|A Northern mockingbird in Mission Viejo, CA. Photo taken Sept. 2010 by JJ Meyer|
The noisy culprit is likely a Northern mockingbird. It has a vocal repertoire of more than 400 songs and can imitate other birds, barking dogs and even musical instruments. Generally it's a male that sings all night, especially during the breeding season when it's trying to attract a mate. But his song fests continues throughout the nesting season to defend it's territory and reinforce the pair bond with its mate.
So if you have a resident mockingbird in your yard, the best you can do is close the window or buy earplugs, because the singing will not likely fade until July.