Getting the dimensions/proportions and details were challenging. But taking note of the warbler's position in relation to the leaves and the branches helped a lot. Through a photo, I noticed more of the details and the richness of the colors that I likely wouldn't have picked up from a drawing. I suspect I'll need to take photos first when I begin field sketching. My eyesight is not great and I feel like I'd miss a lot of the birds' details along with their environment.