35 out of 120 red-beaked wombats nest in trees, while 78 out of 99 purple-tongued wombats nest in trees. do the two species show differences in their tree nesting behavior?

Yes, both species have different instincts of nesting behaviors.

Explanation:

Nesting behavior is an instinct of species to a desire for a protected nest for their newborns. Typically, it is more common in pregnant animals due to the production of a hormone "Estradiol".

According to the conditions given in the question, nesting instinct in red-beaked wombats is ~29% whereas for purple-tongued wombats is ~79%. This difference suggest the stronger desire of red-beaked wombats to make a nest in the trees compared to the purple-tongued wombats (purple-tongued wombats may have desire for places other than trees). Here, we could argue that this high desire of nesting behavior in trees for red-beaked wombats was might be due to the high production of Estradiol. In any case, there was a clear difference in the nesting behavior for both species.

i think that it is plants