I have always liked warblers and finding and photographing the less common ones can be exciting if not thrilling. Identifying the various species is sometimes challenging -- especially without the added of a camera, binoculars, or spotting scope.
Like many bird species, the males are often the more colorful making them easier to identify. The male hummingbirds for example. However, the female hummingbirds are a little more challenging. Same is true of Cardinals and Pyrrhuloxias. Males easy, females less so.
And the same is true of warblers.
Plumage in both the Olive Warbler and Hermit Warbler are different between their sexes. As you can clearly see from the photos below, the plumage in the two males is strikingly different. The male Olive has a "butterscotch" head, throat, upper breast and a black mask. The male Hermit has a yellowish head with black throat and upper breast, with a variably dark cheek patch.
|Male Olive Warbler|
|Male Hermit Warbler|
However the plumage in the female Olive is quite similar to a young female Hermit Warbler making it challenging to identify in the wild without the add of song. Both females have a yellowish head and throat with a variable darkish cheek patch. As the female Hermit Warbler ages, some black in the throat begins to appear, but even that is variable. As a general rule the wing bars are weaker in the Olive, but again that is variable. Here are photos of the females:
|Female Hermit Warbler|
|Female Olive Warbler|
Both of these warblers are constantly foraging and partially (or fully) hidden in Ponderosa Pine Clutches. The Hermit Warbler doesn't restrict itself to Ponderosa Pines as the Olive typically does, so that can be a clue when seen elsewhere. When both are foraging in Ponderosa Pines, I usually find it too difficult to accurately identify the females until I download the photos and take a closer look.
I never understood why the Olive Warbler was so named. The male has no visible "olive" color. But on close examination of the female Olive Warbler you can see the olive color on its crown and nape. On the other hand, maybe it was named after my grandmother whose name was "Olive." Here is a photo of the female showing the olive color:
|Female Olive Warbler|