Where the shape comes from
A short-tailed bird perched and seen from the side, the twin of 鳥, which draws the long-tailed kind. Small and paired with 小, little, it gives 雀, a sparrow; perched together on a tree, several of these birds once gave 集, to gather, to collect, a flock settling on the same branch before the picture wore down to a single bird over wood.
汉字 filed under 隹
No published character on HSK Guide is filed under this radical yet. 汉字库.