As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THE CREW REPORTED THAT AFTER APPROX 1 HOUR OF CRUISE FLIGHT AT 36000 THEY RECEIVED AN EICAS MESSAGE "HYD 1 LOW LEVEL". THE MESSAGE EXTINGUISHED WITH GEAR EXTENTION. THE CREW DECLARED AN EMERGENCY AND LANDED WITHOUT INCIDENT. THE ACFT WAS REMOVED FROM SERVICE. SERVICED NR1 HYD SYS TO 5 QUARTS. NO LEAKS NOTED IAW AMM 12-13-01. THE ACFT OK FOR SERVICE.