This animal is sitting in the garden and jumping. Are they fleas?

Answer

Best,

More likely they are springtails or Colembola (a group of six-legged arthropods next to the insects).

However, the photo is not sharp enough to say much more about it. You may be able to search further with this.

An extensive source of information can be found at: www.collembola.be. An introduction can be found here.

Regards,

Pieter