What does Officer Delinko realize while on night duty at the construction site in Chapter 18?

In Chapter 18, Officer Delinko is daydreaming about becoming a detective when he trips over an owl burrow with babies inside. While backing away from the baby owl, so its parents can get to it, Officer Delinko bumps into the bulldozer and realizes that if he does his job, the owls will lose their home and likely die. He is very upset by the realization.