I don’t think this strip requires an explanation, but just in case.
An ornithologist is a scientist that studies birds. A brown booby is an aquatic bird. Booby is also a synonym for breast.
There is also apparently a bird called a “great tit.” I am NOT making this up.
https://en.wikipedia.org/wiki/Great_tit
This joke also would have worked with great tits but I think that one may have actually required an explanation to most folks.
This comic is my entry for @cobmaximus’ Steemit Webcomics Funny Comic Strip Contest Week #31. The theme for this week’s contest was “birds.” Hence the booby joke. I hope next week the contest theme is melons, that will save me from having to draw a new strip. 😀