First, warblers are small birds, typically around 5" in length. So they are much harder to spot and watch than bigger birds, such as Mockingbirds and Cardinals.
Second, many warblers tend to flit around high in the tree tops, forcing birders to strain their heads back in order to watch the birds. The result is "warbler neck," a common affliction among birdwatchers during migration seasons.
Then there is the problem of movement. Unlike many other birds, warblers rarely perch for long in one place or in exposed positions. They are insect-eaters and so they are constantly in motion, foraging among leaves and twigs, looking for bugs. This makes it very difficult to get good looks at them. And it makes it extremely difficult to get good photos or video of them! (Video is particularly hard to shoot: For a still picture you need the bird to stay in one place for a fraction of a second, but for video you need it to stay there for several seconds.)
This morning I decided to use my coffee break to film some of the warblers that have been frequenting our campus nature trail. Finding the birds was easy: Within 5 minutes I'd spotted an American Redstart and Wilson's, Chestnut-sided and Black-throated Greeen Warblers. Filming the birds was a different matter. After 20 minutes of clambering through undergrowth and being eaten alive by mosquitoes, I had lots of video footage of leaves with only the occasional blurred frame of part of a wing or tail.
I decided to give up and go back to work. That was when a Black-throated Green Warbler took pity on me and allowed me to film the short clips shown below.