The scoop on eagles

ok,,,i got some of questions concerning eagles
1. how did Thorondor die?
2. is Gwaihir Thorondor's son?
3. Are the eagles in the third age still under Manwe's command?
4. i've read somewhere that most of the eagles were'nt very nice,,,who were these eagles?

basically,,,anything you know bout eagles let me know.

Po-ta-toes