Cormorants look like they were designed by a committee of non-experts, probably at an old government office full of mid-level managers and underpaid engineers.  Here's how I imagine the process went: 
Person 1:  We want a bird. 
Engineers:  No problem. 
Person 2:  But the bird can swim. 
Engineers:  Uh ... yeah we can do that.  Webbed feet and whatnot. 
Person 3:  But it needs to swim underwater to catch fish. 
Engineers:  Oh ... hmm ... ok.  Just remove some buoyancy so it can sink better.  It'll need to have gills so it can--
Person 1:  No, it needs to breathe air! 
Engineers:  Ok ... I guess we can have it resurface every so often.  But it's just gonna stick its head and neck out of the water because it's midsection is too dense to float, so it'll look like a snake. 
Person 3:  That's fine.  And then it can fly away and do other bird things. 
Engineers:  Not exactly.  Because of its extra density, it'll have a hard time taking off out of the water. 
Person 2:  But it can fly, right? 
Engineers:  Yes, but it'll need to dry its wings before any amount of extended flight.  The decreased buoyancy and underwater swimming mean its entire body gets soaked to the bone, so it'll need to stand around with its wing outstretched, which is a perfect time for predators to attack it. 
Person 3:  Can you put a gun on its head? 
Engineers:  We'll try that in version 2.
Thankfully version 2 never made it to market. #nature