The Garden warbler is one of our more difficult birds to photograph. Like Nightingales they can be done singing by simply standing around in a territory with a large lens. They will sing very close to you, but so hidden away in the leaves that they are invisible. Nightingales are much easier, as they do show themselves from time to time, but Garden warblers like the thickest cover. I have succeeded in the past, but not often.
While putting the time into trying I have come across a nest more than once and did so this year in a large isolated Bramble bush. They are not much easier by the nest either. They come in low and slip though the Bramble unobserved from the back. The only possibility was to sit on a stool in the open and hope that one would hop up on a branch in curiosity to see what I was doing. If I had sat in a hide they would never show. I had to get their interest and whenever they approached would move a little or start talking to them.
From time to time they would show briefly, but it was best to do short sessions. They were more inclined to show when I first arrived and lost interest in me after while.
Mike Lane's Ramblings 