The Brass Bird Lamp is the twenty-fifth treasure that can be found in Uncharted 2: Among Thieves.
The Brass Bird Lamp is found in Chapter 6 - Desperate Times . The key to this treasure is the large, sign-strewn electrical pole in front of the truck where the RPG-wielding enemy was stationed. If you're facing the temple, it'll be to your right. From ground-level, you'll no doubt see a glimmer of a treasure on an object at the very top of the tall pole. However, you can't shoot it down. Instead, you have to use the signs and other objects around the lamppost as a makeshift ladder leading upward. Once you get to the top, you can obtain this treasure rather easily. It's initially spotting it and climbing up to it that's the difficult part.