Why Can A Loon Only Take Off From The Water?

I was reading on the Wikipedia that loons can only take off for flight when they are on the water. Why is this? I understand from the article the legs of the loon are very far back so does this mean the birds need to get a running start to take off. I mean robins and such can take off from a standing position.

I realize a robin is no waterfowl so I guess another question do big or bigger birds always have to run to take off into flight?

I think the issue is the fact that the legs are so far back means the bird pretty much can’t walk on land at all. Being diving birds also I think they are relatively heavy for their size. Put the two together and you have a bird that needs a running start from the water’s surface to take off.

I’m trying to think of large birds that don’t need to run to take off. Of course many large birds like hawks and eagles land and then take off in trees which means they can afford to drop down a little on takeoff.

I know ravens which are pretty big birds can pretty much jump into the air and takeoff with little if any running.

Loons are indeed unusually heavy for their size and wing area. Among other things, this means a high flying speed. This site says they weigh 8 to 12 pounds and can fly at 75 mph. Here are some “fun facts” from that site:

I have flown with them in a sailplane and can confirm that they fly fast. When they circle in lift they continue flapping. When you see loons circling, you can be quite sure that they are in strong lift (typically at least 500 feet per minute).

But most hawks and eagles take prey on the ground. They are perfectly capable of taking of from a standing start. Not only that but they can take off carrying sizable protions of their own body weight with just a couple of hops. Pretty impressive really.

Yeah, they pretty much can’t walk on land they just sort of flap and push themselves forward but they don’t spend much time on land anyway.

Personal observation:

I have worked on hawks and loons. A large red tail hawk is amazingly light weight. A loon of the same approximate size is like a concrete block in comparison. When I lived in Philadelphia, snow storms would sometimes cause loons to land, and they sometimes would mistake a road for a river/stream. Once the birds were rehabed, they would be taken to a body of water for release.