Millions of seabirds die each year due to our plastic waste. I'm focusing on the Laysan Albatross; which is mainly located in the Northern-western Hawaiian Islands.
How does this happen? They use a technique of diving down into the ocean to catch fish, using their beaks to skim the water. While they're skimming the water they pick up plastic along the way.
How is this harmful to the seabirds? Well for obvious reasons its plastic, and is not meant to be digested. 98% of Laysan Albatross has swallowed some kind of plastic. This can cause obstruction in the digestive tract, and can puncture internal organs.
What can you do? Clean up after yourself, use and recycle products, and when you see trash or plastic left behind from a previous "owner" pick it up.
Finally just to be clear it is all birds not just Laysan Alabatross. Plastic affects a lot of animals in general. The plastic industry doubles every 11 years.