Chaffinch Calls

[Blackdogjnr]

A few weeks ago there was a Chaffinch who took up residence in a tree outside my house.

His wonderful 'chee chee chee chir chir chir choo choo choo twittertwitter' call echoed across our lane nonstop from sunrise to sunset, it actually got quite annoying

After a week or so of quietitude he has returned (or perhaps a juvenile) and instead drowns the village with a much sharper one note 'chreeep', again, repeated all day every day, tirelessly from a tree or rooftop.

Any ideas what these two calls mean?
Could the first be calling a mate and the second an establishing territory thing maybe?

[Rob_D]

Theres a research paper with some info here Perch selection by singing chaffinches: a better view of surroundings and the risk of predation -- Krams 12 (3): 295 -- Behavioral Ecology

As with most song birds, the song functions to attract a mate and deter rival males from a territory. Not sure the exact function of the repeated "chreep" call, but it maybe just generally signalling his location to his mate and warn of predators (if he stops or moves) - it doesn't say much about the health or strength of the bird like the song does. It gets on your nerves after a while doesn't it?