Mars - Flying Objects

What would be fly above the surface of Mars like this. Multiple images at the bottom of the page linked below. Taken moments apart only one has these flying objects.

https://mars.nasa.gov/msl/multimedia/raw-images/?order=sol+desc%2Cinstrument_sort+asc%2Csample_type_sort+asc%2C+date_taken+desc&per_page=50&page=3&mission=msl&begin_sol=2631&end_sol=2631