From Nature:
Frogs in the Australian metropolis of Melbourne are having trouble getting together to mate, and the culprit is traffic noise, according to Kirsten Parris, an ecologist at the University of Melbourne. One species of frog is even changing the pitch of its love song to be heard above the roar of the road, she reported on 20 August at the International Congress of Ecology in Brisbane, Australia.
Parris visited many urban ponds and pools inhabited by frogs, measuring traffic noise, which is, unfortunately, at the same low frequencies as many frog mating calls. For a frog such as the onomatopoeic 'pobblebonk' (Limnodynastes dumerilii), she found that a call that could originally be heard by a female 800 metres away may only carry 98 metres above 60 decibels of traffic noise, an average value for Melbourne. She has also discovered that the southern brown tree frog (Litoria ewingii) seems to be compensating for the traffic noise by increasing the pitch of its calls (listen to before and after calls).
More here.