The pigeon stretch is getting the lion’s share of the attention when it comes to hip and gluteal stretches, Both the pigeon and the very similar and lesser known eagle stretches have great value and target slightly different structures. The eagle stretch affects the sacroiliac and surrounding ligaments and muscular origins. It is more central and often overlooked. The pigeon stretch ( supine version instead of the traditional prone yoga version) affects muscles closer to the lateral and inferior part of the buttock muscles.

https://www.youtube.com/watch?v=hv6Tu6pAeyw