small insectivorous birds of the family Parulidae that live mostly in woodland or woodland edges. They are generally not any bigger than 6-8". Sometimes being smaller than 3". They are active foragers and have many strategies for catching insects and larvae, including flycatching;most glean insects directly from branches, as vireos do. They are generally easiest to ID in the spring when they are in full breeding plumage. When fall comes around, they lose their spring colors and become drab and plain, making them more difficult to ID.
So now you know about Iding the family. What about species?
Once again, divide the birds into different groups. Start by dividing them into Warblers with wingbars and warblers without wingbars. Now you have two distinct groups. The warbler family and sub-families are divided into 18 genera in N America. I will be focusing on the major genera and mostly eastern warblers. The genera I will be focusing on will be mostly Dendroica, Vermivora, Wilsonia and Oprornis warblers because these are the biggest groups and are the most easily recognized.
Now take your "warblers without wingbars" group and separate the Oprornis Warblers. The 4 Oprornis warblers are Mourning, Connecticut, MacGilivray's and Kentucky Warblers. These warblers are easy to ID in any season because fall plumage is very similar to spring plumage. Within this group, only Mourning and Connecticut are difficult to tell apart. Connecticut though, has a bold, complete, white eye ring. This feature is probably the best one to use to tell them apart.
Oprornis warblers are medium size, rather chunky looking warblers that prefer brushy woodland habitat. usually with some source of water nearby. The best way to ID these birds is to learn their songs. You almost never actually see them since the tend to stay deep in the undergrowth. In fact, usually the only way you know they're there is because you heard them. Connecticuts have a distinctive "tip tupa teepa tupa teepo". Kentucky warblers sound more similar to Carolina Wrens or Ovenbirds with their warbled "churree churree churreee". Mourning warblers sound similar except that they say Churree churree churree" with a whistled "to meet you" at the end.
Anyway, back to warblers. I could write a whole essay on differences between Oprornis warblers.
(to be continued.......)