That is because when the esp8266 boots the baudrate is 74880, until you change it in your sketch. What you are seeing are boot time messages. These messages can help with debugging.
I prefer to run my sketches at 74880 so that I can see the boot time messages. 74880 is sufficient for most purposes.
So. how do I manage to use the non standard 74880 baud rate?
I use CoolTerm set to run at the 74880 non-standard baud rate by using a simple baudrates.ini file, see here :-http://forums.the-meiers.org/viewtopic.php?f=4&t=479
One day the Arduino IDE may support 74880. Until that day arrives.........