Sentence:  Then from his lofty stand on that high tree Down he alights among the <WSD>sportful</WSD> herd Of those four-footed kinds, himself now one, Now other, as their shape served best his end Nearer to view his prey, and, unespied, To mark what of their state he more might learn, By word or action marked. 
Meaning of the word marked with <WSD> tags:  playful, merry