Humans play gooseberry with tit love

I dread to think what the above headline will do to my Google profile, but I couldn’t resist!

A couple of years ago, I discussed some zoological research which shows that city birds tend to sing at a higher pitch than their country cousins. This urban adaptation is a response to low-frequency noise associated with human activity.

It appears that singing high to be heard has negative consequences for the love life of Great Tits (Parus major). The problem is that male tits rely on low-pitched song to appear sexy to females. This makes it difficult for them to be heard above the city din, but chirping higher to compensate is a turn-off for the ladies. Researchers in Leiden led by doctoral student Wouter Halfwerk say that this explains why husky-voiced bird species breed in lower numbers close to busy highways.

Halfwerk et al., “Low-frequency songs lose their potency in noisy urban conditions”, PNAS (in press, 2011)