Is it known to which bird species 雎鸠 refers?
雎鸠 https://baike.baidu.com/item/%E9%9B%8E%E9%B8%A0
今江东呼之为鹗 (is called 鹗 in Jiangdong today)
好在江渚山边食鱼。(like to hunt fish in river and mountainside)
《毛诗·传》日：鸟鹫而有别 (similar to eagle but different, and we know hawk and osprey look similar but smaller than eagle)

From Google Translate:

鹗: osprey
osprey: 鱼鹰; 鹗; 雎

Based on the search results, 雎鸠 or 雎 is &quot;osprey&quot; (&quot;fish hawk&quot; seems like it's nickname) . Since zoology is a recent thing, what the author described, might be some kind of small sized raptor bird that hunted nearby river, very likely been osprey or fish hawk (if they are not the same thing)