Python – Avoid passing logger reference between functions?

You can either use the root (default) logger, and thus the module level functions logging.debug, … or get your logger in the function using it.
Indeed, the getLogger function is a factory-like function with a registry (singleton like), i.e. it always returns the same instance for the given logger name.
You can thus get your logger in count_parrots by simply using

logger = logging.getLogger("my logger") 

at the beginning. However, the convention is to use a dotted hierarchical name for your logger. See http://docs.python.org/library/logging.html#logging.getLogger

EDIT:

You can use a decorator to add the logging behaviour to your individual functions, for example:

def debug(loggername):
    logger = logging.getLogger(loggername) 
    def log_(enter_message, exit_message=None):
        def wrapper(f):
            def wrapped(*args, **kargs):
                logger.debug(enter_message)
                r = f(*args, **kargs)
                if exit_message:
                    logger.debug(exit_message)
                return r
            return wrapped
        return wrapper
    return log_

my_debug = debug('my.logger')

@my_debug('enter foo', 'exit foo')
def foo(a, b):
    return a+b

you can “hardcode” the logger name and remove the top-level closure and my_debug.