(1) Promising success; favorable. (2) Fortunate, prosperous.
Martha was mildly superstitious, so breaking her mirror didn't seem an auspicious start to the day.
In ancient Rome there was an entire order of priests, the auspices, whose job it was to watch birds fly across the Roman sky. After noting what kind of birds and how many had flown in which direction, they delivered prophecies according to what they had seen. For example, two eagles flying from east to west was usually considered auspicious, or favorable; two or more vultures flying west to east was inauspicious, unless the Romans were looking forward to a war. Thus, the auspices were birdwatchers, although not quite like birdwatchers today.