Redtail Rise everything's not lost

What did she mean they weren’t birds?

His frustration morphed into confusion, then elation. This meant an adventure—one that would earn Lilia many brownie points in his eyes.
 
After she stooped and ruffled his head, he looked up at her and gave her a grateful lick on the nose.

Yes yes!! We go find!!

His tail wagged vigorously as he pranced a few paces away, brimming with excitement. Instinct told him to put his tiny nose to the ground and sniff wildly, which he did, though he wasn’t completely sure what to be sniffing for. Picking his head back up, he perked his ears instead and did as Lilia told him to, listen. 

Except, with the chorus of sound, it was impossible for him to figure out where it was coming from.

Thoundth where?? He complained.

He turned and bounded back toward her, body wriggling with inpatient enthusiasm as he waited for her to follow.