The short answer is yes, you can eat bottle gourds! But as you may know, these are the same items that, left on the vine to dry, will hollow out and can then be made into birdhouses! Here are some instructions by Birds and Bloom should you wish to make your own birdhouse out of a dried gourd.
For eating, young gourds picked far from maturity, are best. This is when the gourd can be peeled and then split open to reveal off-white flesh. Most people prefer to remove the spongy center along with all the seeds. What remains can be cut into chunks and cooked how you like it! The photo below shows a type of bottle gourd that I prefer for eating over the birdhouse-shaped type. This gourd is eaten all over the world and goes by many names. In markets near me, they're often labelled "long squash".
I'm Wendy Kiang-Spray, gardener, home cook, and author of The Chinese Kitchen Garden. Learn more about the book here. Enjoy the blog and be sure to like The Chinese Kitchen Garden Facebook page for notifications when there are new posts.