I know I say this about this time every winter, but to the birds: stop it already!
For the last week, my resident male cardinal and numerous Eurasian collared doves have been singing their mating calls. It's only early January, guys! Give it a rest!
Of course, if this summer is like last (and the weather people say it will be) then the best chance of raising a brood is before the heat hits. Last year I remember one or more 100-degree days in April.