DIY treatments may help minor issues, but professionals provide long-term solutions and prevent recurrence.

Both spikes and loose nets can be installed over nest sites to prevent the bird from returning, but nets are not a humane option since birds and other wildlife can get tangled in them. 

Spikes are a humane alternative that deter nesting without harming the birds. In small areas, like vents, a very fine mesh net can be installed to prevent the bird from returning. These nets don't generally pose a risk to the birds.

Some birds of prey, like owls, hunt at night. Hawks are diurnal and need good light to see their prey. You could see them circling anytime from dawn to dusk. Species like the common red-tailed hawk are most active in the early morning and late evening when their prey is also typically on the go.

DIY removal of birds or bats is not recommended due to safety risks and potential legal protections for certain species. While simple prevention methods can be done yourself, actual removal and control of an infestation should be handled by professionals who are familiar with safe, humane, and effective techniques.