The approval of the following answer-blog to the riddle has been delayed for three days for unknown reason. Maybe our editors are very busy on the reforming  of the Forum!

Twenty birds line up flying north
2020-07-26

Do you believe that the title was a riddle that I invented in the staff office: One of my colleagues was named ‘seagull'(海燕)。 The special structure of 燕 aroused me much interest. I stared at it for minutes then I stroke the riddle as the following: Twenty creatures are going to the north who are in one line!  Please guess it into a Chinese character.  My problem puzzled everyone including Miss Seagull.

The top of 燕 is  double  ‘’十"(ten） which certainly means "twenty";

Its middle component 口 is 'mouth’ and in many cases it refers to an animal or a man;

北 is ‘north’ with each part symbols a kind of ancient weapon. In Chinese traditional culture ‘north’ always represents power and authority;

The bottom of 燕 is called ‘four-dot-water’ which symbols ‘hot water or the surface of water’, such as 煮 (cook) , 点 (point). Here I took the dots as the birds in the sky. 

In late Spring as a routine job the swallows always march to the north. 燕 is the beautiful scenery picture when you look up into the sky when hearing their singing!

Yesterday I revealed the answer through a blog which has not been approved! Now let's observe the key word 燕 in another way: 

The 口 is the center of the bird;

北 is its two wings while the four dots at bottom acting as the tail, it is so vivid that the wings and tail are stretching out for flying!;

Then what is the long horizon line at the top？ Maybe the bird is biting a thin tree-branch for nest-construction, or it is fish that the parent wants to bring home for feeding kids!

As a whole the outlook of 燕 is so attractive to my eyeballs that contains too much body-language information.  How wonderful our traditional culture is!