Despite all appearances, Rod and Nathalie didn't have sex through their clothes. Rod has no idea what sex entails and Nathalie was able to convince him that just making out on their bed constituted "sex".
An unintentional one, but the sounds the birds - which look like hawks or Aquila eagles - produce are made by Bald Eagles. Due to the rather annoying and unimpressive nature of the Bald Eagle call, they are dubbed in fiction with the cries of other birds of prey. So basically, not only is that is that situation reversed here, but in a way it's very karmically apropriate.